Aggregator

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1205 AM CDT Mon May 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY INTO TUESDAY NIGHT ACROSS PARTS OF CENTRAL AND WESTERN TEXAS INTO SOUTHEASTERN NEW MEXICO.... ...SUMMARY... Strong thunderstorms, perhaps including a few supercells and a couple of organizing clusters posing a risk for severe wind and hail, are possible across much of central into western Texas and southeastern New Mexico Tuesday afternoon into Tuesday evening. ...Synopsis... The westerlies are forecast to remain modestly amplified and progressive across the northern mid-latitudes of the Pacific into western North America through this period. Within this regime, models indicate that large-scale mid-level troughing will shift inland of the British Columbia and Pacific Northwest coast through the Canadian and northern U.S. Rockies, while downstream ridging overspreads the eastern Canadian Prairies and northern U.S. Great Plains. Farther east, the progression of larger-scale troughing east of the upper Mississippi Valley may be slower, as one notable embedded short wave digs southeast of the Upper Midwest toward the lower Ohio Valley, but a preceding impulse may accelerate east-northeast of the lower Great Lakes region into the St. Lawrence Valley. This likely will be accompanied by a weakening surface cyclone, and trailing reinforcing surges of cooler/drier air through much of the Northeast, Mid Atlantic and Ohio into middle Mississippi Valleys. An initial surge of cooler and drier air likely will advance across the remainder of the Southeast, into the Florida Peninsula and north central Gulf coast, and later, beneath ridging within weaker westerlies across the southern mid- and subtropical latitudes, through the southern Great Plains. ...Texas and portions of adjacent states... Latest model output, including the NAM in particular, suggests that the southern Great Plains portion of the lead cold front may become reinforced by outflow from convection as it spreads across and south of the Red River Valley early Tuesday. This convection likely will be initially rooted within lower/mid-tropospheric warm advection, aided by forcing for ascent associated with at least one mid/upper perturbation progressing through the larger-scale ridging. Beneath warm and capping elevated mixed-layer air, daytime heating to the south of the front will contribute to strengthening differential heating across the front/outflow, with residual seasonably moist air to the south of this boundary becoming characterized by large mixed-layer CAPE on the order of 2000-4000 J/kg. As the initial convection increasingly acquires inflow of this air, substantive further intensification is probable as it propagates southward toward the upper Texas/Louisiana coastal plain, accompanied by potential damaging wind gusts. Upstream, it appears that a trailing perturbation may support renewed thunderstorm development across parts of the Texas South Plains and Big Country by mid to late afternoon. Although lower/mid-tropospheric wind fields may be modest in strength, turning with height beneath stronger flow aloft may be supportive of supercells initially, accompanied by potential to produce large hail before consolidating and growing upscale. It appears that this activity may tend to track southeastward along outflow trailing the initial convection, accompanied by substantive further intensification. This may include an evolving mesoscale convective vortex, strengthening rear-inflow, and cold pool with potentially sustained strong to severe surface gusts propagating southeastward and southward toward the Texas Hill Country and through the Edwards Plateau into Tuesday evening. It is possible severe wind probabilities may need to be increased a bit further in later outlooks, as model spread decreases and potential convective evolution becomes a bit clearer. Otherwise, isolated supercell storms remain a possibility near the dryline initially across parts of the Permian Basin. ...Northern Intermountain Region/Rockies... Models indicate that weak destabilization ahead of the inland advancing mid-level trough will support increasing thunderstorm development Tuesday afternoon and evening. The NAM, in particular, continues to suggest that activity may consolidate across the mountains of central Idaho into western Montana, where evaporative cooling within a well-mixed sub-cloud boundary layer may contribute to downward mixing of 40-50 kt southwesterly lower/mid-tropospheric flow and a strengthening cold pool. It is possible that strong to severe surface gusts may spread east of the continental divide Tuesday evening, even as more weakly unstable inflow begins to weaken convection. ..Kerr.. 05/27/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon May 27 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST STATES INTO THE MID-ATLANTIC AND LOWER GREAT LAKES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the lower Great Lakes, Mid-Atlantic, and Southeast. More isolated severe thunderstorms are possible across much of central and eastern Texas, as well as southwest Oklahoma this afternoon and overnight. ...Synopsis... Strong to severe thunderstorm potential today and tonight will be focused along a composite cold frontal/outflow boundary draped from the Great Lakes region into the Mid-Atlantic/Southeast and westward into the southern Plains. 05 UTC surface observations reveal a mature surface low over the upper Great Lakes. A diffuse cold front is noted extending from the mid-MS/lower OH River Valleys (where a severe MCS is ongoing) into the southern Plains, with an additional cold frontal surge analyzed across parts of the Midwest. These features should migrate to the east/southeast over the next 12-24 hours as the synoptic surface low moves into the lower Great Lakes region by late tonight, driven primarily by large scale ascent ahead of a low-amplitude upper wave (observed over the mid-MS/lower OH River Valleys at around 05 UTC). Although only modest deepening of the surface low is anticipated over the forecast period, mid to upper-level flow will likely remain fairly strong (40-60 knots between 700 to 500 mb) ahead of the upper wave. This will support moderate to strong deep-layer shear over much of an expansive warm sector stretching from the Southern Plains into the Southeast/Mid-Atlantic and northward to the lower Great Lakes. Thunderstorms developing along the aforementioned cold front and/or outflow boundary will likely see some degree of organization with an attendant severe risk. ...Pennsylvania and western New York... Northward moisture return is ongoing across PA and NY in the wake of a decaying QLCS. Although lapse rates across the lower Great Lakes into PA will remain fairly marginal, increasing low-level moisture and diurnal heating should erode weak MLCIN by around 18 UTC. Concurrently, a weak mid-level perturbation, most likely associated with the remains of the ongoing MCS across the OH River Valley, will overspread the region around early afternoon resulting in scattered thunderstorm development. While buoyancy will be meager (500-1000 J/kg MLCAPE), 40-45 knot flow above the surface should mix down within stronger downdrafts, supporting a damaging/severe wind threat. A second round of thunderstorms is possible during the late afternoon/evening hours across western PA as a secondary cold frontal surge pushes east. The intensity of this activity will likely be dependent on the degree of overturning and air mass recovery in the wake of the early afternoon thunderstorms. However, a severe wind threat may materialize if sufficient recovery can occur. ...Mid-Atlantic... A moist air mass is currently in place across the Mid-Atlantic with upper 60s/low 70s dewpoints observed from the Carolinas into MD. 6-7 K/km lapse rates are also noted in 00 UTC soundings, which should support 2000-2500 MLCAPE by mid-afternoon across the region. The approach of the upper wave should promote troughing in the lee of the Appalachians. It remains unclear whether convection will primarily be focused along the lee trough or along a residual outflow boundary emanating from the ongoing MCS to the west. Regardless, sufficient buoyancy and deep-layer shear will support organized convection, including the potential for supercells with an attendant risk for large hail, severe wind, and a few tornadoes if sufficient low-level SRH along and ahead of the boundary can be realized, as hinted by some model solutions. ...Southeast... The ongoing MCS is forecast to gradually decay as it moves into central/southern MS/AL/GA by 12 UTC, though embedded segments within the line may pose a severe threat at the start of the forecast period. Regardless, an outflow boundary should become apparent somewhere across the Southeastern states by mid-morning, though guidance varies on the exact placement. Weak capping is noted in 00 UTC soundings from across the region, suggesting that diurnal heating, aided by weak ascent along the boundary, should foster thunderstorm development by early afternoon. MLCAPE upwards of 2000 J/kg combined with around 30 knots of deep-layer shear should allow for some initial storm organization, including the potential for a few supercells. Ambient low-level vorticity along the boundary may support a brief tornado threat with initial convection. However, mean west/southwesterly winds should yield poor boundary-normal deep-layer shear, which suggests storm interactions along the boundary may promote upscale growth by late afternoon with an increase in damaging to severe wind potential. ...Midwest... A mid-level perturbation is noted in water-vapor imagery across northern MT. This feature is forecast to reach the Midwest region by peak heating this afternoon. Cool temperatures aloft over a somewhat dry air mass should promote modest (500-1000 J/kg) MLCAPE. Deep-layer wind shear is expected to be marginal, but lift ahead of the vorticity maximum should promote isolated to scattered thunderstorm development with the potential for strong to severe winds - especially if more consolidated/organized clusters can become established. ...Texas into southwest Oklahoma... Surface observations show the cold front slowly moving south across central TX, but this boundary should become increasingly diffuse through the day amid strong diurnal heating across much of TX. Thermally-induced surface pressure falls to the west of a dryline (noted from west-central TX to the Big Bend region) will maintain east/southeasterly low-level winds through the day. This will not only maintain an influx of rich Gulf moisture (dewpoints in the mid/upper 70s), but will support hodograph elongation given 40-50 knot westerly flow aloft. Forecast soundings suggest sufficient heating will erode MLCIN by early afternoon, but weak confluence along the dryline and neutral to rising heights aloft may limit convective coverage. Consequently, confidence on storm coverage and location is low with considerable spread noted in 00z CAM solutions. However, this appears to be a low-probability, but potentially high impact scenario with the potential for significant hail (2 inches in diameter or larger), severe wind, and perhaps a tornado where storms can develop. Elevated convection appears possible well into the overnight hours across northern TX into southwest OK as isentropic ascent atop the stalled frontal boundary increases with the onset of the nocturnal low-level jet. This activity should primarily pose a severe hail/wind threat that may persist into the early morning hours Tuesday. ..Moore.. 05/27/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon May 27 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST STATES INTO THE MID-ATLANTIC AND LOWER GREAT LAKES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the lower Great Lakes, Mid-Atlantic, and Southeast. More isolated severe thunderstorms are possible across much of central and eastern Texas, as well as southwest Oklahoma this afternoon and overnight. ...Synopsis... Strong to severe thunderstorm potential today and tonight will be focused along a composite cold frontal/outflow boundary draped from the Great Lakes region into the Mid-Atlantic/Southeast and westward into the southern Plains. 05 UTC surface observations reveal a mature surface low over the upper Great Lakes. A diffuse cold front is noted extending from the mid-MS/lower OH River Valleys (where a severe MCS is ongoing) into the southern Plains, with an additional cold frontal surge analyzed across parts of the Midwest. These features should migrate to the east/southeast over the next 12-24 hours as the synoptic surface low moves into the lower Great Lakes region by late tonight, driven primarily by large scale ascent ahead of a low-amplitude upper wave (observed over the mid-MS/lower OH River Valleys at around 05 UTC). Although only modest deepening of the surface low is anticipated over the forecast period, mid to upper-level flow will likely remain fairly strong (40-60 knots between 700 to 500 mb) ahead of the upper wave. This will support moderate to strong deep-layer shear over much of an expansive warm sector stretching from the Southern Plains into the Southeast/Mid-Atlantic and northward to the lower Great Lakes. Thunderstorms developing along the aforementioned cold front and/or outflow boundary will likely see some degree of organization with an attendant severe risk. ...Pennsylvania and western New York... Northward moisture return is ongoing across PA and NY in the wake of a decaying QLCS. Although lapse rates across the lower Great Lakes into PA will remain fairly marginal, increasing low-level moisture and diurnal heating should erode weak MLCIN by around 18 UTC. Concurrently, a weak mid-level perturbation, most likely associated with the remains of the ongoing MCS across the OH River Valley, will overspread the region around early afternoon resulting in scattered thunderstorm development. While buoyancy will be meager (500-1000 J/kg MLCAPE), 40-45 knot flow above the surface should mix down within stronger downdrafts, supporting a damaging/severe wind threat. A second round of thunderstorms is possible during the late afternoon/evening hours across western PA as a secondary cold frontal surge pushes east. The intensity of this activity will likely be dependent on the degree of overturning and air mass recovery in the wake of the early afternoon thunderstorms. However, a severe wind threat may materialize if sufficient recovery can occur. ...Mid-Atlantic... A moist air mass is currently in place across the Mid-Atlantic with upper 60s/low 70s dewpoints observed from the Carolinas into MD. 6-7 K/km lapse rates are also noted in 00 UTC soundings, which should support 2000-2500 MLCAPE by mid-afternoon across the region. The approach of the upper wave should promote troughing in the lee of the Appalachians. It remains unclear whether convection will primarily be focused along the lee trough or along a residual outflow boundary emanating from the ongoing MCS to the west. Regardless, sufficient buoyancy and deep-layer shear will support organized convection, including the potential for supercells with an attendant risk for large hail, severe wind, and a few tornadoes if sufficient low-level SRH along and ahead of the boundary can be realized, as hinted by some model solutions. ...Southeast... The ongoing MCS is forecast to gradually decay as it moves into central/southern MS/AL/GA by 12 UTC, though embedded segments within the line may pose a severe threat at the start of the forecast period. Regardless, an outflow boundary should become apparent somewhere across the Southeastern states by mid-morning, though guidance varies on the exact placement. Weak capping is noted in 00 UTC soundings from across the region, suggesting that diurnal heating, aided by weak ascent along the boundary, should foster thunderstorm development by early afternoon. MLCAPE upwards of 2000 J/kg combined with around 30 knots of deep-layer shear should allow for some initial storm organization, including the potential for a few supercells. Ambient low-level vorticity along the boundary may support a brief tornado threat with initial convection. However, mean west/southwesterly winds should yield poor boundary-normal deep-layer shear, which suggests storm interactions along the boundary may promote upscale growth by late afternoon with an increase in damaging to severe wind potential. ...Midwest... A mid-level perturbation is noted in water-vapor imagery across northern MT. This feature is forecast to reach the Midwest region by peak heating this afternoon. Cool temperatures aloft over a somewhat dry air mass should promote modest (500-1000 J/kg) MLCAPE. Deep-layer wind shear is expected to be marginal, but lift ahead of the vorticity maximum should promote isolated to scattered thunderstorm development with the potential for strong to severe winds - especially if more consolidated/organized clusters can become established. ...Texas into southwest Oklahoma... Surface observations show the cold front slowly moving south across central TX, but this boundary should become increasingly diffuse through the day amid strong diurnal heating across much of TX. Thermally-induced surface pressure falls to the west of a dryline (noted from west-central TX to the Big Bend region) will maintain east/southeasterly low-level winds through the day. This will not only maintain an influx of rich Gulf moisture (dewpoints in the mid/upper 70s), but will support hodograph elongation given 40-50 knot westerly flow aloft. Forecast soundings suggest sufficient heating will erode MLCIN by early afternoon, but weak confluence along the dryline and neutral to rising heights aloft may limit convective coverage. Consequently, confidence on storm coverage and location is low with considerable spread noted in 00z CAM solutions. However, this appears to be a low-probability, but potentially high impact scenario with the potential for significant hail (2 inches in diameter or larger), severe wind, and perhaps a tornado where storms can develop. Elevated convection appears possible well into the overnight hours across northern TX into southwest OK as isentropic ascent atop the stalled frontal boundary increases with the onset of the nocturnal low-level jet. This activity should primarily pose a severe hail/wind threat that may persist into the early morning hours Tuesday. ..Moore.. 05/27/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon May 27 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST STATES INTO THE MID-ATLANTIC AND LOWER GREAT LAKES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the lower Great Lakes, Mid-Atlantic, and Southeast. More isolated severe thunderstorms are possible across much of central and eastern Texas, as well as southwest Oklahoma this afternoon and overnight. ...Synopsis... Strong to severe thunderstorm potential today and tonight will be focused along a composite cold frontal/outflow boundary draped from the Great Lakes region into the Mid-Atlantic/Southeast and westward into the southern Plains. 05 UTC surface observations reveal a mature surface low over the upper Great Lakes. A diffuse cold front is noted extending from the mid-MS/lower OH River Valleys (where a severe MCS is ongoing) into the southern Plains, with an additional cold frontal surge analyzed across parts of the Midwest. These features should migrate to the east/southeast over the next 12-24 hours as the synoptic surface low moves into the lower Great Lakes region by late tonight, driven primarily by large scale ascent ahead of a low-amplitude upper wave (observed over the mid-MS/lower OH River Valleys at around 05 UTC). Although only modest deepening of the surface low is anticipated over the forecast period, mid to upper-level flow will likely remain fairly strong (40-60 knots between 700 to 500 mb) ahead of the upper wave. This will support moderate to strong deep-layer shear over much of an expansive warm sector stretching from the Southern Plains into the Southeast/Mid-Atlantic and northward to the lower Great Lakes. Thunderstorms developing along the aforementioned cold front and/or outflow boundary will likely see some degree of organization with an attendant severe risk. ...Pennsylvania and western New York... Northward moisture return is ongoing across PA and NY in the wake of a decaying QLCS. Although lapse rates across the lower Great Lakes into PA will remain fairly marginal, increasing low-level moisture and diurnal heating should erode weak MLCIN by around 18 UTC. Concurrently, a weak mid-level perturbation, most likely associated with the remains of the ongoing MCS across the OH River Valley, will overspread the region around early afternoon resulting in scattered thunderstorm development. While buoyancy will be meager (500-1000 J/kg MLCAPE), 40-45 knot flow above the surface should mix down within stronger downdrafts, supporting a damaging/severe wind threat. A second round of thunderstorms is possible during the late afternoon/evening hours across western PA as a secondary cold frontal surge pushes east. The intensity of this activity will likely be dependent on the degree of overturning and air mass recovery in the wake of the early afternoon thunderstorms. However, a severe wind threat may materialize if sufficient recovery can occur. ...Mid-Atlantic... A moist air mass is currently in place across the Mid-Atlantic with upper 60s/low 70s dewpoints observed from the Carolinas into MD. 6-7 K/km lapse rates are also noted in 00 UTC soundings, which should support 2000-2500 MLCAPE by mid-afternoon across the region. The approach of the upper wave should promote troughing in the lee of the Appalachians. It remains unclear whether convection will primarily be focused along the lee trough or along a residual outflow boundary emanating from the ongoing MCS to the west. Regardless, sufficient buoyancy and deep-layer shear will support organized convection, including the potential for supercells with an attendant risk for large hail, severe wind, and a few tornadoes if sufficient low-level SRH along and ahead of the boundary can be realized, as hinted by some model solutions. ...Southeast... The ongoing MCS is forecast to gradually decay as it moves into central/southern MS/AL/GA by 12 UTC, though embedded segments within the line may pose a severe threat at the start of the forecast period. Regardless, an outflow boundary should become apparent somewhere across the Southeastern states by mid-morning, though guidance varies on the exact placement. Weak capping is noted in 00 UTC soundings from across the region, suggesting that diurnal heating, aided by weak ascent along the boundary, should foster thunderstorm development by early afternoon. MLCAPE upwards of 2000 J/kg combined with around 30 knots of deep-layer shear should allow for some initial storm organization, including the potential for a few supercells. Ambient low-level vorticity along the boundary may support a brief tornado threat with initial convection. However, mean west/southwesterly winds should yield poor boundary-normal deep-layer shear, which suggests storm interactions along the boundary may promote upscale growth by late afternoon with an increase in damaging to severe wind potential. ...Midwest... A mid-level perturbation is noted in water-vapor imagery across northern MT. This feature is forecast to reach the Midwest region by peak heating this afternoon. Cool temperatures aloft over a somewhat dry air mass should promote modest (500-1000 J/kg) MLCAPE. Deep-layer wind shear is expected to be marginal, but lift ahead of the vorticity maximum should promote isolated to scattered thunderstorm development with the potential for strong to severe winds - especially if more consolidated/organized clusters can become established. ...Texas into southwest Oklahoma... Surface observations show the cold front slowly moving south across central TX, but this boundary should become increasingly diffuse through the day amid strong diurnal heating across much of TX. Thermally-induced surface pressure falls to the west of a dryline (noted from west-central TX to the Big Bend region) will maintain east/southeasterly low-level winds through the day. This will not only maintain an influx of rich Gulf moisture (dewpoints in the mid/upper 70s), but will support hodograph elongation given 40-50 knot westerly flow aloft. Forecast soundings suggest sufficient heating will erode MLCIN by early afternoon, but weak confluence along the dryline and neutral to rising heights aloft may limit convective coverage. Consequently, confidence on storm coverage and location is low with considerable spread noted in 00z CAM solutions. However, this appears to be a low-probability, but potentially high impact scenario with the potential for significant hail (2 inches in diameter or larger), severe wind, and perhaps a tornado where storms can develop. Elevated convection appears possible well into the overnight hours across northern TX into southwest OK as isentropic ascent atop the stalled frontal boundary increases with the onset of the nocturnal low-level jet. This activity should primarily pose a severe hail/wind threat that may persist into the early morning hours Tuesday. ..Moore.. 05/27/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon May 27 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST STATES INTO THE MID-ATLANTIC AND LOWER GREAT LAKES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the lower Great Lakes, Mid-Atlantic, and Southeast. More isolated severe thunderstorms are possible across much of central and eastern Texas, as well as southwest Oklahoma this afternoon and overnight. ...Synopsis... Strong to severe thunderstorm potential today and tonight will be focused along a composite cold frontal/outflow boundary draped from the Great Lakes region into the Mid-Atlantic/Southeast and westward into the southern Plains. 05 UTC surface observations reveal a mature surface low over the upper Great Lakes. A diffuse cold front is noted extending from the mid-MS/lower OH River Valleys (where a severe MCS is ongoing) into the southern Plains, with an additional cold frontal surge analyzed across parts of the Midwest. These features should migrate to the east/southeast over the next 12-24 hours as the synoptic surface low moves into the lower Great Lakes region by late tonight, driven primarily by large scale ascent ahead of a low-amplitude upper wave (observed over the mid-MS/lower OH River Valleys at around 05 UTC). Although only modest deepening of the surface low is anticipated over the forecast period, mid to upper-level flow will likely remain fairly strong (40-60 knots between 700 to 500 mb) ahead of the upper wave. This will support moderate to strong deep-layer shear over much of an expansive warm sector stretching from the Southern Plains into the Southeast/Mid-Atlantic and northward to the lower Great Lakes. Thunderstorms developing along the aforementioned cold front and/or outflow boundary will likely see some degree of organization with an attendant severe risk. ...Pennsylvania and western New York... Northward moisture return is ongoing across PA and NY in the wake of a decaying QLCS. Although lapse rates across the lower Great Lakes into PA will remain fairly marginal, increasing low-level moisture and diurnal heating should erode weak MLCIN by around 18 UTC. Concurrently, a weak mid-level perturbation, most likely associated with the remains of the ongoing MCS across the OH River Valley, will overspread the region around early afternoon resulting in scattered thunderstorm development. While buoyancy will be meager (500-1000 J/kg MLCAPE), 40-45 knot flow above the surface should mix down within stronger downdrafts, supporting a damaging/severe wind threat. A second round of thunderstorms is possible during the late afternoon/evening hours across western PA as a secondary cold frontal surge pushes east. The intensity of this activity will likely be dependent on the degree of overturning and air mass recovery in the wake of the early afternoon thunderstorms. However, a severe wind threat may materialize if sufficient recovery can occur. ...Mid-Atlantic... A moist air mass is currently in place across the Mid-Atlantic with upper 60s/low 70s dewpoints observed from the Carolinas into MD. 6-7 K/km lapse rates are also noted in 00 UTC soundings, which should support 2000-2500 MLCAPE by mid-afternoon across the region. The approach of the upper wave should promote troughing in the lee of the Appalachians. It remains unclear whether convection will primarily be focused along the lee trough or along a residual outflow boundary emanating from the ongoing MCS to the west. Regardless, sufficient buoyancy and deep-layer shear will support organized convection, including the potential for supercells with an attendant risk for large hail, severe wind, and a few tornadoes if sufficient low-level SRH along and ahead of the boundary can be realized, as hinted by some model solutions. ...Southeast... The ongoing MCS is forecast to gradually decay as it moves into central/southern MS/AL/GA by 12 UTC, though embedded segments within the line may pose a severe threat at the start of the forecast period. Regardless, an outflow boundary should become apparent somewhere across the Southeastern states by mid-morning, though guidance varies on the exact placement. Weak capping is noted in 00 UTC soundings from across the region, suggesting that diurnal heating, aided by weak ascent along the boundary, should foster thunderstorm development by early afternoon. MLCAPE upwards of 2000 J/kg combined with around 30 knots of deep-layer shear should allow for some initial storm organization, including the potential for a few supercells. Ambient low-level vorticity along the boundary may support a brief tornado threat with initial convection. However, mean west/southwesterly winds should yield poor boundary-normal deep-layer shear, which suggests storm interactions along the boundary may promote upscale growth by late afternoon with an increase in damaging to severe wind potential. ...Midwest... A mid-level perturbation is noted in water-vapor imagery across northern MT. This feature is forecast to reach the Midwest region by peak heating this afternoon. Cool temperatures aloft over a somewhat dry air mass should promote modest (500-1000 J/kg) MLCAPE. Deep-layer wind shear is expected to be marginal, but lift ahead of the vorticity maximum should promote isolated to scattered thunderstorm development with the potential for strong to severe winds - especially if more consolidated/organized clusters can become established. ...Texas into southwest Oklahoma... Surface observations show the cold front slowly moving south across central TX, but this boundary should become increasingly diffuse through the day amid strong diurnal heating across much of TX. Thermally-induced surface pressure falls to the west of a dryline (noted from west-central TX to the Big Bend region) will maintain east/southeasterly low-level winds through the day. This will not only maintain an influx of rich Gulf moisture (dewpoints in the mid/upper 70s), but will support hodograph elongation given 40-50 knot westerly flow aloft. Forecast soundings suggest sufficient heating will erode MLCIN by early afternoon, but weak confluence along the dryline and neutral to rising heights aloft may limit convective coverage. Consequently, confidence on storm coverage and location is low with considerable spread noted in 00z CAM solutions. However, this appears to be a low-probability, but potentially high impact scenario with the potential for significant hail (2 inches in diameter or larger), severe wind, and perhaps a tornado where storms can develop. Elevated convection appears possible well into the overnight hours across northern TX into southwest OK as isentropic ascent atop the stalled frontal boundary increases with the onset of the nocturnal low-level jet. This activity should primarily pose a severe hail/wind threat that may persist into the early morning hours Tuesday. ..Moore.. 05/27/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon May 27 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST STATES INTO THE MID-ATLANTIC AND LOWER GREAT LAKES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the lower Great Lakes, Mid-Atlantic, and Southeast. More isolated severe thunderstorms are possible across much of central and eastern Texas, as well as southwest Oklahoma this afternoon and overnight. ...Synopsis... Strong to severe thunderstorm potential today and tonight will be focused along a composite cold frontal/outflow boundary draped from the Great Lakes region into the Mid-Atlantic/Southeast and westward into the southern Plains. 05 UTC surface observations reveal a mature surface low over the upper Great Lakes. A diffuse cold front is noted extending from the mid-MS/lower OH River Valleys (where a severe MCS is ongoing) into the southern Plains, with an additional cold frontal surge analyzed across parts of the Midwest. These features should migrate to the east/southeast over the next 12-24 hours as the synoptic surface low moves into the lower Great Lakes region by late tonight, driven primarily by large scale ascent ahead of a low-amplitude upper wave (observed over the mid-MS/lower OH River Valleys at around 05 UTC). Although only modest deepening of the surface low is anticipated over the forecast period, mid to upper-level flow will likely remain fairly strong (40-60 knots between 700 to 500 mb) ahead of the upper wave. This will support moderate to strong deep-layer shear over much of an expansive warm sector stretching from the Southern Plains into the Southeast/Mid-Atlantic and northward to the lower Great Lakes. Thunderstorms developing along the aforementioned cold front and/or outflow boundary will likely see some degree of organization with an attendant severe risk. ...Pennsylvania and western New York... Northward moisture return is ongoing across PA and NY in the wake of a decaying QLCS. Although lapse rates across the lower Great Lakes into PA will remain fairly marginal, increasing low-level moisture and diurnal heating should erode weak MLCIN by around 18 UTC. Concurrently, a weak mid-level perturbation, most likely associated with the remains of the ongoing MCS across the OH River Valley, will overspread the region around early afternoon resulting in scattered thunderstorm development. While buoyancy will be meager (500-1000 J/kg MLCAPE), 40-45 knot flow above the surface should mix down within stronger downdrafts, supporting a damaging/severe wind threat. A second round of thunderstorms is possible during the late afternoon/evening hours across western PA as a secondary cold frontal surge pushes east. The intensity of this activity will likely be dependent on the degree of overturning and air mass recovery in the wake of the early afternoon thunderstorms. However, a severe wind threat may materialize if sufficient recovery can occur. ...Mid-Atlantic... A moist air mass is currently in place across the Mid-Atlantic with upper 60s/low 70s dewpoints observed from the Carolinas into MD. 6-7 K/km lapse rates are also noted in 00 UTC soundings, which should support 2000-2500 MLCAPE by mid-afternoon across the region. The approach of the upper wave should promote troughing in the lee of the Appalachians. It remains unclear whether convection will primarily be focused along the lee trough or along a residual outflow boundary emanating from the ongoing MCS to the west. Regardless, sufficient buoyancy and deep-layer shear will support organized convection, including the potential for supercells with an attendant risk for large hail, severe wind, and a few tornadoes if sufficient low-level SRH along and ahead of the boundary can be realized, as hinted by some model solutions. ...Southeast... The ongoing MCS is forecast to gradually decay as it moves into central/southern MS/AL/GA by 12 UTC, though embedded segments within the line may pose a severe threat at the start of the forecast period. Regardless, an outflow boundary should become apparent somewhere across the Southeastern states by mid-morning, though guidance varies on the exact placement. Weak capping is noted in 00 UTC soundings from across the region, suggesting that diurnal heating, aided by weak ascent along the boundary, should foster thunderstorm development by early afternoon. MLCAPE upwards of 2000 J/kg combined with around 30 knots of deep-layer shear should allow for some initial storm organization, including the potential for a few supercells. Ambient low-level vorticity along the boundary may support a brief tornado threat with initial convection. However, mean west/southwesterly winds should yield poor boundary-normal deep-layer shear, which suggests storm interactions along the boundary may promote upscale growth by late afternoon with an increase in damaging to severe wind potential. ...Midwest... A mid-level perturbation is noted in water-vapor imagery across northern MT. This feature is forecast to reach the Midwest region by peak heating this afternoon. Cool temperatures aloft over a somewhat dry air mass should promote modest (500-1000 J/kg) MLCAPE. Deep-layer wind shear is expected to be marginal, but lift ahead of the vorticity maximum should promote isolated to scattered thunderstorm development with the potential for strong to severe winds - especially if more consolidated/organized clusters can become established. ...Texas into southwest Oklahoma... Surface observations show the cold front slowly moving south across central TX, but this boundary should become increasingly diffuse through the day amid strong diurnal heating across much of TX. Thermally-induced surface pressure falls to the west of a dryline (noted from west-central TX to the Big Bend region) will maintain east/southeasterly low-level winds through the day. This will not only maintain an influx of rich Gulf moisture (dewpoints in the mid/upper 70s), but will support hodograph elongation given 40-50 knot westerly flow aloft. Forecast soundings suggest sufficient heating will erode MLCIN by early afternoon, but weak confluence along the dryline and neutral to rising heights aloft may limit convective coverage. Consequently, confidence on storm coverage and location is low with considerable spread noted in 00z CAM solutions. However, this appears to be a low-probability, but potentially high impact scenario with the potential for significant hail (2 inches in diameter or larger), severe wind, and perhaps a tornado where storms can develop. Elevated convection appears possible well into the overnight hours across northern TX into southwest OK as isentropic ascent atop the stalled frontal boundary increases with the onset of the nocturnal low-level jet. This activity should primarily pose a severe hail/wind threat that may persist into the early morning hours Tuesday. ..Moore.. 05/27/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon May 27 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST STATES INTO THE MID-ATLANTIC AND LOWER GREAT LAKES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the lower Great Lakes, Mid-Atlantic, and Southeast. More isolated severe thunderstorms are possible across much of central and eastern Texas, as well as southwest Oklahoma this afternoon and overnight. ...Synopsis... Strong to severe thunderstorm potential today and tonight will be focused along a composite cold frontal/outflow boundary draped from the Great Lakes region into the Mid-Atlantic/Southeast and westward into the southern Plains. 05 UTC surface observations reveal a mature surface low over the upper Great Lakes. A diffuse cold front is noted extending from the mid-MS/lower OH River Valleys (where a severe MCS is ongoing) into the southern Plains, with an additional cold frontal surge analyzed across parts of the Midwest. These features should migrate to the east/southeast over the next 12-24 hours as the synoptic surface low moves into the lower Great Lakes region by late tonight, driven primarily by large scale ascent ahead of a low-amplitude upper wave (observed over the mid-MS/lower OH River Valleys at around 05 UTC). Although only modest deepening of the surface low is anticipated over the forecast period, mid to upper-level flow will likely remain fairly strong (40-60 knots between 700 to 500 mb) ahead of the upper wave. This will support moderate to strong deep-layer shear over much of an expansive warm sector stretching from the Southern Plains into the Southeast/Mid-Atlantic and northward to the lower Great Lakes. Thunderstorms developing along the aforementioned cold front and/or outflow boundary will likely see some degree of organization with an attendant severe risk. ...Pennsylvania and western New York... Northward moisture return is ongoing across PA and NY in the wake of a decaying QLCS. Although lapse rates across the lower Great Lakes into PA will remain fairly marginal, increasing low-level moisture and diurnal heating should erode weak MLCIN by around 18 UTC. Concurrently, a weak mid-level perturbation, most likely associated with the remains of the ongoing MCS across the OH River Valley, will overspread the region around early afternoon resulting in scattered thunderstorm development. While buoyancy will be meager (500-1000 J/kg MLCAPE), 40-45 knot flow above the surface should mix down within stronger downdrafts, supporting a damaging/severe wind threat. A second round of thunderstorms is possible during the late afternoon/evening hours across western PA as a secondary cold frontal surge pushes east. The intensity of this activity will likely be dependent on the degree of overturning and air mass recovery in the wake of the early afternoon thunderstorms. However, a severe wind threat may materialize if sufficient recovery can occur. ...Mid-Atlantic... A moist air mass is currently in place across the Mid-Atlantic with upper 60s/low 70s dewpoints observed from the Carolinas into MD. 6-7 K/km lapse rates are also noted in 00 UTC soundings, which should support 2000-2500 MLCAPE by mid-afternoon across the region. The approach of the upper wave should promote troughing in the lee of the Appalachians. It remains unclear whether convection will primarily be focused along the lee trough or along a residual outflow boundary emanating from the ongoing MCS to the west. Regardless, sufficient buoyancy and deep-layer shear will support organized convection, including the potential for supercells with an attendant risk for large hail, severe wind, and a few tornadoes if sufficient low-level SRH along and ahead of the boundary can be realized, as hinted by some model solutions. ...Southeast... The ongoing MCS is forecast to gradually decay as it moves into central/southern MS/AL/GA by 12 UTC, though embedded segments within the line may pose a severe threat at the start of the forecast period. Regardless, an outflow boundary should become apparent somewhere across the Southeastern states by mid-morning, though guidance varies on the exact placement. Weak capping is noted in 00 UTC soundings from across the region, suggesting that diurnal heating, aided by weak ascent along the boundary, should foster thunderstorm development by early afternoon. MLCAPE upwards of 2000 J/kg combined with around 30 knots of deep-layer shear should allow for some initial storm organization, including the potential for a few supercells. Ambient low-level vorticity along the boundary may support a brief tornado threat with initial convection. However, mean west/southwesterly winds should yield poor boundary-normal deep-layer shear, which suggests storm interactions along the boundary may promote upscale growth by late afternoon with an increase in damaging to severe wind potential. ...Midwest... A mid-level perturbation is noted in water-vapor imagery across northern MT. This feature is forecast to reach the Midwest region by peak heating this afternoon. Cool temperatures aloft over a somewhat dry air mass should promote modest (500-1000 J/kg) MLCAPE. Deep-layer wind shear is expected to be marginal, but lift ahead of the vorticity maximum should promote isolated to scattered thunderstorm development with the potential for strong to severe winds - especially if more consolidated/organized clusters can become established. ...Texas into southwest Oklahoma... Surface observations show the cold front slowly moving south across central TX, but this boundary should become increasingly diffuse through the day amid strong diurnal heating across much of TX. Thermally-induced surface pressure falls to the west of a dryline (noted from west-central TX to the Big Bend region) will maintain east/southeasterly low-level winds through the day. This will not only maintain an influx of rich Gulf moisture (dewpoints in the mid/upper 70s), but will support hodograph elongation given 40-50 knot westerly flow aloft. Forecast soundings suggest sufficient heating will erode MLCIN by early afternoon, but weak confluence along the dryline and neutral to rising heights aloft may limit convective coverage. Consequently, confidence on storm coverage and location is low with considerable spread noted in 00z CAM solutions. However, this appears to be a low-probability, but potentially high impact scenario with the potential for significant hail (2 inches in diameter or larger), severe wind, and perhaps a tornado where storms can develop. Elevated convection appears possible well into the overnight hours across northern TX into southwest OK as isentropic ascent atop the stalled frontal boundary increases with the onset of the nocturnal low-level jet. This activity should primarily pose a severe hail/wind threat that may persist into the early morning hours Tuesday. ..Moore.. 05/27/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon May 27 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST STATES INTO THE MID-ATLANTIC AND LOWER GREAT LAKES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the lower Great Lakes, Mid-Atlantic, and Southeast. More isolated severe thunderstorms are possible across much of central and eastern Texas, as well as southwest Oklahoma this afternoon and overnight. ...Synopsis... Strong to severe thunderstorm potential today and tonight will be focused along a composite cold frontal/outflow boundary draped from the Great Lakes region into the Mid-Atlantic/Southeast and westward into the southern Plains. 05 UTC surface observations reveal a mature surface low over the upper Great Lakes. A diffuse cold front is noted extending from the mid-MS/lower OH River Valleys (where a severe MCS is ongoing) into the southern Plains, with an additional cold frontal surge analyzed across parts of the Midwest. These features should migrate to the east/southeast over the next 12-24 hours as the synoptic surface low moves into the lower Great Lakes region by late tonight, driven primarily by large scale ascent ahead of a low-amplitude upper wave (observed over the mid-MS/lower OH River Valleys at around 05 UTC). Although only modest deepening of the surface low is anticipated over the forecast period, mid to upper-level flow will likely remain fairly strong (40-60 knots between 700 to 500 mb) ahead of the upper wave. This will support moderate to strong deep-layer shear over much of an expansive warm sector stretching from the Southern Plains into the Southeast/Mid-Atlantic and northward to the lower Great Lakes. Thunderstorms developing along the aforementioned cold front and/or outflow boundary will likely see some degree of organization with an attendant severe risk. ...Pennsylvania and western New York... Northward moisture return is ongoing across PA and NY in the wake of a decaying QLCS. Although lapse rates across the lower Great Lakes into PA will remain fairly marginal, increasing low-level moisture and diurnal heating should erode weak MLCIN by around 18 UTC. Concurrently, a weak mid-level perturbation, most likely associated with the remains of the ongoing MCS across the OH River Valley, will overspread the region around early afternoon resulting in scattered thunderstorm development. While buoyancy will be meager (500-1000 J/kg MLCAPE), 40-45 knot flow above the surface should mix down within stronger downdrafts, supporting a damaging/severe wind threat. A second round of thunderstorms is possible during the late afternoon/evening hours across western PA as a secondary cold frontal surge pushes east. The intensity of this activity will likely be dependent on the degree of overturning and air mass recovery in the wake of the early afternoon thunderstorms. However, a severe wind threat may materialize if sufficient recovery can occur. ...Mid-Atlantic... A moist air mass is currently in place across the Mid-Atlantic with upper 60s/low 70s dewpoints observed from the Carolinas into MD. 6-7 K/km lapse rates are also noted in 00 UTC soundings, which should support 2000-2500 MLCAPE by mid-afternoon across the region. The approach of the upper wave should promote troughing in the lee of the Appalachians. It remains unclear whether convection will primarily be focused along the lee trough or along a residual outflow boundary emanating from the ongoing MCS to the west. Regardless, sufficient buoyancy and deep-layer shear will support organized convection, including the potential for supercells with an attendant risk for large hail, severe wind, and a few tornadoes if sufficient low-level SRH along and ahead of the boundary can be realized, as hinted by some model solutions. ...Southeast... The ongoing MCS is forecast to gradually decay as it moves into central/southern MS/AL/GA by 12 UTC, though embedded segments within the line may pose a severe threat at the start of the forecast period. Regardless, an outflow boundary should become apparent somewhere across the Southeastern states by mid-morning, though guidance varies on the exact placement. Weak capping is noted in 00 UTC soundings from across the region, suggesting that diurnal heating, aided by weak ascent along the boundary, should foster thunderstorm development by early afternoon. MLCAPE upwards of 2000 J/kg combined with around 30 knots of deep-layer shear should allow for some initial storm organization, including the potential for a few supercells. Ambient low-level vorticity along the boundary may support a brief tornado threat with initial convection. However, mean west/southwesterly winds should yield poor boundary-normal deep-layer shear, which suggests storm interactions along the boundary may promote upscale growth by late afternoon with an increase in damaging to severe wind potential. ...Midwest... A mid-level perturbation is noted in water-vapor imagery across northern MT. This feature is forecast to reach the Midwest region by peak heating this afternoon. Cool temperatures aloft over a somewhat dry air mass should promote modest (500-1000 J/kg) MLCAPE. Deep-layer wind shear is expected to be marginal, but lift ahead of the vorticity maximum should promote isolated to scattered thunderstorm development with the potential for strong to severe winds - especially if more consolidated/organized clusters can become established. ...Texas into southwest Oklahoma... Surface observations show the cold front slowly moving south across central TX, but this boundary should become increasingly diffuse through the day amid strong diurnal heating across much of TX. Thermally-induced surface pressure falls to the west of a dryline (noted from west-central TX to the Big Bend region) will maintain east/southeasterly low-level winds through the day. This will not only maintain an influx of rich Gulf moisture (dewpoints in the mid/upper 70s), but will support hodograph elongation given 40-50 knot westerly flow aloft. Forecast soundings suggest sufficient heating will erode MLCIN by early afternoon, but weak confluence along the dryline and neutral to rising heights aloft may limit convective coverage. Consequently, confidence on storm coverage and location is low with considerable spread noted in 00z CAM solutions. However, this appears to be a low-probability, but potentially high impact scenario with the potential for significant hail (2 inches in diameter or larger), severe wind, and perhaps a tornado where storms can develop. Elevated convection appears possible well into the overnight hours across northern TX into southwest OK as isentropic ascent atop the stalled frontal boundary increases with the onset of the nocturnal low-level jet. This activity should primarily pose a severe hail/wind threat that may persist into the early morning hours Tuesday. ..Moore.. 05/27/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon May 27 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST STATES INTO THE MID-ATLANTIC AND LOWER GREAT LAKES... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening across parts of the lower Great Lakes, Mid-Atlantic, and Southeast. More isolated severe thunderstorms are possible across much of central and eastern Texas, as well as southwest Oklahoma this afternoon and overnight. ...Synopsis... Strong to severe thunderstorm potential today and tonight will be focused along a composite cold frontal/outflow boundary draped from the Great Lakes region into the Mid-Atlantic/Southeast and westward into the southern Plains. 05 UTC surface observations reveal a mature surface low over the upper Great Lakes. A diffuse cold front is noted extending from the mid-MS/lower OH River Valleys (where a severe MCS is ongoing) into the southern Plains, with an additional cold frontal surge analyzed across parts of the Midwest. These features should migrate to the east/southeast over the next 12-24 hours as the synoptic surface low moves into the lower Great Lakes region by late tonight, driven primarily by large scale ascent ahead of a low-amplitude upper wave (observed over the mid-MS/lower OH River Valleys at around 05 UTC). Although only modest deepening of the surface low is anticipated over the forecast period, mid to upper-level flow will likely remain fairly strong (40-60 knots between 700 to 500 mb) ahead of the upper wave. This will support moderate to strong deep-layer shear over much of an expansive warm sector stretching from the Southern Plains into the Southeast/Mid-Atlantic and northward to the lower Great Lakes. Thunderstorms developing along the aforementioned cold front and/or outflow boundary will likely see some degree of organization with an attendant severe risk. ...Pennsylvania and western New York... Northward moisture return is ongoing across PA and NY in the wake of a decaying QLCS. Although lapse rates across the lower Great Lakes into PA will remain fairly marginal, increasing low-level moisture and diurnal heating should erode weak MLCIN by around 18 UTC. Concurrently, a weak mid-level perturbation, most likely associated with the remains of the ongoing MCS across the OH River Valley, will overspread the region around early afternoon resulting in scattered thunderstorm development. While buoyancy will be meager (500-1000 J/kg MLCAPE), 40-45 knot flow above the surface should mix down within stronger downdrafts, supporting a damaging/severe wind threat. A second round of thunderstorms is possible during the late afternoon/evening hours across western PA as a secondary cold frontal surge pushes east. The intensity of this activity will likely be dependent on the degree of overturning and air mass recovery in the wake of the early afternoon thunderstorms. However, a severe wind threat may materialize if sufficient recovery can occur. ...Mid-Atlantic... A moist air mass is currently in place across the Mid-Atlantic with upper 60s/low 70s dewpoints observed from the Carolinas into MD. 6-7 K/km lapse rates are also noted in 00 UTC soundings, which should support 2000-2500 MLCAPE by mid-afternoon across the region. The approach of the upper wave should promote troughing in the lee of the Appalachians. It remains unclear whether convection will primarily be focused along the lee trough or along a residual outflow boundary emanating from the ongoing MCS to the west. Regardless, sufficient buoyancy and deep-layer shear will support organized convection, including the potential for supercells with an attendant risk for large hail, severe wind, and a few tornadoes if sufficient low-level SRH along and ahead of the boundary can be realized, as hinted by some model solutions. ...Southeast... The ongoing MCS is forecast to gradually decay as it moves into central/southern MS/AL/GA by 12 UTC, though embedded segments within the line may pose a severe threat at the start of the forecast period. Regardless, an outflow boundary should become apparent somewhere across the Southeastern states by mid-morning, though guidance varies on the exact placement. Weak capping is noted in 00 UTC soundings from across the region, suggesting that diurnal heating, aided by weak ascent along the boundary, should foster thunderstorm development by early afternoon. MLCAPE upwards of 2000 J/kg combined with around 30 knots of deep-layer shear should allow for some initial storm organization, including the potential for a few supercells. Ambient low-level vorticity along the boundary may support a brief tornado threat with initial convection. However, mean west/southwesterly winds should yield poor boundary-normal deep-layer shear, which suggests storm interactions along the boundary may promote upscale growth by late afternoon with an increase in damaging to severe wind potential. ...Midwest... A mid-level perturbation is noted in water-vapor imagery across northern MT. This feature is forecast to reach the Midwest region by peak heating this afternoon. Cool temperatures aloft over a somewhat dry air mass should promote modest (500-1000 J/kg) MLCAPE. Deep-layer wind shear is expected to be marginal, but lift ahead of the vorticity maximum should promote isolated to scattered thunderstorm development with the potential for strong to severe winds - especially if more consolidated/organized clusters can become established. ...Texas into southwest Oklahoma... Surface observations show the cold front slowly moving south across central TX, but this boundary should become increasingly diffuse through the day amid strong diurnal heating across much of TX. Thermally-induced surface pressure falls to the west of a dryline (noted from west-central TX to the Big Bend region) will maintain east/southeasterly low-level winds through the day. This will not only maintain an influx of rich Gulf moisture (dewpoints in the mid/upper 70s), but will support hodograph elongation given 40-50 knot westerly flow aloft. Forecast soundings suggest sufficient heating will erode MLCIN by early afternoon, but weak confluence along the dryline and neutral to rising heights aloft may limit convective coverage. Consequently, confidence on storm coverage and location is low with considerable spread noted in 00z CAM solutions. However, this appears to be a low-probability, but potentially high impact scenario with the potential for significant hail (2 inches in diameter or larger), severe wind, and perhaps a tornado where storms can develop. Elevated convection appears possible well into the overnight hours across northern TX into southwest OK as isentropic ascent atop the stalled frontal boundary increases with the onset of the nocturnal low-level jet. This activity should primarily pose a severe hail/wind threat that may persist into the early morning hours Tuesday. ..Moore.. 05/27/2024 Read more