Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Wed Mar 13 2024 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF NORTHEASTERN KANSAS AND NORTHWESTERN MISSOURI... ...SUMMARY... Large to very large hail, severe thunderstorm gusts and a few tornadoes are expected this afternoon into evening across parts of the central Plains and lower Missouri Valley. Isolated severe storms may occur late this afternoon across parts of the southern Plains. ...Synopsis... The mid/upper-level synoptic pattern will amplify through the period and into day 2, as a shortwave trough now over the interior Northwest digs mostly southward and strengthens. The main vorticity max, then over the Great Basin, and the associated/developing closed 500-mb circulation, will make their closest approach to the outlook area during the afternoon into early evening. Meanwhile, smaller perturbations -- evident in moisture-channel imagery over southwestern and eastern CO -- will move northeastward toward positions over northern NE and western KS by 00Z. This will occur in a regime of broadly difluent flow aloft, leftward of the 500-300-mb jet maxima. By 12Z, the 500-mb low that will anchor a multi-day, cutoff Southwestern cyclone should be located near LAS. A series of vorticity lobes/maxima will extend from the southeastern quadrant of the cyclone, over AZ, northeastward across the central Plains to near southern Lake Michigan. At the surface, 11Z analysis showed weak lows near MCI and between SPD-LBL, connected by a quasistationary frontal zone that arched across southeastern KS and northwestern OK. The western low should deepen and migrate eastward then northeastward across western/ central KS into this evening, prompting the boundary to move northward across central/eastern KS and central/northern MO as a warm front. A dryline -- initially analyzed from a frontal intersection over northern OK to west-central TX then southward into Coahuila -- should mix eastward today. The dryline should arch from central to southeastern KS, northeastern to south-central OK, and north-central TX into the Edwards Plateau by late afternoon, before retreating westward. ...Central Plains/Lower MO Valley... Isolated to scattered thunderstorms are expected to develop this afternoon, in an arc extending from near the western KS low eastward to east-northeastward over northern KS, then east-southeastward across central/eastern MO and perhaps south-central IL. Supercells with all severe hazards are possible, including at least a few tornadoes and significant (2+ inch) hail. The greatest concentration of severe threat appears to be in northeastern KS and northwestern MO, in and near the "enhanced" area. Activity should develop preferentially along/near the frontal zone and shift northward to northeastward only a little faster than the boundary, thereby remaining in a narrow sector of favorable buoyancy, low-level shear and boundary-layer vorticity for some time before moving into cooler air and weakening. Nearby parts of the dryline also might form a storm or two. In the frontal corridor near I-70 in northern KS to northwestern MO, modified model soundings depict strong veering of flow with height (contributing to locally favorable hodographs and SRH), steep midlevel lapse rates, and adequate low-level moisture, with dewpoints commonly reaching the low/mid 50s F. MLCAPE should range from around 500-1000 J/kg over a very narrow, northward-moving sliver of west-central/ north-central KS to a broader area of 1500-2500 J/kg developing to between MHK-COU, then weaker (but still sufficient for strong-severe storms) eastward into IL. Deep shear should be favorable in I-70 corridor as well, though it will be maximized farther south ahead of the dryline where initiation is more uncertain. Many models (including most HREF members) have been depicting earliest convection initiation near or after 00Z, which seems somewhat late given: 1. Their known biases (e.g., excess RAP/HRRR mixing/drying, too-cool NAM surface conditions, poor resolution of very narrow warm sectors, etc.), 2. The overall pattern and history of similar scenarios, with sufficient frontal convergence/lift for convection typically earlier in the afternoon and closer to the low, and 3. Expected diurnal destabilization (from both warm advection and surface heating) around the dryline, frontal zone and leading edge of the dry slot aloft. Notably, experimental MPAS members are sooner to initiate and farther south, more in line with conceptual models. During late afternoon and early evening, a window of tornado opportunity may be maximized with discrete cells in LLJ-enlarged hodographs, before the near-surface layer nocturnally stabilizes too much. Coverage is expected to increase for a few hours after 00Z, maximizing hail/wind threat density, though at least isolated severe potential may persist into the following morning over eastern parts of the outlook area. ...Southern Plains... Isolated thunderstorm(s) may form late this afternoon along a roughly 300-nm long segment of the dryline over portions of south-central/southeastern KS, into east-central OK and adjoining parts of north TX. While development and maintenance of any cells forming in this regime is in question due to EML-related capping, any sustained storms can become supercells with all hazards possible -- including very large hail. Except for the strong CINH, the parameter space will be favorable, with stronger surface heating, greater low-level moisture (dewpoints mid 50s to low 60s F) and faster mid/upper winds (contributing to 50-60 kt effective-shear magnitudes) than farther north. However, uncertainty is too great to focus larger unconditional probabilities on any particular part of this corridor. ..Edwards/Dean.. 03/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Wed Mar 13 2024 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF NORTHEASTERN KANSAS AND NORTHWESTERN MISSOURI... ...SUMMARY... Large to very large hail, severe thunderstorm gusts and a few tornadoes are expected this afternoon into evening across parts of the central Plains and lower Missouri Valley. Isolated severe storms may occur late this afternoon across parts of the southern Plains. ...Synopsis... The mid/upper-level synoptic pattern will amplify through the period and into day 2, as a shortwave trough now over the interior Northwest digs mostly southward and strengthens. The main vorticity max, then over the Great Basin, and the associated/developing closed 500-mb circulation, will make their closest approach to the outlook area during the afternoon into early evening. Meanwhile, smaller perturbations -- evident in moisture-channel imagery over southwestern and eastern CO -- will move northeastward toward positions over northern NE and western KS by 00Z. This will occur in a regime of broadly difluent flow aloft, leftward of the 500-300-mb jet maxima. By 12Z, the 500-mb low that will anchor a multi-day, cutoff Southwestern cyclone should be located near LAS. A series of vorticity lobes/maxima will extend from the southeastern quadrant of the cyclone, over AZ, northeastward across the central Plains to near southern Lake Michigan. At the surface, 11Z analysis showed weak lows near MCI and between SPD-LBL, connected by a quasistationary frontal zone that arched across southeastern KS and northwestern OK. The western low should deepen and migrate eastward then northeastward across western/ central KS into this evening, prompting the boundary to move northward across central/eastern KS and central/northern MO as a warm front. A dryline -- initially analyzed from a frontal intersection over northern OK to west-central TX then southward into Coahuila -- should mix eastward today. The dryline should arch from central to southeastern KS, northeastern to south-central OK, and north-central TX into the Edwards Plateau by late afternoon, before retreating westward. ...Central Plains/Lower MO Valley... Isolated to scattered thunderstorms are expected to develop this afternoon, in an arc extending from near the western KS low eastward to east-northeastward over northern KS, then east-southeastward across central/eastern MO and perhaps south-central IL. Supercells with all severe hazards are possible, including at least a few tornadoes and significant (2+ inch) hail. The greatest concentration of severe threat appears to be in northeastern KS and northwestern MO, in and near the "enhanced" area. Activity should develop preferentially along/near the frontal zone and shift northward to northeastward only a little faster than the boundary, thereby remaining in a narrow sector of favorable buoyancy, low-level shear and boundary-layer vorticity for some time before moving into cooler air and weakening. Nearby parts of the dryline also might form a storm or two. In the frontal corridor near I-70 in northern KS to northwestern MO, modified model soundings depict strong veering of flow with height (contributing to locally favorable hodographs and SRH), steep midlevel lapse rates, and adequate low-level moisture, with dewpoints commonly reaching the low/mid 50s F. MLCAPE should range from around 500-1000 J/kg over a very narrow, northward-moving sliver of west-central/ north-central KS to a broader area of 1500-2500 J/kg developing to between MHK-COU, then weaker (but still sufficient for strong-severe storms) eastward into IL. Deep shear should be favorable in I-70 corridor as well, though it will be maximized farther south ahead of the dryline where initiation is more uncertain. Many models (including most HREF members) have been depicting earliest convection initiation near or after 00Z, which seems somewhat late given: 1. Their known biases (e.g., excess RAP/HRRR mixing/drying, too-cool NAM surface conditions, poor resolution of very narrow warm sectors, etc.), 2. The overall pattern and history of similar scenarios, with sufficient frontal convergence/lift for convection typically earlier in the afternoon and closer to the low, and 3. Expected diurnal destabilization (from both warm advection and surface heating) around the dryline, frontal zone and leading edge of the dry slot aloft. Notably, experimental MPAS members are sooner to initiate and farther south, more in line with conceptual models. During late afternoon and early evening, a window of tornado opportunity may be maximized with discrete cells in LLJ-enlarged hodographs, before the near-surface layer nocturnally stabilizes too much. Coverage is expected to increase for a few hours after 00Z, maximizing hail/wind threat density, though at least isolated severe potential may persist into the following morning over eastern parts of the outlook area. ...Southern Plains... Isolated thunderstorm(s) may form late this afternoon along a roughly 300-nm long segment of the dryline over portions of south-central/southeastern KS, into east-central OK and adjoining parts of north TX. While development and maintenance of any cells forming in this regime is in question due to EML-related capping, any sustained storms can become supercells with all hazards possible -- including very large hail. Except for the strong CINH, the parameter space will be favorable, with stronger surface heating, greater low-level moisture (dewpoints mid 50s to low 60s F) and faster mid/upper winds (contributing to 50-60 kt effective-shear magnitudes) than farther north. However, uncertainty is too great to focus larger unconditional probabilities on any particular part of this corridor. ..Edwards/Dean.. 03/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 AM CDT Wed Mar 13 2024 Valid 131300Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF NORTHEASTERN KANSAS AND NORTHWESTERN MISSOURI... ...SUMMARY... Large to very large hail, severe thunderstorm gusts and a few tornadoes are expected this afternoon into evening across parts of the central Plains and lower Missouri Valley. Isolated severe storms may occur late this afternoon across parts of the southern Plains. ...Synopsis... The mid/upper-level synoptic pattern will amplify through the period and into day 2, as a shortwave trough now over the interior Northwest digs mostly southward and strengthens. The main vorticity max, then over the Great Basin, and the associated/developing closed 500-mb circulation, will make their closest approach to the outlook area during the afternoon into early evening. Meanwhile, smaller perturbations -- evident in moisture-channel imagery over southwestern and eastern CO -- will move northeastward toward positions over northern NE and western KS by 00Z. This will occur in a regime of broadly difluent flow aloft, leftward of the 500-300-mb jet maxima. By 12Z, the 500-mb low that will anchor a multi-day, cutoff Southwestern cyclone should be located near LAS. A series of vorticity lobes/maxima will extend from the southeastern quadrant of the cyclone, over AZ, northeastward across the central Plains to near southern Lake Michigan. At the surface, 11Z analysis showed weak lows near MCI and between SPD-LBL, connected by a quasistationary frontal zone that arched across southeastern KS and northwestern OK. The western low should deepen and migrate eastward then northeastward across western/ central KS into this evening, prompting the boundary to move northward across central/eastern KS and central/northern MO as a warm front. A dryline -- initially analyzed from a frontal intersection over northern OK to west-central TX then southward into Coahuila -- should mix eastward today. The dryline should arch from central to southeastern KS, northeastern to south-central OK, and north-central TX into the Edwards Plateau by late afternoon, before retreating westward. ...Central Plains/Lower MO Valley... Isolated to scattered thunderstorms are expected to develop this afternoon, in an arc extending from near the western KS low eastward to east-northeastward over northern KS, then east-southeastward across central/eastern MO and perhaps south-central IL. Supercells with all severe hazards are possible, including at least a few tornadoes and significant (2+ inch) hail. The greatest concentration of severe threat appears to be in northeastern KS and northwestern MO, in and near the "enhanced" area. Activity should develop preferentially along/near the frontal zone and shift northward to northeastward only a little faster than the boundary, thereby remaining in a narrow sector of favorable buoyancy, low-level shear and boundary-layer vorticity for some time before moving into cooler air and weakening. Nearby parts of the dryline also might form a storm or two. In the frontal corridor near I-70 in northern KS to northwestern MO, modified model soundings depict strong veering of flow with height (contributing to locally favorable hodographs and SRH), steep midlevel lapse rates, and adequate low-level moisture, with dewpoints commonly reaching the low/mid 50s F. MLCAPE should range from around 500-1000 J/kg over a very narrow, northward-moving sliver of west-central/ north-central KS to a broader area of 1500-2500 J/kg developing to between MHK-COU, then weaker (but still sufficient for strong-severe storms) eastward into IL. Deep shear should be favorable in I-70 corridor as well, though it will be maximized farther south ahead of the dryline where initiation is more uncertain. Many models (including most HREF members) have been depicting earliest convection initiation near or after 00Z, which seems somewhat late given: 1. Their known biases (e.g., excess RAP/HRRR mixing/drying, too-cool NAM surface conditions, poor resolution of very narrow warm sectors, etc.), 2. The overall pattern and history of similar scenarios, with sufficient frontal convergence/lift for convection typically earlier in the afternoon and closer to the low, and 3. Expected diurnal destabilization (from both warm advection and surface heating) around the dryline, frontal zone and leading edge of the dry slot aloft. Notably, experimental MPAS members are sooner to initiate and farther south, more in line with conceptual models. During late afternoon and early evening, a window of tornado opportunity may be maximized with discrete cells in LLJ-enlarged hodographs, before the near-surface layer nocturnally stabilizes too much. Coverage is expected to increase for a few hours after 00Z, maximizing hail/wind threat density, though at least isolated severe potential may persist into the following morning over eastern parts of the outlook area. ...Southern Plains... Isolated thunderstorm(s) may form late this afternoon along a roughly 300-nm long segment of the dryline over portions of south-central/southeastern KS, into east-central OK and adjoining parts of north TX. While development and maintenance of any cells forming in this regime is in question due to EML-related capping, any sustained storms can become supercells with all hazards possible -- including very large hail. Except for the strong CINH, the parameter space will be favorable, with stronger surface heating, greater low-level moisture (dewpoints mid 50s to low 60s F) and faster mid/upper winds (contributing to 50-60 kt effective-shear magnitudes) than farther north. However, uncertainty is too great to focus larger unconditional probabilities on any particular part of this corridor. ..Edwards/Dean.. 03/13/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Wed Mar 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Medium-range guidance continues to suggest that an upper low will remain over southern CA, the southern Great Basin, and AZ through the weekend. A reservoir of low-level moisture will likely still be in place from the TX Coastal Plains through the Southeast on D4/Saturday and D5/Sunday, with thunderstorms possible along a stalled front. Severe potential will be tempered by modest buoyancy. While the Southwest upper low remains largely in place, upper troughing is forecast to deepen considerably across the central and eastern CONUS on D6/Monday. As it does, the remnant front across the TX Coastal Plain and Southeast will shift offshore, scouring any remaining low-level moisture. Multi-model consensus suggests the deep upper troughing over the eastern CONUS will move offshore by early D8/Wednesday, with some potential for moisture return across the southern Plains ahead of an approaching shortwave trough. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Wed Mar 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Medium-range guidance continues to suggest that an upper low will remain over southern CA, the southern Great Basin, and AZ through the weekend. A reservoir of low-level moisture will likely still be in place from the TX Coastal Plains through the Southeast on D4/Saturday and D5/Sunday, with thunderstorms possible along a stalled front. Severe potential will be tempered by modest buoyancy. While the Southwest upper low remains largely in place, upper troughing is forecast to deepen considerably across the central and eastern CONUS on D6/Monday. As it does, the remnant front across the TX Coastal Plain and Southeast will shift offshore, scouring any remaining low-level moisture. Multi-model consensus suggests the deep upper troughing over the eastern CONUS will move offshore by early D8/Wednesday, with some potential for moisture return across the southern Plains ahead of an approaching shortwave trough. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Wed Mar 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Medium-range guidance continues to suggest that an upper low will remain over southern CA, the southern Great Basin, and AZ through the weekend. A reservoir of low-level moisture will likely still be in place from the TX Coastal Plains through the Southeast on D4/Saturday and D5/Sunday, with thunderstorms possible along a stalled front. Severe potential will be tempered by modest buoyancy. While the Southwest upper low remains largely in place, upper troughing is forecast to deepen considerably across the central and eastern CONUS on D6/Monday. As it does, the remnant front across the TX Coastal Plain and Southeast will shift offshore, scouring any remaining low-level moisture. Multi-model consensus suggests the deep upper troughing over the eastern CONUS will move offshore by early D8/Wednesday, with some potential for moisture return across the southern Plains ahead of an approaching shortwave trough. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Wed Mar 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Medium-range guidance continues to suggest that an upper low will remain over southern CA, the southern Great Basin, and AZ through the weekend. A reservoir of low-level moisture will likely still be in place from the TX Coastal Plains through the Southeast on D4/Saturday and D5/Sunday, with thunderstorms possible along a stalled front. Severe potential will be tempered by modest buoyancy. While the Southwest upper low remains largely in place, upper troughing is forecast to deepen considerably across the central and eastern CONUS on D6/Monday. As it does, the remnant front across the TX Coastal Plain and Southeast will shift offshore, scouring any remaining low-level moisture. Multi-model consensus suggests the deep upper troughing over the eastern CONUS will move offshore by early D8/Wednesday, with some potential for moisture return across the southern Plains ahead of an approaching shortwave trough. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Wed Mar 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Medium-range guidance continues to suggest that an upper low will remain over southern CA, the southern Great Basin, and AZ through the weekend. A reservoir of low-level moisture will likely still be in place from the TX Coastal Plains through the Southeast on D4/Saturday and D5/Sunday, with thunderstorms possible along a stalled front. Severe potential will be tempered by modest buoyancy. While the Southwest upper low remains largely in place, upper troughing is forecast to deepen considerably across the central and eastern CONUS on D6/Monday. As it does, the remnant front across the TX Coastal Plain and Southeast will shift offshore, scouring any remaining low-level moisture. Multi-model consensus suggests the deep upper troughing over the eastern CONUS will move offshore by early D8/Wednesday, with some potential for moisture return across the southern Plains ahead of an approaching shortwave trough. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0346 AM CDT Wed Mar 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Medium-range guidance continues to suggest that an upper low will remain over southern CA, the southern Great Basin, and AZ through the weekend. A reservoir of low-level moisture will likely still be in place from the TX Coastal Plains through the Southeast on D4/Saturday and D5/Sunday, with thunderstorms possible along a stalled front. Severe potential will be tempered by modest buoyancy. While the Southwest upper low remains largely in place, upper troughing is forecast to deepen considerably across the central and eastern CONUS on D6/Monday. As it does, the remnant front across the TX Coastal Plain and Southeast will shift offshore, scouring any remaining low-level moisture. Multi-model consensus suggests the deep upper troughing over the eastern CONUS will move offshore by early D8/Wednesday, with some potential for moisture return across the southern Plains ahead of an approaching shortwave trough. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Mar 13 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EAST TEXAS INTO THE SOUTHEAST STATES... ...SUMMARY... Isolated severe thunderstorms are possible from east Texas into the Southeast States on Friday. ...Synopsis and Discussion... Upper pattern early Friday morning is forecast to feature a mature southern-stream upper low over the Lower CO River Valley, covering much of southern/central CA, the western Great Basin, and AZ. Shortwave ridging is anticipated downstream of this upper low from the southern Plains into the central High Plains, with largely zonal flow anticipated within the more confluent, single-stream flow east of the MS River. A northern-stream shortwave trough is expected to drop through the Canadian Prairie Provinces through the day, but the general upper pattern is expected to remain relatively unchanged across the CONUS. Surface pattern on Friday morning will likely feature a low over the Hudson Valley, with a stationary front extending westward from this low to another low over the Middle OH Valley. An extensive cold front is expected to extend southwestward from this Middle OH Valley low through the TX Hill Country. This cold front is forecast to make gradual southeastward progress during the day, with thunderstorms likely along and just ahead it throughout the period. Buoyancy is expected to remain relatively modest ahead of this front, largely a result of cloud cover and limited heating. Even so, deep-layer shear should remain strong enough for some organized storm structures and an isolated severe threat, particularly across the Southeast where slightly stronger mid-level flow is anticipated during the afternoon. ..Mosier.. 03/13/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Mar 13 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EAST TEXAS INTO THE SOUTHEAST STATES... ...SUMMARY... Isolated severe thunderstorms are possible from east Texas into the Southeast States on Friday. ...Synopsis and Discussion... Upper pattern early Friday morning is forecast to feature a mature southern-stream upper low over the Lower CO River Valley, covering much of southern/central CA, the western Great Basin, and AZ. Shortwave ridging is anticipated downstream of this upper low from the southern Plains into the central High Plains, with largely zonal flow anticipated within the more confluent, single-stream flow east of the MS River. A northern-stream shortwave trough is expected to drop through the Canadian Prairie Provinces through the day, but the general upper pattern is expected to remain relatively unchanged across the CONUS. Surface pattern on Friday morning will likely feature a low over the Hudson Valley, with a stationary front extending westward from this low to another low over the Middle OH Valley. An extensive cold front is expected to extend southwestward from this Middle OH Valley low through the TX Hill Country. This cold front is forecast to make gradual southeastward progress during the day, with thunderstorms likely along and just ahead it throughout the period. Buoyancy is expected to remain relatively modest ahead of this front, largely a result of cloud cover and limited heating. Even so, deep-layer shear should remain strong enough for some organized storm structures and an isolated severe threat, particularly across the Southeast where slightly stronger mid-level flow is anticipated during the afternoon. ..Mosier.. 03/13/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Mar 13 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EAST TEXAS INTO THE SOUTHEAST STATES... ...SUMMARY... Isolated severe thunderstorms are possible from east Texas into the Southeast States on Friday. ...Synopsis and Discussion... Upper pattern early Friday morning is forecast to feature a mature southern-stream upper low over the Lower CO River Valley, covering much of southern/central CA, the western Great Basin, and AZ. Shortwave ridging is anticipated downstream of this upper low from the southern Plains into the central High Plains, with largely zonal flow anticipated within the more confluent, single-stream flow east of the MS River. A northern-stream shortwave trough is expected to drop through the Canadian Prairie Provinces through the day, but the general upper pattern is expected to remain relatively unchanged across the CONUS. Surface pattern on Friday morning will likely feature a low over the Hudson Valley, with a stationary front extending westward from this low to another low over the Middle OH Valley. An extensive cold front is expected to extend southwestward from this Middle OH Valley low through the TX Hill Country. This cold front is forecast to make gradual southeastward progress during the day, with thunderstorms likely along and just ahead it throughout the period. Buoyancy is expected to remain relatively modest ahead of this front, largely a result of cloud cover and limited heating. Even so, deep-layer shear should remain strong enough for some organized storm structures and an isolated severe threat, particularly across the Southeast where slightly stronger mid-level flow is anticipated during the afternoon. ..Mosier.. 03/13/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Mar 13 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EAST TEXAS INTO THE SOUTHEAST STATES... ...SUMMARY... Isolated severe thunderstorms are possible from east Texas into the Southeast States on Friday. ...Synopsis and Discussion... Upper pattern early Friday morning is forecast to feature a mature southern-stream upper low over the Lower CO River Valley, covering much of southern/central CA, the western Great Basin, and AZ. Shortwave ridging is anticipated downstream of this upper low from the southern Plains into the central High Plains, with largely zonal flow anticipated within the more confluent, single-stream flow east of the MS River. A northern-stream shortwave trough is expected to drop through the Canadian Prairie Provinces through the day, but the general upper pattern is expected to remain relatively unchanged across the CONUS. Surface pattern on Friday morning will likely feature a low over the Hudson Valley, with a stationary front extending westward from this low to another low over the Middle OH Valley. An extensive cold front is expected to extend southwestward from this Middle OH Valley low through the TX Hill Country. This cold front is forecast to make gradual southeastward progress during the day, with thunderstorms likely along and just ahead it throughout the period. Buoyancy is expected to remain relatively modest ahead of this front, largely a result of cloud cover and limited heating. Even so, deep-layer shear should remain strong enough for some organized storm structures and an isolated severe threat, particularly across the Southeast where slightly stronger mid-level flow is anticipated during the afternoon. ..Mosier.. 03/13/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0227 AM CDT Wed Mar 13 2024 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EAST TEXAS INTO THE SOUTHEAST STATES... ...SUMMARY... Isolated severe thunderstorms are possible from east Texas into the Southeast States on Friday. ...Synopsis and Discussion... Upper pattern early Friday morning is forecast to feature a mature southern-stream upper low over the Lower CO River Valley, covering much of southern/central CA, the western Great Basin, and AZ. Shortwave ridging is anticipated downstream of this upper low from the southern Plains into the central High Plains, with largely zonal flow anticipated within the more confluent, single-stream flow east of the MS River. A northern-stream shortwave trough is expected to drop through the Canadian Prairie Provinces through the day, but the general upper pattern is expected to remain relatively unchanged across the CONUS. Surface pattern on Friday morning will likely feature a low over the Hudson Valley, with a stationary front extending westward from this low to another low over the Middle OH Valley. An extensive cold front is expected to extend southwestward from this Middle OH Valley low through the TX Hill Country. This cold front is forecast to make gradual southeastward progress during the day, with thunderstorms likely along and just ahead it throughout the period. Buoyancy is expected to remain relatively modest ahead of this front, largely a result of cloud cover and limited heating. Even so, deep-layer shear should remain strong enough for some organized storm structures and an isolated severe threat, particularly across the Southeast where slightly stronger mid-level flow is anticipated during the afternoon. ..Mosier.. 03/13/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0153 AM CDT Wed Mar 13 2024 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns are expected to remain low on Thursday. Winds are expected to be much lighter as surface gradients decrease across the southern High Plains, where the driest conditions will overlap the driest fuels. A cold front will move southward across the Southern Plains late Thursday, accompanied by much cooler temperatures and increasing precipitation chances. ..Thornton.. 03/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0153 AM CDT Wed Mar 13 2024 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns are expected to remain low on Thursday. Winds are expected to be much lighter as surface gradients decrease across the southern High Plains, where the driest conditions will overlap the driest fuels. A cold front will move southward across the Southern Plains late Thursday, accompanied by much cooler temperatures and increasing precipitation chances. ..Thornton.. 03/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0153 AM CDT Wed Mar 13 2024 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns are expected to remain low on Thursday. Winds are expected to be much lighter as surface gradients decrease across the southern High Plains, where the driest conditions will overlap the driest fuels. A cold front will move southward across the Southern Plains late Thursday, accompanied by much cooler temperatures and increasing precipitation chances. ..Thornton.. 03/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0153 AM CDT Wed Mar 13 2024 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns are expected to remain low on Thursday. Winds are expected to be much lighter as surface gradients decrease across the southern High Plains, where the driest conditions will overlap the driest fuels. A cold front will move southward across the Southern Plains late Thursday, accompanied by much cooler temperatures and increasing precipitation chances. ..Thornton.. 03/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0153 AM CDT Wed Mar 13 2024 Valid 141200Z - 151200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns are expected to remain low on Thursday. Winds are expected to be much lighter as surface gradients decrease across the southern High Plains, where the driest conditions will overlap the driest fuels. A cold front will move southward across the Southern Plains late Thursday, accompanied by much cooler temperatures and increasing precipitation chances. ..Thornton.. 03/13/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Wed Mar 13 2024 Valid 141200Z - 151200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST OK INTO WESTERN AR AND FAR SOUTHWEST MO... ...SUMMARY... Strong to severe thunderstorms are possible across a large area from the Middle Mississippi Valley into eastern Oklahoma, East Texas, and the Lower Mississippi Valley on Thursday. Greatest threat is currently expected to be from southeast Oklahoma into western Arkansas. ...Synopsis... A surface low is forecast to be over the NE/IA/MO border intersection vicinity early Thursday morning. A cold front will extend from this low southwestward through southeast KS and central OK into the TX Hill Country. A warm front will extend from this low east-northeastward through central IL. A broad warm sector will exist ahead of the cold front Thursday morning, characterized by dewpoints ranging from the mid/upper 60s over east TX to the mid 50s near the IA/MO border. This reservoir of low-level moisture will exist beneath steep mid-level lapse rates, resulting in moderate to strong buoyancy as heating destabilizes the air mass. As such, thunderstorms are anticipated across much of the warm sector as the cold front gradually shifts eastward throughout the day. Some strong to severe storms are possible, particularly in the corridor from northern MO into the Arklatex. ...Mid MS Valley Thursday morning into late afternoon/early evening... Showers and thunderstorms will likely be ongoing near the surface low and warm front early Thursday morning. General expectation is for most of this activity to be north of the warm front, with an attendant threat for isolated hail. However, there is some potential for the southern edge of these storms (and associated outflow) to move within the far northern corridor of the warm sector, resulting in some threat for damaging gusts as well as hail. This activity is expected to continue eastward, reaching the Middle OH Valley by the afternoon. The presence of these early morning storms could act to shift the position of entire the frontal zone southward, with an attendant shift of the afternoon severe threat as well. Additionally, if strong outflow is realized, the resulting boundary could act as a focus for afternoon development across MO. Evolution of these mesoscale details varies within the guidance, but the more favorable area for afternoon development does appear to be over central MO, which is farther south than forecast yesterday when the area just south of the warm front looked more plausible. Given steep mid-level lapse rates and strong deep-layer vertical shear, large to very large hail is still anticipated with the initial more cellular late afternoon storms. Strong downdrafts are possible as well, with potential for upscale growth into one or more bowing clusters. Veered low-level flow is forecast to limit the tornado potential, although interaction with any boundaries could lead to mesoscale corridors of slightly greater tornado threat. ...Middle OH Valley during the afternoon and evening... As the activity initially over the Mid MS Valley continues eastward, there is some potential it transitions from elevated to surface based (or at least near-surface based) as it interacts with the warm front progressing northward across the region. Buoyancy will be modest, but moderate southerly low-level flow beneath strong westerlies will result in vertically veering low-level hodographs that could support updraft organization and even a few tornadoes. Uncertainties regarding the position of the front as well as how the convection evolves out of the Mid MS Valley limit forecast confidence with this outlook, but future guidance will be evaluated closely, and upgrades may be considered in later outlooks. ...Far Northeast TX and eastern OK into AR during the afternoon and evening... Large-scale forcing for ascent will be nebulous over the region, with some guidance even showing height rises during the afternoon. Even so, weak surface troughing is expected to interact with an increasingly unstable airmass across the region during the afternoon, resulting scattered thunderstorms from far northeast TX into eastern OK and western AR between 18Z and 21Z. Given robust buoyancy and moderate vertical shear, initial development will likely be supercellular and capable of all severe hazards, including very large hail. Low-level southerly flow (perhaps even southeasterly) is also anticipated, resulting in low-level hodographs that support tornadogenesis, particularly from far southeast OK into western AR. Even with favorable hodographs, storm interactions could prevent the discreteness needed for updraft organization. ...Mid MS Valley into the Mid-South during evening and overnight... After the initial development described above, some upscale growth into one or more clusters appears plausible, with an attendant threat for damaging gusts as these clusters move eastward. Buoyancy will gradually decrease with eastward extent, leading to the expectation that whatever line segments do develop will lose intensity as they continue eastward overnight. ..Mosier.. 03/13/2024 Read more