SPC Jul 18, 2025 0600 UTC Day 2 Convective Outlook

4 days 16 hours ago
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY INTO SATURDAY NIGHT ACROSS PARTS OF EASTERN IOWA...SOUTHERN WISCONSIN...NORTHERN AND CENTRAL ILLINOIS AND INDIANA...CENTRAL AND SOUTHERN LOWER MICHIGAN...NORTHERN AND WESTERN OHIO...PARTS OF NORTHWESTERN PENNSYLVANIA AND WESTERN NEW YORK STATE... ...SUMMARY... Strong thunderstorms, including one or two organizing clusters, are possible across southern portions of the Great Lakes region and adjacent portions of the Ohio Valley Saturday into Saturday night, with more widely scattered strong thunderstorm development across the northern Rockies into adjacent high plains. ...Discussion... Models indicate that at least some amplification to the mid/upper flow across the northern tier of the U.S. is probable during this period. It appears that this will include digging troughing across the Pacific Northwest through northern Rockies, downstream of increasingly prominent ridging building across the northeastern Pacific. Farther east, troughing is forecast to dig across and to the east of the Great Lakes, in advance of significant troughing within a separate branch of westerlies, pivoting southeast of Hudson Bay. In lower levels, the better defined remnants of an ongoing cold frontal intrusion to the lee of the Rockies, perhaps aided by stronger differential surface heating during the day Saturday, may shift east of the middle Mississippi through the lower Ohio Valley. At the same time, a reinforcing intrusion of cooler and drier air is forecast to advance across and south of the Upper Midwest and Great Lakes, probably in the wake of a weak eastward migrating surface low. ...Midwest through Great Lakes/Ohio Valley... Model depictions concerning synoptic and sub-synoptic features, including potential convective evolution remain rather varied. In general, it appears that low-level moistening ahead of the reinforcing cold front will contribute to moderate destabilization as far north as the southern Great Lakes during the day Saturday. On the southern fringe of the stronger westerlies, 30-50 kt flow in the 850-500 mb layer across southern Wisconsin and Lower Michigan into the lower Great Lakes will contribute to potential for organized convective development. This may include a couple of supercells and perhaps an upscale growing cluster. Although mid-level lapse rates may be modest, this may be accompanied by some risk for hail, in addition to strong to severe surface gusts and perhaps a tornado or two. Southwestward toward the middle Mississippi into Ohio Valleys, deep-layer mean wind fields are likely to be weaker, but shear beneath west-northwesterly mid-level flow may still support potential for organized thunderstorm development, in the presence of a seasonably moist boundary-layer becoming characterized by sizable CAPE with daytime heating. Forcing for this activity remains unclear, and probably will hinge on convectively generated or augmented perturbations migrating around the northern periphery of mid/upper ridging encompassing much of the central and southern tier of the U.S. to the east of the Rockies. ...Lee of the northern Rockies... Downstream of the digging mid/upper troughing across the Northwest, moisture return to deepening lee surface troughing is forecast to contribute to at least a narrow corridor of moderate to large mixed-layer CAPE, in the presence of steep lower/mid-tropospheric lapse rates. Veering of winds with height probably will contribute to sufficient shear for organized thunderstorm development, including supercells, as widely scattered to scattered thunderstorms develop off the higher terrain into the high plains late Saturday afternoon and evening. It is possible that severe weather probabilities could still be increased in later outlooks for this period. ..Kerr.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 2 Convective Outlook

4 days 16 hours ago
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY INTO SATURDAY NIGHT ACROSS PARTS OF EASTERN IOWA...SOUTHERN WISCONSIN...NORTHERN AND CENTRAL ILLINOIS AND INDIANA...CENTRAL AND SOUTHERN LOWER MICHIGAN...NORTHERN AND WESTERN OHIO...PARTS OF NORTHWESTERN PENNSYLVANIA AND WESTERN NEW YORK STATE... ...SUMMARY... Strong thunderstorms, including one or two organizing clusters, are possible across southern portions of the Great Lakes region and adjacent portions of the Ohio Valley Saturday into Saturday night, with more widely scattered strong thunderstorm development across the northern Rockies into adjacent high plains. ...Discussion... Models indicate that at least some amplification to the mid/upper flow across the northern tier of the U.S. is probable during this period. It appears that this will include digging troughing across the Pacific Northwest through northern Rockies, downstream of increasingly prominent ridging building across the northeastern Pacific. Farther east, troughing is forecast to dig across and to the east of the Great Lakes, in advance of significant troughing within a separate branch of westerlies, pivoting southeast of Hudson Bay. In lower levels, the better defined remnants of an ongoing cold frontal intrusion to the lee of the Rockies, perhaps aided by stronger differential surface heating during the day Saturday, may shift east of the middle Mississippi through the lower Ohio Valley. At the same time, a reinforcing intrusion of cooler and drier air is forecast to advance across and south of the Upper Midwest and Great Lakes, probably in the wake of a weak eastward migrating surface low. ...Midwest through Great Lakes/Ohio Valley... Model depictions concerning synoptic and sub-synoptic features, including potential convective evolution remain rather varied. In general, it appears that low-level moistening ahead of the reinforcing cold front will contribute to moderate destabilization as far north as the southern Great Lakes during the day Saturday. On the southern fringe of the stronger westerlies, 30-50 kt flow in the 850-500 mb layer across southern Wisconsin and Lower Michigan into the lower Great Lakes will contribute to potential for organized convective development. This may include a couple of supercells and perhaps an upscale growing cluster. Although mid-level lapse rates may be modest, this may be accompanied by some risk for hail, in addition to strong to severe surface gusts and perhaps a tornado or two. Southwestward toward the middle Mississippi into Ohio Valleys, deep-layer mean wind fields are likely to be weaker, but shear beneath west-northwesterly mid-level flow may still support potential for organized thunderstorm development, in the presence of a seasonably moist boundary-layer becoming characterized by sizable CAPE with daytime heating. Forcing for this activity remains unclear, and probably will hinge on convectively generated or augmented perturbations migrating around the northern periphery of mid/upper ridging encompassing much of the central and southern tier of the U.S. to the east of the Rockies. ...Lee of the northern Rockies... Downstream of the digging mid/upper troughing across the Northwest, moisture return to deepening lee surface troughing is forecast to contribute to at least a narrow corridor of moderate to large mixed-layer CAPE, in the presence of steep lower/mid-tropospheric lapse rates. Veering of winds with height probably will contribute to sufficient shear for organized thunderstorm development, including supercells, as widely scattered to scattered thunderstorms develop off the higher terrain into the high plains late Saturday afternoon and evening. It is possible that severe weather probabilities could still be increased in later outlooks for this period. ..Kerr.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 2 Convective Outlook

4 days 16 hours ago
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY INTO SATURDAY NIGHT ACROSS PARTS OF EASTERN IOWA...SOUTHERN WISCONSIN...NORTHERN AND CENTRAL ILLINOIS AND INDIANA...CENTRAL AND SOUTHERN LOWER MICHIGAN...NORTHERN AND WESTERN OHIO...PARTS OF NORTHWESTERN PENNSYLVANIA AND WESTERN NEW YORK STATE... ...SUMMARY... Strong thunderstorms, including one or two organizing clusters, are possible across southern portions of the Great Lakes region and adjacent portions of the Ohio Valley Saturday into Saturday night, with more widely scattered strong thunderstorm development across the northern Rockies into adjacent high plains. ...Discussion... Models indicate that at least some amplification to the mid/upper flow across the northern tier of the U.S. is probable during this period. It appears that this will include digging troughing across the Pacific Northwest through northern Rockies, downstream of increasingly prominent ridging building across the northeastern Pacific. Farther east, troughing is forecast to dig across and to the east of the Great Lakes, in advance of significant troughing within a separate branch of westerlies, pivoting southeast of Hudson Bay. In lower levels, the better defined remnants of an ongoing cold frontal intrusion to the lee of the Rockies, perhaps aided by stronger differential surface heating during the day Saturday, may shift east of the middle Mississippi through the lower Ohio Valley. At the same time, a reinforcing intrusion of cooler and drier air is forecast to advance across and south of the Upper Midwest and Great Lakes, probably in the wake of a weak eastward migrating surface low. ...Midwest through Great Lakes/Ohio Valley... Model depictions concerning synoptic and sub-synoptic features, including potential convective evolution remain rather varied. In general, it appears that low-level moistening ahead of the reinforcing cold front will contribute to moderate destabilization as far north as the southern Great Lakes during the day Saturday. On the southern fringe of the stronger westerlies, 30-50 kt flow in the 850-500 mb layer across southern Wisconsin and Lower Michigan into the lower Great Lakes will contribute to potential for organized convective development. This may include a couple of supercells and perhaps an upscale growing cluster. Although mid-level lapse rates may be modest, this may be accompanied by some risk for hail, in addition to strong to severe surface gusts and perhaps a tornado or two. Southwestward toward the middle Mississippi into Ohio Valleys, deep-layer mean wind fields are likely to be weaker, but shear beneath west-northwesterly mid-level flow may still support potential for organized thunderstorm development, in the presence of a seasonably moist boundary-layer becoming characterized by sizable CAPE with daytime heating. Forcing for this activity remains unclear, and probably will hinge on convectively generated or augmented perturbations migrating around the northern periphery of mid/upper ridging encompassing much of the central and southern tier of the U.S. to the east of the Rockies. ...Lee of the northern Rockies... Downstream of the digging mid/upper troughing across the Northwest, moisture return to deepening lee surface troughing is forecast to contribute to at least a narrow corridor of moderate to large mixed-layer CAPE, in the presence of steep lower/mid-tropospheric lapse rates. Veering of winds with height probably will contribute to sufficient shear for organized thunderstorm development, including supercells, as widely scattered to scattered thunderstorms develop off the higher terrain into the high plains late Saturday afternoon and evening. It is possible that severe weather probabilities could still be increased in later outlooks for this period. ..Kerr.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 2 Convective Outlook

4 days 16 hours ago
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY INTO SATURDAY NIGHT ACROSS PARTS OF EASTERN IOWA...SOUTHERN WISCONSIN...NORTHERN AND CENTRAL ILLINOIS AND INDIANA...CENTRAL AND SOUTHERN LOWER MICHIGAN...NORTHERN AND WESTERN OHIO...PARTS OF NORTHWESTERN PENNSYLVANIA AND WESTERN NEW YORK STATE... ...SUMMARY... Strong thunderstorms, including one or two organizing clusters, are possible across southern portions of the Great Lakes region and adjacent portions of the Ohio Valley Saturday into Saturday night, with more widely scattered strong thunderstorm development across the northern Rockies into adjacent high plains. ...Discussion... Models indicate that at least some amplification to the mid/upper flow across the northern tier of the U.S. is probable during this period. It appears that this will include digging troughing across the Pacific Northwest through northern Rockies, downstream of increasingly prominent ridging building across the northeastern Pacific. Farther east, troughing is forecast to dig across and to the east of the Great Lakes, in advance of significant troughing within a separate branch of westerlies, pivoting southeast of Hudson Bay. In lower levels, the better defined remnants of an ongoing cold frontal intrusion to the lee of the Rockies, perhaps aided by stronger differential surface heating during the day Saturday, may shift east of the middle Mississippi through the lower Ohio Valley. At the same time, a reinforcing intrusion of cooler and drier air is forecast to advance across and south of the Upper Midwest and Great Lakes, probably in the wake of a weak eastward migrating surface low. ...Midwest through Great Lakes/Ohio Valley... Model depictions concerning synoptic and sub-synoptic features, including potential convective evolution remain rather varied. In general, it appears that low-level moistening ahead of the reinforcing cold front will contribute to moderate destabilization as far north as the southern Great Lakes during the day Saturday. On the southern fringe of the stronger westerlies, 30-50 kt flow in the 850-500 mb layer across southern Wisconsin and Lower Michigan into the lower Great Lakes will contribute to potential for organized convective development. This may include a couple of supercells and perhaps an upscale growing cluster. Although mid-level lapse rates may be modest, this may be accompanied by some risk for hail, in addition to strong to severe surface gusts and perhaps a tornado or two. Southwestward toward the middle Mississippi into Ohio Valleys, deep-layer mean wind fields are likely to be weaker, but shear beneath west-northwesterly mid-level flow may still support potential for organized thunderstorm development, in the presence of a seasonably moist boundary-layer becoming characterized by sizable CAPE with daytime heating. Forcing for this activity remains unclear, and probably will hinge on convectively generated or augmented perturbations migrating around the northern periphery of mid/upper ridging encompassing much of the central and southern tier of the U.S. to the east of the Rockies. ...Lee of the northern Rockies... Downstream of the digging mid/upper troughing across the Northwest, moisture return to deepening lee surface troughing is forecast to contribute to at least a narrow corridor of moderate to large mixed-layer CAPE, in the presence of steep lower/mid-tropospheric lapse rates. Veering of winds with height probably will contribute to sufficient shear for organized thunderstorm development, including supercells, as widely scattered to scattered thunderstorms develop off the higher terrain into the high plains late Saturday afternoon and evening. It is possible that severe weather probabilities could still be increased in later outlooks for this period. ..Kerr.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 2 Convective Outlook

4 days 16 hours ago
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY INTO SATURDAY NIGHT ACROSS PARTS OF EASTERN IOWA...SOUTHERN WISCONSIN...NORTHERN AND CENTRAL ILLINOIS AND INDIANA...CENTRAL AND SOUTHERN LOWER MICHIGAN...NORTHERN AND WESTERN OHIO...PARTS OF NORTHWESTERN PENNSYLVANIA AND WESTERN NEW YORK STATE... ...SUMMARY... Strong thunderstorms, including one or two organizing clusters, are possible across southern portions of the Great Lakes region and adjacent portions of the Ohio Valley Saturday into Saturday night, with more widely scattered strong thunderstorm development across the northern Rockies into adjacent high plains. ...Discussion... Models indicate that at least some amplification to the mid/upper flow across the northern tier of the U.S. is probable during this period. It appears that this will include digging troughing across the Pacific Northwest through northern Rockies, downstream of increasingly prominent ridging building across the northeastern Pacific. Farther east, troughing is forecast to dig across and to the east of the Great Lakes, in advance of significant troughing within a separate branch of westerlies, pivoting southeast of Hudson Bay. In lower levels, the better defined remnants of an ongoing cold frontal intrusion to the lee of the Rockies, perhaps aided by stronger differential surface heating during the day Saturday, may shift east of the middle Mississippi through the lower Ohio Valley. At the same time, a reinforcing intrusion of cooler and drier air is forecast to advance across and south of the Upper Midwest and Great Lakes, probably in the wake of a weak eastward migrating surface low. ...Midwest through Great Lakes/Ohio Valley... Model depictions concerning synoptic and sub-synoptic features, including potential convective evolution remain rather varied. In general, it appears that low-level moistening ahead of the reinforcing cold front will contribute to moderate destabilization as far north as the southern Great Lakes during the day Saturday. On the southern fringe of the stronger westerlies, 30-50 kt flow in the 850-500 mb layer across southern Wisconsin and Lower Michigan into the lower Great Lakes will contribute to potential for organized convective development. This may include a couple of supercells and perhaps an upscale growing cluster. Although mid-level lapse rates may be modest, this may be accompanied by some risk for hail, in addition to strong to severe surface gusts and perhaps a tornado or two. Southwestward toward the middle Mississippi into Ohio Valleys, deep-layer mean wind fields are likely to be weaker, but shear beneath west-northwesterly mid-level flow may still support potential for organized thunderstorm development, in the presence of a seasonably moist boundary-layer becoming characterized by sizable CAPE with daytime heating. Forcing for this activity remains unclear, and probably will hinge on convectively generated or augmented perturbations migrating around the northern periphery of mid/upper ridging encompassing much of the central and southern tier of the U.S. to the east of the Rockies. ...Lee of the northern Rockies... Downstream of the digging mid/upper troughing across the Northwest, moisture return to deepening lee surface troughing is forecast to contribute to at least a narrow corridor of moderate to large mixed-layer CAPE, in the presence of steep lower/mid-tropospheric lapse rates. Veering of winds with height probably will contribute to sufficient shear for organized thunderstorm development, including supercells, as widely scattered to scattered thunderstorms develop off the higher terrain into the high plains late Saturday afternoon and evening. It is possible that severe weather probabilities could still be increased in later outlooks for this period. ..Kerr.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 2 Convective Outlook

4 days 16 hours ago
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY INTO SATURDAY NIGHT ACROSS PARTS OF EASTERN IOWA...SOUTHERN WISCONSIN...NORTHERN AND CENTRAL ILLINOIS AND INDIANA...CENTRAL AND SOUTHERN LOWER MICHIGAN...NORTHERN AND WESTERN OHIO...PARTS OF NORTHWESTERN PENNSYLVANIA AND WESTERN NEW YORK STATE... ...SUMMARY... Strong thunderstorms, including one or two organizing clusters, are possible across southern portions of the Great Lakes region and adjacent portions of the Ohio Valley Saturday into Saturday night, with more widely scattered strong thunderstorm development across the northern Rockies into adjacent high plains. ...Discussion... Models indicate that at least some amplification to the mid/upper flow across the northern tier of the U.S. is probable during this period. It appears that this will include digging troughing across the Pacific Northwest through northern Rockies, downstream of increasingly prominent ridging building across the northeastern Pacific. Farther east, troughing is forecast to dig across and to the east of the Great Lakes, in advance of significant troughing within a separate branch of westerlies, pivoting southeast of Hudson Bay. In lower levels, the better defined remnants of an ongoing cold frontal intrusion to the lee of the Rockies, perhaps aided by stronger differential surface heating during the day Saturday, may shift east of the middle Mississippi through the lower Ohio Valley. At the same time, a reinforcing intrusion of cooler and drier air is forecast to advance across and south of the Upper Midwest and Great Lakes, probably in the wake of a weak eastward migrating surface low. ...Midwest through Great Lakes/Ohio Valley... Model depictions concerning synoptic and sub-synoptic features, including potential convective evolution remain rather varied. In general, it appears that low-level moistening ahead of the reinforcing cold front will contribute to moderate destabilization as far north as the southern Great Lakes during the day Saturday. On the southern fringe of the stronger westerlies, 30-50 kt flow in the 850-500 mb layer across southern Wisconsin and Lower Michigan into the lower Great Lakes will contribute to potential for organized convective development. This may include a couple of supercells and perhaps an upscale growing cluster. Although mid-level lapse rates may be modest, this may be accompanied by some risk for hail, in addition to strong to severe surface gusts and perhaps a tornado or two. Southwestward toward the middle Mississippi into Ohio Valleys, deep-layer mean wind fields are likely to be weaker, but shear beneath west-northwesterly mid-level flow may still support potential for organized thunderstorm development, in the presence of a seasonably moist boundary-layer becoming characterized by sizable CAPE with daytime heating. Forcing for this activity remains unclear, and probably will hinge on convectively generated or augmented perturbations migrating around the northern periphery of mid/upper ridging encompassing much of the central and southern tier of the U.S. to the east of the Rockies. ...Lee of the northern Rockies... Downstream of the digging mid/upper troughing across the Northwest, moisture return to deepening lee surface troughing is forecast to contribute to at least a narrow corridor of moderate to large mixed-layer CAPE, in the presence of steep lower/mid-tropospheric lapse rates. Veering of winds with height probably will contribute to sufficient shear for organized thunderstorm development, including supercells, as widely scattered to scattered thunderstorms develop off the higher terrain into the high plains late Saturday afternoon and evening. It is possible that severe weather probabilities could still be increased in later outlooks for this period. ..Kerr.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 2 Convective Outlook

4 days 16 hours ago
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY INTO SATURDAY NIGHT ACROSS PARTS OF EASTERN IOWA...SOUTHERN WISCONSIN...NORTHERN AND CENTRAL ILLINOIS AND INDIANA...CENTRAL AND SOUTHERN LOWER MICHIGAN...NORTHERN AND WESTERN OHIO...PARTS OF NORTHWESTERN PENNSYLVANIA AND WESTERN NEW YORK STATE... ...SUMMARY... Strong thunderstorms, including one or two organizing clusters, are possible across southern portions of the Great Lakes region and adjacent portions of the Ohio Valley Saturday into Saturday night, with more widely scattered strong thunderstorm development across the northern Rockies into adjacent high plains. ...Discussion... Models indicate that at least some amplification to the mid/upper flow across the northern tier of the U.S. is probable during this period. It appears that this will include digging troughing across the Pacific Northwest through northern Rockies, downstream of increasingly prominent ridging building across the northeastern Pacific. Farther east, troughing is forecast to dig across and to the east of the Great Lakes, in advance of significant troughing within a separate branch of westerlies, pivoting southeast of Hudson Bay. In lower levels, the better defined remnants of an ongoing cold frontal intrusion to the lee of the Rockies, perhaps aided by stronger differential surface heating during the day Saturday, may shift east of the middle Mississippi through the lower Ohio Valley. At the same time, a reinforcing intrusion of cooler and drier air is forecast to advance across and south of the Upper Midwest and Great Lakes, probably in the wake of a weak eastward migrating surface low. ...Midwest through Great Lakes/Ohio Valley... Model depictions concerning synoptic and sub-synoptic features, including potential convective evolution remain rather varied. In general, it appears that low-level moistening ahead of the reinforcing cold front will contribute to moderate destabilization as far north as the southern Great Lakes during the day Saturday. On the southern fringe of the stronger westerlies, 30-50 kt flow in the 850-500 mb layer across southern Wisconsin and Lower Michigan into the lower Great Lakes will contribute to potential for organized convective development. This may include a couple of supercells and perhaps an upscale growing cluster. Although mid-level lapse rates may be modest, this may be accompanied by some risk for hail, in addition to strong to severe surface gusts and perhaps a tornado or two. Southwestward toward the middle Mississippi into Ohio Valleys, deep-layer mean wind fields are likely to be weaker, but shear beneath west-northwesterly mid-level flow may still support potential for organized thunderstorm development, in the presence of a seasonably moist boundary-layer becoming characterized by sizable CAPE with daytime heating. Forcing for this activity remains unclear, and probably will hinge on convectively generated or augmented perturbations migrating around the northern periphery of mid/upper ridging encompassing much of the central and southern tier of the U.S. to the east of the Rockies. ...Lee of the northern Rockies... Downstream of the digging mid/upper troughing across the Northwest, moisture return to deepening lee surface troughing is forecast to contribute to at least a narrow corridor of moderate to large mixed-layer CAPE, in the presence of steep lower/mid-tropospheric lapse rates. Veering of winds with height probably will contribute to sufficient shear for organized thunderstorm development, including supercells, as widely scattered to scattered thunderstorms develop off the higher terrain into the high plains late Saturday afternoon and evening. It is possible that severe weather probabilities could still be increased in later outlooks for this period. ..Kerr.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 1 Convective Outlook

4 days 16 hours ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Fri Jul 18 2025 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF VA/NC AND NE/SD/MN/IA... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a few tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and northern North Carolina this afternoon. ...SD/MN/IA/NE... A low-amplitude shortwave impulse along the international border over the northern Great Plains will progress across the Upper Midwest/Great Lakes and ON. A belt of seasonably strong mid-level westerlies should be centered this afternoon from central MN to Lake Huron. Elevated convection is expected to be ongoing at 12Z across parts of the eastern Dakotas into northern MN ahead of the mid-level impulse, amid a low-level warm theta-e advection regime. As this overspreads a preceding cool/dry surface airmass over the Upper Midwest, pronounced differential diabatic surface heating will strengthen a baroclinic zone across southeast SD bisecting IA to the southeast by late afternoon. Thunderstorm development in this time frame should be confined to along/northeast of the surface warm front across far eastern SD and southern MN. Large-scale ascent appears nebulous, but a strengthening low-level jet should aid in convection flanking to the southwest across the Mid-MO Valley during the evening. This may merge with high-based convection shifting east from western NE. Deep-layer shear will be sufficient for initial supercells that will probably grow upscale into multiple clusters and/or an MCS tonight. The latter may accelerate east-southeast for a time in the western IA vicinity before weakening during the early morning. A mix of all severe hazards are possible in this setup with hail being favored early and wind later. Moderately enlarged low-level hodographs should also support a tornado threat with any sustained supercell to QLCS evolution. ...VA/NC... 00Z HREF guidance supports scattered to numerous thunderstorms this afternoon with transient organizational structures that should be sufficient for a scattered damaging wind threat. This appears to be largely in response to the eastward progression of an MCV currently near the IN/OH/KY border. A compact belt of enhanced mid-level westerlies should overspread the northern periphery of ample MLCAPE emanating from the South Atlantic Coastal Plain. Multicell clusters that can progress towards a warmer/deeper boundary layer across the Piedmont and Coastal Plain should produce strong to sporadic severe gusts through early evening. ..Grams/Wendt.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 1 Convective Outlook

4 days 16 hours ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Fri Jul 18 2025 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF VA/NC AND NE/SD/MN/IA... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a few tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and northern North Carolina this afternoon. ...SD/MN/IA/NE... A low-amplitude shortwave impulse along the international border over the northern Great Plains will progress across the Upper Midwest/Great Lakes and ON. A belt of seasonably strong mid-level westerlies should be centered this afternoon from central MN to Lake Huron. Elevated convection is expected to be ongoing at 12Z across parts of the eastern Dakotas into northern MN ahead of the mid-level impulse, amid a low-level warm theta-e advection regime. As this overspreads a preceding cool/dry surface airmass over the Upper Midwest, pronounced differential diabatic surface heating will strengthen a baroclinic zone across southeast SD bisecting IA to the southeast by late afternoon. Thunderstorm development in this time frame should be confined to along/northeast of the surface warm front across far eastern SD and southern MN. Large-scale ascent appears nebulous, but a strengthening low-level jet should aid in convection flanking to the southwest across the Mid-MO Valley during the evening. This may merge with high-based convection shifting east from western NE. Deep-layer shear will be sufficient for initial supercells that will probably grow upscale into multiple clusters and/or an MCS tonight. The latter may accelerate east-southeast for a time in the western IA vicinity before weakening during the early morning. A mix of all severe hazards are possible in this setup with hail being favored early and wind later. Moderately enlarged low-level hodographs should also support a tornado threat with any sustained supercell to QLCS evolution. ...VA/NC... 00Z HREF guidance supports scattered to numerous thunderstorms this afternoon with transient organizational structures that should be sufficient for a scattered damaging wind threat. This appears to be largely in response to the eastward progression of an MCV currently near the IN/OH/KY border. A compact belt of enhanced mid-level westerlies should overspread the northern periphery of ample MLCAPE emanating from the South Atlantic Coastal Plain. Multicell clusters that can progress towards a warmer/deeper boundary layer across the Piedmont and Coastal Plain should produce strong to sporadic severe gusts through early evening. ..Grams/Wendt.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 1 Convective Outlook

4 days 16 hours ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Fri Jul 18 2025 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF VA/NC AND NE/SD/MN/IA... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a few tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and northern North Carolina this afternoon. ...SD/MN/IA/NE... A low-amplitude shortwave impulse along the international border over the northern Great Plains will progress across the Upper Midwest/Great Lakes and ON. A belt of seasonably strong mid-level westerlies should be centered this afternoon from central MN to Lake Huron. Elevated convection is expected to be ongoing at 12Z across parts of the eastern Dakotas into northern MN ahead of the mid-level impulse, amid a low-level warm theta-e advection regime. As this overspreads a preceding cool/dry surface airmass over the Upper Midwest, pronounced differential diabatic surface heating will strengthen a baroclinic zone across southeast SD bisecting IA to the southeast by late afternoon. Thunderstorm development in this time frame should be confined to along/northeast of the surface warm front across far eastern SD and southern MN. Large-scale ascent appears nebulous, but a strengthening low-level jet should aid in convection flanking to the southwest across the Mid-MO Valley during the evening. This may merge with high-based convection shifting east from western NE. Deep-layer shear will be sufficient for initial supercells that will probably grow upscale into multiple clusters and/or an MCS tonight. The latter may accelerate east-southeast for a time in the western IA vicinity before weakening during the early morning. A mix of all severe hazards are possible in this setup with hail being favored early and wind later. Moderately enlarged low-level hodographs should also support a tornado threat with any sustained supercell to QLCS evolution. ...VA/NC... 00Z HREF guidance supports scattered to numerous thunderstorms this afternoon with transient organizational structures that should be sufficient for a scattered damaging wind threat. This appears to be largely in response to the eastward progression of an MCV currently near the IN/OH/KY border. A compact belt of enhanced mid-level westerlies should overspread the northern periphery of ample MLCAPE emanating from the South Atlantic Coastal Plain. Multicell clusters that can progress towards a warmer/deeper boundary layer across the Piedmont and Coastal Plain should produce strong to sporadic severe gusts through early evening. ..Grams/Wendt.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 1 Convective Outlook

4 days 16 hours ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Fri Jul 18 2025 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF VA/NC AND NE/SD/MN/IA... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a few tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and northern North Carolina this afternoon. ...SD/MN/IA/NE... A low-amplitude shortwave impulse along the international border over the northern Great Plains will progress across the Upper Midwest/Great Lakes and ON. A belt of seasonably strong mid-level westerlies should be centered this afternoon from central MN to Lake Huron. Elevated convection is expected to be ongoing at 12Z across parts of the eastern Dakotas into northern MN ahead of the mid-level impulse, amid a low-level warm theta-e advection regime. As this overspreads a preceding cool/dry surface airmass over the Upper Midwest, pronounced differential diabatic surface heating will strengthen a baroclinic zone across southeast SD bisecting IA to the southeast by late afternoon. Thunderstorm development in this time frame should be confined to along/northeast of the surface warm front across far eastern SD and southern MN. Large-scale ascent appears nebulous, but a strengthening low-level jet should aid in convection flanking to the southwest across the Mid-MO Valley during the evening. This may merge with high-based convection shifting east from western NE. Deep-layer shear will be sufficient for initial supercells that will probably grow upscale into multiple clusters and/or an MCS tonight. The latter may accelerate east-southeast for a time in the western IA vicinity before weakening during the early morning. A mix of all severe hazards are possible in this setup with hail being favored early and wind later. Moderately enlarged low-level hodographs should also support a tornado threat with any sustained supercell to QLCS evolution. ...VA/NC... 00Z HREF guidance supports scattered to numerous thunderstorms this afternoon with transient organizational structures that should be sufficient for a scattered damaging wind threat. This appears to be largely in response to the eastward progression of an MCV currently near the IN/OH/KY border. A compact belt of enhanced mid-level westerlies should overspread the northern periphery of ample MLCAPE emanating from the South Atlantic Coastal Plain. Multicell clusters that can progress towards a warmer/deeper boundary layer across the Piedmont and Coastal Plain should produce strong to sporadic severe gusts through early evening. ..Grams/Wendt.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 1 Convective Outlook

4 days 16 hours ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Fri Jul 18 2025 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF VA/NC AND NE/SD/MN/IA... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a few tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and northern North Carolina this afternoon. ...SD/MN/IA/NE... A low-amplitude shortwave impulse along the international border over the northern Great Plains will progress across the Upper Midwest/Great Lakes and ON. A belt of seasonably strong mid-level westerlies should be centered this afternoon from central MN to Lake Huron. Elevated convection is expected to be ongoing at 12Z across parts of the eastern Dakotas into northern MN ahead of the mid-level impulse, amid a low-level warm theta-e advection regime. As this overspreads a preceding cool/dry surface airmass over the Upper Midwest, pronounced differential diabatic surface heating will strengthen a baroclinic zone across southeast SD bisecting IA to the southeast by late afternoon. Thunderstorm development in this time frame should be confined to along/northeast of the surface warm front across far eastern SD and southern MN. Large-scale ascent appears nebulous, but a strengthening low-level jet should aid in convection flanking to the southwest across the Mid-MO Valley during the evening. This may merge with high-based convection shifting east from western NE. Deep-layer shear will be sufficient for initial supercells that will probably grow upscale into multiple clusters and/or an MCS tonight. The latter may accelerate east-southeast for a time in the western IA vicinity before weakening during the early morning. A mix of all severe hazards are possible in this setup with hail being favored early and wind later. Moderately enlarged low-level hodographs should also support a tornado threat with any sustained supercell to QLCS evolution. ...VA/NC... 00Z HREF guidance supports scattered to numerous thunderstorms this afternoon with transient organizational structures that should be sufficient for a scattered damaging wind threat. This appears to be largely in response to the eastward progression of an MCV currently near the IN/OH/KY border. A compact belt of enhanced mid-level westerlies should overspread the northern periphery of ample MLCAPE emanating from the South Atlantic Coastal Plain. Multicell clusters that can progress towards a warmer/deeper boundary layer across the Piedmont and Coastal Plain should produce strong to sporadic severe gusts through early evening. ..Grams/Wendt.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 1 Convective Outlook

4 days 16 hours ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Fri Jul 18 2025 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF VA/NC AND NE/SD/MN/IA... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a few tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and northern North Carolina this afternoon. ...SD/MN/IA/NE... A low-amplitude shortwave impulse along the international border over the northern Great Plains will progress across the Upper Midwest/Great Lakes and ON. A belt of seasonably strong mid-level westerlies should be centered this afternoon from central MN to Lake Huron. Elevated convection is expected to be ongoing at 12Z across parts of the eastern Dakotas into northern MN ahead of the mid-level impulse, amid a low-level warm theta-e advection regime. As this overspreads a preceding cool/dry surface airmass over the Upper Midwest, pronounced differential diabatic surface heating will strengthen a baroclinic zone across southeast SD bisecting IA to the southeast by late afternoon. Thunderstorm development in this time frame should be confined to along/northeast of the surface warm front across far eastern SD and southern MN. Large-scale ascent appears nebulous, but a strengthening low-level jet should aid in convection flanking to the southwest across the Mid-MO Valley during the evening. This may merge with high-based convection shifting east from western NE. Deep-layer shear will be sufficient for initial supercells that will probably grow upscale into multiple clusters and/or an MCS tonight. The latter may accelerate east-southeast for a time in the western IA vicinity before weakening during the early morning. A mix of all severe hazards are possible in this setup with hail being favored early and wind later. Moderately enlarged low-level hodographs should also support a tornado threat with any sustained supercell to QLCS evolution. ...VA/NC... 00Z HREF guidance supports scattered to numerous thunderstorms this afternoon with transient organizational structures that should be sufficient for a scattered damaging wind threat. This appears to be largely in response to the eastward progression of an MCV currently near the IN/OH/KY border. A compact belt of enhanced mid-level westerlies should overspread the northern periphery of ample MLCAPE emanating from the South Atlantic Coastal Plain. Multicell clusters that can progress towards a warmer/deeper boundary layer across the Piedmont and Coastal Plain should produce strong to sporadic severe gusts through early evening. ..Grams/Wendt.. 07/18/2025 Read more

SPC Jul 18, 2025 0600 UTC Day 1 Convective Outlook

4 days 16 hours ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Fri Jul 18 2025 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF VA/NC AND NE/SD/MN/IA... ...SUMMARY... Scattered severe thunderstorms with large hail, damaging winds, and a few tornadoes are possible across parts of the Corn Belt in Iowa, Minnesota, Nebraska, and South Dakota this evening into tonight. Scattered damaging winds are possible across parts of Virginia and northern North Carolina this afternoon. ...SD/MN/IA/NE... A low-amplitude shortwave impulse along the international border over the northern Great Plains will progress across the Upper Midwest/Great Lakes and ON. A belt of seasonably strong mid-level westerlies should be centered this afternoon from central MN to Lake Huron. Elevated convection is expected to be ongoing at 12Z across parts of the eastern Dakotas into northern MN ahead of the mid-level impulse, amid a low-level warm theta-e advection regime. As this overspreads a preceding cool/dry surface airmass over the Upper Midwest, pronounced differential diabatic surface heating will strengthen a baroclinic zone across southeast SD bisecting IA to the southeast by late afternoon. Thunderstorm development in this time frame should be confined to along/northeast of the surface warm front across far eastern SD and southern MN. Large-scale ascent appears nebulous, but a strengthening low-level jet should aid in convection flanking to the southwest across the Mid-MO Valley during the evening. This may merge with high-based convection shifting east from western NE. Deep-layer shear will be sufficient for initial supercells that will probably grow upscale into multiple clusters and/or an MCS tonight. The latter may accelerate east-southeast for a time in the western IA vicinity before weakening during the early morning. A mix of all severe hazards are possible in this setup with hail being favored early and wind later. Moderately enlarged low-level hodographs should also support a tornado threat with any sustained supercell to QLCS evolution. ...VA/NC... 00Z HREF guidance supports scattered to numerous thunderstorms this afternoon with transient organizational structures that should be sufficient for a scattered damaging wind threat. This appears to be largely in response to the eastward progression of an MCV currently near the IN/OH/KY border. A compact belt of enhanced mid-level westerlies should overspread the northern periphery of ample MLCAPE emanating from the South Atlantic Coastal Plain. Multicell clusters that can progress towards a warmer/deeper boundary layer across the Piedmont and Coastal Plain should produce strong to sporadic severe gusts through early evening. ..Grams/Wendt.. 07/18/2025 Read more

SPC Day 2 Fire Weather Outlook

4 days 16 hours ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1218 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...Synopsis... A low-amplitude upper level trough will pivot through the Northwest on Saturday. In the lee of the northern Rockies, a surface low will deepen in central Montana. Mid-level moisture will be pushed slightly southward and eastward by the sagging upper trough in the Northwest. Additional thunderstorms are possible in the parts of the central/eastern Great Basin. However, PWAT values and slower storm motions do not suggest a significant threat for new ignitions. ...Columbia Basin and northern Nevada/southern Idaho... Elevated fire weather conditions are again expected in the Columbia Basin. With the core of the mid-level jet primarily being east of the region by the afternoon, the overall setup should favor slightly less strong wind coverage. Winds of 15-20 mph are still possible. RH may be a touch higher than on Friday with around 20% being probable during the afternoon. With the trough sagging southward and the surface low deepening, a zone of 15-20 mph (locally higher) winds is possible in parts of the northern Great Basin. RH could fall as low as 10-15% by the afternoon. ..Wendt.. 07/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

4 days 16 hours ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1218 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...Synopsis... A low-amplitude upper level trough will pivot through the Northwest on Saturday. In the lee of the northern Rockies, a surface low will deepen in central Montana. Mid-level moisture will be pushed slightly southward and eastward by the sagging upper trough in the Northwest. Additional thunderstorms are possible in the parts of the central/eastern Great Basin. However, PWAT values and slower storm motions do not suggest a significant threat for new ignitions. ...Columbia Basin and northern Nevada/southern Idaho... Elevated fire weather conditions are again expected in the Columbia Basin. With the core of the mid-level jet primarily being east of the region by the afternoon, the overall setup should favor slightly less strong wind coverage. Winds of 15-20 mph are still possible. RH may be a touch higher than on Friday with around 20% being probable during the afternoon. With the trough sagging southward and the surface low deepening, a zone of 15-20 mph (locally higher) winds is possible in parts of the northern Great Basin. RH could fall as low as 10-15% by the afternoon. ..Wendt.. 07/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

4 days 16 hours ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1218 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...Synopsis... A low-amplitude upper level trough will pivot through the Northwest on Saturday. In the lee of the northern Rockies, a surface low will deepen in central Montana. Mid-level moisture will be pushed slightly southward and eastward by the sagging upper trough in the Northwest. Additional thunderstorms are possible in the parts of the central/eastern Great Basin. However, PWAT values and slower storm motions do not suggest a significant threat for new ignitions. ...Columbia Basin and northern Nevada/southern Idaho... Elevated fire weather conditions are again expected in the Columbia Basin. With the core of the mid-level jet primarily being east of the region by the afternoon, the overall setup should favor slightly less strong wind coverage. Winds of 15-20 mph are still possible. RH may be a touch higher than on Friday with around 20% being probable during the afternoon. With the trough sagging southward and the surface low deepening, a zone of 15-20 mph (locally higher) winds is possible in parts of the northern Great Basin. RH could fall as low as 10-15% by the afternoon. ..Wendt.. 07/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

4 days 16 hours ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1218 AM CDT Fri Jul 18 2025 Valid 191200Z - 201200Z ...Synopsis... A low-amplitude upper level trough will pivot through the Northwest on Saturday. In the lee of the northern Rockies, a surface low will deepen in central Montana. Mid-level moisture will be pushed slightly southward and eastward by the sagging upper trough in the Northwest. Additional thunderstorms are possible in the parts of the central/eastern Great Basin. However, PWAT values and slower storm motions do not suggest a significant threat for new ignitions. ...Columbia Basin and northern Nevada/southern Idaho... Elevated fire weather conditions are again expected in the Columbia Basin. With the core of the mid-level jet primarily being east of the region by the afternoon, the overall setup should favor slightly less strong wind coverage. Winds of 15-20 mph are still possible. RH may be a touch higher than on Friday with around 20% being probable during the afternoon. With the trough sagging southward and the surface low deepening, a zone of 15-20 mph (locally higher) winds is possible in parts of the northern Great Basin. RH could fall as low as 10-15% by the afternoon. ..Wendt.. 07/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more