Severe Storms

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0316 AM CDT Mon Sep 01 2025 Valid 041200Z - 091200Z ...DISCUSSION... A pronounced mid-level trough will gradually advance eastward across the eastern U.S. through the remainder of the week into this weekend, with multiple embedded mid-level perturbations expected to pivot around the upper trough. The upper trough and associated impulses will reinforce surface high pressure and cooler air across much of the U.S. between the Mississippi River and Appalachians through the extended forecast period. The surface cold front will encounter seasonably rich low-level moisture while encroaching on the Eastern Seaboard, prompting the development of at least scattered thunderstorms. At the moment, the best chance for strong storms, perhaps accompanied by an isolated severe threat, will be along the central and northern Appalachians into the Mid Atlantic within the Days 4-6 (Thursday-Saturday) time frame. Meanwhile, as surface high pressure builds over the OH/TN Valley regions, and the Interior West, seasonal moisture return is expected across parts of the southern Plains due to surface lee troughing. The aforementioned impulses pivoting around the broader scale upper trough may graze the southern Plains, perhaps promoting enough vertical wind shear atop a moist low-level airmass to support isolated severe thunderstorms Days 4-6 (Thursday-Saturday). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0316 AM CDT Mon Sep 01 2025 Valid 041200Z - 091200Z ...DISCUSSION... A pronounced mid-level trough will gradually advance eastward across the eastern U.S. through the remainder of the week into this weekend, with multiple embedded mid-level perturbations expected to pivot around the upper trough. The upper trough and associated impulses will reinforce surface high pressure and cooler air across much of the U.S. between the Mississippi River and Appalachians through the extended forecast period. The surface cold front will encounter seasonably rich low-level moisture while encroaching on the Eastern Seaboard, prompting the development of at least scattered thunderstorms. At the moment, the best chance for strong storms, perhaps accompanied by an isolated severe threat, will be along the central and northern Appalachians into the Mid Atlantic within the Days 4-6 (Thursday-Saturday) time frame. Meanwhile, as surface high pressure builds over the OH/TN Valley regions, and the Interior West, seasonal moisture return is expected across parts of the southern Plains due to surface lee troughing. The aforementioned impulses pivoting around the broader scale upper trough may graze the southern Plains, perhaps promoting enough vertical wind shear atop a moist low-level airmass to support isolated severe thunderstorms Days 4-6 (Thursday-Saturday). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0316 AM CDT Mon Sep 01 2025 Valid 041200Z - 091200Z ...DISCUSSION... A pronounced mid-level trough will gradually advance eastward across the eastern U.S. through the remainder of the week into this weekend, with multiple embedded mid-level perturbations expected to pivot around the upper trough. The upper trough and associated impulses will reinforce surface high pressure and cooler air across much of the U.S. between the Mississippi River and Appalachians through the extended forecast period. The surface cold front will encounter seasonably rich low-level moisture while encroaching on the Eastern Seaboard, prompting the development of at least scattered thunderstorms. At the moment, the best chance for strong storms, perhaps accompanied by an isolated severe threat, will be along the central and northern Appalachians into the Mid Atlantic within the Days 4-6 (Thursday-Saturday) time frame. Meanwhile, as surface high pressure builds over the OH/TN Valley regions, and the Interior West, seasonal moisture return is expected across parts of the southern Plains due to surface lee troughing. The aforementioned impulses pivoting around the broader scale upper trough may graze the southern Plains, perhaps promoting enough vertical wind shear atop a moist low-level airmass to support isolated severe thunderstorms Days 4-6 (Thursday-Saturday). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0316 AM CDT Mon Sep 01 2025 Valid 041200Z - 091200Z ...DISCUSSION... A pronounced mid-level trough will gradually advance eastward across the eastern U.S. through the remainder of the week into this weekend, with multiple embedded mid-level perturbations expected to pivot around the upper trough. The upper trough and associated impulses will reinforce surface high pressure and cooler air across much of the U.S. between the Mississippi River and Appalachians through the extended forecast period. The surface cold front will encounter seasonably rich low-level moisture while encroaching on the Eastern Seaboard, prompting the development of at least scattered thunderstorms. At the moment, the best chance for strong storms, perhaps accompanied by an isolated severe threat, will be along the central and northern Appalachians into the Mid Atlantic within the Days 4-6 (Thursday-Saturday) time frame. Meanwhile, as surface high pressure builds over the OH/TN Valley regions, and the Interior West, seasonal moisture return is expected across parts of the southern Plains due to surface lee troughing. The aforementioned impulses pivoting around the broader scale upper trough may graze the southern Plains, perhaps promoting enough vertical wind shear atop a moist low-level airmass to support isolated severe thunderstorms Days 4-6 (Thursday-Saturday). Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0316 AM CDT Mon Sep 01 2025 Valid 041200Z - 091200Z ...DISCUSSION... A pronounced mid-level trough will gradually advance eastward across the eastern U.S. through the remainder of the week into this weekend, with multiple embedded mid-level perturbations expected to pivot around the upper trough. The upper trough and associated impulses will reinforce surface high pressure and cooler air across much of the U.S. between the Mississippi River and Appalachians through the extended forecast period. The surface cold front will encounter seasonably rich low-level moisture while encroaching on the Eastern Seaboard, prompting the development of at least scattered thunderstorms. At the moment, the best chance for strong storms, perhaps accompanied by an isolated severe threat, will be along the central and northern Appalachians into the Mid Atlantic within the Days 4-6 (Thursday-Saturday) time frame. Meanwhile, as surface high pressure builds over the OH/TN Valley regions, and the Interior West, seasonal moisture return is expected across parts of the southern Plains due to surface lee troughing. The aforementioned impulses pivoting around the broader scale upper trough may graze the southern Plains, perhaps promoting enough vertical wind shear atop a moist low-level airmass to support isolated severe thunderstorms Days 4-6 (Thursday-Saturday). Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated severe storms are possible over portions of the central Plains on Wednesday. ...Synopsis... A mid-level trough will deepen while also taken on a more neutral tilt over the Midwest as upper ridging persists west of the Rockies on Wednesday. The deepening mid-level trough will encourage the continued southward progression of a surface cold front over the central Plains into the OH Valley. Seasonal low-level moisture ahead of the front will promote buoyancy to support thunderstorms, which should develop with the aid of low-level frontal convergence. Since stronger northwesterly flow aloft will begin to overspread the pre-frontal airmass and support adequate vertical wind shear aloft, isolated severe thunderstorms are possible across parts of the central Plains. ...Portions of the Central Plains... By afternoon, surface temperatures should warm well into the 70s F amid mid 60s F dewpoints, which when overspread by 7+ C/km mid-level lapse rates, will yield over 2000 J/kg MLCAPE, especially over eastern KS. Winds will gradually veer with height, from southwest to northwest through the boundary layer, then increase from 20 kts around 700 mb, to about 40 kts in the 500-300 mb layer. This profile will support modestly elongated and curved hodographs and 40-50 kts of effective bulk shear. The stronger storms that develop ahead of the cold front will likely be mixed modal between multicells and supercells, capable of at least isolated severe hail and wind. Category 1/Marginal Risk severe probabilities have been introduced, though higher probabilities may be needed if it becomes clear that more sustained supercells can materialize over eastern KS. ..Squitieri.. 09/01/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated severe storms are possible over portions of the central Plains on Wednesday. ...Synopsis... A mid-level trough will deepen while also taken on a more neutral tilt over the Midwest as upper ridging persists west of the Rockies on Wednesday. The deepening mid-level trough will encourage the continued southward progression of a surface cold front over the central Plains into the OH Valley. Seasonal low-level moisture ahead of the front will promote buoyancy to support thunderstorms, which should develop with the aid of low-level frontal convergence. Since stronger northwesterly flow aloft will begin to overspread the pre-frontal airmass and support adequate vertical wind shear aloft, isolated severe thunderstorms are possible across parts of the central Plains. ...Portions of the Central Plains... By afternoon, surface temperatures should warm well into the 70s F amid mid 60s F dewpoints, which when overspread by 7+ C/km mid-level lapse rates, will yield over 2000 J/kg MLCAPE, especially over eastern KS. Winds will gradually veer with height, from southwest to northwest through the boundary layer, then increase from 20 kts around 700 mb, to about 40 kts in the 500-300 mb layer. This profile will support modestly elongated and curved hodographs and 40-50 kts of effective bulk shear. The stronger storms that develop ahead of the cold front will likely be mixed modal between multicells and supercells, capable of at least isolated severe hail and wind. Category 1/Marginal Risk severe probabilities have been introduced, though higher probabilities may be needed if it becomes clear that more sustained supercells can materialize over eastern KS. ..Squitieri.. 09/01/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated severe storms are possible over portions of the central Plains on Wednesday. ...Synopsis... A mid-level trough will deepen while also taken on a more neutral tilt over the Midwest as upper ridging persists west of the Rockies on Wednesday. The deepening mid-level trough will encourage the continued southward progression of a surface cold front over the central Plains into the OH Valley. Seasonal low-level moisture ahead of the front will promote buoyancy to support thunderstorms, which should develop with the aid of low-level frontal convergence. Since stronger northwesterly flow aloft will begin to overspread the pre-frontal airmass and support adequate vertical wind shear aloft, isolated severe thunderstorms are possible across parts of the central Plains. ...Portions of the Central Plains... By afternoon, surface temperatures should warm well into the 70s F amid mid 60s F dewpoints, which when overspread by 7+ C/km mid-level lapse rates, will yield over 2000 J/kg MLCAPE, especially over eastern KS. Winds will gradually veer with height, from southwest to northwest through the boundary layer, then increase from 20 kts around 700 mb, to about 40 kts in the 500-300 mb layer. This profile will support modestly elongated and curved hodographs and 40-50 kts of effective bulk shear. The stronger storms that develop ahead of the cold front will likely be mixed modal between multicells and supercells, capable of at least isolated severe hail and wind. Category 1/Marginal Risk severe probabilities have been introduced, though higher probabilities may be needed if it becomes clear that more sustained supercells can materialize over eastern KS. ..Squitieri.. 09/01/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated severe storms are possible over portions of the central Plains on Wednesday. ...Synopsis... A mid-level trough will deepen while also taken on a more neutral tilt over the Midwest as upper ridging persists west of the Rockies on Wednesday. The deepening mid-level trough will encourage the continued southward progression of a surface cold front over the central Plains into the OH Valley. Seasonal low-level moisture ahead of the front will promote buoyancy to support thunderstorms, which should develop with the aid of low-level frontal convergence. Since stronger northwesterly flow aloft will begin to overspread the pre-frontal airmass and support adequate vertical wind shear aloft, isolated severe thunderstorms are possible across parts of the central Plains. ...Portions of the Central Plains... By afternoon, surface temperatures should warm well into the 70s F amid mid 60s F dewpoints, which when overspread by 7+ C/km mid-level lapse rates, will yield over 2000 J/kg MLCAPE, especially over eastern KS. Winds will gradually veer with height, from southwest to northwest through the boundary layer, then increase from 20 kts around 700 mb, to about 40 kts in the 500-300 mb layer. This profile will support modestly elongated and curved hodographs and 40-50 kts of effective bulk shear. The stronger storms that develop ahead of the cold front will likely be mixed modal between multicells and supercells, capable of at least isolated severe hail and wind. Category 1/Marginal Risk severe probabilities have been introduced, though higher probabilities may be needed if it becomes clear that more sustained supercells can materialize over eastern KS. ..Squitieri.. 09/01/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated severe storms are possible over portions of the central Plains on Wednesday. ...Synopsis... A mid-level trough will deepen while also taken on a more neutral tilt over the Midwest as upper ridging persists west of the Rockies on Wednesday. The deepening mid-level trough will encourage the continued southward progression of a surface cold front over the central Plains into the OH Valley. Seasonal low-level moisture ahead of the front will promote buoyancy to support thunderstorms, which should develop with the aid of low-level frontal convergence. Since stronger northwesterly flow aloft will begin to overspread the pre-frontal airmass and support adequate vertical wind shear aloft, isolated severe thunderstorms are possible across parts of the central Plains. ...Portions of the Central Plains... By afternoon, surface temperatures should warm well into the 70s F amid mid 60s F dewpoints, which when overspread by 7+ C/km mid-level lapse rates, will yield over 2000 J/kg MLCAPE, especially over eastern KS. Winds will gradually veer with height, from southwest to northwest through the boundary layer, then increase from 20 kts around 700 mb, to about 40 kts in the 500-300 mb layer. This profile will support modestly elongated and curved hodographs and 40-50 kts of effective bulk shear. The stronger storms that develop ahead of the cold front will likely be mixed modal between multicells and supercells, capable of at least isolated severe hail and wind. Category 1/Marginal Risk severe probabilities have been introduced, though higher probabilities may be needed if it becomes clear that more sustained supercells can materialize over eastern KS. ..Squitieri.. 09/01/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Mon Sep 01 2025 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated severe storms are possible over portions of the central Plains on Wednesday. ...Synopsis... A mid-level trough will deepen while also taken on a more neutral tilt over the Midwest as upper ridging persists west of the Rockies on Wednesday. The deepening mid-level trough will encourage the continued southward progression of a surface cold front over the central Plains into the OH Valley. Seasonal low-level moisture ahead of the front will promote buoyancy to support thunderstorms, which should develop with the aid of low-level frontal convergence. Since stronger northwesterly flow aloft will begin to overspread the pre-frontal airmass and support adequate vertical wind shear aloft, isolated severe thunderstorms are possible across parts of the central Plains. ...Portions of the Central Plains... By afternoon, surface temperatures should warm well into the 70s F amid mid 60s F dewpoints, which when overspread by 7+ C/km mid-level lapse rates, will yield over 2000 J/kg MLCAPE, especially over eastern KS. Winds will gradually veer with height, from southwest to northwest through the boundary layer, then increase from 20 kts around 700 mb, to about 40 kts in the 500-300 mb layer. This profile will support modestly elongated and curved hodographs and 40-50 kts of effective bulk shear. The stronger storms that develop ahead of the cold front will likely be mixed modal between multicells and supercells, capable of at least isolated severe hail and wind. Category 1/Marginal Risk severe probabilities have been introduced, though higher probabilities may be needed if it becomes clear that more sustained supercells can materialize over eastern KS. ..Squitieri.. 09/01/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS INTO THE UPPER MIDWEST... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the northern Plains into the Upper Midwest tomorrow (Tuesday). ...Synopsis... Broad cyclonic mid-level flow will persist along the Eastern Seaboard while upper ridging continues west of the Rockies, with the central U.S. placed under a northwesterly upper-flow regime tomorrow (Tuesday). A large and pronounced embedded mid-level shortwave will quickly translate southeastward from Canada and overspread the Upper MS Valley through the day, encouraging a surface cold front to surge southward across the northern Plains and Upper Midwest. Thunderstorms will develop ahead of the cold front, a few of which may be severe. ...Northern Plains into the Upper Midwest... Preceding the cold front will be a warm and seasonally moist airmass, overspread by 6.5-7.5 C/km mid-level lapse rates, yielding MLCAPE peaking in the 1500-2000 J/kg range by afternoon. Strengthening northwest flow with height will also yield modestly curved and elongated hodographs and 35+ kts of speed/effective bulk shear. These conditions will favor the development of multicells and perhaps a transient supercell with the stronger updrafts that manage to form ahead of the cold front. Isolated severe gusts or instances of hail are plausible, warranting the introduction of Category 1/Marginal risk severe probabilities this outlook. ..Squitieri.. 09/01/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS INTO THE UPPER MIDWEST... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the northern Plains into the Upper Midwest tomorrow (Tuesday). ...Synopsis... Broad cyclonic mid-level flow will persist along the Eastern Seaboard while upper ridging continues west of the Rockies, with the central U.S. placed under a northwesterly upper-flow regime tomorrow (Tuesday). A large and pronounced embedded mid-level shortwave will quickly translate southeastward from Canada and overspread the Upper MS Valley through the day, encouraging a surface cold front to surge southward across the northern Plains and Upper Midwest. Thunderstorms will develop ahead of the cold front, a few of which may be severe. ...Northern Plains into the Upper Midwest... Preceding the cold front will be a warm and seasonally moist airmass, overspread by 6.5-7.5 C/km mid-level lapse rates, yielding MLCAPE peaking in the 1500-2000 J/kg range by afternoon. Strengthening northwest flow with height will also yield modestly curved and elongated hodographs and 35+ kts of speed/effective bulk shear. These conditions will favor the development of multicells and perhaps a transient supercell with the stronger updrafts that manage to form ahead of the cold front. Isolated severe gusts or instances of hail are plausible, warranting the introduction of Category 1/Marginal risk severe probabilities this outlook. ..Squitieri.. 09/01/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS INTO THE UPPER MIDWEST... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the northern Plains into the Upper Midwest tomorrow (Tuesday). ...Synopsis... Broad cyclonic mid-level flow will persist along the Eastern Seaboard while upper ridging continues west of the Rockies, with the central U.S. placed under a northwesterly upper-flow regime tomorrow (Tuesday). A large and pronounced embedded mid-level shortwave will quickly translate southeastward from Canada and overspread the Upper MS Valley through the day, encouraging a surface cold front to surge southward across the northern Plains and Upper Midwest. Thunderstorms will develop ahead of the cold front, a few of which may be severe. ...Northern Plains into the Upper Midwest... Preceding the cold front will be a warm and seasonally moist airmass, overspread by 6.5-7.5 C/km mid-level lapse rates, yielding MLCAPE peaking in the 1500-2000 J/kg range by afternoon. Strengthening northwest flow with height will also yield modestly curved and elongated hodographs and 35+ kts of speed/effective bulk shear. These conditions will favor the development of multicells and perhaps a transient supercell with the stronger updrafts that manage to form ahead of the cold front. Isolated severe gusts or instances of hail are plausible, warranting the introduction of Category 1/Marginal risk severe probabilities this outlook. ..Squitieri.. 09/01/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS INTO THE UPPER MIDWEST... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the northern Plains into the Upper Midwest tomorrow (Tuesday). ...Synopsis... Broad cyclonic mid-level flow will persist along the Eastern Seaboard while upper ridging continues west of the Rockies, with the central U.S. placed under a northwesterly upper-flow regime tomorrow (Tuesday). A large and pronounced embedded mid-level shortwave will quickly translate southeastward from Canada and overspread the Upper MS Valley through the day, encouraging a surface cold front to surge southward across the northern Plains and Upper Midwest. Thunderstorms will develop ahead of the cold front, a few of which may be severe. ...Northern Plains into the Upper Midwest... Preceding the cold front will be a warm and seasonally moist airmass, overspread by 6.5-7.5 C/km mid-level lapse rates, yielding MLCAPE peaking in the 1500-2000 J/kg range by afternoon. Strengthening northwest flow with height will also yield modestly curved and elongated hodographs and 35+ kts of speed/effective bulk shear. These conditions will favor the development of multicells and perhaps a transient supercell with the stronger updrafts that manage to form ahead of the cold front. Isolated severe gusts or instances of hail are plausible, warranting the introduction of Category 1/Marginal risk severe probabilities this outlook. ..Squitieri.. 09/01/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS INTO THE UPPER MIDWEST... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the northern Plains into the Upper Midwest tomorrow (Tuesday). ...Synopsis... Broad cyclonic mid-level flow will persist along the Eastern Seaboard while upper ridging continues west of the Rockies, with the central U.S. placed under a northwesterly upper-flow regime tomorrow (Tuesday). A large and pronounced embedded mid-level shortwave will quickly translate southeastward from Canada and overspread the Upper MS Valley through the day, encouraging a surface cold front to surge southward across the northern Plains and Upper Midwest. Thunderstorms will develop ahead of the cold front, a few of which may be severe. ...Northern Plains into the Upper Midwest... Preceding the cold front will be a warm and seasonally moist airmass, overspread by 6.5-7.5 C/km mid-level lapse rates, yielding MLCAPE peaking in the 1500-2000 J/kg range by afternoon. Strengthening northwest flow with height will also yield modestly curved and elongated hodographs and 35+ kts of speed/effective bulk shear. These conditions will favor the development of multicells and perhaps a transient supercell with the stronger updrafts that manage to form ahead of the cold front. Isolated severe gusts or instances of hail are plausible, warranting the introduction of Category 1/Marginal risk severe probabilities this outlook. ..Squitieri.. 09/01/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CDT Mon Sep 01 2025 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS INTO THE UPPER MIDWEST... ...SUMMARY... Isolated severe thunderstorms are possible across parts of the northern Plains into the Upper Midwest tomorrow (Tuesday). ...Synopsis... Broad cyclonic mid-level flow will persist along the Eastern Seaboard while upper ridging continues west of the Rockies, with the central U.S. placed under a northwesterly upper-flow regime tomorrow (Tuesday). A large and pronounced embedded mid-level shortwave will quickly translate southeastward from Canada and overspread the Upper MS Valley through the day, encouraging a surface cold front to surge southward across the northern Plains and Upper Midwest. Thunderstorms will develop ahead of the cold front, a few of which may be severe. ...Northern Plains into the Upper Midwest... Preceding the cold front will be a warm and seasonally moist airmass, overspread by 6.5-7.5 C/km mid-level lapse rates, yielding MLCAPE peaking in the 1500-2000 J/kg range by afternoon. Strengthening northwest flow with height will also yield modestly curved and elongated hodographs and 35+ kts of speed/effective bulk shear. These conditions will favor the development of multicells and perhaps a transient supercell with the stronger updrafts that manage to form ahead of the cold front. Isolated severe gusts or instances of hail are plausible, warranting the introduction of Category 1/Marginal risk severe probabilities this outlook. ..Squitieri.. 09/01/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1238 AM CDT Mon Sep 01 2025 Valid 011200Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The severe potential appears relatively low today across the continental U.S., though a few strong storms will be possible across parts of the Great Plains. ...DISCUSSION... At mid-levels, a ridge will be in place across the western U.S., with northwesterly flow located from the Rockies eastward to the Appalachians. A north-to-south corridor of low-level moisture will present in the Great Plains, where warming surface heating will contribute to scattered convective initiation. Throughout this airmass, surface dewpoints will be mostly in the 60s with weak instability developing by afternoon. Minimal deep-layer shear, poor lapse rates and a lack of large-scale ascent will limit the severe weather potential. Further west into the Pacific Northwest, a mid-level low will remain offshore from the Washington Coast. An axis of instability will develop across western Washington during the day. Isolated thunderstorms will be possible in the afternoon, but the environment should be insufficient for severe storms. Elsewhere across the continental United States, no severe threat is expected. ..Broyles/Moore.. 09/01/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1238 AM CDT Mon Sep 01 2025 Valid 011200Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The severe potential appears relatively low today across the continental U.S., though a few strong storms will be possible across parts of the Great Plains. ...DISCUSSION... At mid-levels, a ridge will be in place across the western U.S., with northwesterly flow located from the Rockies eastward to the Appalachians. A north-to-south corridor of low-level moisture will present in the Great Plains, where warming surface heating will contribute to scattered convective initiation. Throughout this airmass, surface dewpoints will be mostly in the 60s with weak instability developing by afternoon. Minimal deep-layer shear, poor lapse rates and a lack of large-scale ascent will limit the severe weather potential. Further west into the Pacific Northwest, a mid-level low will remain offshore from the Washington Coast. An axis of instability will develop across western Washington during the day. Isolated thunderstorms will be possible in the afternoon, but the environment should be insufficient for severe storms. Elsewhere across the continental United States, no severe threat is expected. ..Broyles/Moore.. 09/01/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1238 AM CDT Mon Sep 01 2025 Valid 011200Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The severe potential appears relatively low today across the continental U.S., though a few strong storms will be possible across parts of the Great Plains. ...DISCUSSION... At mid-levels, a ridge will be in place across the western U.S., with northwesterly flow located from the Rockies eastward to the Appalachians. A north-to-south corridor of low-level moisture will present in the Great Plains, where warming surface heating will contribute to scattered convective initiation. Throughout this airmass, surface dewpoints will be mostly in the 60s with weak instability developing by afternoon. Minimal deep-layer shear, poor lapse rates and a lack of large-scale ascent will limit the severe weather potential. Further west into the Pacific Northwest, a mid-level low will remain offshore from the Washington Coast. An axis of instability will develop across western Washington during the day. Isolated thunderstorms will be possible in the afternoon, but the environment should be insufficient for severe storms. Elsewhere across the continental United States, no severe threat is expected. ..Broyles/Moore.. 09/01/2025 Read more