Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu Sep 04 2025 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO AND TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS... ...SUMMARY... Scattered thunderstorms capable of producing damaging wind gusts and isolated large hail are expected across parts of the Ohio and Tennessee Valleys into the Central Appalachians on Friday. ...Synopsis... A deep/vertically stacked cyclone will move gradually northward across Ontario toward Hudson Bay through the period, as an accompanying midlevel jet streak advances from the Great Lakes into Quebec. Peripheral to the deep cyclone, broad midlevel troughing will persist across much of the eastern CONUS. An accompanying cold front will extend from the Great Lakes region southwestward across the OH Valley into the southern Plains. Given the slowly evolving/amplified upper-level pattern, the cold front will only move gradually east-southeastward through the period. ...Ohio/Tennessee Valleys into the Central Appalachians... Ahead of the cold front, ample diurnal heating amid upper 60s dewpoints will contribute to a moderately unstable (around 2500 J/kg MLCAPE), uncapped pre-convective air mass. Potentially aided by a convectively augmented midlevel impulse approaching the OH Valley from the west, scattered thunderstorms should develop along/immediately ahead of the front during the afternoon into evening/overnight. The aforementioned buoyancy and around 30-40 kt of effective shear should promote convective organization into clusters/small line segments and perhaps transient supercell structures. The stronger/longer-lived storms will be capable of producing damaging wind gusts and isolated severe hail. The best overlap of moderate buoyancy (higher with southward extent) and favorable deep-layer shear (stronger with northward extent) should exist over KY and surrounding states, where a Slight Risk was added. ...Mid-South into the Southern Plains... The cold front will be oriented more west-east over this region, with the stronger deep shear confined to the cool side of the boundary. Additionally, convective initiation may occur later into the evening/overnight hours along the sharpening cold front. Nevertheless, moderate-strong buoyancy aided by steep deep-layer lapse rates will promote strong storms capable of producing locally damaging gusts and sporadic, marginally severe hail. ..Weinman.. 09/04/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Sep 04 2025 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEW YORK INTO THE MID-ATLANTIC AND TENNESSEE VALLEY...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... Isolated damaging winds may occur across parts of New York to the Mid-Atlantic and Tennessee Valley this afternoon. Isolated severe gusts are also possible across parts of the mid Missouri Valley late this afternoon and early evening. ...New York into the Mid-Atlantic and Tennessee Valley... A closed mid/upper-level low will remain centered over Ontario today. Multiple mid-level perturbations will rotate around this feature through the period, including a shortwave trough forecast to advance generally east-northeastward across parts of the central Appalachians/Mid-Atlantic into the Northeast. Showers and thunderstorms are ongoing mainly ahead of a surface cold front from parts of western NY southward to the TN Valley in a low/mid-level moisture plume. Generally clear skies ahead of this activity should allow for ample daytime heating of a modestly moistened low-level airmass. Even so, 12Z observed soundings from BUF, IAD, and RNK/GSO show rather poor mid-level lapse rates, which will likely hinder updraft strength even as weak instability develops this afternoon with continued diurnal heating. Modestly enhanced southwesterly low/mid-level flow should still aid in some thunderstorm organization even with the apparent thermodynamic limitations, with multicells the dominant convective mode. Wherever low-level lapse rates can become steepened, a risk for at least isolated damaging winds remains apparent. Some hail may also occur with the strongest cores across parts of the TN Valley/southern Appalachians where locally greater instability should be present this afternoon. The Marginal Risk has been adjusted for ongoing trends, but the potential for a more focused corridor of scattered severe/damaging winds remains unclear. ...Mid Missouri Valley... A mid-level shortwave trough and attendant strong speed maximum will move quickly southeastward today from central Canada and the northern Plains towards the mid MO Valley and vicinity. Pronounced ascent associated with this jet should encourage convection to develop by late this afternoon across parts of eastern SD and vicinity. While low-level moisture and MLCAPE are both expected to remain very limited, enhanced low/mid-level northwesterly flow may still support some risk for severe gusts with any low-topped convection that can develop and spread quickly southeastward before weakening this evening with the loss of daytime heating. ...Kansas... A sharp cold front will sweep southward across the central Plains tonight. Elevated convection should form to the cool side of this boundary late tonight through early Friday morning given sufficient MUCAPE. Locally strong surface gusts and small hail may accompany this activity amid robust low-level northerlies, but the overall severe potential should remain fairly low given the tendency for convection to be mostly elevated. ...Arizona/Lower Colorado River Valley... Thunderstorms should develop again today across parts of central/southern AZ and the lower CO River Valley, beneath weak mid-level flow and on the periphery of increasing mid-level moisture associated with Tropical Storm Lorena. Weak shear should keep thunderstorms mostly disorganized, but occasional strong/gusty winds may occur where low-level lapse rates can become steepened. ..Gleason/Lyons.. 09/04/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Sep 04 2025 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEW YORK INTO THE MID-ATLANTIC AND TENNESSEE VALLEY...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... Isolated damaging winds may occur across parts of New York to the Mid-Atlantic and Tennessee Valley this afternoon. Isolated severe gusts are also possible across parts of the mid Missouri Valley late this afternoon and early evening. ...New York into the Mid-Atlantic and Tennessee Valley... A closed mid/upper-level low will remain centered over Ontario today. Multiple mid-level perturbations will rotate around this feature through the period, including a shortwave trough forecast to advance generally east-northeastward across parts of the central Appalachians/Mid-Atlantic into the Northeast. Showers and thunderstorms are ongoing mainly ahead of a surface cold front from parts of western NY southward to the TN Valley in a low/mid-level moisture plume. Generally clear skies ahead of this activity should allow for ample daytime heating of a modestly moistened low-level airmass. Even so, 12Z observed soundings from BUF, IAD, and RNK/GSO show rather poor mid-level lapse rates, which will likely hinder updraft strength even as weak instability develops this afternoon with continued diurnal heating. Modestly enhanced southwesterly low/mid-level flow should still aid in some thunderstorm organization even with the apparent thermodynamic limitations, with multicells the dominant convective mode. Wherever low-level lapse rates can become steepened, a risk for at least isolated damaging winds remains apparent. Some hail may also occur with the strongest cores across parts of the TN Valley/southern Appalachians where locally greater instability should be present this afternoon. The Marginal Risk has been adjusted for ongoing trends, but the potential for a more focused corridor of scattered severe/damaging winds remains unclear. ...Mid Missouri Valley... A mid-level shortwave trough and attendant strong speed maximum will move quickly southeastward today from central Canada and the northern Plains towards the mid MO Valley and vicinity. Pronounced ascent associated with this jet should encourage convection to develop by late this afternoon across parts of eastern SD and vicinity. While low-level moisture and MLCAPE are both expected to remain very limited, enhanced low/mid-level northwesterly flow may still support some risk for severe gusts with any low-topped convection that can develop and spread quickly southeastward before weakening this evening with the loss of daytime heating. ...Kansas... A sharp cold front will sweep southward across the central Plains tonight. Elevated convection should form to the cool side of this boundary late tonight through early Friday morning given sufficient MUCAPE. Locally strong surface gusts and small hail may accompany this activity amid robust low-level northerlies, but the overall severe potential should remain fairly low given the tendency for convection to be mostly elevated. ...Arizona/Lower Colorado River Valley... Thunderstorms should develop again today across parts of central/southern AZ and the lower CO River Valley, beneath weak mid-level flow and on the periphery of increasing mid-level moisture associated with Tropical Storm Lorena. Weak shear should keep thunderstorms mostly disorganized, but occasional strong/gusty winds may occur where low-level lapse rates can become steepened. ..Gleason/Lyons.. 09/04/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Sep 04 2025 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEW YORK INTO THE MID-ATLANTIC AND TENNESSEE VALLEY...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... Isolated damaging winds may occur across parts of New York to the Mid-Atlantic and Tennessee Valley this afternoon. Isolated severe gusts are also possible across parts of the mid Missouri Valley late this afternoon and early evening. ...New York into the Mid-Atlantic and Tennessee Valley... A closed mid/upper-level low will remain centered over Ontario today. Multiple mid-level perturbations will rotate around this feature through the period, including a shortwave trough forecast to advance generally east-northeastward across parts of the central Appalachians/Mid-Atlantic into the Northeast. Showers and thunderstorms are ongoing mainly ahead of a surface cold front from parts of western NY southward to the TN Valley in a low/mid-level moisture plume. Generally clear skies ahead of this activity should allow for ample daytime heating of a modestly moistened low-level airmass. Even so, 12Z observed soundings from BUF, IAD, and RNK/GSO show rather poor mid-level lapse rates, which will likely hinder updraft strength even as weak instability develops this afternoon with continued diurnal heating. Modestly enhanced southwesterly low/mid-level flow should still aid in some thunderstorm organization even with the apparent thermodynamic limitations, with multicells the dominant convective mode. Wherever low-level lapse rates can become steepened, a risk for at least isolated damaging winds remains apparent. Some hail may also occur with the strongest cores across parts of the TN Valley/southern Appalachians where locally greater instability should be present this afternoon. The Marginal Risk has been adjusted for ongoing trends, but the potential for a more focused corridor of scattered severe/damaging winds remains unclear. ...Mid Missouri Valley... A mid-level shortwave trough and attendant strong speed maximum will move quickly southeastward today from central Canada and the northern Plains towards the mid MO Valley and vicinity. Pronounced ascent associated with this jet should encourage convection to develop by late this afternoon across parts of eastern SD and vicinity. While low-level moisture and MLCAPE are both expected to remain very limited, enhanced low/mid-level northwesterly flow may still support some risk for severe gusts with any low-topped convection that can develop and spread quickly southeastward before weakening this evening with the loss of daytime heating. ...Kansas... A sharp cold front will sweep southward across the central Plains tonight. Elevated convection should form to the cool side of this boundary late tonight through early Friday morning given sufficient MUCAPE. Locally strong surface gusts and small hail may accompany this activity amid robust low-level northerlies, but the overall severe potential should remain fairly low given the tendency for convection to be mostly elevated. ...Arizona/Lower Colorado River Valley... Thunderstorms should develop again today across parts of central/southern AZ and the lower CO River Valley, beneath weak mid-level flow and on the periphery of increasing mid-level moisture associated with Tropical Storm Lorena. Weak shear should keep thunderstorms mostly disorganized, but occasional strong/gusty winds may occur where low-level lapse rates can become steepened. ..Gleason/Lyons.. 09/04/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Sep 04 2025 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEW YORK INTO THE MID-ATLANTIC AND TENNESSEE VALLEY...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... Isolated damaging winds may occur across parts of New York to the Mid-Atlantic and Tennessee Valley this afternoon. Isolated severe gusts are also possible across parts of the mid Missouri Valley late this afternoon and early evening. ...New York into the Mid-Atlantic and Tennessee Valley... A closed mid/upper-level low will remain centered over Ontario today. Multiple mid-level perturbations will rotate around this feature through the period, including a shortwave trough forecast to advance generally east-northeastward across parts of the central Appalachians/Mid-Atlantic into the Northeast. Showers and thunderstorms are ongoing mainly ahead of a surface cold front from parts of western NY southward to the TN Valley in a low/mid-level moisture plume. Generally clear skies ahead of this activity should allow for ample daytime heating of a modestly moistened low-level airmass. Even so, 12Z observed soundings from BUF, IAD, and RNK/GSO show rather poor mid-level lapse rates, which will likely hinder updraft strength even as weak instability develops this afternoon with continued diurnal heating. Modestly enhanced southwesterly low/mid-level flow should still aid in some thunderstorm organization even with the apparent thermodynamic limitations, with multicells the dominant convective mode. Wherever low-level lapse rates can become steepened, a risk for at least isolated damaging winds remains apparent. Some hail may also occur with the strongest cores across parts of the TN Valley/southern Appalachians where locally greater instability should be present this afternoon. The Marginal Risk has been adjusted for ongoing trends, but the potential for a more focused corridor of scattered severe/damaging winds remains unclear. ...Mid Missouri Valley... A mid-level shortwave trough and attendant strong speed maximum will move quickly southeastward today from central Canada and the northern Plains towards the mid MO Valley and vicinity. Pronounced ascent associated with this jet should encourage convection to develop by late this afternoon across parts of eastern SD and vicinity. While low-level moisture and MLCAPE are both expected to remain very limited, enhanced low/mid-level northwesterly flow may still support some risk for severe gusts with any low-topped convection that can develop and spread quickly southeastward before weakening this evening with the loss of daytime heating. ...Kansas... A sharp cold front will sweep southward across the central Plains tonight. Elevated convection should form to the cool side of this boundary late tonight through early Friday morning given sufficient MUCAPE. Locally strong surface gusts and small hail may accompany this activity amid robust low-level northerlies, but the overall severe potential should remain fairly low given the tendency for convection to be mostly elevated. ...Arizona/Lower Colorado River Valley... Thunderstorms should develop again today across parts of central/southern AZ and the lower CO River Valley, beneath weak mid-level flow and on the periphery of increasing mid-level moisture associated with Tropical Storm Lorena. Weak shear should keep thunderstorms mostly disorganized, but occasional strong/gusty winds may occur where low-level lapse rates can become steepened. ..Gleason/Lyons.. 09/04/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Sep 04 2025 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEW YORK INTO THE MID-ATLANTIC AND TENNESSEE VALLEY...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... Isolated damaging winds may occur across parts of New York to the Mid-Atlantic and Tennessee Valley this afternoon. Isolated severe gusts are also possible across parts of the mid Missouri Valley late this afternoon and early evening. ...New York into the Mid-Atlantic and Tennessee Valley... A closed mid/upper-level low will remain centered over Ontario today. Multiple mid-level perturbations will rotate around this feature through the period, including a shortwave trough forecast to advance generally east-northeastward across parts of the central Appalachians/Mid-Atlantic into the Northeast. Showers and thunderstorms are ongoing mainly ahead of a surface cold front from parts of western NY southward to the TN Valley in a low/mid-level moisture plume. Generally clear skies ahead of this activity should allow for ample daytime heating of a modestly moistened low-level airmass. Even so, 12Z observed soundings from BUF, IAD, and RNK/GSO show rather poor mid-level lapse rates, which will likely hinder updraft strength even as weak instability develops this afternoon with continued diurnal heating. Modestly enhanced southwesterly low/mid-level flow should still aid in some thunderstorm organization even with the apparent thermodynamic limitations, with multicells the dominant convective mode. Wherever low-level lapse rates can become steepened, a risk for at least isolated damaging winds remains apparent. Some hail may also occur with the strongest cores across parts of the TN Valley/southern Appalachians where locally greater instability should be present this afternoon. The Marginal Risk has been adjusted for ongoing trends, but the potential for a more focused corridor of scattered severe/damaging winds remains unclear. ...Mid Missouri Valley... A mid-level shortwave trough and attendant strong speed maximum will move quickly southeastward today from central Canada and the northern Plains towards the mid MO Valley and vicinity. Pronounced ascent associated with this jet should encourage convection to develop by late this afternoon across parts of eastern SD and vicinity. While low-level moisture and MLCAPE are both expected to remain very limited, enhanced low/mid-level northwesterly flow may still support some risk for severe gusts with any low-topped convection that can develop and spread quickly southeastward before weakening this evening with the loss of daytime heating. ...Kansas... A sharp cold front will sweep southward across the central Plains tonight. Elevated convection should form to the cool side of this boundary late tonight through early Friday morning given sufficient MUCAPE. Locally strong surface gusts and small hail may accompany this activity amid robust low-level northerlies, but the overall severe potential should remain fairly low given the tendency for convection to be mostly elevated. ...Arizona/Lower Colorado River Valley... Thunderstorms should develop again today across parts of central/southern AZ and the lower CO River Valley, beneath weak mid-level flow and on the periphery of increasing mid-level moisture associated with Tropical Storm Lorena. Weak shear should keep thunderstorms mostly disorganized, but occasional strong/gusty winds may occur where low-level lapse rates can become steepened. ..Gleason/Lyons.. 09/04/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Sep 04 2025 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEW YORK INTO THE MID-ATLANTIC AND TENNESSEE VALLEY...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... Isolated damaging winds may occur across parts of New York to the Mid-Atlantic and Tennessee Valley this afternoon. Isolated severe gusts are also possible across parts of the mid Missouri Valley late this afternoon and early evening. ...New York into the Mid-Atlantic and Tennessee Valley... A closed mid/upper-level low will remain centered over Ontario today. Multiple mid-level perturbations will rotate around this feature through the period, including a shortwave trough forecast to advance generally east-northeastward across parts of the central Appalachians/Mid-Atlantic into the Northeast. Showers and thunderstorms are ongoing mainly ahead of a surface cold front from parts of western NY southward to the TN Valley in a low/mid-level moisture plume. Generally clear skies ahead of this activity should allow for ample daytime heating of a modestly moistened low-level airmass. Even so, 12Z observed soundings from BUF, IAD, and RNK/GSO show rather poor mid-level lapse rates, which will likely hinder updraft strength even as weak instability develops this afternoon with continued diurnal heating. Modestly enhanced southwesterly low/mid-level flow should still aid in some thunderstorm organization even with the apparent thermodynamic limitations, with multicells the dominant convective mode. Wherever low-level lapse rates can become steepened, a risk for at least isolated damaging winds remains apparent. Some hail may also occur with the strongest cores across parts of the TN Valley/southern Appalachians where locally greater instability should be present this afternoon. The Marginal Risk has been adjusted for ongoing trends, but the potential for a more focused corridor of scattered severe/damaging winds remains unclear. ...Mid Missouri Valley... A mid-level shortwave trough and attendant strong speed maximum will move quickly southeastward today from central Canada and the northern Plains towards the mid MO Valley and vicinity. Pronounced ascent associated with this jet should encourage convection to develop by late this afternoon across parts of eastern SD and vicinity. While low-level moisture and MLCAPE are both expected to remain very limited, enhanced low/mid-level northwesterly flow may still support some risk for severe gusts with any low-topped convection that can develop and spread quickly southeastward before weakening this evening with the loss of daytime heating. ...Kansas... A sharp cold front will sweep southward across the central Plains tonight. Elevated convection should form to the cool side of this boundary late tonight through early Friday morning given sufficient MUCAPE. Locally strong surface gusts and small hail may accompany this activity amid robust low-level northerlies, but the overall severe potential should remain fairly low given the tendency for convection to be mostly elevated. ...Arizona/Lower Colorado River Valley... Thunderstorms should develop again today across parts of central/southern AZ and the lower CO River Valley, beneath weak mid-level flow and on the periphery of increasing mid-level moisture associated with Tropical Storm Lorena. Weak shear should keep thunderstorms mostly disorganized, but occasional strong/gusty winds may occur where low-level lapse rates can become steepened. ..Gleason/Lyons.. 09/04/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Sep 04 2025 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEW YORK INTO THE MID-ATLANTIC AND TENNESSEE VALLEY...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... Isolated damaging winds may occur across parts of New York to the Mid-Atlantic and Tennessee Valley this afternoon. Isolated severe gusts are also possible across parts of the mid Missouri Valley late this afternoon and early evening. ...New York into the Mid-Atlantic and Tennessee Valley... A closed mid/upper-level low will remain centered over Ontario today. Multiple mid-level perturbations will rotate around this feature through the period, including a shortwave trough forecast to advance generally east-northeastward across parts of the central Appalachians/Mid-Atlantic into the Northeast. Showers and thunderstorms are ongoing mainly ahead of a surface cold front from parts of western NY southward to the TN Valley in a low/mid-level moisture plume. Generally clear skies ahead of this activity should allow for ample daytime heating of a modestly moistened low-level airmass. Even so, 12Z observed soundings from BUF, IAD, and RNK/GSO show rather poor mid-level lapse rates, which will likely hinder updraft strength even as weak instability develops this afternoon with continued diurnal heating. Modestly enhanced southwesterly low/mid-level flow should still aid in some thunderstorm organization even with the apparent thermodynamic limitations, with multicells the dominant convective mode. Wherever low-level lapse rates can become steepened, a risk for at least isolated damaging winds remains apparent. Some hail may also occur with the strongest cores across parts of the TN Valley/southern Appalachians where locally greater instability should be present this afternoon. The Marginal Risk has been adjusted for ongoing trends, but the potential for a more focused corridor of scattered severe/damaging winds remains unclear. ...Mid Missouri Valley... A mid-level shortwave trough and attendant strong speed maximum will move quickly southeastward today from central Canada and the northern Plains towards the mid MO Valley and vicinity. Pronounced ascent associated with this jet should encourage convection to develop by late this afternoon across parts of eastern SD and vicinity. While low-level moisture and MLCAPE are both expected to remain very limited, enhanced low/mid-level northwesterly flow may still support some risk for severe gusts with any low-topped convection that can develop and spread quickly southeastward before weakening this evening with the loss of daytime heating. ...Kansas... A sharp cold front will sweep southward across the central Plains tonight. Elevated convection should form to the cool side of this boundary late tonight through early Friday morning given sufficient MUCAPE. Locally strong surface gusts and small hail may accompany this activity amid robust low-level northerlies, but the overall severe potential should remain fairly low given the tendency for convection to be mostly elevated. ...Arizona/Lower Colorado River Valley... Thunderstorms should develop again today across parts of central/southern AZ and the lower CO River Valley, beneath weak mid-level flow and on the periphery of increasing mid-level moisture associated with Tropical Storm Lorena. Weak shear should keep thunderstorms mostly disorganized, but occasional strong/gusty winds may occur where low-level lapse rates can become steepened. ..Gleason/Lyons.. 09/04/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Sep 04 2025 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEW YORK INTO THE MID-ATLANTIC AND TENNESSEE VALLEY...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... Isolated damaging winds may occur across parts of New York to the Mid-Atlantic and Tennessee Valley this afternoon. Isolated severe gusts are also possible across parts of the mid Missouri Valley late this afternoon and early evening. ...New York into the Mid-Atlantic and Tennessee Valley... A closed mid/upper-level low will remain centered over Ontario today. Multiple mid-level perturbations will rotate around this feature through the period, including a shortwave trough forecast to advance generally east-northeastward across parts of the central Appalachians/Mid-Atlantic into the Northeast. Showers and thunderstorms are ongoing mainly ahead of a surface cold front from parts of western NY southward to the TN Valley in a low/mid-level moisture plume. Generally clear skies ahead of this activity should allow for ample daytime heating of a modestly moistened low-level airmass. Even so, 12Z observed soundings from BUF, IAD, and RNK/GSO show rather poor mid-level lapse rates, which will likely hinder updraft strength even as weak instability develops this afternoon with continued diurnal heating. Modestly enhanced southwesterly low/mid-level flow should still aid in some thunderstorm organization even with the apparent thermodynamic limitations, with multicells the dominant convective mode. Wherever low-level lapse rates can become steepened, a risk for at least isolated damaging winds remains apparent. Some hail may also occur with the strongest cores across parts of the TN Valley/southern Appalachians where locally greater instability should be present this afternoon. The Marginal Risk has been adjusted for ongoing trends, but the potential for a more focused corridor of scattered severe/damaging winds remains unclear. ...Mid Missouri Valley... A mid-level shortwave trough and attendant strong speed maximum will move quickly southeastward today from central Canada and the northern Plains towards the mid MO Valley and vicinity. Pronounced ascent associated with this jet should encourage convection to develop by late this afternoon across parts of eastern SD and vicinity. While low-level moisture and MLCAPE are both expected to remain very limited, enhanced low/mid-level northwesterly flow may still support some risk for severe gusts with any low-topped convection that can develop and spread quickly southeastward before weakening this evening with the loss of daytime heating. ...Kansas... A sharp cold front will sweep southward across the central Plains tonight. Elevated convection should form to the cool side of this boundary late tonight through early Friday morning given sufficient MUCAPE. Locally strong surface gusts and small hail may accompany this activity amid robust low-level northerlies, but the overall severe potential should remain fairly low given the tendency for convection to be mostly elevated. ...Arizona/Lower Colorado River Valley... Thunderstorms should develop again today across parts of central/southern AZ and the lower CO River Valley, beneath weak mid-level flow and on the periphery of increasing mid-level moisture associated with Tropical Storm Lorena. Weak shear should keep thunderstorms mostly disorganized, but occasional strong/gusty winds may occur where low-level lapse rates can become steepened. ..Gleason/Lyons.. 09/04/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Thu Sep 04 2025 Valid 041630Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NEW YORK INTO THE MID-ATLANTIC AND TENNESSEE VALLEY...AND PORTIONS OF THE MID MISSOURI VALLEY... ...SUMMARY... Isolated damaging winds may occur across parts of New York to the Mid-Atlantic and Tennessee Valley this afternoon. Isolated severe gusts are also possible across parts of the mid Missouri Valley late this afternoon and early evening. ...New York into the Mid-Atlantic and Tennessee Valley... A closed mid/upper-level low will remain centered over Ontario today. Multiple mid-level perturbations will rotate around this feature through the period, including a shortwave trough forecast to advance generally east-northeastward across parts of the central Appalachians/Mid-Atlantic into the Northeast. Showers and thunderstorms are ongoing mainly ahead of a surface cold front from parts of western NY southward to the TN Valley in a low/mid-level moisture plume. Generally clear skies ahead of this activity should allow for ample daytime heating of a modestly moistened low-level airmass. Even so, 12Z observed soundings from BUF, IAD, and RNK/GSO show rather poor mid-level lapse rates, which will likely hinder updraft strength even as weak instability develops this afternoon with continued diurnal heating. Modestly enhanced southwesterly low/mid-level flow should still aid in some thunderstorm organization even with the apparent thermodynamic limitations, with multicells the dominant convective mode. Wherever low-level lapse rates can become steepened, a risk for at least isolated damaging winds remains apparent. Some hail may also occur with the strongest cores across parts of the TN Valley/southern Appalachians where locally greater instability should be present this afternoon. The Marginal Risk has been adjusted for ongoing trends, but the potential for a more focused corridor of scattered severe/damaging winds remains unclear. ...Mid Missouri Valley... A mid-level shortwave trough and attendant strong speed maximum will move quickly southeastward today from central Canada and the northern Plains towards the mid MO Valley and vicinity. Pronounced ascent associated with this jet should encourage convection to develop by late this afternoon across parts of eastern SD and vicinity. While low-level moisture and MLCAPE are both expected to remain very limited, enhanced low/mid-level northwesterly flow may still support some risk for severe gusts with any low-topped convection that can develop and spread quickly southeastward before weakening this evening with the loss of daytime heating. ...Kansas... A sharp cold front will sweep southward across the central Plains tonight. Elevated convection should form to the cool side of this boundary late tonight through early Friday morning given sufficient MUCAPE. Locally strong surface gusts and small hail may accompany this activity amid robust low-level northerlies, but the overall severe potential should remain fairly low given the tendency for convection to be mostly elevated. ...Arizona/Lower Colorado River Valley... Thunderstorms should develop again today across parts of central/southern AZ and the lower CO River Valley, beneath weak mid-level flow and on the periphery of increasing mid-level moisture associated with Tropical Storm Lorena. Weak shear should keep thunderstorms mostly disorganized, but occasional strong/gusty winds may occur where low-level lapse rates can become steepened. ..Gleason/Lyons.. 09/04/2025 Read more