Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1135 AM CDT Thu Sep 11 2025 Valid 111700Z - 121200Z ...Western Utah... Strong southwest mid-level flow atop a well-mixed boundary layer will support gusty surface winds this afternoon across western Utah as daytime heating progresses under mostly clear skies. Sustained southwest winds of up to 20 mph combined with relative humidity close to 15% will result in Elevated fire weather conditions for portions of western Utah this afternoon. The overall fire weather threat has shifted slightly northeastward based on latest model guidance but remains largely on track. ..Williams.. 09/11/2025 .PREV DISCUSSION... /ISSUED 0117 AM CDT Thu Sep 11 2025/ ...Synopsis... The upper-level trough in the Great Basin will move marginally eastward today. The mid-level dry slot will move over western Utah during the afternoon. Though the mid-level jet will be weakening through the period, there should be enough flow across parts of the eastern Great Basin to promote at least pockets of locally elevated fire weather. With locally stronger winds and drier surface conditions in western Utah, sustained elevated conditions are most likely here. Surface winds of 15-20 mph and RH of 15-20% by the afternoon are expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0705 AM CDT Thu Sep 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible over eastern Montana into western North Dakota late this afternoon through the evening. The primary hazards are severe gusts and large hail. ...Synopsis... Water-vapor imagery shows a large cyclone over the West with a downstream ridge over the Great Plains, and a trough centered over the Lower Great Lakes. Southwesterly mid to high-level flow extends from the base of the larger-scale western U.S. trough northeastward through the Great Basin and into the northern Great Plains. A mid-level disturbance implied in morning water-vapor imagery over western WY, is forecast to move northeast into eastern MT/western ND towards this evening. In the low levels, a plume of seasonably rich moisture will protrude northward from the central Plains into the Dakotas and eastern MT. A lee trough will extend southward from a surface low over the northern High Plains. ...Rockies into the northern Plains... An ongoing cluster of weak thunderstorms associated with warm-air advection near the ND/Manitoba border will continue to move east-northeastward into southern Canada ahead of a pair of MCVs over western ND/eastern MT. Diurnal heating over the higher terrain from near the Four Corners northward into southern MT will favor scattered thunderstorms developing during the midday into the early afternoon. Storm coverage will probably increase further over the central Rockies during the afternoon, with the stronger storms capable of an isolated hail/wind threat. As the airmass destabilizes over the plains, particularly across eastern MT within the moist plume primarily north of the surface low, isolated to scattered storms are forecast by mid to late afternoon. This initial activity will probably develop near the MT/WY border with upscale growth into a cluster possible during the evening. Deep-layer shear supporting organized storm modes coupled with steep lapse rates, will combine to aid in several stronger storms capable of a hail/wind threat. The wind threat will probably continue into ND during the evening within the terminus region of a 35-40 kt southerly LLJ. A gradual transition to increasingly elevated convection is expected late as convective inhibition increases and the overall severe risk lessens. ..Smith/Broyles.. 09/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0705 AM CDT Thu Sep 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible over eastern Montana into western North Dakota late this afternoon through the evening. The primary hazards are severe gusts and large hail. ...Synopsis... Water-vapor imagery shows a large cyclone over the West with a downstream ridge over the Great Plains, and a trough centered over the Lower Great Lakes. Southwesterly mid to high-level flow extends from the base of the larger-scale western U.S. trough northeastward through the Great Basin and into the northern Great Plains. A mid-level disturbance implied in morning water-vapor imagery over western WY, is forecast to move northeast into eastern MT/western ND towards this evening. In the low levels, a plume of seasonably rich moisture will protrude northward from the central Plains into the Dakotas and eastern MT. A lee trough will extend southward from a surface low over the northern High Plains. ...Rockies into the northern Plains... An ongoing cluster of weak thunderstorms associated with warm-air advection near the ND/Manitoba border will continue to move east-northeastward into southern Canada ahead of a pair of MCVs over western ND/eastern MT. Diurnal heating over the higher terrain from near the Four Corners northward into southern MT will favor scattered thunderstorms developing during the midday into the early afternoon. Storm coverage will probably increase further over the central Rockies during the afternoon, with the stronger storms capable of an isolated hail/wind threat. As the airmass destabilizes over the plains, particularly across eastern MT within the moist plume primarily north of the surface low, isolated to scattered storms are forecast by mid to late afternoon. This initial activity will probably develop near the MT/WY border with upscale growth into a cluster possible during the evening. Deep-layer shear supporting organized storm modes coupled with steep lapse rates, will combine to aid in several stronger storms capable of a hail/wind threat. The wind threat will probably continue into ND during the evening within the terminus region of a 35-40 kt southerly LLJ. A gradual transition to increasingly elevated convection is expected late as convective inhibition increases and the overall severe risk lessens. ..Smith/Broyles.. 09/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0705 AM CDT Thu Sep 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible over eastern Montana into western North Dakota late this afternoon through the evening. The primary hazards are severe gusts and large hail. ...Synopsis... Water-vapor imagery shows a large cyclone over the West with a downstream ridge over the Great Plains, and a trough centered over the Lower Great Lakes. Southwesterly mid to high-level flow extends from the base of the larger-scale western U.S. trough northeastward through the Great Basin and into the northern Great Plains. A mid-level disturbance implied in morning water-vapor imagery over western WY, is forecast to move northeast into eastern MT/western ND towards this evening. In the low levels, a plume of seasonably rich moisture will protrude northward from the central Plains into the Dakotas and eastern MT. A lee trough will extend southward from a surface low over the northern High Plains. ...Rockies into the northern Plains... An ongoing cluster of weak thunderstorms associated with warm-air advection near the ND/Manitoba border will continue to move east-northeastward into southern Canada ahead of a pair of MCVs over western ND/eastern MT. Diurnal heating over the higher terrain from near the Four Corners northward into southern MT will favor scattered thunderstorms developing during the midday into the early afternoon. Storm coverage will probably increase further over the central Rockies during the afternoon, with the stronger storms capable of an isolated hail/wind threat. As the airmass destabilizes over the plains, particularly across eastern MT within the moist plume primarily north of the surface low, isolated to scattered storms are forecast by mid to late afternoon. This initial activity will probably develop near the MT/WY border with upscale growth into a cluster possible during the evening. Deep-layer shear supporting organized storm modes coupled with steep lapse rates, will combine to aid in several stronger storms capable of a hail/wind threat. The wind threat will probably continue into ND during the evening within the terminus region of a 35-40 kt southerly LLJ. A gradual transition to increasingly elevated convection is expected late as convective inhibition increases and the overall severe risk lessens. ..Smith/Broyles.. 09/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0705 AM CDT Thu Sep 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible over eastern Montana into western North Dakota late this afternoon through the evening. The primary hazards are severe gusts and large hail. ...Synopsis... Water-vapor imagery shows a large cyclone over the West with a downstream ridge over the Great Plains, and a trough centered over the Lower Great Lakes. Southwesterly mid to high-level flow extends from the base of the larger-scale western U.S. trough northeastward through the Great Basin and into the northern Great Plains. A mid-level disturbance implied in morning water-vapor imagery over western WY, is forecast to move northeast into eastern MT/western ND towards this evening. In the low levels, a plume of seasonably rich moisture will protrude northward from the central Plains into the Dakotas and eastern MT. A lee trough will extend southward from a surface low over the northern High Plains. ...Rockies into the northern Plains... An ongoing cluster of weak thunderstorms associated with warm-air advection near the ND/Manitoba border will continue to move east-northeastward into southern Canada ahead of a pair of MCVs over western ND/eastern MT. Diurnal heating over the higher terrain from near the Four Corners northward into southern MT will favor scattered thunderstorms developing during the midday into the early afternoon. Storm coverage will probably increase further over the central Rockies during the afternoon, with the stronger storms capable of an isolated hail/wind threat. As the airmass destabilizes over the plains, particularly across eastern MT within the moist plume primarily north of the surface low, isolated to scattered storms are forecast by mid to late afternoon. This initial activity will probably develop near the MT/WY border with upscale growth into a cluster possible during the evening. Deep-layer shear supporting organized storm modes coupled with steep lapse rates, will combine to aid in several stronger storms capable of a hail/wind threat. The wind threat will probably continue into ND during the evening within the terminus region of a 35-40 kt southerly LLJ. A gradual transition to increasingly elevated convection is expected late as convective inhibition increases and the overall severe risk lessens. ..Smith/Broyles.. 09/11/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0705 AM CDT Thu Sep 11 2025 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MONTANA INTO WESTERN NORTH DAKOTA... ...SUMMARY... Scattered severe thunderstorms are possible over eastern Montana into western North Dakota late this afternoon through the evening. The primary hazards are severe gusts and large hail. ...Synopsis... Water-vapor imagery shows a large cyclone over the West with a downstream ridge over the Great Plains, and a trough centered over the Lower Great Lakes. Southwesterly mid to high-level flow extends from the base of the larger-scale western U.S. trough northeastward through the Great Basin and into the northern Great Plains. A mid-level disturbance implied in morning water-vapor imagery over western WY, is forecast to move northeast into eastern MT/western ND towards this evening. In the low levels, a plume of seasonably rich moisture will protrude northward from the central Plains into the Dakotas and eastern MT. A lee trough will extend southward from a surface low over the northern High Plains. ...Rockies into the northern Plains... An ongoing cluster of weak thunderstorms associated with warm-air advection near the ND/Manitoba border will continue to move east-northeastward into southern Canada ahead of a pair of MCVs over western ND/eastern MT. Diurnal heating over the higher terrain from near the Four Corners northward into southern MT will favor scattered thunderstorms developing during the midday into the early afternoon. Storm coverage will probably increase further over the central Rockies during the afternoon, with the stronger storms capable of an isolated hail/wind threat. As the airmass destabilizes over the plains, particularly across eastern MT within the moist plume primarily north of the surface low, isolated to scattered storms are forecast by mid to late afternoon. This initial activity will probably develop near the MT/WY border with upscale growth into a cluster possible during the evening. Deep-layer shear supporting organized storm modes coupled with steep lapse rates, will combine to aid in several stronger storms capable of a hail/wind threat. The wind threat will probably continue into ND during the evening within the terminus region of a 35-40 kt southerly LLJ. A gradual transition to increasingly elevated convection is expected late as convective inhibition increases and the overall severe risk lessens. ..Smith/Broyles.. 09/11/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Thu Sep 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... Model guidance is in fairly good agreement that the upper trough over the central US will continue to lift northeastward into the northern Plains and Upper Midwest through early next week. This will drag a surface low and cold front slowly eastward with seasonably high moisture in place. The low will begin to fill as it also lifts into southern Canada. Scattered to numerous thunderstorms appear likely over the Northern Plains and Upper Midwest, and along the trailing front over the southern/central Plains each afternoon, as increasingly meridional flow will parallel the slow moving cold front. This will favor continued storm development/training along the boundary with limited air mass destabilization/recovery. Mid-level lapse rates should also weaken as the upper trough begins to fill. While some marginal severe risk is evident over the northern Plains near the low and front, mainly D4/Sunday, significant uncertainty exists regarding boundary-layer destabilization and its impacts on severe potential through D5/Monday. By D6/Tuesday, mid-level ridging behind the trough is forecast to temporarily strengthen, weakening upper-level flow across the CONUS. A second upper trough over the northern Rockies will begin to approach behind the central US ridge, while a cutoff low develops over the Southeast. This should limit broader overlap of instability and stronger mid-level flow across much of the CONUS. Widespread severe weather appears unlikely through next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Thu Sep 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... Model guidance is in fairly good agreement that the upper trough over the central US will continue to lift northeastward into the northern Plains and Upper Midwest through early next week. This will drag a surface low and cold front slowly eastward with seasonably high moisture in place. The low will begin to fill as it also lifts into southern Canada. Scattered to numerous thunderstorms appear likely over the Northern Plains and Upper Midwest, and along the trailing front over the southern/central Plains each afternoon, as increasingly meridional flow will parallel the slow moving cold front. This will favor continued storm development/training along the boundary with limited air mass destabilization/recovery. Mid-level lapse rates should also weaken as the upper trough begins to fill. While some marginal severe risk is evident over the northern Plains near the low and front, mainly D4/Sunday, significant uncertainty exists regarding boundary-layer destabilization and its impacts on severe potential through D5/Monday. By D6/Tuesday, mid-level ridging behind the trough is forecast to temporarily strengthen, weakening upper-level flow across the CONUS. A second upper trough over the northern Rockies will begin to approach behind the central US ridge, while a cutoff low develops over the Southeast. This should limit broader overlap of instability and stronger mid-level flow across much of the CONUS. Widespread severe weather appears unlikely through next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Thu Sep 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... Model guidance is in fairly good agreement that the upper trough over the central US will continue to lift northeastward into the northern Plains and Upper Midwest through early next week. This will drag a surface low and cold front slowly eastward with seasonably high moisture in place. The low will begin to fill as it also lifts into southern Canada. Scattered to numerous thunderstorms appear likely over the Northern Plains and Upper Midwest, and along the trailing front over the southern/central Plains each afternoon, as increasingly meridional flow will parallel the slow moving cold front. This will favor continued storm development/training along the boundary with limited air mass destabilization/recovery. Mid-level lapse rates should also weaken as the upper trough begins to fill. While some marginal severe risk is evident over the northern Plains near the low and front, mainly D4/Sunday, significant uncertainty exists regarding boundary-layer destabilization and its impacts on severe potential through D5/Monday. By D6/Tuesday, mid-level ridging behind the trough is forecast to temporarily strengthen, weakening upper-level flow across the CONUS. A second upper trough over the northern Rockies will begin to approach behind the central US ridge, while a cutoff low develops over the Southeast. This should limit broader overlap of instability and stronger mid-level flow across much of the CONUS. Widespread severe weather appears unlikely through next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Thu Sep 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... Model guidance is in fairly good agreement that the upper trough over the central US will continue to lift northeastward into the northern Plains and Upper Midwest through early next week. This will drag a surface low and cold front slowly eastward with seasonably high moisture in place. The low will begin to fill as it also lifts into southern Canada. Scattered to numerous thunderstorms appear likely over the Northern Plains and Upper Midwest, and along the trailing front over the southern/central Plains each afternoon, as increasingly meridional flow will parallel the slow moving cold front. This will favor continued storm development/training along the boundary with limited air mass destabilization/recovery. Mid-level lapse rates should also weaken as the upper trough begins to fill. While some marginal severe risk is evident over the northern Plains near the low and front, mainly D4/Sunday, significant uncertainty exists regarding boundary-layer destabilization and its impacts on severe potential through D5/Monday. By D6/Tuesday, mid-level ridging behind the trough is forecast to temporarily strengthen, weakening upper-level flow across the CONUS. A second upper trough over the northern Rockies will begin to approach behind the central US ridge, while a cutoff low develops over the Southeast. This should limit broader overlap of instability and stronger mid-level flow across much of the CONUS. Widespread severe weather appears unlikely through next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0354 AM CDT Thu Sep 11 2025 Valid 141200Z - 191200Z ...DISCUSSION... Model guidance is in fairly good agreement that the upper trough over the central US will continue to lift northeastward into the northern Plains and Upper Midwest through early next week. This will drag a surface low and cold front slowly eastward with seasonably high moisture in place. The low will begin to fill as it also lifts into southern Canada. Scattered to numerous thunderstorms appear likely over the Northern Plains and Upper Midwest, and along the trailing front over the southern/central Plains each afternoon, as increasingly meridional flow will parallel the slow moving cold front. This will favor continued storm development/training along the boundary with limited air mass destabilization/recovery. Mid-level lapse rates should also weaken as the upper trough begins to fill. While some marginal severe risk is evident over the northern Plains near the low and front, mainly D4/Sunday, significant uncertainty exists regarding boundary-layer destabilization and its impacts on severe potential through D5/Monday. By D6/Tuesday, mid-level ridging behind the trough is forecast to temporarily strengthen, weakening upper-level flow across the CONUS. A second upper trough over the northern Rockies will begin to approach behind the central US ridge, while a cutoff low develops over the Southeast. This should limit broader overlap of instability and stronger mid-level flow across much of the CONUS. Widespread severe weather appears unlikely through next week. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms, capable of strong wind gusts, are possible over parts of the southern and central High Plains Saturday. Scattered to numerous storms are also possible over the northern Plains and Midwest, though confidence in severe potential is lower here. ..Central and southern High Plains... A cold front associated with a broad upper trough ejecting over the central US is forecast to move east over the central/southern High Plains Saturday. Southerly low-level flow is expected ahead of the front, supporting weak moisture advection. Showers/storms and remnant cloud cover are likely early in the day which could impact later destabilization. Still, most guidance shows a loose band of storms developing by early afternoon along the front within stronger southwesterly flow aloft favorable for marginally organized lines/clusters. Some heating ahead of these storms is expected to modestly steepen low-level lapse rates, which could support isolated severe gusts with the strongest storms Saturday afternoon and evening. ...Northern Plains... The broad upper trough will slowly move eastward over the Plains as shortwave ridging builds over the upper Midwest. East of the trough, a weak surface low and stalled front will persist over the Dakotas while a weak cold front moves eastward out of the Rockies. Scattered storms are likely to be ongoing near the surface low across the Dakotas early Saturday. Some isolated gusty winds or hail are possible near the cold front/low if sufficient destabilization can occur at the surface. However, there remains significant uncertainty in this occurring given the potential for widespread convection. ...Midwest and Great Lakes... A second upper trough will move out of southern Canada over the eastern Great Lakes and northeast States east of the ridge. Northerly flow aloft will be modestly enhanced with the passage of the trough. Some thunderstorms are possible along the western flank of the trough near a stalled front across the western Great Lakes and Midwest. Moderate buoyancy across southern MN/WI into northern IL/IA could support a few stronger storms during the afternoon, though the modest flow aloft is unlikely to support much organization or severe potential. ..Lyons.. 09/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms, capable of strong wind gusts, are possible over parts of the southern and central High Plains Saturday. Scattered to numerous storms are also possible over the northern Plains and Midwest, though confidence in severe potential is lower here. ..Central and southern High Plains... A cold front associated with a broad upper trough ejecting over the central US is forecast to move east over the central/southern High Plains Saturday. Southerly low-level flow is expected ahead of the front, supporting weak moisture advection. Showers/storms and remnant cloud cover are likely early in the day which could impact later destabilization. Still, most guidance shows a loose band of storms developing by early afternoon along the front within stronger southwesterly flow aloft favorable for marginally organized lines/clusters. Some heating ahead of these storms is expected to modestly steepen low-level lapse rates, which could support isolated severe gusts with the strongest storms Saturday afternoon and evening. ...Northern Plains... The broad upper trough will slowly move eastward over the Plains as shortwave ridging builds over the upper Midwest. East of the trough, a weak surface low and stalled front will persist over the Dakotas while a weak cold front moves eastward out of the Rockies. Scattered storms are likely to be ongoing near the surface low across the Dakotas early Saturday. Some isolated gusty winds or hail are possible near the cold front/low if sufficient destabilization can occur at the surface. However, there remains significant uncertainty in this occurring given the potential for widespread convection. ...Midwest and Great Lakes... A second upper trough will move out of southern Canada over the eastern Great Lakes and northeast States east of the ridge. Northerly flow aloft will be modestly enhanced with the passage of the trough. Some thunderstorms are possible along the western flank of the trough near a stalled front across the western Great Lakes and Midwest. Moderate buoyancy across southern MN/WI into northern IL/IA could support a few stronger storms during the afternoon, though the modest flow aloft is unlikely to support much organization or severe potential. ..Lyons.. 09/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms, capable of strong wind gusts, are possible over parts of the southern and central High Plains Saturday. Scattered to numerous storms are also possible over the northern Plains and Midwest, though confidence in severe potential is lower here. ..Central and southern High Plains... A cold front associated with a broad upper trough ejecting over the central US is forecast to move east over the central/southern High Plains Saturday. Southerly low-level flow is expected ahead of the front, supporting weak moisture advection. Showers/storms and remnant cloud cover are likely early in the day which could impact later destabilization. Still, most guidance shows a loose band of storms developing by early afternoon along the front within stronger southwesterly flow aloft favorable for marginally organized lines/clusters. Some heating ahead of these storms is expected to modestly steepen low-level lapse rates, which could support isolated severe gusts with the strongest storms Saturday afternoon and evening. ...Northern Plains... The broad upper trough will slowly move eastward over the Plains as shortwave ridging builds over the upper Midwest. East of the trough, a weak surface low and stalled front will persist over the Dakotas while a weak cold front moves eastward out of the Rockies. Scattered storms are likely to be ongoing near the surface low across the Dakotas early Saturday. Some isolated gusty winds or hail are possible near the cold front/low if sufficient destabilization can occur at the surface. However, there remains significant uncertainty in this occurring given the potential for widespread convection. ...Midwest and Great Lakes... A second upper trough will move out of southern Canada over the eastern Great Lakes and northeast States east of the ridge. Northerly flow aloft will be modestly enhanced with the passage of the trough. Some thunderstorms are possible along the western flank of the trough near a stalled front across the western Great Lakes and Midwest. Moderate buoyancy across southern MN/WI into northern IL/IA could support a few stronger storms during the afternoon, though the modest flow aloft is unlikely to support much organization or severe potential. ..Lyons.. 09/11/2025 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Thu Sep 11 2025 Valid 131200Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN HIGH PLAINS... ...SUMMARY... Strong to severe storms, capable of strong wind gusts, are possible over parts of the southern and central High Plains Saturday. Scattered to numerous storms are also possible over the northern Plains and Midwest, though confidence in severe potential is lower here. ..Central and southern High Plains... A cold front associated with a broad upper trough ejecting over the central US is forecast to move east over the central/southern High Plains Saturday. Southerly low-level flow is expected ahead of the front, supporting weak moisture advection. Showers/storms and remnant cloud cover are likely early in the day which could impact later destabilization. Still, most guidance shows a loose band of storms developing by early afternoon along the front within stronger southwesterly flow aloft favorable for marginally organized lines/clusters. Some heating ahead of these storms is expected to modestly steepen low-level lapse rates, which could support isolated severe gusts with the strongest storms Saturday afternoon and evening. ...Northern Plains... The broad upper trough will slowly move eastward over the Plains as shortwave ridging builds over the upper Midwest. East of the trough, a weak surface low and stalled front will persist over the Dakotas while a weak cold front moves eastward out of the Rockies. Scattered storms are likely to be ongoing near the surface low across the Dakotas early Saturday. Some isolated gusty winds or hail are possible near the cold front/low if sufficient destabilization can occur at the surface. However, there remains significant uncertainty in this occurring given the potential for widespread convection. ...Midwest and Great Lakes... A second upper trough will move out of southern Canada over the eastern Great Lakes and northeast States east of the ridge. Northerly flow aloft will be modestly enhanced with the passage of the trough. Some thunderstorms are possible along the western flank of the trough near a stalled front across the western Great Lakes and Midwest. Moderate buoyancy across southern MN/WI into northern IL/IA could support a few stronger storms during the afternoon, though the modest flow aloft is unlikely to support much organization or severe potential. ..Lyons.. 09/11/2025 Read more