Severe Storms

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Synopsis and Discussion... A mature mid-latitude cyclone is forecast to be over central Alberta/Saskatchewan early Thursday morning before then continuing gradually eastward and ending the period over the central Saskatchewan/Manitoba border vicinity. Extensive surface troughing will precede this system, likely extending from central Saskatchewan into the central High Plains early Thursday. Primary surface low associated with this system is forecast to occlude over central Saskatchewan while a secondary low develops over southern Manitoba and moves eastward/northeastward into far northwestern Ontario. As the secondary surface low moves east, an attendant cold front is expected to move eastward/southeastward across the Dakotas and western MN. A very moist airmass, characterized by dewpoints in the upper 60s/low 70s, will precede this front. This low-level moisture beneath steep mid-level lapse rates will result in very strong buoyancy (3000+ J/kg of MLCAPE). Despite ample low-level moisture, substantial capping will likely persist across much of the northern Plains given the very warm low/mid-level temperatures (on the order 20 to 25 deg C at 850 mb). Forcing along the front should be strong enough to overcome this capping across eastern ND, with uncertainty regarding storm development and coverage increasing with southern extent across SD. The strong buoyancy and moderate vertical shear will support large to potentially very large hail with the initially more cellular storms. Warm and dry low to mid-levels suggest strong downdrafts are possible with mature storms as well. Upscale growth is uncertain given the prevailing capping and more limited buoyancy downstream into MN. ..Mosier.. 08/12/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Synopsis and Discussion... A mature mid-latitude cyclone is forecast to be over central Alberta/Saskatchewan early Thursday morning before then continuing gradually eastward and ending the period over the central Saskatchewan/Manitoba border vicinity. Extensive surface troughing will precede this system, likely extending from central Saskatchewan into the central High Plains early Thursday. Primary surface low associated with this system is forecast to occlude over central Saskatchewan while a secondary low develops over southern Manitoba and moves eastward/northeastward into far northwestern Ontario. As the secondary surface low moves east, an attendant cold front is expected to move eastward/southeastward across the Dakotas and western MN. A very moist airmass, characterized by dewpoints in the upper 60s/low 70s, will precede this front. This low-level moisture beneath steep mid-level lapse rates will result in very strong buoyancy (3000+ J/kg of MLCAPE). Despite ample low-level moisture, substantial capping will likely persist across much of the northern Plains given the very warm low/mid-level temperatures (on the order 20 to 25 deg C at 850 mb). Forcing along the front should be strong enough to overcome this capping across eastern ND, with uncertainty regarding storm development and coverage increasing with southern extent across SD. The strong buoyancy and moderate vertical shear will support large to potentially very large hail with the initially more cellular storms. Warm and dry low to mid-levels suggest strong downdrafts are possible with mature storms as well. Upscale growth is uncertain given the prevailing capping and more limited buoyancy downstream into MN. ..Mosier.. 08/12/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Synopsis and Discussion... A mature mid-latitude cyclone is forecast to be over central Alberta/Saskatchewan early Thursday morning before then continuing gradually eastward and ending the period over the central Saskatchewan/Manitoba border vicinity. Extensive surface troughing will precede this system, likely extending from central Saskatchewan into the central High Plains early Thursday. Primary surface low associated with this system is forecast to occlude over central Saskatchewan while a secondary low develops over southern Manitoba and moves eastward/northeastward into far northwestern Ontario. As the secondary surface low moves east, an attendant cold front is expected to move eastward/southeastward across the Dakotas and western MN. A very moist airmass, characterized by dewpoints in the upper 60s/low 70s, will precede this front. This low-level moisture beneath steep mid-level lapse rates will result in very strong buoyancy (3000+ J/kg of MLCAPE). Despite ample low-level moisture, substantial capping will likely persist across much of the northern Plains given the very warm low/mid-level temperatures (on the order 20 to 25 deg C at 850 mb). Forcing along the front should be strong enough to overcome this capping across eastern ND, with uncertainty regarding storm development and coverage increasing with southern extent across SD. The strong buoyancy and moderate vertical shear will support large to potentially very large hail with the initially more cellular storms. Warm and dry low to mid-levels suggest strong downdrafts are possible with mature storms as well. Upscale growth is uncertain given the prevailing capping and more limited buoyancy downstream into MN. ..Mosier.. 08/12/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Synopsis and Discussion... A mature mid-latitude cyclone is forecast to be over central Alberta/Saskatchewan early Thursday morning before then continuing gradually eastward and ending the period over the central Saskatchewan/Manitoba border vicinity. Extensive surface troughing will precede this system, likely extending from central Saskatchewan into the central High Plains early Thursday. Primary surface low associated with this system is forecast to occlude over central Saskatchewan while a secondary low develops over southern Manitoba and moves eastward/northeastward into far northwestern Ontario. As the secondary surface low moves east, an attendant cold front is expected to move eastward/southeastward across the Dakotas and western MN. A very moist airmass, characterized by dewpoints in the upper 60s/low 70s, will precede this front. This low-level moisture beneath steep mid-level lapse rates will result in very strong buoyancy (3000+ J/kg of MLCAPE). Despite ample low-level moisture, substantial capping will likely persist across much of the northern Plains given the very warm low/mid-level temperatures (on the order 20 to 25 deg C at 850 mb). Forcing along the front should be strong enough to overcome this capping across eastern ND, with uncertainty regarding storm development and coverage increasing with southern extent across SD. The strong buoyancy and moderate vertical shear will support large to potentially very large hail with the initially more cellular storms. Warm and dry low to mid-levels suggest strong downdrafts are possible with mature storms as well. Upscale growth is uncertain given the prevailing capping and more limited buoyancy downstream into MN. ..Mosier.. 08/12/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Synopsis and Discussion... A mature mid-latitude cyclone is forecast to be over central Alberta/Saskatchewan early Thursday morning before then continuing gradually eastward and ending the period over the central Saskatchewan/Manitoba border vicinity. Extensive surface troughing will precede this system, likely extending from central Saskatchewan into the central High Plains early Thursday. Primary surface low associated with this system is forecast to occlude over central Saskatchewan while a secondary low develops over southern Manitoba and moves eastward/northeastward into far northwestern Ontario. As the secondary surface low moves east, an attendant cold front is expected to move eastward/southeastward across the Dakotas and western MN. A very moist airmass, characterized by dewpoints in the upper 60s/low 70s, will precede this front. This low-level moisture beneath steep mid-level lapse rates will result in very strong buoyancy (3000+ J/kg of MLCAPE). Despite ample low-level moisture, substantial capping will likely persist across much of the northern Plains given the very warm low/mid-level temperatures (on the order 20 to 25 deg C at 850 mb). Forcing along the front should be strong enough to overcome this capping across eastern ND, with uncertainty regarding storm development and coverage increasing with southern extent across SD. The strong buoyancy and moderate vertical shear will support large to potentially very large hail with the initially more cellular storms. Warm and dry low to mid-levels suggest strong downdrafts are possible with mature storms as well. Upscale growth is uncertain given the prevailing capping and more limited buoyancy downstream into MN. ..Mosier.. 08/12/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Synopsis and Discussion... A mature mid-latitude cyclone is forecast to be over central Alberta/Saskatchewan early Thursday morning before then continuing gradually eastward and ending the period over the central Saskatchewan/Manitoba border vicinity. Extensive surface troughing will precede this system, likely extending from central Saskatchewan into the central High Plains early Thursday. Primary surface low associated with this system is forecast to occlude over central Saskatchewan while a secondary low develops over southern Manitoba and moves eastward/northeastward into far northwestern Ontario. As the secondary surface low moves east, an attendant cold front is expected to move eastward/southeastward across the Dakotas and western MN. A very moist airmass, characterized by dewpoints in the upper 60s/low 70s, will precede this front. This low-level moisture beneath steep mid-level lapse rates will result in very strong buoyancy (3000+ J/kg of MLCAPE). Despite ample low-level moisture, substantial capping will likely persist across much of the northern Plains given the very warm low/mid-level temperatures (on the order 20 to 25 deg C at 850 mb). Forcing along the front should be strong enough to overcome this capping across eastern ND, with uncertainty regarding storm development and coverage increasing with southern extent across SD. The strong buoyancy and moderate vertical shear will support large to potentially very large hail with the initially more cellular storms. Warm and dry low to mid-levels suggest strong downdrafts are possible with mature storms as well. Upscale growth is uncertain given the prevailing capping and more limited buoyancy downstream into MN. ..Mosier.. 08/12/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Tue Aug 12 2025 Valid 141200Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO NORTHWEST MINNESOTA... ...SUMMARY... Severe storms producing hail and wind are possible mainly from eastern North Dakota into northwest Minnesota Thursday afternoon and evening. ...Synopsis and Discussion... A mature mid-latitude cyclone is forecast to be over central Alberta/Saskatchewan early Thursday morning before then continuing gradually eastward and ending the period over the central Saskatchewan/Manitoba border vicinity. Extensive surface troughing will precede this system, likely extending from central Saskatchewan into the central High Plains early Thursday. Primary surface low associated with this system is forecast to occlude over central Saskatchewan while a secondary low develops over southern Manitoba and moves eastward/northeastward into far northwestern Ontario. As the secondary surface low moves east, an attendant cold front is expected to move eastward/southeastward across the Dakotas and western MN. A very moist airmass, characterized by dewpoints in the upper 60s/low 70s, will precede this front. This low-level moisture beneath steep mid-level lapse rates will result in very strong buoyancy (3000+ J/kg of MLCAPE). Despite ample low-level moisture, substantial capping will likely persist across much of the northern Plains given the very warm low/mid-level temperatures (on the order 20 to 25 deg C at 850 mb). Forcing along the front should be strong enough to overcome this capping across eastern ND, with uncertainty regarding storm development and coverage increasing with southern extent across SD. The strong buoyancy and moderate vertical shear will support large to potentially very large hail with the initially more cellular storms. Warm and dry low to mid-levels suggest strong downdrafts are possible with mature storms as well. Upscale growth is uncertain given the prevailing capping and more limited buoyancy downstream into MN. ..Mosier.. 08/12/2025 Read more

No Mesoscale Discussions are in effect as of Tue Aug 12 19:29:01 UTC 2025.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ...SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ...Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ...Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ..Mosier.. 08/12/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ...SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ...Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ...Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ..Mosier.. 08/12/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ...SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ...Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ...Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ..Mosier.. 08/12/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ...SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ...Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ...Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ..Mosier.. 08/12/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ...SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ...Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ...Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ..Mosier.. 08/12/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ...SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ...Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ...Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ..Mosier.. 08/12/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ...SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ...Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ...Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ..Mosier.. 08/12/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ...SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ...Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ...Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ..Mosier.. 08/12/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL SOUTH DAKOTA AND FAR NORTH-CENTRAL NEBRASKA... ...SUMMARY... The evolution of an organized cluster of thunderstorms accompanied by strong to severe wind gusts appears possible across parts of central through eastern South Dakota and far north-central Nebraska by Wednesday evening. ...Synopsis... Upper ridging will remain anchored over the Southwest/Four Corners, with subtropical ridging staying over FL as well. A pair of low-amplitude shortwave troughs will progress through the westerly flow north of this ridging. The easternmost wave will likely move through the Lower OH and TN Valleys while the westernmost wave progresses along the MT/WY border and through SD. This western wave is forecast to interact with an unstable airmass to support strong to severe thunderstorms from eastern WY into the Dakota and NE. Additional thunderstorms are expected across much of the eastern CONUS. Storms over the Northeast will be fostered by glancing ascent attendant to a shortwave trough moving through Quebec while the previously mentioned shortwave trough moving the TN Valley will promote development from KY/TN into northern AL/MS. Weak shear should limit storm organization and strength throughout the eastern CONUS. ...Eastern WY into the Dakotas and NE... Elevated showers and thunderstorms will likely be ongoing across western/central SD Wednesday morning. These storms are generally expected to be subsevere but will likely persist while gradually shifting eastward throughout the morning into the afternoon. The evolution of these storms, and their associated outflow and cloud cover, introduces some uncertainty into the forecast, particularly across southeast SD and northeast NE where there is at least a low probability for reintensification of storms within this cluster. At this time, given potential capping and varied model solutions confidence is low in the reintensification scenario. A more probable severe potential will result from the thunderstorm development that initiates farther west across the Black Hills. Here, increased forcing for ascent attendant to the approaching shortwave trough amid a warm, deeply mixed, and unstable airmass will support convective initiation late Wednesday afternoon. These initially high-based storms will pose a risk for damaging gusts and isolated hail. Moisture and buoyancy will increase with eastern extent, which will combine with moderate vertical shear to support a corridor of higher severe-wind probability across south-central SD and north-central NE during the late evening. Thereafter, increasing convective inhibition should result in gradually diminishing storm intensity. Additionally, elevated thunderstorms with some hail risk may develop ahead of the convective line across eastern SD during the late evening and overnight. Here, a strengthening low-level jet and associated warm-air advection amid steep mid-level lapse rates and moderate deep-layer shear could support a few storms capable of large hail. ..Mosier.. 08/12/2025 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1140 AM CDT Tue Aug 12 2025 Valid 121700Z - 131200Z No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 08/12/2025 .PREV DISCUSSION... /ISSUED 0128 AM CDT Tue Aug 12 2025/ ...Synopsis... Fire weather concerns will be focused across parts of central and eastern Arizona this afternoon, though more local concerns may emerge across portions of Oregon. ...Central to eastern Arizona... A mixture of wet and dry thunderstorms is expected again this afternoon along the Mogollon Rim. An evening 00z sounding from ABQ sampled a very deep, dry boundary layer along with steep mid-level lapse rates and PWAT values near 0.5 inch. This dry, but weakly buoyant, thermodynamic environment on the northern fringe of the deeper monsoonal moisture yielded a mix of wet and dry thunderstorms across the region yesterday. Similar conditions are likely today and should pose a fire weather concern over areas with receptive fuels. Dry thunderstorms are possible further east into western NM, but recent rainfall and improved fuels should mitigate the fire risk. ...Oregon... A weak mid-level wave is noted in early-morning water-vapor imagery off the Pacific Northwest coast. This feature will migrate east through the day and overspread the Cascades through peak heating. The associated westerly mid-level flow will not be overly strong, but will still induce a downslope flow regime on the eastern slopes of the Cascades. Compressional heating/drying, coupled with peak heating and full insolation, will promote RH reductions between 10-20%. Sustained winds between 10-15 mph appear most probable based on latest ensemble consensus, but gusts between 20-25 mph (especially wind-prone locations within the terrain) are possible. ...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 1140 AM CDT Tue Aug 12 2025 Valid 121700Z - 131200Z No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 08/12/2025 .PREV DISCUSSION... /ISSUED 0128 AM CDT Tue Aug 12 2025/ ...Synopsis... Fire weather concerns will be focused across parts of central and eastern Arizona this afternoon, though more local concerns may emerge across portions of Oregon. ...Central to eastern Arizona... A mixture of wet and dry thunderstorms is expected again this afternoon along the Mogollon Rim. An evening 00z sounding from ABQ sampled a very deep, dry boundary layer along with steep mid-level lapse rates and PWAT values near 0.5 inch. This dry, but weakly buoyant, thermodynamic environment on the northern fringe of the deeper monsoonal moisture yielded a mix of wet and dry thunderstorms across the region yesterday. Similar conditions are likely today and should pose a fire weather concern over areas with receptive fuels. Dry thunderstorms are possible further east into western NM, but recent rainfall and improved fuels should mitigate the fire risk. ...Oregon... A weak mid-level wave is noted in early-morning water-vapor imagery off the Pacific Northwest coast. This feature will migrate east through the day and overspread the Cascades through peak heating. The associated westerly mid-level flow will not be overly strong, but will still induce a downslope flow regime on the eastern slopes of the Cascades. Compressional heating/drying, coupled with peak heating and full insolation, will promote RH reductions between 10-20%. Sustained winds between 10-15 mph appear most probable based on latest ensemble consensus, but gusts between 20-25 mph (especially wind-prone locations within the terrain) are possible. ...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 1140 AM CDT Tue Aug 12 2025 Valid 121700Z - 131200Z No changes are needed to the current D1 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 08/12/2025 .PREV DISCUSSION... /ISSUED 0128 AM CDT Tue Aug 12 2025/ ...Synopsis... Fire weather concerns will be focused across parts of central and eastern Arizona this afternoon, though more local concerns may emerge across portions of Oregon. ...Central to eastern Arizona... A mixture of wet and dry thunderstorms is expected again this afternoon along the Mogollon Rim. An evening 00z sounding from ABQ sampled a very deep, dry boundary layer along with steep mid-level lapse rates and PWAT values near 0.5 inch. This dry, but weakly buoyant, thermodynamic environment on the northern fringe of the deeper monsoonal moisture yielded a mix of wet and dry thunderstorms across the region yesterday. Similar conditions are likely today and should pose a fire weather concern over areas with receptive fuels. Dry thunderstorms are possible further east into western NM, but recent rainfall and improved fuels should mitigate the fire risk. ...Oregon... A weak mid-level wave is noted in early-morning water-vapor imagery off the Pacific Northwest coast. This feature will migrate east through the day and overspread the Cascades through peak heating. The associated westerly mid-level flow will not be overly strong, but will still induce a downslope flow regime on the eastern slopes of the Cascades. Compressional heating/drying, coupled with peak heating and full insolation, will promote RH reductions between 10-20%. Sustained winds between 10-15 mph appear most probable based on latest ensemble consensus, but gusts between 20-25 mph (especially wind-prone locations within the terrain) are possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more