Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0234 PM CDT Tue Aug 12 2025 Valid 131200Z - 141200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN IDAHO... A Critical area was added across portions of the Snake River Plain in southern Idaho with this outlook. Ensemble guidance shows reasonable agreement that sustained winds around 20 mph will overlap with relative humidity reductions to around 15 percent across this region amid critically dry fuels. The Isolated Dry Thunderstorm chances were also expanded further east into southern Idaho in agreement with latest trends in hi-res guidance suggesting convection will be possible across the high terrain. The broad Elevated region across much of the Great Basin, Pacific Northwest, and Northern Rockies. See previous discussion for more information. ..Thornton.. 08/12/2025 .PREV DISCUSSION... /ISSUED 0200 AM CDT Tue Aug 12 2025/ ...Synopsis... Fire weather concerns will become more widespread across the West on Wednesday as a strong upper-level wave moves across the region. Short to medium-range guidance shows reasonably good agreement in the southeastward progression of an amplifying upper wave (currently over the northeast Pacific) across the Pacific Northwest and northern Rockies through Wednesday afternoon/evening. Strengthening downslope winds off the Cascades and Sierra Nevada will promote windy and dry conditions across western NV into eastern WA/OR. Further east, robust surface pressure falls attendant to the upper wave will promote strengthening surface winds across a broad swath of the eastern Great Basin and central/northern Rockies. Latest ensemble guidance suggests sustained winds in the upper teens are most probable, though some regions may see sustained winds between 20-25 mph. Spread between ensemble and deterministic solutions limits confidence on where such corridors of higher winds will emerge, but given high probabilities for sub-15% RH, swaths of critical fire weather conditions appear possible. Elevated fire weather conditions may emerge across portions of northern MT as well, but recent fuel guidance suggests fuels are not overly receptive across this region (though fuel trends will be monitored given the forecast for dry/windy conditions). Dry thunderstorms are also possible across the Great Basin Wednesday afternoon. A plume of mid-level moisture moving northward off the CA coast will likely phase with the passage of the upper wave and support adequate buoyancy for high-based convection across portions of east-central CA, central NV, and perhaps into southern ID. Strong diurnal heating and mixing will push LCL heights to above 4 km, which, in conjunction with 20 knot storm motions, will limit precipitation totals and favor dry thunderstorms. While coverage of thunderstorms may be limited, dry fuels across the region should support the fire weather concern. ...Please see www.spc.noaa.gov/fire for graphic product... 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

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