Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 PM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z The IsoDryT area was expanded based on the latest high-resolution forecast guidance. High-based showers and thunderstorms may be ongoing tomorrow morning over portions of northern Utah into western/central Wyoming. High-based showers and thunderstorms may continue overnight from east-central Nevada through central Utah as well. Locally elevated conditions are likely across swaths of the Great Basin into Wyoming and Colorado due to hot/dry/breezy conditions in pre/post-frontal environments. Additionally, a thermal trough will strengthen over the West Coast tomorrow with hot/dry/unstable and locally breezy conditions expected from southern California into the Pacific Northwest, west of the Cascades. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0157 AM CDT Wed Aug 20 2025/ ...Synopsis... The strong ridge over the western US is expected to continue to break down under the shortwave trough passing through the northern Rockies. This will support continued advection of monsoon moisture northward into the Great Basin and parts of southern California. By Thursday afternoon, PWAT values are likely to be between 0.5-0.8" with a dry sub-cloud layer and steep low-level lapse rates. Despite slower storm motions and isolated coverage over Utah and parts of Nevada, little wetting rainfall is expected. This should support isolated dry thunderstorm potential the under the upper high and into portions of eastern Idaho and western Wyoming. With dry fuels in place, some lightning ignitions are possible. In addition to the potential for thunderstorms, very warm and unstable conditions are expected on the periphery of the deeper monsoon moisture surge over parts of the southern Great Basin and southern California. Steep mid-level lapse rates and marginal buoyancy will support unstable conditions over much of the Southwest. This could support plume dominated fire growth and pyroconvection near large active fires, with localized extreme fire behavior possible. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE DAKOTAS INTO MINNESOTA... ...SUMMARY... An isolated severe threat is expected to develop Thursday into Thursday night over parts of the Dakotas into Minnesota, with severe gusts and hail possible. ...Northern Plains into Minnesota... An upper shortwave trough/cyclone will deepen and develop east across the Canadian Prairies on Thursday. This will result in dampening of the upper ridge/height falls across the northern Plains vicinity. Early in the day, a weak shortwave impulse and remnant convection/cloud debris will move across portions of ND/MN. Meanwhile, a cold front will develop east/southeast across the Dakotas into northern MN through early Friday. A corridor of rich boundary layer moisture with dewpoints generally in the mid 60s to near 70 F will be in place ahead of the cold front. However, stronger forcing for ascent will not arrive until later in the evening/overnight. It is unclear how much diurnal convection may develop due to weaker forcing and capping. If a storm can form ahead of the front during the afternoon, a corridor of 2000-3000 J/kg MLCAPE will be in place amid 30+ kt effective shear. Strong gusts and hail would be possible with cellular activity through early evening. More likely, convection will develop during the evening/nighttime hours across parts of the region. Initial storms may develop in the post-frontal upslope regime across eastern WY/western SD and develop east across SD overnight. It is unclear how intense these initial storms further west will be, and probabilities may need to be expanded westward in subsequent outlooks if confidence increases. Once storms interact with better moisture/instability further east, isolated severe gusts or marginal hail will be possible. ..Leitman.. 08/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE DAKOTAS INTO MINNESOTA... ...SUMMARY... An isolated severe threat is expected to develop Thursday into Thursday night over parts of the Dakotas into Minnesota, with severe gusts and hail possible. ...Northern Plains into Minnesota... An upper shortwave trough/cyclone will deepen and develop east across the Canadian Prairies on Thursday. This will result in dampening of the upper ridge/height falls across the northern Plains vicinity. Early in the day, a weak shortwave impulse and remnant convection/cloud debris will move across portions of ND/MN. Meanwhile, a cold front will develop east/southeast across the Dakotas into northern MN through early Friday. A corridor of rich boundary layer moisture with dewpoints generally in the mid 60s to near 70 F will be in place ahead of the cold front. However, stronger forcing for ascent will not arrive until later in the evening/overnight. It is unclear how much diurnal convection may develop due to weaker forcing and capping. If a storm can form ahead of the front during the afternoon, a corridor of 2000-3000 J/kg MLCAPE will be in place amid 30+ kt effective shear. Strong gusts and hail would be possible with cellular activity through early evening. More likely, convection will develop during the evening/nighttime hours across parts of the region. Initial storms may develop in the post-frontal upslope regime across eastern WY/western SD and develop east across SD overnight. It is unclear how intense these initial storms further west will be, and probabilities may need to be expanded westward in subsequent outlooks if confidence increases. Once storms interact with better moisture/instability further east, isolated severe gusts or marginal hail will be possible. ..Leitman.. 08/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE DAKOTAS INTO MINNESOTA... ...SUMMARY... An isolated severe threat is expected to develop Thursday into Thursday night over parts of the Dakotas into Minnesota, with severe gusts and hail possible. ...Northern Plains into Minnesota... An upper shortwave trough/cyclone will deepen and develop east across the Canadian Prairies on Thursday. This will result in dampening of the upper ridge/height falls across the northern Plains vicinity. Early in the day, a weak shortwave impulse and remnant convection/cloud debris will move across portions of ND/MN. Meanwhile, a cold front will develop east/southeast across the Dakotas into northern MN through early Friday. A corridor of rich boundary layer moisture with dewpoints generally in the mid 60s to near 70 F will be in place ahead of the cold front. However, stronger forcing for ascent will not arrive until later in the evening/overnight. It is unclear how much diurnal convection may develop due to weaker forcing and capping. If a storm can form ahead of the front during the afternoon, a corridor of 2000-3000 J/kg MLCAPE will be in place amid 30+ kt effective shear. Strong gusts and hail would be possible with cellular activity through early evening. More likely, convection will develop during the evening/nighttime hours across parts of the region. Initial storms may develop in the post-frontal upslope regime across eastern WY/western SD and develop east across SD overnight. It is unclear how intense these initial storms further west will be, and probabilities may need to be expanded westward in subsequent outlooks if confidence increases. Once storms interact with better moisture/instability further east, isolated severe gusts or marginal hail will be possible. ..Leitman.. 08/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE DAKOTAS INTO MINNESOTA... ...SUMMARY... An isolated severe threat is expected to develop Thursday into Thursday night over parts of the Dakotas into Minnesota, with severe gusts and hail possible. ...Northern Plains into Minnesota... An upper shortwave trough/cyclone will deepen and develop east across the Canadian Prairies on Thursday. This will result in dampening of the upper ridge/height falls across the northern Plains vicinity. Early in the day, a weak shortwave impulse and remnant convection/cloud debris will move across portions of ND/MN. Meanwhile, a cold front will develop east/southeast across the Dakotas into northern MN through early Friday. A corridor of rich boundary layer moisture with dewpoints generally in the mid 60s to near 70 F will be in place ahead of the cold front. However, stronger forcing for ascent will not arrive until later in the evening/overnight. It is unclear how much diurnal convection may develop due to weaker forcing and capping. If a storm can form ahead of the front during the afternoon, a corridor of 2000-3000 J/kg MLCAPE will be in place amid 30+ kt effective shear. Strong gusts and hail would be possible with cellular activity through early evening. More likely, convection will develop during the evening/nighttime hours across parts of the region. Initial storms may develop in the post-frontal upslope regime across eastern WY/western SD and develop east across SD overnight. It is unclear how intense these initial storms further west will be, and probabilities may need to be expanded westward in subsequent outlooks if confidence increases. Once storms interact with better moisture/instability further east, isolated severe gusts or marginal hail will be possible. ..Leitman.. 08/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE DAKOTAS INTO MINNESOTA... ...SUMMARY... An isolated severe threat is expected to develop Thursday into Thursday night over parts of the Dakotas into Minnesota, with severe gusts and hail possible. ...Northern Plains into Minnesota... An upper shortwave trough/cyclone will deepen and develop east across the Canadian Prairies on Thursday. This will result in dampening of the upper ridge/height falls across the northern Plains vicinity. Early in the day, a weak shortwave impulse and remnant convection/cloud debris will move across portions of ND/MN. Meanwhile, a cold front will develop east/southeast across the Dakotas into northern MN through early Friday. A corridor of rich boundary layer moisture with dewpoints generally in the mid 60s to near 70 F will be in place ahead of the cold front. However, stronger forcing for ascent will not arrive until later in the evening/overnight. It is unclear how much diurnal convection may develop due to weaker forcing and capping. If a storm can form ahead of the front during the afternoon, a corridor of 2000-3000 J/kg MLCAPE will be in place amid 30+ kt effective shear. Strong gusts and hail would be possible with cellular activity through early evening. More likely, convection will develop during the evening/nighttime hours across parts of the region. Initial storms may develop in the post-frontal upslope regime across eastern WY/western SD and develop east across SD overnight. It is unclear how intense these initial storms further west will be, and probabilities may need to be expanded westward in subsequent outlooks if confidence increases. Once storms interact with better moisture/instability further east, isolated severe gusts or marginal hail will be possible. ..Leitman.. 08/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE DAKOTAS INTO MINNESOTA... ...SUMMARY... An isolated severe threat is expected to develop Thursday into Thursday night over parts of the Dakotas into Minnesota, with severe gusts and hail possible. ...Northern Plains into Minnesota... An upper shortwave trough/cyclone will deepen and develop east across the Canadian Prairies on Thursday. This will result in dampening of the upper ridge/height falls across the northern Plains vicinity. Early in the day, a weak shortwave impulse and remnant convection/cloud debris will move across portions of ND/MN. Meanwhile, a cold front will develop east/southeast across the Dakotas into northern MN through early Friday. A corridor of rich boundary layer moisture with dewpoints generally in the mid 60s to near 70 F will be in place ahead of the cold front. However, stronger forcing for ascent will not arrive until later in the evening/overnight. It is unclear how much diurnal convection may develop due to weaker forcing and capping. If a storm can form ahead of the front during the afternoon, a corridor of 2000-3000 J/kg MLCAPE will be in place amid 30+ kt effective shear. Strong gusts and hail would be possible with cellular activity through early evening. More likely, convection will develop during the evening/nighttime hours across parts of the region. Initial storms may develop in the post-frontal upslope regime across eastern WY/western SD and develop east across SD overnight. It is unclear how intense these initial storms further west will be, and probabilities may need to be expanded westward in subsequent outlooks if confidence increases. Once storms interact with better moisture/instability further east, isolated severe gusts or marginal hail will be possible. ..Leitman.. 08/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE DAKOTAS INTO MINNESOTA... ...SUMMARY... An isolated severe threat is expected to develop Thursday into Thursday night over parts of the Dakotas into Minnesota, with severe gusts and hail possible. ...Northern Plains into Minnesota... An upper shortwave trough/cyclone will deepen and develop east across the Canadian Prairies on Thursday. This will result in dampening of the upper ridge/height falls across the northern Plains vicinity. Early in the day, a weak shortwave impulse and remnant convection/cloud debris will move across portions of ND/MN. Meanwhile, a cold front will develop east/southeast across the Dakotas into northern MN through early Friday. A corridor of rich boundary layer moisture with dewpoints generally in the mid 60s to near 70 F will be in place ahead of the cold front. However, stronger forcing for ascent will not arrive until later in the evening/overnight. It is unclear how much diurnal convection may develop due to weaker forcing and capping. If a storm can form ahead of the front during the afternoon, a corridor of 2000-3000 J/kg MLCAPE will be in place amid 30+ kt effective shear. Strong gusts and hail would be possible with cellular activity through early evening. More likely, convection will develop during the evening/nighttime hours across parts of the region. Initial storms may develop in the post-frontal upslope regime across eastern WY/western SD and develop east across SD overnight. It is unclear how intense these initial storms further west will be, and probabilities may need to be expanded westward in subsequent outlooks if confidence increases. Once storms interact with better moisture/instability further east, isolated severe gusts or marginal hail will be possible. ..Leitman.. 08/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE DAKOTAS INTO MINNESOTA... ...SUMMARY... An isolated severe threat is expected to develop Thursday into Thursday night over parts of the Dakotas into Minnesota, with severe gusts and hail possible. ...Northern Plains into Minnesota... An upper shortwave trough/cyclone will deepen and develop east across the Canadian Prairies on Thursday. This will result in dampening of the upper ridge/height falls across the northern Plains vicinity. Early in the day, a weak shortwave impulse and remnant convection/cloud debris will move across portions of ND/MN. Meanwhile, a cold front will develop east/southeast across the Dakotas into northern MN through early Friday. A corridor of rich boundary layer moisture with dewpoints generally in the mid 60s to near 70 F will be in place ahead of the cold front. However, stronger forcing for ascent will not arrive until later in the evening/overnight. It is unclear how much diurnal convection may develop due to weaker forcing and capping. If a storm can form ahead of the front during the afternoon, a corridor of 2000-3000 J/kg MLCAPE will be in place amid 30+ kt effective shear. Strong gusts and hail would be possible with cellular activity through early evening. More likely, convection will develop during the evening/nighttime hours across parts of the region. Initial storms may develop in the post-frontal upslope regime across eastern WY/western SD and develop east across SD overnight. It is unclear how intense these initial storms further west will be, and probabilities may need to be expanded westward in subsequent outlooks if confidence increases. Once storms interact with better moisture/instability further east, isolated severe gusts or marginal hail will be possible. ..Leitman.. 08/20/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Aug 20 2025 Valid 211200Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE DAKOTAS INTO MINNESOTA... ...SUMMARY... An isolated severe threat is expected to develop Thursday into Thursday night over parts of the Dakotas into Minnesota, with severe gusts and hail possible. ...Northern Plains into Minnesota... An upper shortwave trough/cyclone will deepen and develop east across the Canadian Prairies on Thursday. This will result in dampening of the upper ridge/height falls across the northern Plains vicinity. Early in the day, a weak shortwave impulse and remnant convection/cloud debris will move across portions of ND/MN. Meanwhile, a cold front will develop east/southeast across the Dakotas into northern MN through early Friday. A corridor of rich boundary layer moisture with dewpoints generally in the mid 60s to near 70 F will be in place ahead of the cold front. However, stronger forcing for ascent will not arrive until later in the evening/overnight. It is unclear how much diurnal convection may develop due to weaker forcing and capping. If a storm can form ahead of the front during the afternoon, a corridor of 2000-3000 J/kg MLCAPE will be in place amid 30+ kt effective shear. Strong gusts and hail would be possible with cellular activity through early evening. More likely, convection will develop during the evening/nighttime hours across parts of the region. Initial storms may develop in the post-frontal upslope regime across eastern WY/western SD and develop east across SD overnight. It is unclear how intense these initial storms further west will be, and probabilities may need to be expanded westward in subsequent outlooks if confidence increases. Once storms interact with better moisture/instability further east, isolated severe gusts or marginal hail will be possible. ..Leitman.. 08/20/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Wed Aug 20 2025 Valid 201630Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. ..Gleason/Wendt.. 08/20/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Wed Aug 20 2025 Valid 201630Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. ..Gleason/Wendt.. 08/20/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Wed Aug 20 2025 Valid 201630Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEAST...AND THE NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Southeast may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across parts of central/eastern Montana and northern North Dakota, mainly this evening and overnight. ...Texas into the Lower Mississippi Valley and Southeast... A convectively reinforced front/outflow boundary from earlier/ongoing convection should once again provide a focus for renewed convective development this afternoon from parts of west-central TX eastward into the lower MS Valley and Southeast. Mid-level flow and related deep-layer shear are expected to remain weak, which should generally limit thunderstorm organization. Still, a moderately to strongly unstable environment will exist along/south of the front with continued daytime heating, with scattered to numerous thunderstorms likely. Similar to yesterday, wet microbursts from convective downdrafts may produce isolated damaging winds as low-level lapse rates become steepened. These thunderstorms should weaken through the evening with the loss of daytime heating. ...Northern Plains... The northern Plains will be influenced by late-day/overnight mid-level height falls as a shortwave trough moves eastward from the Canadian/northern Rockies, with a related cold front moving across central/eastern MT into ND tonight. A narrow corridor of moderate to strong instability will likely develop along/ahead of the cold front, and near a pre-frontal surface trough. But, warm mid-level temperatures and a capped airmass will likely exist along/south of the international border, which should inhibit robust convective development for much of the day. One exception may be in the post-frontal environment across eastern MT this evening/tonight. The environment here should be conducive to isolated severe thunderstorms capable of producing both large hail and severe gusts. While the risk for severe thunderstorms appears more conditional into ND where stronger destabilization is expected, isolated convective development may still occur across northwestern ND in proximity to the surface low/front late this afternoon, and perhaps more so this evening/overnight. Should this occur, forecast soundings indicate the environment would support isolated supercell development with a related hail/wind threat. ..Gleason/Wendt.. 08/20/2025 Read more