Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Wed Aug 27 2025 Valid 271200Z - 281200Z ...Synopsis... A pair of convectively augmented midlevel lows will track northward across the Northwest today. The associated forcing for ascent coupled with an influx of deepening midlevel moisture will support sufficient buoyancy for isolated/embedded lightning within high-based showers. While storm coverage may be somewhat limited (5-10 percent), any embedded storms may pose a risk of lightning-induced ignitions and locally gusty winds across parts of WA into the ID Panhandle and far northwest MT, given dry fuels. Farther south, a continuation of mixed wet/dry thunderstorms are expected across OR into northern CA, though preceding days of modest rainfall limits confidence in the overall threat. ..Weinman.. 08/27/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Wed Aug 27 2025 Valid 281200Z - 291200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE ARKLATEX... ...SUMMARY... Strong thunderstorms, with an isolated severe wind and hail threat, are possible across parts of the southern Plains into the Arklatex tomorrow (Thursday) afternoon and evening. ...Synopsis... A mid-level trough will amplify along the East Coast as an upper ridge builds across the southern High Plains tomorrow (Thursday). A mid-level impulse will rotate around the upper trough and traverse the southern Plains/Southeast through the period, encouraging the southward sagging of a surface cold front. Multiple rounds of thunderstorms are likely across portions of the southern Plains into the Arklatex ahead of this front. The best chance for stronger thunderstorms will be during the afternoon, where storms will benefit from an optimal combination of modest buoyancy and vertical wind shear. ...Southern High Plains into the Arklatex... An MCS will likely be ongoing at the start of the period somewhere along the eastern fringes of the southern Plains. An outflow boundary is expected to sag southward, in tandem with or just ahead of the aforementioned cold front, acting as a source of lift to rejuvenate thunderstorm activity with afternoon heating. Surface temperatures will warm into the 90s F amid upper 60s to 70 F surface dewpoints, yielding over 2000 J/kg MLCAPE. Southwesterly surface winds, veering to northwesterly while strengthening with height, will support 25-35 kts of effective bulk shear. Any storms that redevelop along the aforementioned outflow boundary in this environment could become strong, from central OK to the AR/LA border. A few of the more intense storms may be accompanied by an isolated severe wind/hail threat, warranting the introduction of Category 1/Marginal risk probabilities. ..Squitieri.. 08/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Wed Aug 27 2025 Valid 281200Z - 291200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE ARKLATEX... ...SUMMARY... Strong thunderstorms, with an isolated severe wind and hail threat, are possible across parts of the southern Plains into the Arklatex tomorrow (Thursday) afternoon and evening. ...Synopsis... A mid-level trough will amplify along the East Coast as an upper ridge builds across the southern High Plains tomorrow (Thursday). A mid-level impulse will rotate around the upper trough and traverse the southern Plains/Southeast through the period, encouraging the southward sagging of a surface cold front. Multiple rounds of thunderstorms are likely across portions of the southern Plains into the Arklatex ahead of this front. The best chance for stronger thunderstorms will be during the afternoon, where storms will benefit from an optimal combination of modest buoyancy and vertical wind shear. ...Southern High Plains into the Arklatex... An MCS will likely be ongoing at the start of the period somewhere along the eastern fringes of the southern Plains. An outflow boundary is expected to sag southward, in tandem with or just ahead of the aforementioned cold front, acting as a source of lift to rejuvenate thunderstorm activity with afternoon heating. Surface temperatures will warm into the 90s F amid upper 60s to 70 F surface dewpoints, yielding over 2000 J/kg MLCAPE. Southwesterly surface winds, veering to northwesterly while strengthening with height, will support 25-35 kts of effective bulk shear. Any storms that redevelop along the aforementioned outflow boundary in this environment could become strong, from central OK to the AR/LA border. A few of the more intense storms may be accompanied by an isolated severe wind/hail threat, warranting the introduction of Category 1/Marginal risk probabilities. ..Squitieri.. 08/27/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CDT Wed Aug 27 2025 Valid 281200Z - 291200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE ARKLATEX... ...SUMMARY... Strong thunderstorms, with an isolated severe wind and hail threat, are possible across parts of the southern Plains into the Arklatex tomorrow (Thursday) afternoon and evening. ...Synopsis... A mid-level trough will amplify along the East Coast as an upper ridge builds across the southern High Plains tomorrow (Thursday). A mid-level impulse will rotate around the upper trough and traverse the southern Plains/Southeast through the period, encouraging the southward sagging of a surface cold front. Multiple rounds of thunderstorms are likely across portions of the southern Plains into the Arklatex ahead of this front. The best chance for stronger thunderstorms will be during the afternoon, where storms will benefit from an optimal combination of modest buoyancy and vertical wind shear. ...Southern High Plains into the Arklatex... An MCS will likely be ongoing at the start of the period somewhere along the eastern fringes of the southern Plains. An outflow boundary is expected to sag southward, in tandem with or just ahead of the aforementioned cold front, acting as a source of lift to rejuvenate thunderstorm activity with afternoon heating. Surface temperatures will warm into the 90s F amid upper 60s to 70 F surface dewpoints, yielding over 2000 J/kg MLCAPE. Southwesterly surface winds, veering to northwesterly while strengthening with height, will support 25-35 kts of effective bulk shear. Any storms that redevelop along the aforementioned outflow boundary in this environment could become strong, from central OK to the AR/LA border. A few of the more intense storms may be accompanied by an isolated severe wind/hail threat, warranting the introduction of Category 1/Marginal risk probabilities. ..Squitieri.. 08/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Wed Aug 27 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. today, though a few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range where locally gusty winds and small hail are possible. ...Synopsis... A broad upper-level trough will be present across the eastern CONUS today with weak ridging across the western CONUS. Surface high pressure will weaken slightly and shift east across the Appalachians into the Mid-Atlantic/Carolinas. A cold front along the Gulf Coast will extend into the Central Plains. ...Upper Midwest... A region of moderate instability and shear is forecast to develop across southern Minnesota this afternoon. A lead shortwave trough (currently across north Dakota) is expected to move through southern Minnesota around mid-day with weak height rises and subsidence in its wake. However, by the evening, an additional shortwave trough (traversing the western edge of the broader trough) may result in isolated storm development by late afternoon/early evening. Some forecast sounding, particularly the NAM, would support a few strong to isolated severe storms with a threat for large hail. However, consensus guidance is not as unstable and therefore, any severe threat may remain mostly isolated. Therefore, no severe weather probabilities will be included at this time. ...Central High Plains into western Kansas... Thunderstorms across the central High Plains may congeal into a cluster as they move into western Kansas this evening. A belt of stronger mid-level flow (35 to 45 knots) on the southwest periphery of the large-scale trough will provide favorable deep-layer shear across the region. However, despite the favorable shear, weak mid-level lapse rates will limit overall instability. A few stronger storms capable of damaging winds will be possible, but this threat is expected to be too low/limited to warrant severe weather probabilities. ..Bentley/Weinman.. 08/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Wed Aug 27 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. today, though a few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range where locally gusty winds and small hail are possible. ...Synopsis... A broad upper-level trough will be present across the eastern CONUS today with weak ridging across the western CONUS. Surface high pressure will weaken slightly and shift east across the Appalachians into the Mid-Atlantic/Carolinas. A cold front along the Gulf Coast will extend into the Central Plains. ...Upper Midwest... A region of moderate instability and shear is forecast to develop across southern Minnesota this afternoon. A lead shortwave trough (currently across north Dakota) is expected to move through southern Minnesota around mid-day with weak height rises and subsidence in its wake. However, by the evening, an additional shortwave trough (traversing the western edge of the broader trough) may result in isolated storm development by late afternoon/early evening. Some forecast sounding, particularly the NAM, would support a few strong to isolated severe storms with a threat for large hail. However, consensus guidance is not as unstable and therefore, any severe threat may remain mostly isolated. Therefore, no severe weather probabilities will be included at this time. ...Central High Plains into western Kansas... Thunderstorms across the central High Plains may congeal into a cluster as they move into western Kansas this evening. A belt of stronger mid-level flow (35 to 45 knots) on the southwest periphery of the large-scale trough will provide favorable deep-layer shear across the region. However, despite the favorable shear, weak mid-level lapse rates will limit overall instability. A few stronger storms capable of damaging winds will be possible, but this threat is expected to be too low/limited to warrant severe weather probabilities. ..Bentley/Weinman.. 08/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Wed Aug 27 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. today, though a few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range where locally gusty winds and small hail are possible. ...Synopsis... A broad upper-level trough will be present across the eastern CONUS today with weak ridging across the western CONUS. Surface high pressure will weaken slightly and shift east across the Appalachians into the Mid-Atlantic/Carolinas. A cold front along the Gulf Coast will extend into the Central Plains. ...Upper Midwest... A region of moderate instability and shear is forecast to develop across southern Minnesota this afternoon. A lead shortwave trough (currently across north Dakota) is expected to move through southern Minnesota around mid-day with weak height rises and subsidence in its wake. However, by the evening, an additional shortwave trough (traversing the western edge of the broader trough) may result in isolated storm development by late afternoon/early evening. Some forecast sounding, particularly the NAM, would support a few strong to isolated severe storms with a threat for large hail. However, consensus guidance is not as unstable and therefore, any severe threat may remain mostly isolated. Therefore, no severe weather probabilities will be included at this time. ...Central High Plains into western Kansas... Thunderstorms across the central High Plains may congeal into a cluster as they move into western Kansas this evening. A belt of stronger mid-level flow (35 to 45 knots) on the southwest periphery of the large-scale trough will provide favorable deep-layer shear across the region. However, despite the favorable shear, weak mid-level lapse rates will limit overall instability. A few stronger storms capable of damaging winds will be possible, but this threat is expected to be too low/limited to warrant severe weather probabilities. ..Bentley/Weinman.. 08/27/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Wed Aug 27 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. today, though a few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range where locally gusty winds and small hail are possible. ...Synopsis... A broad upper-level trough will be present across the eastern CONUS today with weak ridging across the western CONUS. Surface high pressure will weaken slightly and shift east across the Appalachians into the Mid-Atlantic/Carolinas. A cold front along the Gulf Coast will extend into the Central Plains. ...Upper Midwest... A region of moderate instability and shear is forecast to develop across southern Minnesota this afternoon. A lead shortwave trough (currently across north Dakota) is expected to move through southern Minnesota around mid-day with weak height rises and subsidence in its wake. However, by the evening, an additional shortwave trough (traversing the western edge of the broader trough) may result in isolated storm development by late afternoon/early evening. Some forecast sounding, particularly the NAM, would support a few strong to isolated severe storms with a threat for large hail. However, consensus guidance is not as unstable and therefore, any severe threat may remain mostly isolated. Therefore, no severe weather probabilities will be included at this time. ...Central High Plains into western Kansas... Thunderstorms across the central High Plains may congeal into a cluster as they move into western Kansas this evening. A belt of stronger mid-level flow (35 to 45 knots) on the southwest periphery of the large-scale trough will provide favorable deep-layer shear across the region. However, despite the favorable shear, weak mid-level lapse rates will limit overall instability. A few stronger storms capable of damaging winds will be possible, but this threat is expected to be too low/limited to warrant severe weather probabilities. ..Bentley/Weinman.. 08/27/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 PM CDT Tue Aug 26 2025 Valid 270100Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...Discussion... Mostly unorganized thunderstorm activity has been prevalent across the western CONUS this evening. A few stronger storms and isolated stronger cores have been present. However, the severe potential has been limited and will remain so through the overnight period. ..Bentley.. 08/27/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 PM CDT Tue Aug 26 2025 Valid 270100Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...Discussion... Mostly unorganized thunderstorm activity has been prevalent across the western CONUS this evening. A few stronger storms and isolated stronger cores have been present. However, the severe potential has been limited and will remain so through the overnight period. ..Bentley.. 08/27/2025 Read more

No watches are valid as of Tue Aug 26 23:33:02 UTC 2025.

No Mesoscale Discussions are in effect as of Tue Aug 26 23:33:02 UTC 2025.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0421 PM CDT Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0421 PM CDT Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0421 PM CDT Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0421 PM CDT Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0421 PM CDT Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0421 PM CDT Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 26 2025 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...20Z Update... Isolated strong storms remain possible in the Four Corners vicinity this afternoon. Observed 18Z soundings from Tucson and Flagstaff indicate relatively poor mid-level lapse rates and marginal effective shear. Areas of stronger surface heating could promote stronger outflow winds, but organized severe storms are still unlikely. Only minor modifications were made to the general thunder area based on current observations. Additional forecast details are in the previous discussion below. ..Wendt.. 08/26/2025 .PREV DISCUSSION... /ISSUED 1120 AM CDT Tue Aug 26 2025/ ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 26 2025 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...20Z Update... Isolated strong storms remain possible in the Four Corners vicinity this afternoon. Observed 18Z soundings from Tucson and Flagstaff indicate relatively poor mid-level lapse rates and marginal effective shear. Areas of stronger surface heating could promote stronger outflow winds, but organized severe storms are still unlikely. Only minor modifications were made to the general thunder area based on current observations. Additional forecast details are in the previous discussion below. ..Wendt.. 08/26/2025 .PREV DISCUSSION... /ISSUED 1120 AM CDT Tue Aug 26 2025/ ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. Read more