Severe Storms

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

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

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

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0954 AM CDT Wed Aug 20 2025 Valid 201700Z - 211200Z Isolated to scattered high-based showers and thunderstorms are moving north-northeast near the Nevada/Utah border into southern/eastern Idaho and western Wyoming this morning. Elevated winds/RH are likely from northeast Wyoming into western Dakota and southeast Montana, but fire danger is near to below average across these areas. Overall, the forecast remains on track, and please see the previous discussion for more details. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Aug 20 2025/ ...Synopsis... A strong ridge of high pressure building over the central US is forecast to gradually move west while a weak trough on the western edge, suppresses the northern extent. The increasingly strong height gradient along the western periphery of the ridge will bolster mid-level winds aloft over the Northwest and northern Great Basin. At the surface, a cold front will move into the western Great Basin before stalling this afternoon. The front, and increased flow aloft will support gusty surface winds and isolated storms, increasing fire danger today and tonight. ...Great Basin... Several hours of dry/breezy conditions are expected this afternoon with the breakdown of the upper-level ridge. Very warm temperatures are expected, supporting deep vertical mixing and low boundary-layer RH. West/southwesterly winds of 15-20 mph with gusts of 20-30 mph near the front, and RH below 15% on a widespread basis will support elevated to locally critical fire-weather conditions from southern ID into the Great Basin. Increased southwesterly flow aloft on the western edge of the ridge will help monsoon moisture (PWATs 0.6-0.8 inches) advect northward over NV and western UT. The surface cold front associated with the upper trough will stall over the western Great Basin, serving as a focus for isolated thunderstorm development through the afternoon. Uncertainty remains high regarding coverage of thunderstorms, especially with southern extent. While moisture and instability will be more limited, enough instability and forcing are expected to produce isolated high-based showers and thunderstorms capable of dry lightning. Should these storms develop they may track eastward, persisting overnight into eastern ID and western MT with a continued threat for dry strikes. Additionally, any active large wildfires may have increased chances of deep pyroconvection/localized extreme fire behavior given the steep lapse rates and unstable troposphere. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0954 AM CDT Wed Aug 20 2025 Valid 201700Z - 211200Z Isolated to scattered high-based showers and thunderstorms are moving north-northeast near the Nevada/Utah border into southern/eastern Idaho and western Wyoming this morning. Elevated winds/RH are likely from northeast Wyoming into western Dakota and southeast Montana, but fire danger is near to below average across these areas. Overall, the forecast remains on track, and please see the previous discussion for more details. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Aug 20 2025/ ...Synopsis... A strong ridge of high pressure building over the central US is forecast to gradually move west while a weak trough on the western edge, suppresses the northern extent. The increasingly strong height gradient along the western periphery of the ridge will bolster mid-level winds aloft over the Northwest and northern Great Basin. At the surface, a cold front will move into the western Great Basin before stalling this afternoon. The front, and increased flow aloft will support gusty surface winds and isolated storms, increasing fire danger today and tonight. ...Great Basin... Several hours of dry/breezy conditions are expected this afternoon with the breakdown of the upper-level ridge. Very warm temperatures are expected, supporting deep vertical mixing and low boundary-layer RH. West/southwesterly winds of 15-20 mph with gusts of 20-30 mph near the front, and RH below 15% on a widespread basis will support elevated to locally critical fire-weather conditions from southern ID into the Great Basin. Increased southwesterly flow aloft on the western edge of the ridge will help monsoon moisture (PWATs 0.6-0.8 inches) advect northward over NV and western UT. The surface cold front associated with the upper trough will stall over the western Great Basin, serving as a focus for isolated thunderstorm development through the afternoon. Uncertainty remains high regarding coverage of thunderstorms, especially with southern extent. While moisture and instability will be more limited, enough instability and forcing are expected to produce isolated high-based showers and thunderstorms capable of dry lightning. Should these storms develop they may track eastward, persisting overnight into eastern ID and western MT with a continued threat for dry strikes. Additionally, any active large wildfires may have increased chances of deep pyroconvection/localized extreme fire behavior given the steep lapse rates and unstable troposphere. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0954 AM CDT Wed Aug 20 2025 Valid 201700Z - 211200Z Isolated to scattered high-based showers and thunderstorms are moving north-northeast near the Nevada/Utah border into southern/eastern Idaho and western Wyoming this morning. Elevated winds/RH are likely from northeast Wyoming into western Dakota and southeast Montana, but fire danger is near to below average across these areas. Overall, the forecast remains on track, and please see the previous discussion for more details. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Aug 20 2025/ ...Synopsis... A strong ridge of high pressure building over the central US is forecast to gradually move west while a weak trough on the western edge, suppresses the northern extent. The increasingly strong height gradient along the western periphery of the ridge will bolster mid-level winds aloft over the Northwest and northern Great Basin. At the surface, a cold front will move into the western Great Basin before stalling this afternoon. The front, and increased flow aloft will support gusty surface winds and isolated storms, increasing fire danger today and tonight. ...Great Basin... Several hours of dry/breezy conditions are expected this afternoon with the breakdown of the upper-level ridge. Very warm temperatures are expected, supporting deep vertical mixing and low boundary-layer RH. West/southwesterly winds of 15-20 mph with gusts of 20-30 mph near the front, and RH below 15% on a widespread basis will support elevated to locally critical fire-weather conditions from southern ID into the Great Basin. Increased southwesterly flow aloft on the western edge of the ridge will help monsoon moisture (PWATs 0.6-0.8 inches) advect northward over NV and western UT. The surface cold front associated with the upper trough will stall over the western Great Basin, serving as a focus for isolated thunderstorm development through the afternoon. Uncertainty remains high regarding coverage of thunderstorms, especially with southern extent. While moisture and instability will be more limited, enough instability and forcing are expected to produce isolated high-based showers and thunderstorms capable of dry lightning. Should these storms develop they may track eastward, persisting overnight into eastern ID and western MT with a continued threat for dry strikes. Additionally, any active large wildfires may have increased chances of deep pyroconvection/localized extreme fire behavior given the steep lapse rates and unstable troposphere. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0954 AM CDT Wed Aug 20 2025 Valid 201700Z - 211200Z Isolated to scattered high-based showers and thunderstorms are moving north-northeast near the Nevada/Utah border into southern/eastern Idaho and western Wyoming this morning. Elevated winds/RH are likely from northeast Wyoming into western Dakota and southeast Montana, but fire danger is near to below average across these areas. Overall, the forecast remains on track, and please see the previous discussion for more details. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Aug 20 2025/ ...Synopsis... A strong ridge of high pressure building over the central US is forecast to gradually move west while a weak trough on the western edge, suppresses the northern extent. The increasingly strong height gradient along the western periphery of the ridge will bolster mid-level winds aloft over the Northwest and northern Great Basin. At the surface, a cold front will move into the western Great Basin before stalling this afternoon. The front, and increased flow aloft will support gusty surface winds and isolated storms, increasing fire danger today and tonight. ...Great Basin... Several hours of dry/breezy conditions are expected this afternoon with the breakdown of the upper-level ridge. Very warm temperatures are expected, supporting deep vertical mixing and low boundary-layer RH. West/southwesterly winds of 15-20 mph with gusts of 20-30 mph near the front, and RH below 15% on a widespread basis will support elevated to locally critical fire-weather conditions from southern ID into the Great Basin. Increased southwesterly flow aloft on the western edge of the ridge will help monsoon moisture (PWATs 0.6-0.8 inches) advect northward over NV and western UT. The surface cold front associated with the upper trough will stall over the western Great Basin, serving as a focus for isolated thunderstorm development through the afternoon. Uncertainty remains high regarding coverage of thunderstorms, especially with southern extent. While moisture and instability will be more limited, enough instability and forcing are expected to produce isolated high-based showers and thunderstorms capable of dry lightning. Should these storms develop they may track eastward, persisting overnight into eastern ID and western MT with a continued threat for dry strikes. Additionally, any active large wildfires may have increased chances of deep pyroconvection/localized extreme fire behavior given the steep lapse rates and unstable troposphere. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0954 AM CDT Wed Aug 20 2025 Valid 201700Z - 211200Z Isolated to scattered high-based showers and thunderstorms are moving north-northeast near the Nevada/Utah border into southern/eastern Idaho and western Wyoming this morning. Elevated winds/RH are likely from northeast Wyoming into western Dakota and southeast Montana, but fire danger is near to below average across these areas. Overall, the forecast remains on track, and please see the previous discussion for more details. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Aug 20 2025/ ...Synopsis... A strong ridge of high pressure building over the central US is forecast to gradually move west while a weak trough on the western edge, suppresses the northern extent. The increasingly strong height gradient along the western periphery of the ridge will bolster mid-level winds aloft over the Northwest and northern Great Basin. At the surface, a cold front will move into the western Great Basin before stalling this afternoon. The front, and increased flow aloft will support gusty surface winds and isolated storms, increasing fire danger today and tonight. ...Great Basin... Several hours of dry/breezy conditions are expected this afternoon with the breakdown of the upper-level ridge. Very warm temperatures are expected, supporting deep vertical mixing and low boundary-layer RH. West/southwesterly winds of 15-20 mph with gusts of 20-30 mph near the front, and RH below 15% on a widespread basis will support elevated to locally critical fire-weather conditions from southern ID into the Great Basin. Increased southwesterly flow aloft on the western edge of the ridge will help monsoon moisture (PWATs 0.6-0.8 inches) advect northward over NV and western UT. The surface cold front associated with the upper trough will stall over the western Great Basin, serving as a focus for isolated thunderstorm development through the afternoon. Uncertainty remains high regarding coverage of thunderstorms, especially with southern extent. While moisture and instability will be more limited, enough instability and forcing are expected to produce isolated high-based showers and thunderstorms capable of dry lightning. Should these storms develop they may track eastward, persisting overnight into eastern ID and western MT with a continued threat for dry strikes. Additionally, any active large wildfires may have increased chances of deep pyroconvection/localized extreme fire behavior given the steep lapse rates and unstable troposphere. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0954 AM CDT Wed Aug 20 2025 Valid 201700Z - 211200Z Isolated to scattered high-based showers and thunderstorms are moving north-northeast near the Nevada/Utah border into southern/eastern Idaho and western Wyoming this morning. Elevated winds/RH are likely from northeast Wyoming into western Dakota and southeast Montana, but fire danger is near to below average across these areas. Overall, the forecast remains on track, and please see the previous discussion for more details. ..Nauslar.. 08/20/2025 .PREV DISCUSSION... /ISSUED 0156 AM CDT Wed Aug 20 2025/ ...Synopsis... A strong ridge of high pressure building over the central US is forecast to gradually move west while a weak trough on the western edge, suppresses the northern extent. The increasingly strong height gradient along the western periphery of the ridge will bolster mid-level winds aloft over the Northwest and northern Great Basin. At the surface, a cold front will move into the western Great Basin before stalling this afternoon. The front, and increased flow aloft will support gusty surface winds and isolated storms, increasing fire danger today and tonight. ...Great Basin... Several hours of dry/breezy conditions are expected this afternoon with the breakdown of the upper-level ridge. Very warm temperatures are expected, supporting deep vertical mixing and low boundary-layer RH. West/southwesterly winds of 15-20 mph with gusts of 20-30 mph near the front, and RH below 15% on a widespread basis will support elevated to locally critical fire-weather conditions from southern ID into the Great Basin. Increased southwesterly flow aloft on the western edge of the ridge will help monsoon moisture (PWATs 0.6-0.8 inches) advect northward over NV and western UT. The surface cold front associated with the upper trough will stall over the western Great Basin, serving as a focus for isolated thunderstorm development through the afternoon. Uncertainty remains high regarding coverage of thunderstorms, especially with southern extent. While moisture and instability will be more limited, enough instability and forcing are expected to produce isolated high-based showers and thunderstorms capable of dry lightning. Should these storms develop they may track eastward, persisting overnight into eastern ID and western MT with a continued threat for dry strikes. Additionally, any active large wildfires may have increased chances of deep pyroconvection/localized extreme fire behavior given the steep lapse rates and unstable troposphere. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0838 AM CDT Wed Aug 20 2025 Valid 201300Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS/DEEP SOUTH AND NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Gulf Coast states may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across eastern Montana and northern North Dakota. ...Texas to Lower Mississippi Valley/Gulf Coast States... A convectively augmented effective front will continue to progress southward, southward-shifting the potential for microburst-related wind damage regionally. Diurnal heating of a moist boundary layer will result in a moderately to strongly unstable and weakly capped airmass by afternoon, with the strongest buoyancy (2500+ J/kg MLCAPE) expected across central/east Texas east-northeastward to Mississippi/western Alabama/southern Tennessee. Some small-scale clusters may evolve, but weak vertical shear will otherwise tend to keep the overall pulse-type damaging wind potential very isolated. ...Northern Plains... The region will be influenced by late-day/nighttime height falls as a shortwave trough emerges eastward from the Canadian Rockies, with an eastward-advancing cold front moving across eastern Montana into North Dakota tonight. A narrow corridor of moderate to large buoyancy is expected along/ahead of the surface cold front, and near a pre-frontal surface trough. Beneath a plume of warm elevated mixed-layer air, mid/upper-level support for the initiation of boundary-layer based thunderstorm development is forecast to generally remain north of the international border. One exception may be in the post-frontal environment across eastern Montana. The environment would be conducive to a few severe storms capable of hail/wind. While the risk for severe thunderstorms appears largely conditional into North Dakota where stronger destabilization is expected, isolated deeper convective development is plausible across northwestern North Dakota in proximity to the surface low/front late this afternoon, and more so this evening. Should this occur, forecast soundings indicate the environment would support isolated supercell development and related severe-weather risks. ..Guyer/Marsh.. 08/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0838 AM CDT Wed Aug 20 2025 Valid 201300Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS/DEEP SOUTH AND NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Gulf Coast states may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across eastern Montana and northern North Dakota. ...Texas to Lower Mississippi Valley/Gulf Coast States... A convectively augmented effective front will continue to progress southward, southward-shifting the potential for microburst-related wind damage regionally. Diurnal heating of a moist boundary layer will result in a moderately to strongly unstable and weakly capped airmass by afternoon, with the strongest buoyancy (2500+ J/kg MLCAPE) expected across central/east Texas east-northeastward to Mississippi/western Alabama/southern Tennessee. Some small-scale clusters may evolve, but weak vertical shear will otherwise tend to keep the overall pulse-type damaging wind potential very isolated. ...Northern Plains... The region will be influenced by late-day/nighttime height falls as a shortwave trough emerges eastward from the Canadian Rockies, with an eastward-advancing cold front moving across eastern Montana into North Dakota tonight. A narrow corridor of moderate to large buoyancy is expected along/ahead of the surface cold front, and near a pre-frontal surface trough. Beneath a plume of warm elevated mixed-layer air, mid/upper-level support for the initiation of boundary-layer based thunderstorm development is forecast to generally remain north of the international border. One exception may be in the post-frontal environment across eastern Montana. The environment would be conducive to a few severe storms capable of hail/wind. While the risk for severe thunderstorms appears largely conditional into North Dakota where stronger destabilization is expected, isolated deeper convective development is plausible across northwestern North Dakota in proximity to the surface low/front late this afternoon, and more so this evening. Should this occur, forecast soundings indicate the environment would support isolated supercell development and related severe-weather risks. ..Guyer/Marsh.. 08/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0838 AM CDT Wed Aug 20 2025 Valid 201300Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS/DEEP SOUTH AND NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Gulf Coast states may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across eastern Montana and northern North Dakota. ...Texas to Lower Mississippi Valley/Gulf Coast States... A convectively augmented effective front will continue to progress southward, southward-shifting the potential for microburst-related wind damage regionally. Diurnal heating of a moist boundary layer will result in a moderately to strongly unstable and weakly capped airmass by afternoon, with the strongest buoyancy (2500+ J/kg MLCAPE) expected across central/east Texas east-northeastward to Mississippi/western Alabama/southern Tennessee. Some small-scale clusters may evolve, but weak vertical shear will otherwise tend to keep the overall pulse-type damaging wind potential very isolated. ...Northern Plains... The region will be influenced by late-day/nighttime height falls as a shortwave trough emerges eastward from the Canadian Rockies, with an eastward-advancing cold front moving across eastern Montana into North Dakota tonight. A narrow corridor of moderate to large buoyancy is expected along/ahead of the surface cold front, and near a pre-frontal surface trough. Beneath a plume of warm elevated mixed-layer air, mid/upper-level support for the initiation of boundary-layer based thunderstorm development is forecast to generally remain north of the international border. One exception may be in the post-frontal environment across eastern Montana. The environment would be conducive to a few severe storms capable of hail/wind. While the risk for severe thunderstorms appears largely conditional into North Dakota where stronger destabilization is expected, isolated deeper convective development is plausible across northwestern North Dakota in proximity to the surface low/front late this afternoon, and more so this evening. Should this occur, forecast soundings indicate the environment would support isolated supercell development and related severe-weather risks. ..Guyer/Marsh.. 08/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0838 AM CDT Wed Aug 20 2025 Valid 201300Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS/DEEP SOUTH AND NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Gulf Coast states may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across eastern Montana and northern North Dakota. ...Texas to Lower Mississippi Valley/Gulf Coast States... A convectively augmented effective front will continue to progress southward, southward-shifting the potential for microburst-related wind damage regionally. Diurnal heating of a moist boundary layer will result in a moderately to strongly unstable and weakly capped airmass by afternoon, with the strongest buoyancy (2500+ J/kg MLCAPE) expected across central/east Texas east-northeastward to Mississippi/western Alabama/southern Tennessee. Some small-scale clusters may evolve, but weak vertical shear will otherwise tend to keep the overall pulse-type damaging wind potential very isolated. ...Northern Plains... The region will be influenced by late-day/nighttime height falls as a shortwave trough emerges eastward from the Canadian Rockies, with an eastward-advancing cold front moving across eastern Montana into North Dakota tonight. A narrow corridor of moderate to large buoyancy is expected along/ahead of the surface cold front, and near a pre-frontal surface trough. Beneath a plume of warm elevated mixed-layer air, mid/upper-level support for the initiation of boundary-layer based thunderstorm development is forecast to generally remain north of the international border. One exception may be in the post-frontal environment across eastern Montana. The environment would be conducive to a few severe storms capable of hail/wind. While the risk for severe thunderstorms appears largely conditional into North Dakota where stronger destabilization is expected, isolated deeper convective development is plausible across northwestern North Dakota in proximity to the surface low/front late this afternoon, and more so this evening. Should this occur, forecast soundings indicate the environment would support isolated supercell development and related severe-weather risks. ..Guyer/Marsh.. 08/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0838 AM CDT Wed Aug 20 2025 Valid 201300Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS/DEEP SOUTH AND NORTHERN PLAINS... ...SUMMARY... Scattered thunderstorms from Texas across the Lower Mississippi Valley and Gulf Coast states may pose a risk for localized damaging wind gusts this afternoon and evening. Isolated severe thunderstorms may also occur across eastern Montana and northern North Dakota. ...Texas to Lower Mississippi Valley/Gulf Coast States... A convectively augmented effective front will continue to progress southward, southward-shifting the potential for microburst-related wind damage regionally. Diurnal heating of a moist boundary layer will result in a moderately to strongly unstable and weakly capped airmass by afternoon, with the strongest buoyancy (2500+ J/kg MLCAPE) expected across central/east Texas east-northeastward to Mississippi/western Alabama/southern Tennessee. Some small-scale clusters may evolve, but weak vertical shear will otherwise tend to keep the overall pulse-type damaging wind potential very isolated. ...Northern Plains... The region will be influenced by late-day/nighttime height falls as a shortwave trough emerges eastward from the Canadian Rockies, with an eastward-advancing cold front moving across eastern Montana into North Dakota tonight. A narrow corridor of moderate to large buoyancy is expected along/ahead of the surface cold front, and near a pre-frontal surface trough. Beneath a plume of warm elevated mixed-layer air, mid/upper-level support for the initiation of boundary-layer based thunderstorm development is forecast to generally remain north of the international border. One exception may be in the post-frontal environment across eastern Montana. The environment would be conducive to a few severe storms capable of hail/wind. While the risk for severe thunderstorms appears largely conditional into North Dakota where stronger destabilization is expected, isolated deeper convective development is plausible across northwestern North Dakota in proximity to the surface low/front late this afternoon, and more so this evening. Should this occur, forecast soundings indicate the environment would support isolated supercell development and related severe-weather risks. ..Guyer/Marsh.. 08/20/2025 Read more