Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0159 AM CDT Tue Aug 26 2025 Valid 261200Z - 271200Z ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ..Weinman.. 08/26/2025 ...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 0159 AM CDT Tue Aug 26 2025 Valid 261200Z - 271200Z ...Synopsis... One or more subtle midlevel disturbances will overspread the Northwest today, where well-established monsoonal moisture is in place. The associated forcing for ascent and sufficient buoyancy should support a mix of wet/dry high-based thunderstorms over the Cascades during afternoon into the evening. While thunderstorm coverage may remain somewhat limited (potentially 5-10 percent), any storms that form may pose a risk of new ignitions and gusty/erratic outflow winds. A continuation of mixed wet/dry thunderstorms is expected farther south into northern CA, though several days of rain casts uncertainty on fuel receptiveness -- precluding highlights at this time. ..Weinman.. 08/26/2025 ...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 1254 AM CDT Tue Aug 26 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. tomorrow (Wednesday). A few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range. ...Synopsis... Broad upper troughing will persist across the eastern U.S., with an embedded impulse ejecting into the Atlantic as a second impulse impinges on the Great Lakes. An upper ridge will persist over the Southwest while a weak mid-level cut-off low meanders across the Pacific Northwest. A surface high will become established east of the MS River, with low-level moisture poised to pivot around the surface high and advect northward across the Plains into the Great Lakes region, with scattered thunderstorms expected. Scattered thunderstorms will also be possible across portions of the High Plains during the afternoon given lee surface troughing, with elevated thunderstorms continuing into the central Plains overnight within a warm-air advection regime. The best chance for any strong storms would be over portions of the Colorado Front Range and the Upper Midwest, where an overlap of marginally favorable shear and instability may exist. ...Parts of the Upper Midwest... The second impulse pivoting around the broader upper trough over the Great Lakes will promote an organized round of thunderstorms within a deep-layer northwesterly flow regime. Modest mid-level lapse rates will overspread low 60s F dewpoints, resulting in up to 1200 J/kg of thin MLCAPE across extreme eastern SD toward the MN/IA border. Modest veering flow with height will encourage 25-35 kts of effective bulk shear as well. As such, a few strong storms with sub-severe wind and hail are possible around afternoon peak heating. ...Colorado Front Range... Upslope low-level flow across the central High Plains will support 60+ f surface dewpoints to advect northwestward toward the Colorado Front Range. Here, increasing westerly flow with height will support some speed shear, evident in forecast soundings as relatively straight hodographs. Lapse rates are expected to be poor (i.e. around 6.5 C/km), with MLCAPE peaking around 1000 J/kg via thin profiles. A few of the stronger storms may produce some wind and hail, but these hazards are currently expected to remain generally below severe limits. ..Squitieri.. 08/26/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue Aug 26 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. tomorrow (Wednesday). A few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range. ...Synopsis... Broad upper troughing will persist across the eastern U.S., with an embedded impulse ejecting into the Atlantic as a second impulse impinges on the Great Lakes. An upper ridge will persist over the Southwest while a weak mid-level cut-off low meanders across the Pacific Northwest. A surface high will become established east of the MS River, with low-level moisture poised to pivot around the surface high and advect northward across the Plains into the Great Lakes region, with scattered thunderstorms expected. Scattered thunderstorms will also be possible across portions of the High Plains during the afternoon given lee surface troughing, with elevated thunderstorms continuing into the central Plains overnight within a warm-air advection regime. The best chance for any strong storms would be over portions of the Colorado Front Range and the Upper Midwest, where an overlap of marginally favorable shear and instability may exist. ...Parts of the Upper Midwest... The second impulse pivoting around the broader upper trough over the Great Lakes will promote an organized round of thunderstorms within a deep-layer northwesterly flow regime. Modest mid-level lapse rates will overspread low 60s F dewpoints, resulting in up to 1200 J/kg of thin MLCAPE across extreme eastern SD toward the MN/IA border. Modest veering flow with height will encourage 25-35 kts of effective bulk shear as well. As such, a few strong storms with sub-severe wind and hail are possible around afternoon peak heating. ...Colorado Front Range... Upslope low-level flow across the central High Plains will support 60+ f surface dewpoints to advect northwestward toward the Colorado Front Range. Here, increasing westerly flow with height will support some speed shear, evident in forecast soundings as relatively straight hodographs. Lapse rates are expected to be poor (i.e. around 6.5 C/km), with MLCAPE peaking around 1000 J/kg via thin profiles. A few of the stronger storms may produce some wind and hail, but these hazards are currently expected to remain generally below severe limits. ..Squitieri.. 08/26/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue Aug 26 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. tomorrow (Wednesday). A few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range. ...Synopsis... Broad upper troughing will persist across the eastern U.S., with an embedded impulse ejecting into the Atlantic as a second impulse impinges on the Great Lakes. An upper ridge will persist over the Southwest while a weak mid-level cut-off low meanders across the Pacific Northwest. A surface high will become established east of the MS River, with low-level moisture poised to pivot around the surface high and advect northward across the Plains into the Great Lakes region, with scattered thunderstorms expected. Scattered thunderstorms will also be possible across portions of the High Plains during the afternoon given lee surface troughing, with elevated thunderstorms continuing into the central Plains overnight within a warm-air advection regime. The best chance for any strong storms would be over portions of the Colorado Front Range and the Upper Midwest, where an overlap of marginally favorable shear and instability may exist. ...Parts of the Upper Midwest... The second impulse pivoting around the broader upper trough over the Great Lakes will promote an organized round of thunderstorms within a deep-layer northwesterly flow regime. Modest mid-level lapse rates will overspread low 60s F dewpoints, resulting in up to 1200 J/kg of thin MLCAPE across extreme eastern SD toward the MN/IA border. Modest veering flow with height will encourage 25-35 kts of effective bulk shear as well. As such, a few strong storms with sub-severe wind and hail are possible around afternoon peak heating. ...Colorado Front Range... Upslope low-level flow across the central High Plains will support 60+ f surface dewpoints to advect northwestward toward the Colorado Front Range. Here, increasing westerly flow with height will support some speed shear, evident in forecast soundings as relatively straight hodographs. Lapse rates are expected to be poor (i.e. around 6.5 C/km), with MLCAPE peaking around 1000 J/kg via thin profiles. A few of the stronger storms may produce some wind and hail, but these hazards are currently expected to remain generally below severe limits. ..Squitieri.. 08/26/2025 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1254 AM CDT Tue Aug 26 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. tomorrow (Wednesday). A few stronger storms are possible across parts of the Upper Midwest and Colorado Front Range. ...Synopsis... Broad upper troughing will persist across the eastern U.S., with an embedded impulse ejecting into the Atlantic as a second impulse impinges on the Great Lakes. An upper ridge will persist over the Southwest while a weak mid-level cut-off low meanders across the Pacific Northwest. A surface high will become established east of the MS River, with low-level moisture poised to pivot around the surface high and advect northward across the Plains into the Great Lakes region, with scattered thunderstorms expected. Scattered thunderstorms will also be possible across portions of the High Plains during the afternoon given lee surface troughing, with elevated thunderstorms continuing into the central Plains overnight within a warm-air advection regime. The best chance for any strong storms would be over portions of the Colorado Front Range and the Upper Midwest, where an overlap of marginally favorable shear and instability may exist. ...Parts of the Upper Midwest... The second impulse pivoting around the broader upper trough over the Great Lakes will promote an organized round of thunderstorms within a deep-layer northwesterly flow regime. Modest mid-level lapse rates will overspread low 60s F dewpoints, resulting in up to 1200 J/kg of thin MLCAPE across extreme eastern SD toward the MN/IA border. Modest veering flow with height will encourage 25-35 kts of effective bulk shear as well. As such, a few strong storms with sub-severe wind and hail are possible around afternoon peak heating. ...Colorado Front Range... Upslope low-level flow across the central High Plains will support 60+ f surface dewpoints to advect northwestward toward the Colorado Front Range. Here, increasing westerly flow with height will support some speed shear, evident in forecast soundings as relatively straight hodographs. Lapse rates are expected to be poor (i.e. around 6.5 C/km), with MLCAPE peaking around 1000 J/kg via thin profiles. A few of the stronger storms may produce some wind and hail, but these hazards are currently expected to remain generally below severe limits. ..Squitieri.. 08/26/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Tue Aug 26 2025 Valid 261200Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are not expected across the continental U.S. on Tuesday. ...Synopsis... An expansive upper-level trough will be present across the eastern CONUS today. At the surface, a cool, dry airmass and high pressure will dominate most of the eastern CONUS, limiting thunderstorm potential. Widespread monsoonal thunderstorm activity will occur across much of the western CONUS. ...Southern Arizona... Weak instability is forecast across southern Arizona with sufficient heating for thunderstorm development this afternoon. Mid-level flow around 20 knots Tuesday morning will weaken slightly by the afternoon. This belt of enhanced flow may provide enough shear for a stronger multicell thunderstorm with an isolated damaging wind threat. However, overall, expect storm organization to be limited with mostly sub-severe convection due to weaker instability and shear than Monday. Given the number of storms across the western CONUS today, isolated damaging wind gusts may be possible. However, a more organized region/threat is not apparent. ..Bentley/Weinman.. 08/26/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Tue Aug 26 2025 Valid 261200Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are not expected across the continental U.S. on Tuesday. ...Synopsis... An expansive upper-level trough will be present across the eastern CONUS today. At the surface, a cool, dry airmass and high pressure will dominate most of the eastern CONUS, limiting thunderstorm potential. Widespread monsoonal thunderstorm activity will occur across much of the western CONUS. ...Southern Arizona... Weak instability is forecast across southern Arizona with sufficient heating for thunderstorm development this afternoon. Mid-level flow around 20 knots Tuesday morning will weaken slightly by the afternoon. This belt of enhanced flow may provide enough shear for a stronger multicell thunderstorm with an isolated damaging wind threat. However, overall, expect storm organization to be limited with mostly sub-severe convection due to weaker instability and shear than Monday. Given the number of storms across the western CONUS today, isolated damaging wind gusts may be possible. However, a more organized region/threat is not apparent. ..Bentley/Weinman.. 08/26/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Tue Aug 26 2025 Valid 261200Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are not expected across the continental U.S. on Tuesday. ...Synopsis... An expansive upper-level trough will be present across the eastern CONUS today. At the surface, a cool, dry airmass and high pressure will dominate most of the eastern CONUS, limiting thunderstorm potential. Widespread monsoonal thunderstorm activity will occur across much of the western CONUS. ...Southern Arizona... Weak instability is forecast across southern Arizona with sufficient heating for thunderstorm development this afternoon. Mid-level flow around 20 knots Tuesday morning will weaken slightly by the afternoon. This belt of enhanced flow may provide enough shear for a stronger multicell thunderstorm with an isolated damaging wind threat. However, overall, expect storm organization to be limited with mostly sub-severe convection due to weaker instability and shear than Monday. Given the number of storms across the western CONUS today, isolated damaging wind gusts may be possible. However, a more organized region/threat is not apparent. ..Bentley/Weinman.. 08/26/2025 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Tue Aug 26 2025 Valid 261200Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are not expected across the continental U.S. on Tuesday. ...Synopsis... An expansive upper-level trough will be present across the eastern CONUS today. At the surface, a cool, dry airmass and high pressure will dominate most of the eastern CONUS, limiting thunderstorm potential. Widespread monsoonal thunderstorm activity will occur across much of the western CONUS. ...Southern Arizona... Weak instability is forecast across southern Arizona with sufficient heating for thunderstorm development this afternoon. Mid-level flow around 20 knots Tuesday morning will weaken slightly by the afternoon. This belt of enhanced flow may provide enough shear for a stronger multicell thunderstorm with an isolated damaging wind threat. However, overall, expect storm organization to be limited with mostly sub-severe convection due to weaker instability and shear than Monday. Given the number of storms across the western CONUS today, isolated damaging wind gusts may be possible. However, a more organized region/threat is not apparent. ..Bentley/Weinman.. 08/26/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 PM CDT Mon Aug 25 2025 Valid 260100Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS A SMALL PORTION OF SOUTH-CENTRAL ARIZONA.... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona for a few more hours this evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...Discussion... A cluster of storms has produced some damaging winds across south-central Arizona. As the boundary layer cools this evening, expect these storms to weaken. However, the threat for isolated damaging winds will persist for a few more hours amid 1000+ J/kg DCAPE and steep low/mid level lapse rates. Elsewhere, diurnal thunderstorms across the western CONUS will wane this evening. Additional storms are expected to develop from the TX Panhandle to western Oklahoma tonight, but weak instability should limit any severe weather potential from this activity. ..Bentley.. 08/26/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 PM CDT Mon Aug 25 2025 Valid 260100Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS A SMALL PORTION OF SOUTH-CENTRAL ARIZONA.... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona for a few more hours this evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...Discussion... A cluster of storms has produced some damaging winds across south-central Arizona. As the boundary layer cools this evening, expect these storms to weaken. However, the threat for isolated damaging winds will persist for a few more hours amid 1000+ J/kg DCAPE and steep low/mid level lapse rates. Elsewhere, diurnal thunderstorms across the western CONUS will wane this evening. Additional storms are expected to develop from the TX Panhandle to western Oklahoma tonight, but weak instability should limit any severe weather potential from this activity. ..Bentley.. 08/26/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 PM CDT Mon Aug 25 2025 Valid 260100Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS A SMALL PORTION OF SOUTH-CENTRAL ARIZONA.... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona for a few more hours this evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...Discussion... A cluster of storms has produced some damaging winds across south-central Arizona. As the boundary layer cools this evening, expect these storms to weaken. However, the threat for isolated damaging winds will persist for a few more hours amid 1000+ J/kg DCAPE and steep low/mid level lapse rates. Elsewhere, diurnal thunderstorms across the western CONUS will wane this evening. Additional storms are expected to develop from the TX Panhandle to western Oklahoma tonight, but weak instability should limit any severe weather potential from this activity. ..Bentley.. 08/26/2025 Read more

No watches are valid as of Mon Aug 25 23:54:01 UTC 2025.

No Mesoscale Discussions are in effect as of Mon Aug 25 23:54:01 UTC 2025.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0439 PM CDT Mon Aug 25 2025 Valid 271200Z - 021200Z Weak upper lows are likely to move north through the northwestern US on Day 3/Wednesday - Day 4/Thursday as the upper-level ridge continues to retreat southeastward. The location and strength of these upper lows will be somewhat dependent on the convection occurring today and tomorrow, but monsoonal moisture will continue to push northward across the Northwest and northern Rockies. The upper-level pattern remains rather quiescent and devoid of major features across the West until an upper-level trough approaches the Pacific Northwest on Day 5/Friday. Forecast guidance remains uncertain regarding the track, timing, and impacts of this upper-level trough. ...Day 3/Wednesday - Day 4/Thursday... As the weak upper lows drift northward with monsoonal moisture, isolated to scattered showers and thunderstorms are likely across the Northwest and northern Rockies. Forcing for ascent and easterly flow aloft indicate the potential for storms to move/develop west of the Cascades. There remains concern that the 10% areas may just have high-based showers with sporadic, occasional lightning at best, especially due to the potential cloud cover. PWAT values are likely to be 0.8-1.1" and some dewpoints will exceed 50F that may mitigate fire weather concerns. However, given the very receptive fuels and history of ignitions with thunderstorms on the leading edge of this monsoonal moisture, the 10% areas were introduced. These may be refined as more high-resolution forecast guidance and rainfall footprints from storms today/tomorrow become available. Monsoonal thunderstorms will continue across much of the Intermountain West on Day 3/Wednesday, but drier air will start to filter in from west to east late this week into the weekend. This will reduce chances and coverage of thunderstorms in California, Northwest, and portions of the Great Basin and lower RH. ..Nauslar.. 08/25/2025 ...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 0439 PM CDT Mon Aug 25 2025 Valid 271200Z - 021200Z Weak upper lows are likely to move north through the northwestern US on Day 3/Wednesday - Day 4/Thursday as the upper-level ridge continues to retreat southeastward. The location and strength of these upper lows will be somewhat dependent on the convection occurring today and tomorrow, but monsoonal moisture will continue to push northward across the Northwest and northern Rockies. The upper-level pattern remains rather quiescent and devoid of major features across the West until an upper-level trough approaches the Pacific Northwest on Day 5/Friday. Forecast guidance remains uncertain regarding the track, timing, and impacts of this upper-level trough. ...Day 3/Wednesday - Day 4/Thursday... As the weak upper lows drift northward with monsoonal moisture, isolated to scattered showers and thunderstorms are likely across the Northwest and northern Rockies. Forcing for ascent and easterly flow aloft indicate the potential for storms to move/develop west of the Cascades. There remains concern that the 10% areas may just have high-based showers with sporadic, occasional lightning at best, especially due to the potential cloud cover. PWAT values are likely to be 0.8-1.1" and some dewpoints will exceed 50F that may mitigate fire weather concerns. However, given the very receptive fuels and history of ignitions with thunderstorms on the leading edge of this monsoonal moisture, the 10% areas were introduced. These may be refined as more high-resolution forecast guidance and rainfall footprints from storms today/tomorrow become available. Monsoonal thunderstorms will continue across much of the Intermountain West on Day 3/Wednesday, but drier air will start to filter in from west to east late this week into the weekend. This will reduce chances and coverage of thunderstorms in California, Northwest, and portions of the Great Basin and lower RH. ..Nauslar.. 08/25/2025 ...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 0439 PM CDT Mon Aug 25 2025 Valid 271200Z - 021200Z Weak upper lows are likely to move north through the northwestern US on Day 3/Wednesday - Day 4/Thursday as the upper-level ridge continues to retreat southeastward. The location and strength of these upper lows will be somewhat dependent on the convection occurring today and tomorrow, but monsoonal moisture will continue to push northward across the Northwest and northern Rockies. The upper-level pattern remains rather quiescent and devoid of major features across the West until an upper-level trough approaches the Pacific Northwest on Day 5/Friday. Forecast guidance remains uncertain regarding the track, timing, and impacts of this upper-level trough. ...Day 3/Wednesday - Day 4/Thursday... As the weak upper lows drift northward with monsoonal moisture, isolated to scattered showers and thunderstorms are likely across the Northwest and northern Rockies. Forcing for ascent and easterly flow aloft indicate the potential for storms to move/develop west of the Cascades. There remains concern that the 10% areas may just have high-based showers with sporadic, occasional lightning at best, especially due to the potential cloud cover. PWAT values are likely to be 0.8-1.1" and some dewpoints will exceed 50F that may mitigate fire weather concerns. However, given the very receptive fuels and history of ignitions with thunderstorms on the leading edge of this monsoonal moisture, the 10% areas were introduced. These may be refined as more high-resolution forecast guidance and rainfall footprints from storms today/tomorrow become available. Monsoonal thunderstorms will continue across much of the Intermountain West on Day 3/Wednesday, but drier air will start to filter in from west to east late this week into the weekend. This will reduce chances and coverage of thunderstorms in California, Northwest, and portions of the Great Basin and lower RH. ..Nauslar.. 08/25/2025 ...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 0439 PM CDT Mon Aug 25 2025 Valid 271200Z - 021200Z Weak upper lows are likely to move north through the northwestern US on Day 3/Wednesday - Day 4/Thursday as the upper-level ridge continues to retreat southeastward. The location and strength of these upper lows will be somewhat dependent on the convection occurring today and tomorrow, but monsoonal moisture will continue to push northward across the Northwest and northern Rockies. The upper-level pattern remains rather quiescent and devoid of major features across the West until an upper-level trough approaches the Pacific Northwest on Day 5/Friday. Forecast guidance remains uncertain regarding the track, timing, and impacts of this upper-level trough. ...Day 3/Wednesday - Day 4/Thursday... As the weak upper lows drift northward with monsoonal moisture, isolated to scattered showers and thunderstorms are likely across the Northwest and northern Rockies. Forcing for ascent and easterly flow aloft indicate the potential for storms to move/develop west of the Cascades. There remains concern that the 10% areas may just have high-based showers with sporadic, occasional lightning at best, especially due to the potential cloud cover. PWAT values are likely to be 0.8-1.1" and some dewpoints will exceed 50F that may mitigate fire weather concerns. However, given the very receptive fuels and history of ignitions with thunderstorms on the leading edge of this monsoonal moisture, the 10% areas were introduced. These may be refined as more high-resolution forecast guidance and rainfall footprints from storms today/tomorrow become available. Monsoonal thunderstorms will continue across much of the Intermountain West on Day 3/Wednesday, but drier air will start to filter in from west to east late this week into the weekend. This will reduce chances and coverage of thunderstorms in California, Northwest, and portions of the Great Basin and lower RH. ..Nauslar.. 08/25/2025 ...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 0439 PM CDT Mon Aug 25 2025 Valid 271200Z - 021200Z Weak upper lows are likely to move north through the northwestern US on Day 3/Wednesday - Day 4/Thursday as the upper-level ridge continues to retreat southeastward. The location and strength of these upper lows will be somewhat dependent on the convection occurring today and tomorrow, but monsoonal moisture will continue to push northward across the Northwest and northern Rockies. The upper-level pattern remains rather quiescent and devoid of major features across the West until an upper-level trough approaches the Pacific Northwest on Day 5/Friday. Forecast guidance remains uncertain regarding the track, timing, and impacts of this upper-level trough. ...Day 3/Wednesday - Day 4/Thursday... As the weak upper lows drift northward with monsoonal moisture, isolated to scattered showers and thunderstorms are likely across the Northwest and northern Rockies. Forcing for ascent and easterly flow aloft indicate the potential for storms to move/develop west of the Cascades. There remains concern that the 10% areas may just have high-based showers with sporadic, occasional lightning at best, especially due to the potential cloud cover. PWAT values are likely to be 0.8-1.1" and some dewpoints will exceed 50F that may mitigate fire weather concerns. However, given the very receptive fuels and history of ignitions with thunderstorms on the leading edge of this monsoonal moisture, the 10% areas were introduced. These may be refined as more high-resolution forecast guidance and rainfall footprints from storms today/tomorrow become available. Monsoonal thunderstorms will continue across much of the Intermountain West on Day 3/Wednesday, but drier air will start to filter in from west to east late this week into the weekend. This will reduce chances and coverage of thunderstorms in California, Northwest, and portions of the Great Basin and lower RH. ..Nauslar.. 08/25/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more