Severe Storms

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

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 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 25 2025 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHERN ARIZONA... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona this afternoon through early evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...20z Update... Scattered storms are currently developing over parts of southern AZ and MX ahead of a weak MCV. Additional development is expected the remainder of the afternoon into this evening. Limited buoyancy (MLCAPE ~1000 J/kg) will support multicell updrafts atop fairly dry low-levels. A few of the semi-organized storm clusters could support stronger downdrafts with damaging gust potential. Minor changes were made to the edges of MRGL risk area, see MCD #2014 for short-term information. Elsewhere, scattered storms are expected over the central and western CONUS today/tonight. Limited buoyancy and vertical shear will keep the severe risk low. See the previous discussion. ..Lyons.. 08/25/2025 .PREV DISCUSSION... /ISSUED 1131 AM CDT Mon Aug 25 2025/ ...Synopsis... A large upper trough will remain over the eastern CONUS today, as several embedded shortwave troughs progress within its southern periphery. Extensive upper ridging that currently extends from the southern Plains into the northern Intermountain West is forecast to remain largely in place. Some dampening may occur along the northwestern periphery of this ridging as a slow-moving vorticity maximum continues northeastward from the CO/OR/NV border vicinity into more of eastern OR. Ample monsoonal moisture exists beneath this ridging, contributing to scattered to numerous thunderstorms from the southern/central Rockies westward across the Southwest and much of the Great Basin. Limited vertical shear and weak buoyancy will mitigate the severe potential across the majority of the region. The only exceptions are across central Rockies and immediate foothills, and portions of southern AZ. ...Southern AZ... Ample monsoonal moisture is in place across the region, evidenced by PW values of 1.66 and 1.83 inches from the Phoenix and Yuma 12Z soundings, respectively. Filtered diurnal heating within this moist airmass will support modest buoyancy and afternoon thunderstorm development. A belt of stronger mid-level southeasterly flow (20-25 kt) is forecast to overspread the region this afternoon, providing ample shear for some multicell storm clusters. Initial storms which are expected to form across the higher terrain in southeast Arizona may result in congealing outflow with a damaging wind threat as storms move generally west-northwestward through the evening. ...Central Rockies... Thunderstorm development is expected across the high terrain by the early afternoon. Poor lapse rates and cooler temperatures will keep buoyancy will be modest, likely limiting overall updraft strength and tempering the severe potential. Even so, moderate northwesterly flow aloft will support long hodographs and the potential for some storm organization if updrafts can become sufficiently deep. An instance or two of hail is possible with any stronger, more long-lived storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 25 2025 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHERN ARIZONA... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona this afternoon through early evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...20z Update... Scattered storms are currently developing over parts of southern AZ and MX ahead of a weak MCV. Additional development is expected the remainder of the afternoon into this evening. Limited buoyancy (MLCAPE ~1000 J/kg) will support multicell updrafts atop fairly dry low-levels. A few of the semi-organized storm clusters could support stronger downdrafts with damaging gust potential. Minor changes were made to the edges of MRGL risk area, see MCD #2014 for short-term information. Elsewhere, scattered storms are expected over the central and western CONUS today/tonight. Limited buoyancy and vertical shear will keep the severe risk low. See the previous discussion. ..Lyons.. 08/25/2025 .PREV DISCUSSION... /ISSUED 1131 AM CDT Mon Aug 25 2025/ ...Synopsis... A large upper trough will remain over the eastern CONUS today, as several embedded shortwave troughs progress within its southern periphery. Extensive upper ridging that currently extends from the southern Plains into the northern Intermountain West is forecast to remain largely in place. Some dampening may occur along the northwestern periphery of this ridging as a slow-moving vorticity maximum continues northeastward from the CO/OR/NV border vicinity into more of eastern OR. Ample monsoonal moisture exists beneath this ridging, contributing to scattered to numerous thunderstorms from the southern/central Rockies westward across the Southwest and much of the Great Basin. Limited vertical shear and weak buoyancy will mitigate the severe potential across the majority of the region. The only exceptions are across central Rockies and immediate foothills, and portions of southern AZ. ...Southern AZ... Ample monsoonal moisture is in place across the region, evidenced by PW values of 1.66 and 1.83 inches from the Phoenix and Yuma 12Z soundings, respectively. Filtered diurnal heating within this moist airmass will support modest buoyancy and afternoon thunderstorm development. A belt of stronger mid-level southeasterly flow (20-25 kt) is forecast to overspread the region this afternoon, providing ample shear for some multicell storm clusters. Initial storms which are expected to form across the higher terrain in southeast Arizona may result in congealing outflow with a damaging wind threat as storms move generally west-northwestward through the evening. ...Central Rockies... Thunderstorm development is expected across the high terrain by the early afternoon. Poor lapse rates and cooler temperatures will keep buoyancy will be modest, likely limiting overall updraft strength and tempering the severe potential. Even so, moderate northwesterly flow aloft will support long hodographs and the potential for some storm organization if updrafts can become sufficiently deep. An instance or two of hail is possible with any stronger, more long-lived storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 25 2025 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHERN ARIZONA... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona this afternoon through early evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...20z Update... Scattered storms are currently developing over parts of southern AZ and MX ahead of a weak MCV. Additional development is expected the remainder of the afternoon into this evening. Limited buoyancy (MLCAPE ~1000 J/kg) will support multicell updrafts atop fairly dry low-levels. A few of the semi-organized storm clusters could support stronger downdrafts with damaging gust potential. Minor changes were made to the edges of MRGL risk area, see MCD #2014 for short-term information. Elsewhere, scattered storms are expected over the central and western CONUS today/tonight. Limited buoyancy and vertical shear will keep the severe risk low. See the previous discussion. ..Lyons.. 08/25/2025 .PREV DISCUSSION... /ISSUED 1131 AM CDT Mon Aug 25 2025/ ...Synopsis... A large upper trough will remain over the eastern CONUS today, as several embedded shortwave troughs progress within its southern periphery. Extensive upper ridging that currently extends from the southern Plains into the northern Intermountain West is forecast to remain largely in place. Some dampening may occur along the northwestern periphery of this ridging as a slow-moving vorticity maximum continues northeastward from the CO/OR/NV border vicinity into more of eastern OR. Ample monsoonal moisture exists beneath this ridging, contributing to scattered to numerous thunderstorms from the southern/central Rockies westward across the Southwest and much of the Great Basin. Limited vertical shear and weak buoyancy will mitigate the severe potential across the majority of the region. The only exceptions are across central Rockies and immediate foothills, and portions of southern AZ. ...Southern AZ... Ample monsoonal moisture is in place across the region, evidenced by PW values of 1.66 and 1.83 inches from the Phoenix and Yuma 12Z soundings, respectively. Filtered diurnal heating within this moist airmass will support modest buoyancy and afternoon thunderstorm development. A belt of stronger mid-level southeasterly flow (20-25 kt) is forecast to overspread the region this afternoon, providing ample shear for some multicell storm clusters. Initial storms which are expected to form across the higher terrain in southeast Arizona may result in congealing outflow with a damaging wind threat as storms move generally west-northwestward through the evening. ...Central Rockies... Thunderstorm development is expected across the high terrain by the early afternoon. Poor lapse rates and cooler temperatures will keep buoyancy will be modest, likely limiting overall updraft strength and tempering the severe potential. Even so, moderate northwesterly flow aloft will support long hodographs and the potential for some storm organization if updrafts can become sufficiently deep. An instance or two of hail is possible with any stronger, more long-lived storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 25 2025 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHERN ARIZONA... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona this afternoon through early evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...20z Update... Scattered storms are currently developing over parts of southern AZ and MX ahead of a weak MCV. Additional development is expected the remainder of the afternoon into this evening. Limited buoyancy (MLCAPE ~1000 J/kg) will support multicell updrafts atop fairly dry low-levels. A few of the semi-organized storm clusters could support stronger downdrafts with damaging gust potential. Minor changes were made to the edges of MRGL risk area, see MCD #2014 for short-term information. Elsewhere, scattered storms are expected over the central and western CONUS today/tonight. Limited buoyancy and vertical shear will keep the severe risk low. See the previous discussion. ..Lyons.. 08/25/2025 .PREV DISCUSSION... /ISSUED 1131 AM CDT Mon Aug 25 2025/ ...Synopsis... A large upper trough will remain over the eastern CONUS today, as several embedded shortwave troughs progress within its southern periphery. Extensive upper ridging that currently extends from the southern Plains into the northern Intermountain West is forecast to remain largely in place. Some dampening may occur along the northwestern periphery of this ridging as a slow-moving vorticity maximum continues northeastward from the CO/OR/NV border vicinity into more of eastern OR. Ample monsoonal moisture exists beneath this ridging, contributing to scattered to numerous thunderstorms from the southern/central Rockies westward across the Southwest and much of the Great Basin. Limited vertical shear and weak buoyancy will mitigate the severe potential across the majority of the region. The only exceptions are across central Rockies and immediate foothills, and portions of southern AZ. ...Southern AZ... Ample monsoonal moisture is in place across the region, evidenced by PW values of 1.66 and 1.83 inches from the Phoenix and Yuma 12Z soundings, respectively. Filtered diurnal heating within this moist airmass will support modest buoyancy and afternoon thunderstorm development. A belt of stronger mid-level southeasterly flow (20-25 kt) is forecast to overspread the region this afternoon, providing ample shear for some multicell storm clusters. Initial storms which are expected to form across the higher terrain in southeast Arizona may result in congealing outflow with a damaging wind threat as storms move generally west-northwestward through the evening. ...Central Rockies... Thunderstorm development is expected across the high terrain by the early afternoon. Poor lapse rates and cooler temperatures will keep buoyancy will be modest, likely limiting overall updraft strength and tempering the severe potential. Even so, moderate northwesterly flow aloft will support long hodographs and the potential for some storm organization if updrafts can become sufficiently deep. An instance or two of hail is possible with any stronger, more long-lived storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 25 2025 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHERN ARIZONA... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona this afternoon through early evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...20z Update... Scattered storms are currently developing over parts of southern AZ and MX ahead of a weak MCV. Additional development is expected the remainder of the afternoon into this evening. Limited buoyancy (MLCAPE ~1000 J/kg) will support multicell updrafts atop fairly dry low-levels. A few of the semi-organized storm clusters could support stronger downdrafts with damaging gust potential. Minor changes were made to the edges of MRGL risk area, see MCD #2014 for short-term information. Elsewhere, scattered storms are expected over the central and western CONUS today/tonight. Limited buoyancy and vertical shear will keep the severe risk low. See the previous discussion. ..Lyons.. 08/25/2025 .PREV DISCUSSION... /ISSUED 1131 AM CDT Mon Aug 25 2025/ ...Synopsis... A large upper trough will remain over the eastern CONUS today, as several embedded shortwave troughs progress within its southern periphery. Extensive upper ridging that currently extends from the southern Plains into the northern Intermountain West is forecast to remain largely in place. Some dampening may occur along the northwestern periphery of this ridging as a slow-moving vorticity maximum continues northeastward from the CO/OR/NV border vicinity into more of eastern OR. Ample monsoonal moisture exists beneath this ridging, contributing to scattered to numerous thunderstorms from the southern/central Rockies westward across the Southwest and much of the Great Basin. Limited vertical shear and weak buoyancy will mitigate the severe potential across the majority of the region. The only exceptions are across central Rockies and immediate foothills, and portions of southern AZ. ...Southern AZ... Ample monsoonal moisture is in place across the region, evidenced by PW values of 1.66 and 1.83 inches from the Phoenix and Yuma 12Z soundings, respectively. Filtered diurnal heating within this moist airmass will support modest buoyancy and afternoon thunderstorm development. A belt of stronger mid-level southeasterly flow (20-25 kt) is forecast to overspread the region this afternoon, providing ample shear for some multicell storm clusters. Initial storms which are expected to form across the higher terrain in southeast Arizona may result in congealing outflow with a damaging wind threat as storms move generally west-northwestward through the evening. ...Central Rockies... Thunderstorm development is expected across the high terrain by the early afternoon. Poor lapse rates and cooler temperatures will keep buoyancy will be modest, likely limiting overall updraft strength and tempering the severe potential. Even so, moderate northwesterly flow aloft will support long hodographs and the potential for some storm organization if updrafts can become sufficiently deep. An instance or two of hail is possible with any stronger, more long-lived storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 25 2025 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHERN ARIZONA... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona this afternoon through early evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...20z Update... Scattered storms are currently developing over parts of southern AZ and MX ahead of a weak MCV. Additional development is expected the remainder of the afternoon into this evening. Limited buoyancy (MLCAPE ~1000 J/kg) will support multicell updrafts atop fairly dry low-levels. A few of the semi-organized storm clusters could support stronger downdrafts with damaging gust potential. Minor changes were made to the edges of MRGL risk area, see MCD #2014 for short-term information. Elsewhere, scattered storms are expected over the central and western CONUS today/tonight. Limited buoyancy and vertical shear will keep the severe risk low. See the previous discussion. ..Lyons.. 08/25/2025 .PREV DISCUSSION... /ISSUED 1131 AM CDT Mon Aug 25 2025/ ...Synopsis... A large upper trough will remain over the eastern CONUS today, as several embedded shortwave troughs progress within its southern periphery. Extensive upper ridging that currently extends from the southern Plains into the northern Intermountain West is forecast to remain largely in place. Some dampening may occur along the northwestern periphery of this ridging as a slow-moving vorticity maximum continues northeastward from the CO/OR/NV border vicinity into more of eastern OR. Ample monsoonal moisture exists beneath this ridging, contributing to scattered to numerous thunderstorms from the southern/central Rockies westward across the Southwest and much of the Great Basin. Limited vertical shear and weak buoyancy will mitigate the severe potential across the majority of the region. The only exceptions are across central Rockies and immediate foothills, and portions of southern AZ. ...Southern AZ... Ample monsoonal moisture is in place across the region, evidenced by PW values of 1.66 and 1.83 inches from the Phoenix and Yuma 12Z soundings, respectively. Filtered diurnal heating within this moist airmass will support modest buoyancy and afternoon thunderstorm development. A belt of stronger mid-level southeasterly flow (20-25 kt) is forecast to overspread the region this afternoon, providing ample shear for some multicell storm clusters. Initial storms which are expected to form across the higher terrain in southeast Arizona may result in congealing outflow with a damaging wind threat as storms move generally west-northwestward through the evening. ...Central Rockies... Thunderstorm development is expected across the high terrain by the early afternoon. Poor lapse rates and cooler temperatures will keep buoyancy will be modest, likely limiting overall updraft strength and tempering the severe potential. Even so, moderate northwesterly flow aloft will support long hodographs and the potential for some storm organization if updrafts can become sufficiently deep. An instance or two of hail is possible with any stronger, more long-lived storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Mon Aug 25 2025 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHERN ARIZONA... ...SUMMARY... Isolated severe wind gusts are possible over parts of south-central Arizona this afternoon through early evening. Otherwise, the potential for severe storms is low across the remainder of the continental U.S. ...20z Update... Scattered storms are currently developing over parts of southern AZ and MX ahead of a weak MCV. Additional development is expected the remainder of the afternoon into this evening. Limited buoyancy (MLCAPE ~1000 J/kg) will support multicell updrafts atop fairly dry low-levels. A few of the semi-organized storm clusters could support stronger downdrafts with damaging gust potential. Minor changes were made to the edges of MRGL risk area, see MCD #2014 for short-term information. Elsewhere, scattered storms are expected over the central and western CONUS today/tonight. Limited buoyancy and vertical shear will keep the severe risk low. See the previous discussion. ..Lyons.. 08/25/2025 .PREV DISCUSSION... /ISSUED 1131 AM CDT Mon Aug 25 2025/ ...Synopsis... A large upper trough will remain over the eastern CONUS today, as several embedded shortwave troughs progress within its southern periphery. Extensive upper ridging that currently extends from the southern Plains into the northern Intermountain West is forecast to remain largely in place. Some dampening may occur along the northwestern periphery of this ridging as a slow-moving vorticity maximum continues northeastward from the CO/OR/NV border vicinity into more of eastern OR. Ample monsoonal moisture exists beneath this ridging, contributing to scattered to numerous thunderstorms from the southern/central Rockies westward across the Southwest and much of the Great Basin. Limited vertical shear and weak buoyancy will mitigate the severe potential across the majority of the region. The only exceptions are across central Rockies and immediate foothills, and portions of southern AZ. ...Southern AZ... Ample monsoonal moisture is in place across the region, evidenced by PW values of 1.66 and 1.83 inches from the Phoenix and Yuma 12Z soundings, respectively. Filtered diurnal heating within this moist airmass will support modest buoyancy and afternoon thunderstorm development. A belt of stronger mid-level southeasterly flow (20-25 kt) is forecast to overspread the region this afternoon, providing ample shear for some multicell storm clusters. Initial storms which are expected to form across the higher terrain in southeast Arizona may result in congealing outflow with a damaging wind threat as storms move generally west-northwestward through the evening. ...Central Rockies... Thunderstorm development is expected across the high terrain by the early afternoon. Poor lapse rates and cooler temperatures will keep buoyancy will be modest, likely limiting overall updraft strength and tempering the severe potential. Even so, moderate northwesterly flow aloft will support long hodographs and the potential for some storm organization if updrafts can become sufficiently deep. An instance or two of hail is possible with any stronger, more long-lived storms. Read more

MD 2014 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHERN ARIZONA
Mesoscale Discussion 2014 NWS Storm Prediction Center Norman OK 0237 PM CDT Mon Aug 25 2025 Areas affected...Southern Arizona Concerning...Severe potential...Watch unlikely Valid 251937Z - 252130Z Probability of Watch Issuance...5 percent SUMMARY...Thunderstorms developing across southeast Arizona may pose a severe wind risk through the late afternoon and early evening hours as they spread west/northwest. Watch issuance is not expected given the localized nature of the threat. DISCUSSION...GOES visible imagery shows a steady increase in coverage and depth of a cumulus field over the higher terrain of southeastern AZ. Recent LightningCast output shows modest, but increasing, probability for lightning flashes across the region and a few flashes have already been noted with one deeper convective tower. Glancing ascent associated with an upstream MCV over the northern Gulf of California, combined with continued daytime heating, should aid in additional thunderstorm development within the next 1-2 hours. Southeasterly mid-level flow will steer isolated to scattered convective cells northwestward into lower elevations. Modest northwesterly low-level winds across south-central AZ will support some degree of hodograph elongation and promote some potential for storm organization and longevity. While small hail is possible, the predominant hazard will be strong to severe gusts given steep low-level lapse rates between 8-9 C/km. Based on the convective environment and recent CAM guidance, sporadic gusts upwards of 50-70 mph appear possible with the stronger downbursts; however, this threat should remain fairly localized given an overall modest kinematic environment. ..Moore/Mosier.. 08/25/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TWC...PSR... LAT...LON 31671233 31921251 32791262 33261255 33571218 33641147 33531100 33351063 33051026 32671000 32100981 31770971 31480969 31270981 31271108 31671233 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0212 PM CDT Mon Aug 25 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. on Wednesday. A few stronger storms cannot be ruled out over parts of Minnesota and Wisconsin late in the day, and over eastern Colorado. ...Synopsis and Discussion... An upper trough will exit the Mid Atlantic/Northeast on Wednesday with a secondary wave developing later in the period into the Upper and Middle MS Valley and Great Lakes. Behind the initial trough, high pressure will already be in place over the OH Valley, which will limit destabilization ahead of the secondary system. However, a narrow plume of low-level moisture with 50s F dewpoints will result in a marginally unstable environment across the upper MS Valley by late afternoon. Cool temperatures aloft and modest deep-layer shear of 20-30 kt may result in a few cells capable of mainly small/non-severe hail. Southwest of this region, east/southeast surface winds will persist over the central plains, as a weak surface trough develops over eastern CO. The moist easterly flow toward the Front Range may result in a few stronger cells, perhaps with hail potential. Lapse rates aloft will not be very steep beneath the weak upper ridge, nor will shear be very favorable. However, at least small hail may occur locally during the late afternoon for a short time near peak heating. ..Jewell.. 08/25/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0212 PM CDT Mon Aug 25 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. on Wednesday. A few stronger storms cannot be ruled out over parts of Minnesota and Wisconsin late in the day, and over eastern Colorado. ...Synopsis and Discussion... An upper trough will exit the Mid Atlantic/Northeast on Wednesday with a secondary wave developing later in the period into the Upper and Middle MS Valley and Great Lakes. Behind the initial trough, high pressure will already be in place over the OH Valley, which will limit destabilization ahead of the secondary system. However, a narrow plume of low-level moisture with 50s F dewpoints will result in a marginally unstable environment across the upper MS Valley by late afternoon. Cool temperatures aloft and modest deep-layer shear of 20-30 kt may result in a few cells capable of mainly small/non-severe hail. Southwest of this region, east/southeast surface winds will persist over the central plains, as a weak surface trough develops over eastern CO. The moist easterly flow toward the Front Range may result in a few stronger cells, perhaps with hail potential. Lapse rates aloft will not be very steep beneath the weak upper ridge, nor will shear be very favorable. However, at least small hail may occur locally during the late afternoon for a short time near peak heating. ..Jewell.. 08/25/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0212 PM CDT Mon Aug 25 2025 Valid 271200Z - 281200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The potential for severe storms appears to be low across the continental U.S. on Wednesday. A few stronger storms cannot be ruled out over parts of Minnesota and Wisconsin late in the day, and over eastern Colorado. ...Synopsis and Discussion... An upper trough will exit the Mid Atlantic/Northeast on Wednesday with a secondary wave developing later in the period into the Upper and Middle MS Valley and Great Lakes. Behind the initial trough, high pressure will already be in place over the OH Valley, which will limit destabilization ahead of the secondary system. However, a narrow plume of low-level moisture with 50s F dewpoints will result in a marginally unstable environment across the upper MS Valley by late afternoon. Cool temperatures aloft and modest deep-layer shear of 20-30 kt may result in a few cells capable of mainly small/non-severe hail. Southwest of this region, east/southeast surface winds will persist over the central plains, as a weak surface trough develops over eastern CO. The moist easterly flow toward the Front Range may result in a few stronger cells, perhaps with hail potential. Lapse rates aloft will not be very steep beneath the weak upper ridge, nor will shear be very favorable. However, at least small hail may occur locally during the late afternoon for a short time near peak heating. ..Jewell.. 08/25/2025 Read more