Storm Prediction Center

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0124 PM CST Sun Dec 21 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not currently forecast across the contiguous United States on Tuesday or Tuesday night. ...California... Within large-scale upper troughing over the eastern Pacific, a mid-level shortwave trough and associated jet will overspread much of northern/central CA Tuesday through Tuesday night. An attendant surface low is forecast to develop northward along/near the coast of northern/central CA late Tuesday night into early Wednesday morning. Ample low-level and deep-layer shear will be present over this region owing to strengthening flow aloft with the approaching shortwave trough. However, considerable uncertainty still exists regarding the depth/quality of low-level moisture and whether enough instability will exist to support a meaningful change for surface-based thunderstorms given the unfavorable time of night and generally modest lapse rates. Some of the more aggressive guidance (12Z RRFS) suggests that weak but sufficient MLCAPE may develop late Tuesday into early Wednesday to support some threat for strong/gusty winds with thunderstorms as mid-level temperatures gradually cool with the shortwave trough overspreading the CA Coast. Based on a consensus of other available guidance, this potential still appears a bit too uncertain/conditional to include low severe probabilities along the CA Coast at this time. Regardless, the chance for elevated convection remains apparent, and the general thunderstorm area has been expanded across more of CA with this update. ..Gleason.. 12/21/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0124 PM CST Sun Dec 21 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not currently forecast across the contiguous United States on Tuesday or Tuesday night. ...California... Within large-scale upper troughing over the eastern Pacific, a mid-level shortwave trough and associated jet will overspread much of northern/central CA Tuesday through Tuesday night. An attendant surface low is forecast to develop northward along/near the coast of northern/central CA late Tuesday night into early Wednesday morning. Ample low-level and deep-layer shear will be present over this region owing to strengthening flow aloft with the approaching shortwave trough. However, considerable uncertainty still exists regarding the depth/quality of low-level moisture and whether enough instability will exist to support a meaningful change for surface-based thunderstorms given the unfavorable time of night and generally modest lapse rates. Some of the more aggressive guidance (12Z RRFS) suggests that weak but sufficient MLCAPE may develop late Tuesday into early Wednesday to support some threat for strong/gusty winds with thunderstorms as mid-level temperatures gradually cool with the shortwave trough overspreading the CA Coast. Based on a consensus of other available guidance, this potential still appears a bit too uncertain/conditional to include low severe probabilities along the CA Coast at this time. Regardless, the chance for elevated convection remains apparent, and the general thunderstorm area has been expanded across more of CA with this update. ..Gleason.. 12/21/2025 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0123 PM CST Sun Dec 21 2025 Valid 212000Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today. ...20z Update... No changes are needed to the D1 Convective Outlook. See previous discussion below. ..Thornton.. 12/21/2025 .PREV DISCUSSION... /ISSUED 0957 AM CST Sun Dec 21 2025/ Thunderstorm potential will be limited across the CONUS. Strong onshore flow and cold temperatures aloft will pose a risk of a few lightning flashes today and tonight over portions of the WA/OR coast and parts of northern CA. Low-level warm advection and an approaching cold front could result in isolated thunderstorms this afternoon over parts of southern LA/MS, and late tonight over south TX. No severe storms are anticipated today. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0123 PM CST Sun Dec 21 2025 Valid 212000Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today. ...20z Update... No changes are needed to the D1 Convective Outlook. See previous discussion below. ..Thornton.. 12/21/2025 .PREV DISCUSSION... /ISSUED 0957 AM CST Sun Dec 21 2025/ Thunderstorm potential will be limited across the CONUS. Strong onshore flow and cold temperatures aloft will pose a risk of a few lightning flashes today and tonight over portions of the WA/OR coast and parts of northern CA. Low-level warm advection and an approaching cold front could result in isolated thunderstorms this afternoon over parts of southern LA/MS, and late tonight over south TX. No severe storms are anticipated today. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1046 AM CST Sun Dec 21 2025 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Monday. ...Synopsis and Discussion... Minimal thunderstorm potential remains evident across much of the CONUS on Monday, as upper-level ridging is maintained over the central U.S. One exception may be across parts of coastal WA/OR as a mid-level shortwave trough progresses eastward from the eastern Pacific into British Columbia and the Pacific Northwest through Monday afternoon/evening. Even though daytime heating and low-level moisture are forecast to remain limited, cool temperatures aloft and weak MUCAPE associated with the shortwave trough may support occasional lightning flashes with low-topped convection moving inland along the immediate WA/OR Coast. A plume of mid-level moisture and associated precipitation will impact parts of northern/central CA through the period, although warmer mid-level temperatures compared to locations farther north and negligible forecast instability suggest little potential for lightning. Elsewhere, very weak forcing aloft should limit thunderstorm potential across coastal TX to the central Gulf Coast, even as low-level moisture gradually increases across these areas. ..Gleason.. 12/21/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1046 AM CST Sun Dec 21 2025 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Monday. ...Synopsis and Discussion... Minimal thunderstorm potential remains evident across much of the CONUS on Monday, as upper-level ridging is maintained over the central U.S. One exception may be across parts of coastal WA/OR as a mid-level shortwave trough progresses eastward from the eastern Pacific into British Columbia and the Pacific Northwest through Monday afternoon/evening. Even though daytime heating and low-level moisture are forecast to remain limited, cool temperatures aloft and weak MUCAPE associated with the shortwave trough may support occasional lightning flashes with low-topped convection moving inland along the immediate WA/OR Coast. A plume of mid-level moisture and associated precipitation will impact parts of northern/central CA through the period, although warmer mid-level temperatures compared to locations farther north and negligible forecast instability suggest little potential for lightning. Elsewhere, very weak forcing aloft should limit thunderstorm potential across coastal TX to the central Gulf Coast, even as low-level moisture gradually increases across these areas. ..Gleason.. 12/21/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1046 AM CST Sun Dec 21 2025 Valid 221200Z - 231200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Monday. ...Synopsis and Discussion... Minimal thunderstorm potential remains evident across much of the CONUS on Monday, as upper-level ridging is maintained over the central U.S. One exception may be across parts of coastal WA/OR as a mid-level shortwave trough progresses eastward from the eastern Pacific into British Columbia and the Pacific Northwest through Monday afternoon/evening. Even though daytime heating and low-level moisture are forecast to remain limited, cool temperatures aloft and weak MUCAPE associated with the shortwave trough may support occasional lightning flashes with low-topped convection moving inland along the immediate WA/OR Coast. A plume of mid-level moisture and associated precipitation will impact parts of northern/central CA through the period, although warmer mid-level temperatures compared to locations farther north and negligible forecast instability suggest little potential for lightning. Elsewhere, very weak forcing aloft should limit thunderstorm potential across coastal TX to the central Gulf Coast, even as low-level moisture gradually increases across these areas. ..Gleason.. 12/21/2025 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1032 AM CST Sun Dec 21 2025 Valid 211700Z - 221200Z ...NO CRITICAL AREAS... .Southern and Central Plains... Surface high pressure translating eastward into the OH River Valley along with a deepening surface trough across the Northern Rockies will initiate return southerly flow across much of the central Plains. Although the landscape remains dry, the considerably cooler, post-frontal air mass has temporarily moderated fuels across much of the southern and central Plains. In addition, limited afternoon RH reductions across the region will mitigate the overall fire weather threat amid sustained south winds of 10-15 mph. ..Williams.. 12/21/2025 .PREV DISCUSSION... /ISSUED 0131 AM CST Sun Dec 21 2025/ ...Synopsis... Upper ridging will build over the CONUS, resulting in surface high pressure overspreading the eastern CONUS as a surface trough becomes established over the Plains today. Relatively cool and/or moist conditions will prevail over most locales east of the Rockies, limiting the potential for significant wildfire spread. ...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 1032 AM CST Sun Dec 21 2025 Valid 211700Z - 221200Z ...NO CRITICAL AREAS... .Southern and Central Plains... Surface high pressure translating eastward into the OH River Valley along with a deepening surface trough across the Northern Rockies will initiate return southerly flow across much of the central Plains. Although the landscape remains dry, the considerably cooler, post-frontal air mass has temporarily moderated fuels across much of the southern and central Plains. In addition, limited afternoon RH reductions across the region will mitigate the overall fire weather threat amid sustained south winds of 10-15 mph. ..Williams.. 12/21/2025 .PREV DISCUSSION... /ISSUED 0131 AM CST Sun Dec 21 2025/ ...Synopsis... Upper ridging will build over the CONUS, resulting in surface high pressure overspreading the eastern CONUS as a surface trough becomes established over the Plains today. Relatively cool and/or moist conditions will prevail over most locales east of the Rockies, limiting the potential for significant wildfire spread. ...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 1032 AM CST Sun Dec 21 2025 Valid 211700Z - 221200Z ...NO CRITICAL AREAS... .Southern and Central Plains... Surface high pressure translating eastward into the OH River Valley along with a deepening surface trough across the Northern Rockies will initiate return southerly flow across much of the central Plains. Although the landscape remains dry, the considerably cooler, post-frontal air mass has temporarily moderated fuels across much of the southern and central Plains. In addition, limited afternoon RH reductions across the region will mitigate the overall fire weather threat amid sustained south winds of 10-15 mph. ..Williams.. 12/21/2025 .PREV DISCUSSION... /ISSUED 0131 AM CST Sun Dec 21 2025/ ...Synopsis... Upper ridging will build over the CONUS, resulting in surface high pressure overspreading the eastern CONUS as a surface trough becomes established over the Plains today. Relatively cool and/or moist conditions will prevail over most locales east of the Rockies, limiting the potential for significant wildfire spread. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0957 AM CST Sun Dec 21 2025 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today. Thunderstorm potential will be limited across the CONUS. Strong onshore flow and cold temperatures aloft will pose a risk of a few lightning flashes today and tonight over portions of the WA/OR coast and parts of northern CA. Low-level warm advection and an approaching cold front could result in isolated thunderstorms this afternoon over parts of southern LA/MS, and late tonight over south TX. No severe storms are anticipated today. ..Hart/Karstens.. 12/21/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0957 AM CST Sun Dec 21 2025 Valid 211630Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today. Thunderstorm potential will be limited across the CONUS. Strong onshore flow and cold temperatures aloft will pose a risk of a few lightning flashes today and tonight over portions of the WA/OR coast and parts of northern CA. Low-level warm advection and an approaching cold front could result in isolated thunderstorms this afternoon over parts of southern LA/MS, and late tonight over south TX. No severe storms are anticipated today. ..Hart/Karstens.. 12/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0653 AM CST Sun Dec 21 2025 Valid 211300Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today. ...Discussion... A progressive/zonal upper-flow pattern will continue over the CONUS. A low-amplitude shortwave trough will move inland across the Pacific Northwest by tonight. Weak buoyancy and cooling temperatures aloft may become sufficient for isolated lightning flashes, particularly near the Washington coast. Farther south, a moisture-rich plume and a marginally favorable thermodynamic environment may allow for some lighting flashes across northern California. Elsewhere, a relatively moist airmass near/south of a southward-moving front, along with continued weak warm/moist advection, will probably be conducive for isolated thunderstorms mainly across southern portions of Louisiana and Mississippi today. ..Guyer/Marsh.. 12/21/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0653 AM CST Sun Dec 21 2025 Valid 211300Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected today. ...Discussion... A progressive/zonal upper-flow pattern will continue over the CONUS. A low-amplitude shortwave trough will move inland across the Pacific Northwest by tonight. Weak buoyancy and cooling temperatures aloft may become sufficient for isolated lightning flashes, particularly near the Washington coast. Farther south, a moisture-rich plume and a marginally favorable thermodynamic environment may allow for some lighting flashes across northern California. Elsewhere, a relatively moist airmass near/south of a southward-moving front, along with continued weak warm/moist advection, will probably be conducive for isolated thunderstorms mainly across southern portions of Louisiana and Mississippi today. ..Guyer/Marsh.. 12/21/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0320 AM CST Sun Dec 21 2025 Valid 241200Z - 291200Z ...DISCUSSION... Medium-range model guidance initially shows a pattern featuring an upper ridge over the central CONUS and trough along the West Coast, transitioning to a more progressive flow regime and lowering heights across the Great Plains during the Thursday-Saturday (D5-D7) period. The inland-moving West Coast trough will potentially yield isolated to scattered thunderstorms on Wednesday into early Thursday over portions of southern and central CA and perhaps a localized risk for a couple of stronger thunderstorms. Details concerning this convective scenario and overall magnitude of severe risk preclude severe highlights. Farther east, some moisture return northward into the southern Great Plains and MS Valley through Friday will likely be modulated by frontal advancements during the latter part of extended period. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0209 AM CST Sun Dec 21 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States on Tuesday or Tuesday night. ...Synopsis... A dominant mid- to upper-level ridge will remain steadfast across central portion of the Lower 48 states. An upper trough will encroach on the West Coast, and a lead mid-level trough will move quickly northeast from the eastern Pacific into the northern CA coastal area late Tuesday night. Scant to weak buoyancy will gradually develop Tuesday night in the vicinity of the CA coast and coastal range from near Point Conception to near the OR border. Scattered showers and isolated thunderstorms will gradually spread inland concurrent with increasing large-scale forcing and instability. Some forecast soundings depict a deep, lower-tropospheric moist layer co-located with intense low-level shear, which could imply storm organization being possible with the strongest low-topped storms. Uncertainty is high at this time for such a scenario given appreciable model variability. Farther east, a weak upper trough near the lower Rio Grande Valley will undercut a mid- to upper-level ridge over the central US. Weak convection is possible in association with this upper feature, but confidence in attaining 10-percent thunderstorm probabilities is low at this time. ..Smith.. 12/21/2025 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0209 AM CST Sun Dec 21 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States on Tuesday or Tuesday night. ...Synopsis... A dominant mid- to upper-level ridge will remain steadfast across central portion of the Lower 48 states. An upper trough will encroach on the West Coast, and a lead mid-level trough will move quickly northeast from the eastern Pacific into the northern CA coastal area late Tuesday night. Scant to weak buoyancy will gradually develop Tuesday night in the vicinity of the CA coast and coastal range from near Point Conception to near the OR border. Scattered showers and isolated thunderstorms will gradually spread inland concurrent with increasing large-scale forcing and instability. Some forecast soundings depict a deep, lower-tropospheric moist layer co-located with intense low-level shear, which could imply storm organization being possible with the strongest low-topped storms. Uncertainty is high at this time for such a scenario given appreciable model variability. Farther east, a weak upper trough near the lower Rio Grande Valley will undercut a mid- to upper-level ridge over the central US. Weak convection is possible in association with this upper feature, but confidence in attaining 10-percent thunderstorm probabilities is low at this time. ..Smith.. 12/21/2025 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0132 AM CST Sun Dec 21 2025 Valid 221200Z - 231200Z ...Synopsis... Upper ridging will persist over the CONUS tomorrow (Monday), with surface lee troughing continuing over the Plains states. Dry downslope flow is expected across the southern High Plains, with 15-20 percent RH becoming common over most locales as the boundary layer mixes Monday afternoon. Guidance consensus depicts a corridor of 15+ mph sustained westerly surface winds overlapping the aforementioned RH for several hours Monday afternoon across eastern New Mexico into the Texas Panhandle. Elevated highlights are warranted for these conditions given the presence of dry fuels. ..Squitieri.. 12/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0132 AM CST Sun Dec 21 2025 Valid 221200Z - 231200Z ...Synopsis... Upper ridging will persist over the CONUS tomorrow (Monday), with surface lee troughing continuing over the Plains states. Dry downslope flow is expected across the southern High Plains, with 15-20 percent RH becoming common over most locales as the boundary layer mixes Monday afternoon. Guidance consensus depicts a corridor of 15+ mph sustained westerly surface winds overlapping the aforementioned RH for several hours Monday afternoon across eastern New Mexico into the Texas Panhandle. Elevated highlights are warranted for these conditions given the presence of dry fuels. ..Squitieri.. 12/21/2025 ...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 0131 AM CST Sun Dec 21 2025 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... ...Synopsis... Upper ridging will build over the CONUS, resulting in surface high pressure overspreading the eastern CONUS as a surface trough becomes established over the Plains today. Relatively cool and/or moist conditions will prevail over most locales east of the Rockies, limiting the potential for significant wildfire spread. ..Squitieri.. 12/21/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more