Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1100 AM CST Mon Jan 20 2025 Valid 201700Z - 211200Z ...EXTREMELY CRITICAL FIRE WEATHER AREA FOR THE SAN GABRIEL MOUNTAINS WEST TOWARDS THE SANTA MONICA MOUNTAINS AND SANTA SUSANA MOUNTAINS...INCLUDING THE MALIBU COAST... ...CRITICAL FIRE WEATHER AREA FOR MUCH OF SOUTHERN CALIFORNIA... The previous forecast (see below) remains on track, and no changes were needed with this update. The LAX-DAG pressure gradient is quickly tightening this morning, with the latest reading (as of 16Z) around -3.8 mb. This trend will continue into the overnight/early morning hours, yielding rapidly strengthening surface winds and decreasing RH. The onset of critical to extremely critical conditions is expected by early afternoon, with the most volatile conditions still expected over the wind-prone Santa Ana corridor of northern/western Los Angeles County into eastern Ventura County during the overnight/early morning hours. Extremely critical conditions will persist into Day 2/Tuesday morning here. ..Weinman.. 01/20/2025 .PREV DISCUSSION... /ISSUED 0208 AM CST Mon Jan 20 2025/ ...Synopsis... While most of the CONUS is dominated by cold air and high pressure, a strong, positively-tilted mid-level trough will move southward across California, with a highly amplified mid-level Pacific ridge following behind it. As the trough axis reaches southern California Monday afternoon, intensifying surface pressure gradients will result in the development of strong Santa Ana winds. The 00Z HREF guidance and global ensembles continue to forecast strong LAX->DAG pressure gradients ranging from -8 mb to -11 mb, with wind speeds trending upward to 40-45 MPH sustained (gusting 70 - 100 MPH on the mountains, 50 - 80 MPH in the valleys/coastal regions). In addition to the upward trend in wind speed and gust forecasts, relative humidity values have trended significantly drier, with values as low as 2%-5%. These Extremely Critical fire-weather conditions, supporting rapid wildfire onset and spread, will begin Monday afternoon and reach peak intensity Monday evening into Tuesday morning. The area of greatest risk lies from the San Gabriel Mountains westward into the Santa Monica Mountains, the Malibu Coast, and the Santa Susana Mountains. Elsewhere, Critical fire-weather conditions extend southward to the U.S./Mexico border, where strong (and critically dry) offshore winds will persist overnight into Tuesday morning. ...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 1028 AM CST Mon Jan 20 2025 Valid 201630Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. ...Synopsis... Another surge of cold air is anticipated across the CONUS, reinforcing the polar airmass already in place. This will result in a maintenance of dry and stable conditions, with no thunderstorms anticipated. Some deeper convection is possible late tonight/early tomorrow along the middle/upper TX Coast as warm-air advection strengthens throughout the warm sector of surface low developing over the western Gulf of Mexico. Model forecast soundings have thermodynamic profiles with scant (and shallow) buoyancy between around 800 to 500 mb. These profiles also suggest sleet will be the predominant precipitation type, with mixed-phase parcels combining with the modest buoyancy to support a few lightning flashes. Even so, the overall thunderstorm probabilities are still expected to be less than 10 percent. ..Mosier.. 01/20/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1028 AM CST Mon Jan 20 2025 Valid 201630Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. ...Synopsis... Another surge of cold air is anticipated across the CONUS, reinforcing the polar airmass already in place. This will result in a maintenance of dry and stable conditions, with no thunderstorms anticipated. Some deeper convection is possible late tonight/early tomorrow along the middle/upper TX Coast as warm-air advection strengthens throughout the warm sector of surface low developing over the western Gulf of Mexico. Model forecast soundings have thermodynamic profiles with scant (and shallow) buoyancy between around 800 to 500 mb. These profiles also suggest sleet will be the predominant precipitation type, with mixed-phase parcels combining with the modest buoyancy to support a few lightning flashes. Even so, the overall thunderstorm probabilities are still expected to be less than 10 percent. ..Mosier.. 01/20/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1028 AM CST Mon Jan 20 2025 Valid 201630Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. ...Synopsis... Another surge of cold air is anticipated across the CONUS, reinforcing the polar airmass already in place. This will result in a maintenance of dry and stable conditions, with no thunderstorms anticipated. Some deeper convection is possible late tonight/early tomorrow along the middle/upper TX Coast as warm-air advection strengthens throughout the warm sector of surface low developing over the western Gulf of Mexico. Model forecast soundings have thermodynamic profiles with scant (and shallow) buoyancy between around 800 to 500 mb. These profiles also suggest sleet will be the predominant precipitation type, with mixed-phase parcels combining with the modest buoyancy to support a few lightning flashes. Even so, the overall thunderstorm probabilities are still expected to be less than 10 percent. ..Mosier.. 01/20/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1028 AM CST Mon Jan 20 2025 Valid 201630Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. ...Synopsis... Another surge of cold air is anticipated across the CONUS, reinforcing the polar airmass already in place. This will result in a maintenance of dry and stable conditions, with no thunderstorms anticipated. Some deeper convection is possible late tonight/early tomorrow along the middle/upper TX Coast as warm-air advection strengthens throughout the warm sector of surface low developing over the western Gulf of Mexico. Model forecast soundings have thermodynamic profiles with scant (and shallow) buoyancy between around 800 to 500 mb. These profiles also suggest sleet will be the predominant precipitation type, with mixed-phase parcels combining with the modest buoyancy to support a few lightning flashes. Even so, the overall thunderstorm probabilities are still expected to be less than 10 percent. ..Mosier.. 01/20/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1028 AM CST Mon Jan 20 2025 Valid 201630Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. ...Synopsis... Another surge of cold air is anticipated across the CONUS, reinforcing the polar airmass already in place. This will result in a maintenance of dry and stable conditions, with no thunderstorms anticipated. Some deeper convection is possible late tonight/early tomorrow along the middle/upper TX Coast as warm-air advection strengthens throughout the warm sector of surface low developing over the western Gulf of Mexico. Model forecast soundings have thermodynamic profiles with scant (and shallow) buoyancy between around 800 to 500 mb. These profiles also suggest sleet will be the predominant precipitation type, with mixed-phase parcels combining with the modest buoyancy to support a few lightning flashes. Even so, the overall thunderstorm probabilities are still expected to be less than 10 percent. ..Mosier.. 01/20/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1028 AM CST Mon Jan 20 2025 Valid 201630Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. ...Synopsis... Another surge of cold air is anticipated across the CONUS, reinforcing the polar airmass already in place. This will result in a maintenance of dry and stable conditions, with no thunderstorms anticipated. Some deeper convection is possible late tonight/early tomorrow along the middle/upper TX Coast as warm-air advection strengthens throughout the warm sector of surface low developing over the western Gulf of Mexico. Model forecast soundings have thermodynamic profiles with scant (and shallow) buoyancy between around 800 to 500 mb. These profiles also suggest sleet will be the predominant precipitation type, with mixed-phase parcels combining with the modest buoyancy to support a few lightning flashes. Even so, the overall thunderstorm probabilities are still expected to be less than 10 percent. ..Mosier.. 01/20/2025 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1028 AM CST Mon Jan 20 2025 Valid 201630Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. ...Synopsis... Another surge of cold air is anticipated across the CONUS, reinforcing the polar airmass already in place. This will result in a maintenance of dry and stable conditions, with no thunderstorms anticipated. Some deeper convection is possible late tonight/early tomorrow along the middle/upper TX Coast as warm-air advection strengthens throughout the warm sector of surface low developing over the western Gulf of Mexico. Model forecast soundings have thermodynamic profiles with scant (and shallow) buoyancy between around 800 to 500 mb. These profiles also suggest sleet will be the predominant precipitation type, with mixed-phase parcels combining with the modest buoyancy to support a few lightning flashes. Even so, the overall thunderstorm probabilities are still expected to be less than 10 percent. ..Mosier.. 01/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0642 AM CST Mon Jan 20 2025 Valid 201300Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. Relatively dry and stable conditions will prevail across the CONUS today, with no thunderstorms expected. ..Hart/Wendt.. 01/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0642 AM CST Mon Jan 20 2025 Valid 201300Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. Relatively dry and stable conditions will prevail across the CONUS today, with no thunderstorms expected. ..Hart/Wendt.. 01/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0642 AM CST Mon Jan 20 2025 Valid 201300Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. Relatively dry and stable conditions will prevail across the CONUS today, with no thunderstorms expected. ..Hart/Wendt.. 01/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0642 AM CST Mon Jan 20 2025 Valid 201300Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. Relatively dry and stable conditions will prevail across the CONUS today, with no thunderstorms expected. ..Hart/Wendt.. 01/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0642 AM CST Mon Jan 20 2025 Valid 201300Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. Relatively dry and stable conditions will prevail across the CONUS today, with no thunderstorms expected. ..Hart/Wendt.. 01/20/2025 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0642 AM CST Mon Jan 20 2025 Valid 201300Z - 211200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... No thunderstorms are expected across the U.S. through tonight. Relatively dry and stable conditions will prevail across the CONUS today, with no thunderstorms expected. ..Hart/Wendt.. 01/20/2025 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0342 AM CST Mon Jan 20 2025 Valid 231200Z - 281200Z ...DISCUSSION... For Thursday/D4 into Friday/D5, a large positive-tilt upper trough will move from central parts of the CONUS toward the East Coast, exiting land late Friday. Although strong winds aloft will overspread the southeastern states, northerly winds are forecast to hold over land. Behind that system, high pressure will maintain stable conditions over the eastern CONUS into Saturday/D6, although more of a zonal flow regime is forecast thereafter. As a result of this possible transition to the pattern, minimal low-level moisture return with low 60s F dewpoints may return to parts of the TX Coast as surface pressure lowers briefly. Beyond the D6 time frame, model spread is large, but the general signal is for the ongoing large trough pattern over the central and eastern CONUS to at least shift northeastward into eastern Canada and the northeastern states, allowing for gradual warming across the South. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0342 AM CST Mon Jan 20 2025 Valid 231200Z - 281200Z ...DISCUSSION... For Thursday/D4 into Friday/D5, a large positive-tilt upper trough will move from central parts of the CONUS toward the East Coast, exiting land late Friday. Although strong winds aloft will overspread the southeastern states, northerly winds are forecast to hold over land. Behind that system, high pressure will maintain stable conditions over the eastern CONUS into Saturday/D6, although more of a zonal flow regime is forecast thereafter. As a result of this possible transition to the pattern, minimal low-level moisture return with low 60s F dewpoints may return to parts of the TX Coast as surface pressure lowers briefly. Beyond the D6 time frame, model spread is large, but the general signal is for the ongoing large trough pattern over the central and eastern CONUS to at least shift northeastward into eastern Canada and the northeastern states, allowing for gradual warming across the South. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0342 AM CST Mon Jan 20 2025 Valid 231200Z - 281200Z ...DISCUSSION... For Thursday/D4 into Friday/D5, a large positive-tilt upper trough will move from central parts of the CONUS toward the East Coast, exiting land late Friday. Although strong winds aloft will overspread the southeastern states, northerly winds are forecast to hold over land. Behind that system, high pressure will maintain stable conditions over the eastern CONUS into Saturday/D6, although more of a zonal flow regime is forecast thereafter. As a result of this possible transition to the pattern, minimal low-level moisture return with low 60s F dewpoints may return to parts of the TX Coast as surface pressure lowers briefly. Beyond the D6 time frame, model spread is large, but the general signal is for the ongoing large trough pattern over the central and eastern CONUS to at least shift northeastward into eastern Canada and the northeastern states, allowing for gradual warming across the South. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0342 AM CST Mon Jan 20 2025 Valid 231200Z - 281200Z ...DISCUSSION... For Thursday/D4 into Friday/D5, a large positive-tilt upper trough will move from central parts of the CONUS toward the East Coast, exiting land late Friday. Although strong winds aloft will overspread the southeastern states, northerly winds are forecast to hold over land. Behind that system, high pressure will maintain stable conditions over the eastern CONUS into Saturday/D6, although more of a zonal flow regime is forecast thereafter. As a result of this possible transition to the pattern, minimal low-level moisture return with low 60s F dewpoints may return to parts of the TX Coast as surface pressure lowers briefly. Beyond the D6 time frame, model spread is large, but the general signal is for the ongoing large trough pattern over the central and eastern CONUS to at least shift northeastward into eastern Canada and the northeastern states, allowing for gradual warming across the South. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0342 AM CST Mon Jan 20 2025 Valid 231200Z - 281200Z ...DISCUSSION... For Thursday/D4 into Friday/D5, a large positive-tilt upper trough will move from central parts of the CONUS toward the East Coast, exiting land late Friday. Although strong winds aloft will overspread the southeastern states, northerly winds are forecast to hold over land. Behind that system, high pressure will maintain stable conditions over the eastern CONUS into Saturday/D6, although more of a zonal flow regime is forecast thereafter. As a result of this possible transition to the pattern, minimal low-level moisture return with low 60s F dewpoints may return to parts of the TX Coast as surface pressure lowers briefly. Beyond the D6 time frame, model spread is large, but the general signal is for the ongoing large trough pattern over the central and eastern CONUS to at least shift northeastward into eastern Canada and the northeastern states, allowing for gradual warming across the South. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0342 AM CST Mon Jan 20 2025 Valid 231200Z - 281200Z ...DISCUSSION... For Thursday/D4 into Friday/D5, a large positive-tilt upper trough will move from central parts of the CONUS toward the East Coast, exiting land late Friday. Although strong winds aloft will overspread the southeastern states, northerly winds are forecast to hold over land. Behind that system, high pressure will maintain stable conditions over the eastern CONUS into Saturday/D6, although more of a zonal flow regime is forecast thereafter. As a result of this possible transition to the pattern, minimal low-level moisture return with low 60s F dewpoints may return to parts of the TX Coast as surface pressure lowers briefly. Beyond the D6 time frame, model spread is large, but the general signal is for the ongoing large trough pattern over the central and eastern CONUS to at least shift northeastward into eastern Canada and the northeastern states, allowing for gradual warming across the South. Read more