Aggregator

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1254 PM CST Tue Jan 07 2025 Valid 081200Z - 091200Z ...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN CALIFORNIA COAST... ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN CALIFORNIA COAST... The previous forecast remains on track with only minor modifications made based on trends in recent guidance. Confidence remains very high in the continuation of critical fire weather conditions for much of Wednesday. Recent HREF and other high-resolution guidance continues to suggest the highest probability for sustained extremely critical conditions remains across Ventura to western Los Angeles counties where RH values should drop into the 5-10% range coincident with 30-40 mph sustained winds for a few hours Wednesday morning and afternoon. See the previous discussion below for additional forecast details. ..Moore.. 01/07/2025 .PREV DISCUSSION... /ISSUED 0138 AM CST Tue Jan 07 2025/ ...Synopsis... A cutoff upper low pressure system within the lower Colorado River Valley into the Gulf of California will slowly continue to sag southeastward on Wednesday. A strong mid-level jet will remain favorably oriented with offshore winds in southern California through mid-afternoon. A strong surface high, though weakening through the day, should remain sufficiently intense to drive strong offshore surface winds across southern California. ...Southern California... Strong surface winds of 25-40 mph (with significant wind gusts within the terrain-favored areas) are expected during the morning into at least the early afternoon. While some locations may experience some RH recovery overnight, RH will begin to drop to around 10-15% as temperatures rise during the day. Given the intensity of the winds, extreme fire behavior appears likely should ignitions occur. Extremely critical fire weather is most likely for portion of Los Angeles and Ventura Counties. With high pressure extending farther south than on Monday, critical fire weather will extend to the San Diego vicinity as well. Even though the upper-level winds will weaken along with the offshore gradient, elevated to critical fire weather is expected to continue into Thursday morning. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1243 PM CST Tue Jan 07 2025 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated, non-severe thunderstorms are possible across parts of the western Gulf Coast States on Thursday into Thursday night. ...TX/LA... A northern-stream shortwave impulse should phase with the closed mid/upper low in the Gulf of CA vicinity, yielding a longwave trough from south-central Canada to northwest Mexico by Thursday night. Downstream low-level warm-moist advection will yield increasingly widespread precipitation across the south-central states on Thursday as a weak surface cyclone becomes established off the western Gulf Coast. Despite ample precipitation coverage, thunder potential appears slim. Very isolated thunder from parcels rooted near 700 mb may linger Thursday morning in the central TX vicinity. Thereafter, scant elevated buoyancy should become confined to the coastal plain, initially across Deep South TX and then shifting north-northeast through the rest of the period. Relatively warm upper-level temperatures in conjunction with weakening mid-level lapse rates may preclude charge separation inland. Some thunder potential is expected near the coast, with greater coverage over the adjacent offshore waters. ..Grams.. 01/07/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1243 PM CST Tue Jan 07 2025 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated, non-severe thunderstorms are possible across parts of the western Gulf Coast States on Thursday into Thursday night. ...TX/LA... A northern-stream shortwave impulse should phase with the closed mid/upper low in the Gulf of CA vicinity, yielding a longwave trough from south-central Canada to northwest Mexico by Thursday night. Downstream low-level warm-moist advection will yield increasingly widespread precipitation across the south-central states on Thursday as a weak surface cyclone becomes established off the western Gulf Coast. Despite ample precipitation coverage, thunder potential appears slim. Very isolated thunder from parcels rooted near 700 mb may linger Thursday morning in the central TX vicinity. Thereafter, scant elevated buoyancy should become confined to the coastal plain, initially across Deep South TX and then shifting north-northeast through the rest of the period. Relatively warm upper-level temperatures in conjunction with weakening mid-level lapse rates may preclude charge separation inland. Some thunder potential is expected near the coast, with greater coverage over the adjacent offshore waters. ..Grams.. 01/07/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1243 PM CST Tue Jan 07 2025 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated, non-severe thunderstorms are possible across parts of the western Gulf Coast States on Thursday into Thursday night. ...TX/LA... A northern-stream shortwave impulse should phase with the closed mid/upper low in the Gulf of CA vicinity, yielding a longwave trough from south-central Canada to northwest Mexico by Thursday night. Downstream low-level warm-moist advection will yield increasingly widespread precipitation across the south-central states on Thursday as a weak surface cyclone becomes established off the western Gulf Coast. Despite ample precipitation coverage, thunder potential appears slim. Very isolated thunder from parcels rooted near 700 mb may linger Thursday morning in the central TX vicinity. Thereafter, scant elevated buoyancy should become confined to the coastal plain, initially across Deep South TX and then shifting north-northeast through the rest of the period. Relatively warm upper-level temperatures in conjunction with weakening mid-level lapse rates may preclude charge separation inland. Some thunder potential is expected near the coast, with greater coverage over the adjacent offshore waters. ..Grams.. 01/07/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1243 PM CST Tue Jan 07 2025 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated, non-severe thunderstorms are possible across parts of the western Gulf Coast States on Thursday into Thursday night. ...TX/LA... A northern-stream shortwave impulse should phase with the closed mid/upper low in the Gulf of CA vicinity, yielding a longwave trough from south-central Canada to northwest Mexico by Thursday night. Downstream low-level warm-moist advection will yield increasingly widespread precipitation across the south-central states on Thursday as a weak surface cyclone becomes established off the western Gulf Coast. Despite ample precipitation coverage, thunder potential appears slim. Very isolated thunder from parcels rooted near 700 mb may linger Thursday morning in the central TX vicinity. Thereafter, scant elevated buoyancy should become confined to the coastal plain, initially across Deep South TX and then shifting north-northeast through the rest of the period. Relatively warm upper-level temperatures in conjunction with weakening mid-level lapse rates may preclude charge separation inland. Some thunder potential is expected near the coast, with greater coverage over the adjacent offshore waters. ..Grams.. 01/07/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1243 PM CST Tue Jan 07 2025 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated, non-severe thunderstorms are possible across parts of the western Gulf Coast States on Thursday into Thursday night. ...TX/LA... A northern-stream shortwave impulse should phase with the closed mid/upper low in the Gulf of CA vicinity, yielding a longwave trough from south-central Canada to northwest Mexico by Thursday night. Downstream low-level warm-moist advection will yield increasingly widespread precipitation across the south-central states on Thursday as a weak surface cyclone becomes established off the western Gulf Coast. Despite ample precipitation coverage, thunder potential appears slim. Very isolated thunder from parcels rooted near 700 mb may linger Thursday morning in the central TX vicinity. Thereafter, scant elevated buoyancy should become confined to the coastal plain, initially across Deep South TX and then shifting north-northeast through the rest of the period. Relatively warm upper-level temperatures in conjunction with weakening mid-level lapse rates may preclude charge separation inland. Some thunder potential is expected near the coast, with greater coverage over the adjacent offshore waters. ..Grams.. 01/07/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1243 PM CST Tue Jan 07 2025 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated, non-severe thunderstorms are possible across parts of the western Gulf Coast States on Thursday into Thursday night. ...TX/LA... A northern-stream shortwave impulse should phase with the closed mid/upper low in the Gulf of CA vicinity, yielding a longwave trough from south-central Canada to northwest Mexico by Thursday night. Downstream low-level warm-moist advection will yield increasingly widespread precipitation across the south-central states on Thursday as a weak surface cyclone becomes established off the western Gulf Coast. Despite ample precipitation coverage, thunder potential appears slim. Very isolated thunder from parcels rooted near 700 mb may linger Thursday morning in the central TX vicinity. Thereafter, scant elevated buoyancy should become confined to the coastal plain, initially across Deep South TX and then shifting north-northeast through the rest of the period. Relatively warm upper-level temperatures in conjunction with weakening mid-level lapse rates may preclude charge separation inland. Some thunder potential is expected near the coast, with greater coverage over the adjacent offshore waters. ..Grams.. 01/07/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 1243 PM CST Tue Jan 07 2025 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated, non-severe thunderstorms are possible across parts of the western Gulf Coast States on Thursday into Thursday night. ...TX/LA... A northern-stream shortwave impulse should phase with the closed mid/upper low in the Gulf of CA vicinity, yielding a longwave trough from south-central Canada to northwest Mexico by Thursday night. Downstream low-level warm-moist advection will yield increasingly widespread precipitation across the south-central states on Thursday as a weak surface cyclone becomes established off the western Gulf Coast. Despite ample precipitation coverage, thunder potential appears slim. Very isolated thunder from parcels rooted near 700 mb may linger Thursday morning in the central TX vicinity. Thereafter, scant elevated buoyancy should become confined to the coastal plain, initially across Deep South TX and then shifting north-northeast through the rest of the period. Relatively warm upper-level temperatures in conjunction with weakening mid-level lapse rates may preclude charge separation inland. Some thunder potential is expected near the coast, with greater coverage over the adjacent offshore waters. ..Grams.. 01/07/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Tue Jan 07 2025 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Very isolated thunderstorms will be possible Wednesday night across parts of west Texas. ...West TX... A closed mid/upper low will drift southeast across the Gulf of CA vicinity. Downstream of this wave, warm-moist advection at 700 mb should eventually yield scant buoyancy with mixed-phase states in elevated parcels amid steep mid-level lapse rates. Isolated convection should develop overnight Wednesday into early Thursday, most of which should occur atop sub-freezing wet-bulb temperatures near the surface. Some of this elevated convection may yield very isolated thunder coverage near 10 percent. ..Grams.. 01/07/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Tue Jan 07 2025 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Very isolated thunderstorms will be possible Wednesday night across parts of west Texas. ...West TX... A closed mid/upper low will drift southeast across the Gulf of CA vicinity. Downstream of this wave, warm-moist advection at 700 mb should eventually yield scant buoyancy with mixed-phase states in elevated parcels amid steep mid-level lapse rates. Isolated convection should develop overnight Wednesday into early Thursday, most of which should occur atop sub-freezing wet-bulb temperatures near the surface. Some of this elevated convection may yield very isolated thunder coverage near 10 percent. ..Grams.. 01/07/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Tue Jan 07 2025 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Very isolated thunderstorms will be possible Wednesday night across parts of west Texas. ...West TX... A closed mid/upper low will drift southeast across the Gulf of CA vicinity. Downstream of this wave, warm-moist advection at 700 mb should eventually yield scant buoyancy with mixed-phase states in elevated parcels amid steep mid-level lapse rates. Isolated convection should develop overnight Wednesday into early Thursday, most of which should occur atop sub-freezing wet-bulb temperatures near the surface. Some of this elevated convection may yield very isolated thunder coverage near 10 percent. ..Grams.. 01/07/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Tue Jan 07 2025 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Very isolated thunderstorms will be possible Wednesday night across parts of west Texas. ...West TX... A closed mid/upper low will drift southeast across the Gulf of CA vicinity. Downstream of this wave, warm-moist advection at 700 mb should eventually yield scant buoyancy with mixed-phase states in elevated parcels amid steep mid-level lapse rates. Isolated convection should develop overnight Wednesday into early Thursday, most of which should occur atop sub-freezing wet-bulb temperatures near the surface. Some of this elevated convection may yield very isolated thunder coverage near 10 percent. ..Grams.. 01/07/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Tue Jan 07 2025 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Very isolated thunderstorms will be possible Wednesday night across parts of west Texas. ...West TX... A closed mid/upper low will drift southeast across the Gulf of CA vicinity. Downstream of this wave, warm-moist advection at 700 mb should eventually yield scant buoyancy with mixed-phase states in elevated parcels amid steep mid-level lapse rates. Isolated convection should develop overnight Wednesday into early Thursday, most of which should occur atop sub-freezing wet-bulb temperatures near the surface. Some of this elevated convection may yield very isolated thunder coverage near 10 percent. ..Grams.. 01/07/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Tue Jan 07 2025 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Very isolated thunderstorms will be possible Wednesday night across parts of west Texas. ...West TX... A closed mid/upper low will drift southeast across the Gulf of CA vicinity. Downstream of this wave, warm-moist advection at 700 mb should eventually yield scant buoyancy with mixed-phase states in elevated parcels amid steep mid-level lapse rates. Isolated convection should develop overnight Wednesday into early Thursday, most of which should occur atop sub-freezing wet-bulb temperatures near the surface. Some of this elevated convection may yield very isolated thunder coverage near 10 percent. ..Grams.. 01/07/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Tue Jan 07 2025 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Very isolated thunderstorms will be possible Wednesday night across parts of west Texas. ...West TX... A closed mid/upper low will drift southeast across the Gulf of CA vicinity. Downstream of this wave, warm-moist advection at 700 mb should eventually yield scant buoyancy with mixed-phase states in elevated parcels amid steep mid-level lapse rates. Isolated convection should develop overnight Wednesday into early Thursday, most of which should occur atop sub-freezing wet-bulb temperatures near the surface. Some of this elevated convection may yield very isolated thunder coverage near 10 percent. ..Grams.. 01/07/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Tue Jan 07 2025 Valid 081200Z - 091200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Very isolated thunderstorms will be possible Wednesday night across parts of west Texas. ...West TX... A closed mid/upper low will drift southeast across the Gulf of CA vicinity. Downstream of this wave, warm-moist advection at 700 mb should eventually yield scant buoyancy with mixed-phase states in elevated parcels amid steep mid-level lapse rates. Isolated convection should develop overnight Wednesday into early Thursday, most of which should occur atop sub-freezing wet-bulb temperatures near the surface. Some of this elevated convection may yield very isolated thunder coverage near 10 percent. ..Grams.. 01/07/2025 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Tue Jan 07 2025 Valid 071700Z - 081200Z ...CRITICAL FIRE WEATHER AREA FOR THE SOUTHERN CALIFORNIA COAST... The previous forecast remains on track with some modifications made to reflect recent observed trends and 12z guidance. Regional radars show light to moderate precipitation falling across southern CA - mainly on the windward side of the coastal terrain. MRMS QPE suggests most locations on the lee side of the coastal ranges have not received wetting rainfall, so impacts to fuels should remain limited. 16 UTC surface observations show downslope winds beginning to increase with gusts between 40-60 mph becoming more common at higher elevation. As of 16 UTC, cloud cover is modulating the influence of downslope warming/drying with RH values generally above 30%; however, relative humidity is expected to quickly decline by mid/late afternoon as cloud cover/precipitation shifts southeast in tandem with the upper trough over the region. Consequently, confidence remains high that the fire weather threat will increase this afternoon through the early morning hours Wednesday. High-resolution guidance suggests peak winds are probable during the 09-15 UTC period Wednesday with gusts between 60-80 mph likely at higher elevation (with locally stronger gusts possible). Critical RH thresholds will likely be maintained through the overnight period across western Los Angeles to Ventura and eastern Santa Barbara counties, but may recover into the upper teens southward along the coast. ..Moore.. 01/07/2025 .PREV DISCUSSION... /ISSUED 0137 AM CST Tue Jan 07 2025/ ...Synopsis... A broad trough across the West will undergo intensification today. A strong mid-level jet will develop in the western Great Basin and California. At the surface, high pressure will strengthen in the Great Basin into the lower Colorado River Valley. ...Southern California... The offshore pressure gradient may be sufficient to support elevated to critical fire weather by this afternoon. RH will be the main uncertainty during the afternoon, but around 20% appears likely and near 15% is certainly possible. Winds this afternoon will peak at 20-25 mph outside of the terrain. Both the offshore gradient and the supporting upper-level winds are expected to increase in magnitude during the evening/overnight into Wednesday morning. The strongest upper-level winds (and thus wind gusts) are most likely around very late today to early Wednesday. How low RH will remain overnight is also somewhat uncertain, but wind strength (25-35 mph) would still support higher-end critical conditions in the typical Santa Ana corridors in LA/Ventura Counties. ...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 1015 AM CST Tue Jan 07 2025 Valid 071700Z - 081200Z ...CRITICAL FIRE WEATHER AREA FOR THE SOUTHERN CALIFORNIA COAST... The previous forecast remains on track with some modifications made to reflect recent observed trends and 12z guidance. Regional radars show light to moderate precipitation falling across southern CA - mainly on the windward side of the coastal terrain. MRMS QPE suggests most locations on the lee side of the coastal ranges have not received wetting rainfall, so impacts to fuels should remain limited. 16 UTC surface observations show downslope winds beginning to increase with gusts between 40-60 mph becoming more common at higher elevation. As of 16 UTC, cloud cover is modulating the influence of downslope warming/drying with RH values generally above 30%; however, relative humidity is expected to quickly decline by mid/late afternoon as cloud cover/precipitation shifts southeast in tandem with the upper trough over the region. Consequently, confidence remains high that the fire weather threat will increase this afternoon through the early morning hours Wednesday. High-resolution guidance suggests peak winds are probable during the 09-15 UTC period Wednesday with gusts between 60-80 mph likely at higher elevation (with locally stronger gusts possible). Critical RH thresholds will likely be maintained through the overnight period across western Los Angeles to Ventura and eastern Santa Barbara counties, but may recover into the upper teens southward along the coast. ..Moore.. 01/07/2025 .PREV DISCUSSION... /ISSUED 0137 AM CST Tue Jan 07 2025/ ...Synopsis... A broad trough across the West will undergo intensification today. A strong mid-level jet will develop in the western Great Basin and California. At the surface, high pressure will strengthen in the Great Basin into the lower Colorado River Valley. ...Southern California... The offshore pressure gradient may be sufficient to support elevated to critical fire weather by this afternoon. RH will be the main uncertainty during the afternoon, but around 20% appears likely and near 15% is certainly possible. Winds this afternoon will peak at 20-25 mph outside of the terrain. Both the offshore gradient and the supporting upper-level winds are expected to increase in magnitude during the evening/overnight into Wednesday morning. The strongest upper-level winds (and thus wind gusts) are most likely around very late today to early Wednesday. How low RH will remain overnight is also somewhat uncertain, but wind strength (25-35 mph) would still support higher-end critical conditions in the typical Santa Ana corridors in LA/Ventura Counties. ...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 1015 AM CST Tue Jan 07 2025 Valid 071700Z - 081200Z ...CRITICAL FIRE WEATHER AREA FOR THE SOUTHERN CALIFORNIA COAST... The previous forecast remains on track with some modifications made to reflect recent observed trends and 12z guidance. Regional radars show light to moderate precipitation falling across southern CA - mainly on the windward side of the coastal terrain. MRMS QPE suggests most locations on the lee side of the coastal ranges have not received wetting rainfall, so impacts to fuels should remain limited. 16 UTC surface observations show downslope winds beginning to increase with gusts between 40-60 mph becoming more common at higher elevation. As of 16 UTC, cloud cover is modulating the influence of downslope warming/drying with RH values generally above 30%; however, relative humidity is expected to quickly decline by mid/late afternoon as cloud cover/precipitation shifts southeast in tandem with the upper trough over the region. Consequently, confidence remains high that the fire weather threat will increase this afternoon through the early morning hours Wednesday. High-resolution guidance suggests peak winds are probable during the 09-15 UTC period Wednesday with gusts between 60-80 mph likely at higher elevation (with locally stronger gusts possible). Critical RH thresholds will likely be maintained through the overnight period across western Los Angeles to Ventura and eastern Santa Barbara counties, but may recover into the upper teens southward along the coast. ..Moore.. 01/07/2025 .PREV DISCUSSION... /ISSUED 0137 AM CST Tue Jan 07 2025/ ...Synopsis... A broad trough across the West will undergo intensification today. A strong mid-level jet will develop in the western Great Basin and California. At the surface, high pressure will strengthen in the Great Basin into the lower Colorado River Valley. ...Southern California... The offshore pressure gradient may be sufficient to support elevated to critical fire weather by this afternoon. RH will be the main uncertainty during the afternoon, but around 20% appears likely and near 15% is certainly possible. Winds this afternoon will peak at 20-25 mph outside of the terrain. Both the offshore gradient and the supporting upper-level winds are expected to increase in magnitude during the evening/overnight into Wednesday morning. The strongest upper-level winds (and thus wind gusts) are most likely around very late today to early Wednesday. How low RH will remain overnight is also somewhat uncertain, but wind strength (25-35 mph) would still support higher-end critical conditions in the typical Santa Ana corridors in LA/Ventura Counties. ...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 1015 AM CST Tue Jan 07 2025 Valid 071700Z - 081200Z ...CRITICAL FIRE WEATHER AREA FOR THE SOUTHERN CALIFORNIA COAST... The previous forecast remains on track with some modifications made to reflect recent observed trends and 12z guidance. Regional radars show light to moderate precipitation falling across southern CA - mainly on the windward side of the coastal terrain. MRMS QPE suggests most locations on the lee side of the coastal ranges have not received wetting rainfall, so impacts to fuels should remain limited. 16 UTC surface observations show downslope winds beginning to increase with gusts between 40-60 mph becoming more common at higher elevation. As of 16 UTC, cloud cover is modulating the influence of downslope warming/drying with RH values generally above 30%; however, relative humidity is expected to quickly decline by mid/late afternoon as cloud cover/precipitation shifts southeast in tandem with the upper trough over the region. Consequently, confidence remains high that the fire weather threat will increase this afternoon through the early morning hours Wednesday. High-resolution guidance suggests peak winds are probable during the 09-15 UTC period Wednesday with gusts between 60-80 mph likely at higher elevation (with locally stronger gusts possible). Critical RH thresholds will likely be maintained through the overnight period across western Los Angeles to Ventura and eastern Santa Barbara counties, but may recover into the upper teens southward along the coast. ..Moore.. 01/07/2025 .PREV DISCUSSION... /ISSUED 0137 AM CST Tue Jan 07 2025/ ...Synopsis... A broad trough across the West will undergo intensification today. A strong mid-level jet will develop in the western Great Basin and California. At the surface, high pressure will strengthen in the Great Basin into the lower Colorado River Valley. ...Southern California... The offshore pressure gradient may be sufficient to support elevated to critical fire weather by this afternoon. RH will be the main uncertainty during the afternoon, but around 20% appears likely and near 15% is certainly possible. Winds this afternoon will peak at 20-25 mph outside of the terrain. Both the offshore gradient and the supporting upper-level winds are expected to increase in magnitude during the evening/overnight into Wednesday morning. The strongest upper-level winds (and thus wind gusts) are most likely around very late today to early Wednesday. How low RH will remain overnight is also somewhat uncertain, but wind strength (25-35 mph) would still support higher-end critical conditions in the typical Santa Ana corridors in LA/Ventura Counties. ...Please see www.spc.noaa.gov/fire for graphic product... Read more