Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1017 AM CST Wed Dec 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible through tonight from the Four Corners into west Texas, and across parts of south Florida. Severe storms are not expected. ...Synopsis/Discussion... A closed mid/upper-level low will continue eastward over the Four Corners area and southern Rockies through tonight, removed from a more progressive belt of westerlies over the northern tier of the CONUS and Canada. Steepening lapse rates and ascent ahead of the aforementioned upper low will support isolated thunderstorm potential from northeast Arizona/southeast Utah into New Mexico especially tonight, while other thunderstorms will be possible today and tonight farther east across eastern New Mexico and western Texas within a persistent warm advection regime. Additionally, a few thunderstorms will be possible across/near south Florida near a convergence zone where a moist air mass persists. ..Guyer/Thornton.. 12/13/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1017 AM CST Wed Dec 13 2023 Valid 131630Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible through tonight from the Four Corners into west Texas, and across parts of south Florida. Severe storms are not expected. ...Synopsis/Discussion... A closed mid/upper-level low will continue eastward over the Four Corners area and southern Rockies through tonight, removed from a more progressive belt of westerlies over the northern tier of the CONUS and Canada. Steepening lapse rates and ascent ahead of the aforementioned upper low will support isolated thunderstorm potential from northeast Arizona/southeast Utah into New Mexico especially tonight, while other thunderstorms will be possible today and tonight farther east across eastern New Mexico and western Texas within a persistent warm advection regime. Additionally, a few thunderstorms will be possible across/near south Florida near a convergence zone where a moist air mass persists. ..Guyer/Thornton.. 12/13/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0908 AM CST Wed Dec 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track with no changes needed. Latest surface observations along the southern CA coast show winds gusting between 30-40 mph, but RH has generally remained above 30%. Some diurnal RH reduction is anticipated this afternoon, and may result in localized fire weather concerns (mainly over Ventura and LA counties). However, the potential for more widespread elevated conditions remains too limited for highlights. ..Moore.. 12/13/2023 .PREV DISCUSSION... /ISSUED 0131 AM CST Wed Dec 13 2023/ ...Synopsis... The CONUS will generally be under the influence of an upper-level ridge today. A cutoff low will slowly progress eastward toward the Four Corners, becoming more of an open wave in the process. At the surface, high pressure will be present across the vast majority of the CONUS. Cooler temperatures, light winds, and precipitation will keep fire weather concerns low for most areas. Some locally elevated fire weather may occur in southern California as modest offshore flow persists through the period. ...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 0908 AM CST Wed Dec 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track with no changes needed. Latest surface observations along the southern CA coast show winds gusting between 30-40 mph, but RH has generally remained above 30%. Some diurnal RH reduction is anticipated this afternoon, and may result in localized fire weather concerns (mainly over Ventura and LA counties). However, the potential for more widespread elevated conditions remains too limited for highlights. ..Moore.. 12/13/2023 .PREV DISCUSSION... /ISSUED 0131 AM CST Wed Dec 13 2023/ ...Synopsis... The CONUS will generally be under the influence of an upper-level ridge today. A cutoff low will slowly progress eastward toward the Four Corners, becoming more of an open wave in the process. At the surface, high pressure will be present across the vast majority of the CONUS. Cooler temperatures, light winds, and precipitation will keep fire weather concerns low for most areas. Some locally elevated fire weather may occur in southern California as modest offshore flow persists through the period. ...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 0908 AM CST Wed Dec 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track with no changes needed. Latest surface observations along the southern CA coast show winds gusting between 30-40 mph, but RH has generally remained above 30%. Some diurnal RH reduction is anticipated this afternoon, and may result in localized fire weather concerns (mainly over Ventura and LA counties). However, the potential for more widespread elevated conditions remains too limited for highlights. ..Moore.. 12/13/2023 .PREV DISCUSSION... /ISSUED 0131 AM CST Wed Dec 13 2023/ ...Synopsis... The CONUS will generally be under the influence of an upper-level ridge today. A cutoff low will slowly progress eastward toward the Four Corners, becoming more of an open wave in the process. At the surface, high pressure will be present across the vast majority of the CONUS. Cooler temperatures, light winds, and precipitation will keep fire weather concerns low for most areas. Some locally elevated fire weather may occur in southern California as modest offshore flow persists through the period. ...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 0908 AM CST Wed Dec 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track with no changes needed. Latest surface observations along the southern CA coast show winds gusting between 30-40 mph, but RH has generally remained above 30%. Some diurnal RH reduction is anticipated this afternoon, and may result in localized fire weather concerns (mainly over Ventura and LA counties). However, the potential for more widespread elevated conditions remains too limited for highlights. ..Moore.. 12/13/2023 .PREV DISCUSSION... /ISSUED 0131 AM CST Wed Dec 13 2023/ ...Synopsis... The CONUS will generally be under the influence of an upper-level ridge today. A cutoff low will slowly progress eastward toward the Four Corners, becoming more of an open wave in the process. At the surface, high pressure will be present across the vast majority of the CONUS. Cooler temperatures, light winds, and precipitation will keep fire weather concerns low for most areas. Some locally elevated fire weather may occur in southern California as modest offshore flow persists through the period. ...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 0908 AM CST Wed Dec 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track with no changes needed. Latest surface observations along the southern CA coast show winds gusting between 30-40 mph, but RH has generally remained above 30%. Some diurnal RH reduction is anticipated this afternoon, and may result in localized fire weather concerns (mainly over Ventura and LA counties). However, the potential for more widespread elevated conditions remains too limited for highlights. ..Moore.. 12/13/2023 .PREV DISCUSSION... /ISSUED 0131 AM CST Wed Dec 13 2023/ ...Synopsis... The CONUS will generally be under the influence of an upper-level ridge today. A cutoff low will slowly progress eastward toward the Four Corners, becoming more of an open wave in the process. At the surface, high pressure will be present across the vast majority of the CONUS. Cooler temperatures, light winds, and precipitation will keep fire weather concerns low for most areas. Some locally elevated fire weather may occur in southern California as modest offshore flow persists through the period. ...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 0908 AM CST Wed Dec 13 2023 Valid 131700Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track with no changes needed. Latest surface observations along the southern CA coast show winds gusting between 30-40 mph, but RH has generally remained above 30%. Some diurnal RH reduction is anticipated this afternoon, and may result in localized fire weather concerns (mainly over Ventura and LA counties). However, the potential for more widespread elevated conditions remains too limited for highlights. ..Moore.. 12/13/2023 .PREV DISCUSSION... /ISSUED 0131 AM CST Wed Dec 13 2023/ ...Synopsis... The CONUS will generally be under the influence of an upper-level ridge today. A cutoff low will slowly progress eastward toward the Four Corners, becoming more of an open wave in the process. At the surface, high pressure will be present across the vast majority of the CONUS. Cooler temperatures, light winds, and precipitation will keep fire weather concerns low for most areas. Some locally elevated fire weather may occur in southern California as modest offshore flow persists through the period. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 AM CST Wed Dec 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms will be possible through tonight from the Four Corners into west Texas, and across parts of south Florida. Severe storms are not expected. ...Synopsis... A closed midlevel low will move slowly eastward over northern AZ toward NM by Thursday morning. Surface ridging and an associated cool air mass will be maintained across most of the central and eastern CONUS, beneath confluent midlevel flow. This low-level flow regime will limit substantial boundary-layer moisture to south FL, where a few thunderstorms will be possible along the convergence zone coincident with the northwest edge of the 68-72 F dewpoints across the Keys and southeast FL. Farther west, a modifying air mass with dewpoints in the low-mid 60s will persist across Deep South TX, though poor lapse rates aloft suggest that convection will remain too shallow for charge separation and lighting production. Steepening midlevel lapse rates and ascent immediately east of the midlevel low could support isolated thunderstorms over the higher terrain of northeast AZ and western NM this evening into tonight. A few lightning flashes with elevated convection will also be possible farther east in the persistent warm advection zone with weak buoyancy over west TX and the TX Panhandle. ..Thompson/Gleason.. 12/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 AM CST Wed Dec 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms will be possible through tonight from the Four Corners into west Texas, and across parts of south Florida. Severe storms are not expected. ...Synopsis... A closed midlevel low will move slowly eastward over northern AZ toward NM by Thursday morning. Surface ridging and an associated cool air mass will be maintained across most of the central and eastern CONUS, beneath confluent midlevel flow. This low-level flow regime will limit substantial boundary-layer moisture to south FL, where a few thunderstorms will be possible along the convergence zone coincident with the northwest edge of the 68-72 F dewpoints across the Keys and southeast FL. Farther west, a modifying air mass with dewpoints in the low-mid 60s will persist across Deep South TX, though poor lapse rates aloft suggest that convection will remain too shallow for charge separation and lighting production. Steepening midlevel lapse rates and ascent immediately east of the midlevel low could support isolated thunderstorms over the higher terrain of northeast AZ and western NM this evening into tonight. A few lightning flashes with elevated convection will also be possible farther east in the persistent warm advection zone with weak buoyancy over west TX and the TX Panhandle. ..Thompson/Gleason.. 12/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 AM CST Wed Dec 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms will be possible through tonight from the Four Corners into west Texas, and across parts of south Florida. Severe storms are not expected. ...Synopsis... A closed midlevel low will move slowly eastward over northern AZ toward NM by Thursday morning. Surface ridging and an associated cool air mass will be maintained across most of the central and eastern CONUS, beneath confluent midlevel flow. This low-level flow regime will limit substantial boundary-layer moisture to south FL, where a few thunderstorms will be possible along the convergence zone coincident with the northwest edge of the 68-72 F dewpoints across the Keys and southeast FL. Farther west, a modifying air mass with dewpoints in the low-mid 60s will persist across Deep South TX, though poor lapse rates aloft suggest that convection will remain too shallow for charge separation and lighting production. Steepening midlevel lapse rates and ascent immediately east of the midlevel low could support isolated thunderstorms over the higher terrain of northeast AZ and western NM this evening into tonight. A few lightning flashes with elevated convection will also be possible farther east in the persistent warm advection zone with weak buoyancy over west TX and the TX Panhandle. ..Thompson/Gleason.. 12/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 AM CST Wed Dec 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms will be possible through tonight from the Four Corners into west Texas, and across parts of south Florida. Severe storms are not expected. ...Synopsis... A closed midlevel low will move slowly eastward over northern AZ toward NM by Thursday morning. Surface ridging and an associated cool air mass will be maintained across most of the central and eastern CONUS, beneath confluent midlevel flow. This low-level flow regime will limit substantial boundary-layer moisture to south FL, where a few thunderstorms will be possible along the convergence zone coincident with the northwest edge of the 68-72 F dewpoints across the Keys and southeast FL. Farther west, a modifying air mass with dewpoints in the low-mid 60s will persist across Deep South TX, though poor lapse rates aloft suggest that convection will remain too shallow for charge separation and lighting production. Steepening midlevel lapse rates and ascent immediately east of the midlevel low could support isolated thunderstorms over the higher terrain of northeast AZ and western NM this evening into tonight. A few lightning flashes with elevated convection will also be possible farther east in the persistent warm advection zone with weak buoyancy over west TX and the TX Panhandle. ..Thompson/Gleason.. 12/13/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0640 AM CST Wed Dec 13 2023 Valid 131300Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms will be possible through tonight from the Four Corners into west Texas, and across parts of south Florida. Severe storms are not expected. ...Synopsis... A closed midlevel low will move slowly eastward over northern AZ toward NM by Thursday morning. Surface ridging and an associated cool air mass will be maintained across most of the central and eastern CONUS, beneath confluent midlevel flow. This low-level flow regime will limit substantial boundary-layer moisture to south FL, where a few thunderstorms will be possible along the convergence zone coincident with the northwest edge of the 68-72 F dewpoints across the Keys and southeast FL. Farther west, a modifying air mass with dewpoints in the low-mid 60s will persist across Deep South TX, though poor lapse rates aloft suggest that convection will remain too shallow for charge separation and lighting production. Steepening midlevel lapse rates and ascent immediately east of the midlevel low could support isolated thunderstorms over the higher terrain of northeast AZ and western NM this evening into tonight. A few lightning flashes with elevated convection will also be possible farther east in the persistent warm advection zone with weak buoyancy over west TX and the TX Panhandle. ..Thompson/Gleason.. 12/13/2023 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0341 AM CST Wed Dec 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... An area-of-interest for at least low probability tornado and damaging wind potential exists late D4 to early D6 over the eastern Gulf to South Atlantic States. Confidence remains too low to warrant a 15 percent severe probability highlight for a specific day and mesoscale-focused area. 00Z deterministic guidance trends support gradually increasing agreement over the past several days with pronounced cyclogenesis in the eastern Gulf to on/off the South Atlantic Coast during D4-6. Multiple synoptic-scale interactions are apparent. First, phasing of northern and southern-stream shortwave troughs should continue from D3 over the central states. Second, a separate convection-induced shortwave impulse appears likely to be generated over eastern Gulf within the favorable right-rear quadrant of an intensifying upper jet in the East. The initial warm-core nature of this leading impulse suggests poor mid-level lapse rates will require sufficient surface-based instability coincident with strengthening low-level wind fields across the FL Peninsula late Saturday into Sunday. 00Z ECMWF ensemble and GEFS members continue to indicate vast spread in the degree of cyclone amplification, as well as substantial spatial and temporal variation of cyclone evolution. This renders low confidence in the timing/location of a conditionally favorable warm-sector environment outside of central/south FL. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0341 AM CST Wed Dec 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... An area-of-interest for at least low probability tornado and damaging wind potential exists late D4 to early D6 over the eastern Gulf to South Atlantic States. Confidence remains too low to warrant a 15 percent severe probability highlight for a specific day and mesoscale-focused area. 00Z deterministic guidance trends support gradually increasing agreement over the past several days with pronounced cyclogenesis in the eastern Gulf to on/off the South Atlantic Coast during D4-6. Multiple synoptic-scale interactions are apparent. First, phasing of northern and southern-stream shortwave troughs should continue from D3 over the central states. Second, a separate convection-induced shortwave impulse appears likely to be generated over eastern Gulf within the favorable right-rear quadrant of an intensifying upper jet in the East. The initial warm-core nature of this leading impulse suggests poor mid-level lapse rates will require sufficient surface-based instability coincident with strengthening low-level wind fields across the FL Peninsula late Saturday into Sunday. 00Z ECMWF ensemble and GEFS members continue to indicate vast spread in the degree of cyclone amplification, as well as substantial spatial and temporal variation of cyclone evolution. This renders low confidence in the timing/location of a conditionally favorable warm-sector environment outside of central/south FL. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0341 AM CST Wed Dec 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... An area-of-interest for at least low probability tornado and damaging wind potential exists late D4 to early D6 over the eastern Gulf to South Atlantic States. Confidence remains too low to warrant a 15 percent severe probability highlight for a specific day and mesoscale-focused area. 00Z deterministic guidance trends support gradually increasing agreement over the past several days with pronounced cyclogenesis in the eastern Gulf to on/off the South Atlantic Coast during D4-6. Multiple synoptic-scale interactions are apparent. First, phasing of northern and southern-stream shortwave troughs should continue from D3 over the central states. Second, a separate convection-induced shortwave impulse appears likely to be generated over eastern Gulf within the favorable right-rear quadrant of an intensifying upper jet in the East. The initial warm-core nature of this leading impulse suggests poor mid-level lapse rates will require sufficient surface-based instability coincident with strengthening low-level wind fields across the FL Peninsula late Saturday into Sunday. 00Z ECMWF ensemble and GEFS members continue to indicate vast spread in the degree of cyclone amplification, as well as substantial spatial and temporal variation of cyclone evolution. This renders low confidence in the timing/location of a conditionally favorable warm-sector environment outside of central/south FL. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0341 AM CST Wed Dec 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... An area-of-interest for at least low probability tornado and damaging wind potential exists late D4 to early D6 over the eastern Gulf to South Atlantic States. Confidence remains too low to warrant a 15 percent severe probability highlight for a specific day and mesoscale-focused area. 00Z deterministic guidance trends support gradually increasing agreement over the past several days with pronounced cyclogenesis in the eastern Gulf to on/off the South Atlantic Coast during D4-6. Multiple synoptic-scale interactions are apparent. First, phasing of northern and southern-stream shortwave troughs should continue from D3 over the central states. Second, a separate convection-induced shortwave impulse appears likely to be generated over eastern Gulf within the favorable right-rear quadrant of an intensifying upper jet in the East. The initial warm-core nature of this leading impulse suggests poor mid-level lapse rates will require sufficient surface-based instability coincident with strengthening low-level wind fields across the FL Peninsula late Saturday into Sunday. 00Z ECMWF ensemble and GEFS members continue to indicate vast spread in the degree of cyclone amplification, as well as substantial spatial and temporal variation of cyclone evolution. This renders low confidence in the timing/location of a conditionally favorable warm-sector environment outside of central/south FL. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0341 AM CST Wed Dec 13 2023 Valid 161200Z - 211200Z ...DISCUSSION... An area-of-interest for at least low probability tornado and damaging wind potential exists late D4 to early D6 over the eastern Gulf to South Atlantic States. Confidence remains too low to warrant a 15 percent severe probability highlight for a specific day and mesoscale-focused area. 00Z deterministic guidance trends support gradually increasing agreement over the past several days with pronounced cyclogenesis in the eastern Gulf to on/off the South Atlantic Coast during D4-6. Multiple synoptic-scale interactions are apparent. First, phasing of northern and southern-stream shortwave troughs should continue from D3 over the central states. Second, a separate convection-induced shortwave impulse appears likely to be generated over eastern Gulf within the favorable right-rear quadrant of an intensifying upper jet in the East. The initial warm-core nature of this leading impulse suggests poor mid-level lapse rates will require sufficient surface-based instability coincident with strengthening low-level wind fields across the FL Peninsula late Saturday into Sunday. 00Z ECMWF ensemble and GEFS members continue to indicate vast spread in the degree of cyclone amplification, as well as substantial spatial and temporal variation of cyclone evolution. This renders low confidence in the timing/location of a conditionally favorable warm-sector environment outside of central/south FL. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0146 AM CST Wed Dec 13 2023 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Friday. ...Central to east TX... Pronounced forcing for ascent ahead of a slow-moving shortwave trough over the southern Great Plains will likely support a continued swath of elevated convection. This activity should be centered on north to west-central TX at 12Z Friday and gradually progress east-southeast into the Sabine Valley to Upper TX Gulf Coast by early Saturday. Elevated parcels should consist of minimal to meager buoyancy as mid-level lapse rates become largely moist-adiabatic in the southeast quadrant of the trough. Embedded thunderstorm coverage will probably remain isolated. Across south TX, confidence is below average in the southward extent of thunder potential. Guidance spread increases with the latitudinal placement of the shortwave trough as it begins to phase with a separate northern-stream shortwave trough amplifying from Alberta into the northern Great Plains. ..Grams.. 12/13/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0146 AM CST Wed Dec 13 2023 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Friday. ...Central to east TX... Pronounced forcing for ascent ahead of a slow-moving shortwave trough over the southern Great Plains will likely support a continued swath of elevated convection. This activity should be centered on north to west-central TX at 12Z Friday and gradually progress east-southeast into the Sabine Valley to Upper TX Gulf Coast by early Saturday. Elevated parcels should consist of minimal to meager buoyancy as mid-level lapse rates become largely moist-adiabatic in the southeast quadrant of the trough. Embedded thunderstorm coverage will probably remain isolated. Across south TX, confidence is below average in the southward extent of thunder potential. Guidance spread increases with the latitudinal placement of the shortwave trough as it begins to phase with a separate northern-stream shortwave trough amplifying from Alberta into the northern Great Plains. ..Grams.. 12/13/2023 Read more