Severe Storms

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CST Wed Dec 20 2023 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are expected across coastal portions of central and southern California, as well as southern Arizona, on Thursday. ...Synopsis... A low-amplitude shortwave trough is expected to begin the period over the southern High Plains before continuing eastward throughout the day across the southern Plains. A modest moist air mass will be in place ahead of this shortwave across TX and OK, with mid 50s dewpoints likely reaching into far northwest TX. Even with this increased low-level moisture, warm mid-level temperatures and resulting poor mid-level lapse rates should temper buoyancy. A few lightning flashes may occur, but the limited buoyancy should keep the majority of updrafts too weak and shallow to produce lightning. Farther west, an upper low is forecast to be centered about 320 miles off the southern CA coast early Thursday morning. This low is expected to drift gradually southward throughout the first part of the day before then tracking more eastward towards the coast overnight and into Friday morning. Persistent forcing for ascent, ample mid-level moisture, and cold mid-level temperatures associated with this low will help support isolated thunderstorm development along the coast throughout the day. As the low moves gradually eastward, showers and thunderstorms are expected to expand eastward across southern Arizona early Friday morning. ..Mosier.. 12/20/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CST Wed Dec 20 2023 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are expected across coastal portions of central and southern California, as well as southern Arizona, on Thursday. ...Synopsis... A low-amplitude shortwave trough is expected to begin the period over the southern High Plains before continuing eastward throughout the day across the southern Plains. A modest moist air mass will be in place ahead of this shortwave across TX and OK, with mid 50s dewpoints likely reaching into far northwest TX. Even with this increased low-level moisture, warm mid-level temperatures and resulting poor mid-level lapse rates should temper buoyancy. A few lightning flashes may occur, but the limited buoyancy should keep the majority of updrafts too weak and shallow to produce lightning. Farther west, an upper low is forecast to be centered about 320 miles off the southern CA coast early Thursday morning. This low is expected to drift gradually southward throughout the first part of the day before then tracking more eastward towards the coast overnight and into Friday morning. Persistent forcing for ascent, ample mid-level moisture, and cold mid-level temperatures associated with this low will help support isolated thunderstorm development along the coast throughout the day. As the low moves gradually eastward, showers and thunderstorms are expected to expand eastward across southern Arizona early Friday morning. ..Mosier.. 12/20/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CST Wed Dec 20 2023 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are expected across coastal portions of central and southern California, as well as southern Arizona, on Thursday. ...Synopsis... A low-amplitude shortwave trough is expected to begin the period over the southern High Plains before continuing eastward throughout the day across the southern Plains. A modest moist air mass will be in place ahead of this shortwave across TX and OK, with mid 50s dewpoints likely reaching into far northwest TX. Even with this increased low-level moisture, warm mid-level temperatures and resulting poor mid-level lapse rates should temper buoyancy. A few lightning flashes may occur, but the limited buoyancy should keep the majority of updrafts too weak and shallow to produce lightning. Farther west, an upper low is forecast to be centered about 320 miles off the southern CA coast early Thursday morning. This low is expected to drift gradually southward throughout the first part of the day before then tracking more eastward towards the coast overnight and into Friday morning. Persistent forcing for ascent, ample mid-level moisture, and cold mid-level temperatures associated with this low will help support isolated thunderstorm development along the coast throughout the day. As the low moves gradually eastward, showers and thunderstorms are expected to expand eastward across southern Arizona early Friday morning. ..Mosier.. 12/20/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1143 PM CST Tue Dec 19 2023 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible across parts of southern/central California and over portions of the Southwest. The severe-thunderstorm threat appears low. ...Synopsis... A deep-layer cyclone is forecast to move slowly southward off of the CA coast through the day. Downstream of this cyclone, a low-amplitude midlevel shortwave trough is forecast to move across parts of the Southwest and southern Rockies. An expansive surface ridge will cover much of the central/eastern CONUS, which should generally preclude thunderstorm development east of the Rockies. Midlevel moistening in advance of the Southwest shortwave will support elevated convection and perhaps sporadic lightning flashes across parts of AZ/NM. Somewhat more vigorous convection and greater thunderstorm coverage will be possible across parts of CA, in association with the offshore low. ...California... Deep southerly flow to the east of the offshore low will maintain modest low/midlevel moisture across near-coastal areas of southern/central CA. While the low will remain offshore through the period, a band of convection may move onshore during the day and possibly persist into the evening, in association with gradual cooling aloft and favorably difluent upper-level flow. Inland destabilization will likely remain quite limited, but increasing vertical shear may support modestly organized convection at times. A couple strong storms will be possible as stronger offshore convection approaches the coast, but instability currently appears too weak to support an organized severe-thunderstorm threat. ..Dean/Squitieri.. 12/20/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1143 PM CST Tue Dec 19 2023 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible across parts of southern/central California and over portions of the Southwest. The severe-thunderstorm threat appears low. ...Synopsis... A deep-layer cyclone is forecast to move slowly southward off of the CA coast through the day. Downstream of this cyclone, a low-amplitude midlevel shortwave trough is forecast to move across parts of the Southwest and southern Rockies. An expansive surface ridge will cover much of the central/eastern CONUS, which should generally preclude thunderstorm development east of the Rockies. Midlevel moistening in advance of the Southwest shortwave will support elevated convection and perhaps sporadic lightning flashes across parts of AZ/NM. Somewhat more vigorous convection and greater thunderstorm coverage will be possible across parts of CA, in association with the offshore low. ...California... Deep southerly flow to the east of the offshore low will maintain modest low/midlevel moisture across near-coastal areas of southern/central CA. While the low will remain offshore through the period, a band of convection may move onshore during the day and possibly persist into the evening, in association with gradual cooling aloft and favorably difluent upper-level flow. Inland destabilization will likely remain quite limited, but increasing vertical shear may support modestly organized convection at times. A couple strong storms will be possible as stronger offshore convection approaches the coast, but instability currently appears too weak to support an organized severe-thunderstorm threat. ..Dean/Squitieri.. 12/20/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1143 PM CST Tue Dec 19 2023 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible across parts of southern/central California and over portions of the Southwest. The severe-thunderstorm threat appears low. ...Synopsis... A deep-layer cyclone is forecast to move slowly southward off of the CA coast through the day. Downstream of this cyclone, a low-amplitude midlevel shortwave trough is forecast to move across parts of the Southwest and southern Rockies. An expansive surface ridge will cover much of the central/eastern CONUS, which should generally preclude thunderstorm development east of the Rockies. Midlevel moistening in advance of the Southwest shortwave will support elevated convection and perhaps sporadic lightning flashes across parts of AZ/NM. Somewhat more vigorous convection and greater thunderstorm coverage will be possible across parts of CA, in association with the offshore low. ...California... Deep southerly flow to the east of the offshore low will maintain modest low/midlevel moisture across near-coastal areas of southern/central CA. While the low will remain offshore through the period, a band of convection may move onshore during the day and possibly persist into the evening, in association with gradual cooling aloft and favorably difluent upper-level flow. Inland destabilization will likely remain quite limited, but increasing vertical shear may support modestly organized convection at times. A couple strong storms will be possible as stronger offshore convection approaches the coast, but instability currently appears too weak to support an organized severe-thunderstorm threat. ..Dean/Squitieri.. 12/20/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1143 PM CST Tue Dec 19 2023 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible across parts of southern/central California and over portions of the Southwest. The severe-thunderstorm threat appears low. ...Synopsis... A deep-layer cyclone is forecast to move slowly southward off of the CA coast through the day. Downstream of this cyclone, a low-amplitude midlevel shortwave trough is forecast to move across parts of the Southwest and southern Rockies. An expansive surface ridge will cover much of the central/eastern CONUS, which should generally preclude thunderstorm development east of the Rockies. Midlevel moistening in advance of the Southwest shortwave will support elevated convection and perhaps sporadic lightning flashes across parts of AZ/NM. Somewhat more vigorous convection and greater thunderstorm coverage will be possible across parts of CA, in association with the offshore low. ...California... Deep southerly flow to the east of the offshore low will maintain modest low/midlevel moisture across near-coastal areas of southern/central CA. While the low will remain offshore through the period, a band of convection may move onshore during the day and possibly persist into the evening, in association with gradual cooling aloft and favorably difluent upper-level flow. Inland destabilization will likely remain quite limited, but increasing vertical shear may support modestly organized convection at times. A couple strong storms will be possible as stronger offshore convection approaches the coast, but instability currently appears too weak to support an organized severe-thunderstorm threat. ..Dean/Squitieri.. 12/20/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0645 PM CST Tue Dec 19 2023 Valid 200100Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected for the remainder of tonight. ...Synopsis... Multiple bands of generally weak convection will persist into this evening across parts of central and northern CA, to the east of a deep-layer cyclone moving southward off the northern CA coast. Weak instability may continue to support sporadic lightning flashes early this evening, before a gradual weakening trend later tonight with the onset of nocturnal cooling/stabilization. Elsewhere, generally dry and stable conditions will limit thunderstorm potential into Wednesday morning. ..Dean.. 12/20/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0645 PM CST Tue Dec 19 2023 Valid 200100Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected for the remainder of tonight. ...Synopsis... Multiple bands of generally weak convection will persist into this evening across parts of central and northern CA, to the east of a deep-layer cyclone moving southward off the northern CA coast. Weak instability may continue to support sporadic lightning flashes early this evening, before a gradual weakening trend later tonight with the onset of nocturnal cooling/stabilization. Elsewhere, generally dry and stable conditions will limit thunderstorm potential into Wednesday morning. ..Dean.. 12/20/2023 Read more

No Mesoscale Discussions are in effect as of Tue Dec 19 23:41:02 UTC 2023.

No watches are valid as of Tue Dec 19 23:41:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0330 PM CST Tue Dec 19 2023 Valid 211200Z - 271200Z An active mid-level flow regime is expected to continue across the CONUS through the extended forecast period. Prominent Pacific troughing is forecast to move inland and continue eastward into the central US late this week and into the weekend. Transient ridging over the eastern and central US will gradually shift eastward as stronger westerly flow develops. Occasional dry offshore flow is possible over parts of the Southeast into the weekend, but winds are expected to remain light. Western US troughing will continue to amplify through the weekend supporting southerly return flow and widespread precipitation over the western and central CONUS. The flow pattern will remain highly amplified into next week as a second Pacific trough approaches the West Coast. As the western troughing shifts eastward, cool and unsettled weather is expected over much of the US through the end of the forecast period. With cool to mild temperatures and widespread precipitation expected over much of the country, significant fire-weather conditions appear unlikely through the next 7 days. ..Lyons.. 12/19/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0330 PM CST Tue Dec 19 2023 Valid 211200Z - 271200Z An active mid-level flow regime is expected to continue across the CONUS through the extended forecast period. Prominent Pacific troughing is forecast to move inland and continue eastward into the central US late this week and into the weekend. Transient ridging over the eastern and central US will gradually shift eastward as stronger westerly flow develops. Occasional dry offshore flow is possible over parts of the Southeast into the weekend, but winds are expected to remain light. Western US troughing will continue to amplify through the weekend supporting southerly return flow and widespread precipitation over the western and central CONUS. The flow pattern will remain highly amplified into next week as a second Pacific trough approaches the West Coast. As the western troughing shifts eastward, cool and unsettled weather is expected over much of the US through the end of the forecast period. With cool to mild temperatures and widespread precipitation expected over much of the country, significant fire-weather conditions appear unlikely through the next 7 days. ..Lyons.. 12/19/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0330 PM CST Tue Dec 19 2023 Valid 211200Z - 271200Z An active mid-level flow regime is expected to continue across the CONUS through the extended forecast period. Prominent Pacific troughing is forecast to move inland and continue eastward into the central US late this week and into the weekend. Transient ridging over the eastern and central US will gradually shift eastward as stronger westerly flow develops. Occasional dry offshore flow is possible over parts of the Southeast into the weekend, but winds are expected to remain light. Western US troughing will continue to amplify through the weekend supporting southerly return flow and widespread precipitation over the western and central CONUS. The flow pattern will remain highly amplified into next week as a second Pacific trough approaches the West Coast. As the western troughing shifts eastward, cool and unsettled weather is expected over much of the US through the end of the forecast period. With cool to mild temperatures and widespread precipitation expected over much of the country, significant fire-weather conditions appear unlikely through the next 7 days. ..Lyons.. 12/19/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0330 PM CST Tue Dec 19 2023 Valid 211200Z - 271200Z An active mid-level flow regime is expected to continue across the CONUS through the extended forecast period. Prominent Pacific troughing is forecast to move inland and continue eastward into the central US late this week and into the weekend. Transient ridging over the eastern and central US will gradually shift eastward as stronger westerly flow develops. Occasional dry offshore flow is possible over parts of the Southeast into the weekend, but winds are expected to remain light. Western US troughing will continue to amplify through the weekend supporting southerly return flow and widespread precipitation over the western and central CONUS. The flow pattern will remain highly amplified into next week as a second Pacific trough approaches the West Coast. As the western troughing shifts eastward, cool and unsettled weather is expected over much of the US through the end of the forecast period. With cool to mild temperatures and widespread precipitation expected over much of the country, significant fire-weather conditions appear unlikely through the next 7 days. ..Lyons.. 12/19/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0155 PM CST Tue Dec 19 2023 Valid 192000Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms remain possible today across parts of central and northern California. ...20Z Update... No changes have been made to the prior forecast. ..Gleason.. 12/19/2023 .PREV DISCUSSION... /ISSUED 1023 AM CST Tue Dec 19 2023/ ...Discussion... Broad/low-amplitude ridging aloft will prevail across most of the U.S. today, in the wake of a trough shifting eastward across the Mid-Atlantic Region and New England. In the West, an eastern Pacific low will continue shifting southeastward, with only a glancing influence across the West Coast states. However, this glancing influence will be enough to keep mid-levels relatively cool, and thus maintain very weak instability across this region. As such, sporadic lightning strikes will remain possible -- mainly across portions of northern and central California through tonight. Elsewhere, with the eastern U.S. surface cold front already offshore, and cool/stable high pressure prevailing east of the Rockies, thunderstorms are not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0155 PM CST Tue Dec 19 2023 Valid 192000Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms remain possible today across parts of central and northern California. ...20Z Update... No changes have been made to the prior forecast. ..Gleason.. 12/19/2023 .PREV DISCUSSION... /ISSUED 1023 AM CST Tue Dec 19 2023/ ...Discussion... Broad/low-amplitude ridging aloft will prevail across most of the U.S. today, in the wake of a trough shifting eastward across the Mid-Atlantic Region and New England. In the West, an eastern Pacific low will continue shifting southeastward, with only a glancing influence across the West Coast states. However, this glancing influence will be enough to keep mid-levels relatively cool, and thus maintain very weak instability across this region. As such, sporadic lightning strikes will remain possible -- mainly across portions of northern and central California through tonight. Elsewhere, with the eastern U.S. surface cold front already offshore, and cool/stable high pressure prevailing east of the Rockies, thunderstorms are not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0155 PM CST Tue Dec 19 2023 Valid 192000Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms remain possible today across parts of central and northern California. ...20Z Update... No changes have been made to the prior forecast. ..Gleason.. 12/19/2023 .PREV DISCUSSION... /ISSUED 1023 AM CST Tue Dec 19 2023/ ...Discussion... Broad/low-amplitude ridging aloft will prevail across most of the U.S. today, in the wake of a trough shifting eastward across the Mid-Atlantic Region and New England. In the West, an eastern Pacific low will continue shifting southeastward, with only a glancing influence across the West Coast states. However, this glancing influence will be enough to keep mid-levels relatively cool, and thus maintain very weak instability across this region. As such, sporadic lightning strikes will remain possible -- mainly across portions of northern and central California through tonight. Elsewhere, with the eastern U.S. surface cold front already offshore, and cool/stable high pressure prevailing east of the Rockies, thunderstorms are not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0155 PM CST Tue Dec 19 2023 Valid 192000Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms remain possible today across parts of central and northern California. ...20Z Update... No changes have been made to the prior forecast. ..Gleason.. 12/19/2023 .PREV DISCUSSION... /ISSUED 1023 AM CST Tue Dec 19 2023/ ...Discussion... Broad/low-amplitude ridging aloft will prevail across most of the U.S. today, in the wake of a trough shifting eastward across the Mid-Atlantic Region and New England. In the West, an eastern Pacific low will continue shifting southeastward, with only a glancing influence across the West Coast states. However, this glancing influence will be enough to keep mid-levels relatively cool, and thus maintain very weak instability across this region. As such, sporadic lightning strikes will remain possible -- mainly across portions of northern and central California through tonight. Elsewhere, with the eastern U.S. surface cold front already offshore, and cool/stable high pressure prevailing east of the Rockies, thunderstorms are not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0155 PM CST Tue Dec 19 2023 Valid 192000Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms remain possible today across parts of central and northern California. ...20Z Update... No changes have been made to the prior forecast. ..Gleason.. 12/19/2023 .PREV DISCUSSION... /ISSUED 1023 AM CST Tue Dec 19 2023/ ...Discussion... Broad/low-amplitude ridging aloft will prevail across most of the U.S. today, in the wake of a trough shifting eastward across the Mid-Atlantic Region and New England. In the West, an eastern Pacific low will continue shifting southeastward, with only a glancing influence across the West Coast states. However, this glancing influence will be enough to keep mid-levels relatively cool, and thus maintain very weak instability across this region. As such, sporadic lightning strikes will remain possible -- mainly across portions of northern and central California through tonight. Elsewhere, with the eastern U.S. surface cold front already offshore, and cool/stable high pressure prevailing east of the Rockies, thunderstorms are not expected. Read more