Severe Storms

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0143 AM CST Wed Dec 06 2023 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE OZARKS TO FAR NORTHEAST TEXAS... ...SUMMARY... Isolated severe thunderstorms will be possible Friday night across parts of the Ozarks to the Red River Valley of southeast Oklahoma and northeast Texas. ...Ozarks to northeast TX... An amplifying shortwave trough over the Great Basin on Friday morning will progress southeast across the Four Corners to the southern High Plains by early Saturday. A surface low initially over the TX Panhandle vicinity should move east towards the Ozark Plateau, along a sharpening front that will accelerate southeast Friday night as surface high pressure builds over the West. While most guidance is fairly consistent on the synoptic scale with some mesoscale differences becoming more apparent by Friday night, the primary uncertainty is with the degree of instability ahead of the aforementioned frontal wave. The 00Z NAM appears to be an outlier among deterministic guidance with its typical cold/saturated bias apparent in the 0-1 km layer, while the GFS is on the more aggressive end of the spectrum relative to the GEFS. With substantial modification necessary of the CP air mass that is currently across all but Deep South TX, guidance may be a bit too aggressive with the northward extent of surface-based instability given the positive-tilt orientation and timing of the amplified shortwave trough. Both the NAM and to some extent ECMWF forecast soundings suggest substantial mid-level dry air will be prevalent within the southwest flow regime, and at least a modestly capped warm sector. As such, low confidence exists in whether surface-based convection can develop prior to 12Z Saturday. The most likely scenario appears to be elevated thunderstorms increasing in coverage Friday night within the low-level warm conveyor, as mid-level height falls gradually overspread the region. This activity should pose a threat for at least isolated severe hail. ..Grams.. 12/06/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0143 AM CST Wed Dec 06 2023 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE OZARKS TO FAR NORTHEAST TEXAS... ...SUMMARY... Isolated severe thunderstorms will be possible Friday night across parts of the Ozarks to the Red River Valley of southeast Oklahoma and northeast Texas. ...Ozarks to northeast TX... An amplifying shortwave trough over the Great Basin on Friday morning will progress southeast across the Four Corners to the southern High Plains by early Saturday. A surface low initially over the TX Panhandle vicinity should move east towards the Ozark Plateau, along a sharpening front that will accelerate southeast Friday night as surface high pressure builds over the West. While most guidance is fairly consistent on the synoptic scale with some mesoscale differences becoming more apparent by Friday night, the primary uncertainty is with the degree of instability ahead of the aforementioned frontal wave. The 00Z NAM appears to be an outlier among deterministic guidance with its typical cold/saturated bias apparent in the 0-1 km layer, while the GFS is on the more aggressive end of the spectrum relative to the GEFS. With substantial modification necessary of the CP air mass that is currently across all but Deep South TX, guidance may be a bit too aggressive with the northward extent of surface-based instability given the positive-tilt orientation and timing of the amplified shortwave trough. Both the NAM and to some extent ECMWF forecast soundings suggest substantial mid-level dry air will be prevalent within the southwest flow regime, and at least a modestly capped warm sector. As such, low confidence exists in whether surface-based convection can develop prior to 12Z Saturday. The most likely scenario appears to be elevated thunderstorms increasing in coverage Friday night within the low-level warm conveyor, as mid-level height falls gradually overspread the region. This activity should pose a threat for at least isolated severe hail. ..Grams.. 12/06/2023 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1226 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO CRITICAL AREAS... ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies on Thursday. At the surface, a cyclone will begin to develop across the central Plains. As a result, dry and warm westerly downslope flow will increase across portions of the Southern Plains. Afternoon relative humidity reductions to around 15 percent will overlap sustained winds at 15-20 mph across portions of eastern New Mexico into the Texas and Oklahoma Panhandles. Fuels within this region are largely near normal moisture and only marginally receptive to spread. Locally Elevated fire weather conditions will be possible in areas where fine fuels have cured and become dormant. ..Thornton.. 12/06/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1226 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO CRITICAL AREAS... ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies on Thursday. At the surface, a cyclone will begin to develop across the central Plains. As a result, dry and warm westerly downslope flow will increase across portions of the Southern Plains. Afternoon relative humidity reductions to around 15 percent will overlap sustained winds at 15-20 mph across portions of eastern New Mexico into the Texas and Oklahoma Panhandles. Fuels within this region are largely near normal moisture and only marginally receptive to spread. Locally Elevated fire weather conditions will be possible in areas where fine fuels have cured and become dormant. ..Thornton.. 12/06/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1226 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO CRITICAL AREAS... ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies on Thursday. At the surface, a cyclone will begin to develop across the central Plains. As a result, dry and warm westerly downslope flow will increase across portions of the Southern Plains. Afternoon relative humidity reductions to around 15 percent will overlap sustained winds at 15-20 mph across portions of eastern New Mexico into the Texas and Oklahoma Panhandles. Fuels within this region are largely near normal moisture and only marginally receptive to spread. Locally Elevated fire weather conditions will be possible in areas where fine fuels have cured and become dormant. ..Thornton.. 12/06/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1226 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO CRITICAL AREAS... ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies on Thursday. At the surface, a cyclone will begin to develop across the central Plains. As a result, dry and warm westerly downslope flow will increase across portions of the Southern Plains. Afternoon relative humidity reductions to around 15 percent will overlap sustained winds at 15-20 mph across portions of eastern New Mexico into the Texas and Oklahoma Panhandles. Fuels within this region are largely near normal moisture and only marginally receptive to spread. Locally Elevated fire weather conditions will be possible in areas where fine fuels have cured and become dormant. ..Thornton.. 12/06/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1226 AM CST Wed Dec 06 2023 Valid 071200Z - 081200Z ...NO CRITICAL AREAS... ...Synopsis... A belt of strong mid-level westerly flow will move across the Rockies on Thursday. At the surface, a cyclone will begin to develop across the central Plains. As a result, dry and warm westerly downslope flow will increase across portions of the Southern Plains. Afternoon relative humidity reductions to around 15 percent will overlap sustained winds at 15-20 mph across portions of eastern New Mexico into the Texas and Oklahoma Panhandles. Fuels within this region are largely near normal moisture and only marginally receptive to spread. Locally Elevated fire weather conditions will be possible in areas where fine fuels have cured and become dormant. ..Thornton.. 12/06/2023 ...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 1224 AM CST Wed Dec 06 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ..Thornton.. 12/06/2023 ...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 1224 AM CST Wed Dec 06 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ..Thornton.. 12/06/2023 ...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 1224 AM CST Wed Dec 06 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ..Thornton.. 12/06/2023 ...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 1224 AM CST Wed Dec 06 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ..Thornton.. 12/06/2023 ...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 1224 AM CST Wed Dec 06 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... ...Synopsis... An upper-level high will continue to shift eastward across the central US as troughing develops across the west coast on Wednesday. Surface pressure gradients will increase between a surface high across the southeast and a surface low across the Rockies, with southwesterly breezes possible across portions of the High Plains. Pockets of locally elevated fire weather are possible in the southern High Plains and perhaps parts of southeast Wyoming should sufficiently dry fine fuels exist. ..Thornton.. 12/06/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 PM CST Tue Dec 05 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Northwest... The next in a series of shortwave troughs will impinge on the OR/CA border area on Thursday morning, before digging across the Great Basin by Thursday night. Already steep 700-500 mb lapse rates in the wake of a trough passage on D1 will steepen further between 8 to 8.5 C/km as cold 500-mb temperatures from -30 to -35 C become common. This should compensate for gradually decreasing boundary-layer moisture as onshore winds become northwesterly with low 40s surface dew points holding along the coast through the afternoon. Scant surface-based buoyancy is anticipated with multiple rounds of scattered low-topped convection. Similar to D1, sporadic lightning flashes will be possible, tending to focus along the OR to far northern CA coast during the morning and afternoon. Very isolated thunderstorms may also occur east of the Cascades in the eastern OR/western ID/northern NV vicinity during the afternoon, within the strongly forced ascent region ahead of the shortwave impulse. Due to minimal buoyancy, thunderstorm probabilities appear to be less than 10 percent. ..Grams.. 12/06/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 PM CST Tue Dec 05 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Northwest... The next in a series of shortwave troughs will impinge on the OR/CA border area on Thursday morning, before digging across the Great Basin by Thursday night. Already steep 700-500 mb lapse rates in the wake of a trough passage on D1 will steepen further between 8 to 8.5 C/km as cold 500-mb temperatures from -30 to -35 C become common. This should compensate for gradually decreasing boundary-layer moisture as onshore winds become northwesterly with low 40s surface dew points holding along the coast through the afternoon. Scant surface-based buoyancy is anticipated with multiple rounds of scattered low-topped convection. Similar to D1, sporadic lightning flashes will be possible, tending to focus along the OR to far northern CA coast during the morning and afternoon. Very isolated thunderstorms may also occur east of the Cascades in the eastern OR/western ID/northern NV vicinity during the afternoon, within the strongly forced ascent region ahead of the shortwave impulse. Due to minimal buoyancy, thunderstorm probabilities appear to be less than 10 percent. ..Grams.. 12/06/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 PM CST Tue Dec 05 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Northwest... The next in a series of shortwave troughs will impinge on the OR/CA border area on Thursday morning, before digging across the Great Basin by Thursday night. Already steep 700-500 mb lapse rates in the wake of a trough passage on D1 will steepen further between 8 to 8.5 C/km as cold 500-mb temperatures from -30 to -35 C become common. This should compensate for gradually decreasing boundary-layer moisture as onshore winds become northwesterly with low 40s surface dew points holding along the coast through the afternoon. Scant surface-based buoyancy is anticipated with multiple rounds of scattered low-topped convection. Similar to D1, sporadic lightning flashes will be possible, tending to focus along the OR to far northern CA coast during the morning and afternoon. Very isolated thunderstorms may also occur east of the Cascades in the eastern OR/western ID/northern NV vicinity during the afternoon, within the strongly forced ascent region ahead of the shortwave impulse. Due to minimal buoyancy, thunderstorm probabilities appear to be less than 10 percent. ..Grams.. 12/06/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 PM CST Tue Dec 05 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Northwest... The next in a series of shortwave troughs will impinge on the OR/CA border area on Thursday morning, before digging across the Great Basin by Thursday night. Already steep 700-500 mb lapse rates in the wake of a trough passage on D1 will steepen further between 8 to 8.5 C/km as cold 500-mb temperatures from -30 to -35 C become common. This should compensate for gradually decreasing boundary-layer moisture as onshore winds become northwesterly with low 40s surface dew points holding along the coast through the afternoon. Scant surface-based buoyancy is anticipated with multiple rounds of scattered low-topped convection. Similar to D1, sporadic lightning flashes will be possible, tending to focus along the OR to far northern CA coast during the morning and afternoon. Very isolated thunderstorms may also occur east of the Cascades in the eastern OR/western ID/northern NV vicinity during the afternoon, within the strongly forced ascent region ahead of the shortwave impulse. Due to minimal buoyancy, thunderstorm probabilities appear to be less than 10 percent. ..Grams.. 12/06/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1126 PM CST Tue Dec 05 2023 Valid 071200Z - 081200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Northwest... The next in a series of shortwave troughs will impinge on the OR/CA border area on Thursday morning, before digging across the Great Basin by Thursday night. Already steep 700-500 mb lapse rates in the wake of a trough passage on D1 will steepen further between 8 to 8.5 C/km as cold 500-mb temperatures from -30 to -35 C become common. This should compensate for gradually decreasing boundary-layer moisture as onshore winds become northwesterly with low 40s surface dew points holding along the coast through the afternoon. Scant surface-based buoyancy is anticipated with multiple rounds of scattered low-topped convection. Similar to D1, sporadic lightning flashes will be possible, tending to focus along the OR to far northern CA coast during the morning and afternoon. Very isolated thunderstorms may also occur east of the Cascades in the eastern OR/western ID/northern NV vicinity during the afternoon, within the strongly forced ascent region ahead of the shortwave impulse. Due to minimal buoyancy, thunderstorm probabilities appear to be less than 10 percent. ..Grams.. 12/06/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1115 PM CST Tue Dec 05 2023 Valid 061200Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Some lightning potential exists with convection along parts of the northern Pacific Coast. ...Pacific Coast... Upper ridge currently observed over the western US will shift east and break down as a strong short-wave trough ejects inland along the northern Pacific Coast. Latest model guidance suggests 500mb speed max will translate across northern CA into the Great Basin by the end of the period. Along and north of this jet, thermal profiles will cool/steepen such that weak buoyancy will evolve in support of convection. Forecast soundings across this region suggest the greatest risk for deep convection, capable of generating lighting, will occur during the latter half of the period. During this time, 500mb temperatures will cool to near -30C over WA/OR, and at least -20C across most of northern CA. ..Darrow/Thornton.. 12/06/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1115 PM CST Tue Dec 05 2023 Valid 061200Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Some lightning potential exists with convection along parts of the northern Pacific Coast. ...Pacific Coast... Upper ridge currently observed over the western US will shift east and break down as a strong short-wave trough ejects inland along the northern Pacific Coast. Latest model guidance suggests 500mb speed max will translate across northern CA into the Great Basin by the end of the period. Along and north of this jet, thermal profiles will cool/steepen such that weak buoyancy will evolve in support of convection. Forecast soundings across this region suggest the greatest risk for deep convection, capable of generating lighting, will occur during the latter half of the period. During this time, 500mb temperatures will cool to near -30C over WA/OR, and at least -20C across most of northern CA. ..Darrow/Thornton.. 12/06/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1115 PM CST Tue Dec 05 2023 Valid 061200Z - 071200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Some lightning potential exists with convection along parts of the northern Pacific Coast. ...Pacific Coast... Upper ridge currently observed over the western US will shift east and break down as a strong short-wave trough ejects inland along the northern Pacific Coast. Latest model guidance suggests 500mb speed max will translate across northern CA into the Great Basin by the end of the period. Along and north of this jet, thermal profiles will cool/steepen such that weak buoyancy will evolve in support of convection. Forecast soundings across this region suggest the greatest risk for deep convection, capable of generating lighting, will occur during the latter half of the period. During this time, 500mb temperatures will cool to near -30C over WA/OR, and at least -20C across most of northern CA. ..Darrow/Thornton.. 12/06/2023 Read more