Severe Storms

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0200 AM CST Mon Dec 18 2023 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated lightning flashes are possible along the central and southern California coast on Wednesday. ...Synopsis... High pressure associated with a dry continental air mass will dominant the sensible weather across much of the central and eastern CONUS during the period. Some limited air mass modification is anticipated across the southern Plains as a low-amplitude shortwave trough approaches from the west. Some precipitation is possible in vicinity of this shortwave, but thermodynamic conditions are not expected to support lightning production. Farther west, an upper low is forecast to begin the period centered about 275 miles west-southwest of SFO, before then progressing southward/south-southwestward throughout the period. Persistent southwesterly flow aloft will help keep profiles moist over much of the central and southern CA coast. Mid-level temperatures across this region are expected to cool throughout the day as the upper low move southward. Modest buoyancy associated with these cooling profiles could support isolated lightning flashes within any deeper, more sustained updrafts. ..Mosier.. 12/18/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0200 AM CST Mon Dec 18 2023 Valid 201200Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated lightning flashes are possible along the central and southern California coast on Wednesday. ...Synopsis... High pressure associated with a dry continental air mass will dominant the sensible weather across much of the central and eastern CONUS during the period. Some limited air mass modification is anticipated across the southern Plains as a low-amplitude shortwave trough approaches from the west. Some precipitation is possible in vicinity of this shortwave, but thermodynamic conditions are not expected to support lightning production. Farther west, an upper low is forecast to begin the period centered about 275 miles west-southwest of SFO, before then progressing southward/south-southwestward throughout the period. Persistent southwesterly flow aloft will help keep profiles moist over much of the central and southern CA coast. Mid-level temperatures across this region are expected to cool throughout the day as the upper low move southward. Modest buoyancy associated with these cooling profiles could support isolated lightning flashes within any deeper, more sustained updrafts. ..Mosier.. 12/18/2023 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0147 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will meander along the West Coast as upper ridging persists from the Interior West toward the Appalachians tomorrow/Tuesday. While surface lee troughing is expected across the High Plains, surface high pressure and associated cooler air should dominate over the rest of the CONUS. Similar to Day 1, quiescent fire weather conditions are expected over the U.S. ..Squitieri.. 12/18/2023 ...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 0147 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will meander along the West Coast as upper ridging persists from the Interior West toward the Appalachians tomorrow/Tuesday. While surface lee troughing is expected across the High Plains, surface high pressure and associated cooler air should dominate over the rest of the CONUS. Similar to Day 1, quiescent fire weather conditions are expected over the U.S. ..Squitieri.. 12/18/2023 ...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 0147 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will meander along the West Coast as upper ridging persists from the Interior West toward the Appalachians tomorrow/Tuesday. While surface lee troughing is expected across the High Plains, surface high pressure and associated cooler air should dominate over the rest of the CONUS. Similar to Day 1, quiescent fire weather conditions are expected over the U.S. ..Squitieri.. 12/18/2023 ...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 0147 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will meander along the West Coast as upper ridging persists from the Interior West toward the Appalachians tomorrow/Tuesday. While surface lee troughing is expected across the High Plains, surface high pressure and associated cooler air should dominate over the rest of the CONUS. Similar to Day 1, quiescent fire weather conditions are expected over the U.S. ..Squitieri.. 12/18/2023 ...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 0147 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will meander along the West Coast as upper ridging persists from the Interior West toward the Appalachians tomorrow/Tuesday. While surface lee troughing is expected across the High Plains, surface high pressure and associated cooler air should dominate over the rest of the CONUS. Similar to Day 1, quiescent fire weather conditions are expected over the U.S. ..Squitieri.. 12/18/2023 ...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 0146 AM CST Mon Dec 18 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will amplify along the East Coast as a second mid-level trough impinges on California, with abundant rainfall expected in both regions today. Meanwhile, surface high pressure and associated cooler air will overspread the central CONUS. The net result will be quiescent fire weather conditions across the U.S., especially considering that fuels will be poorly receptive to wildfire spread for many locales. ..Squitieri.. 12/18/2023 ...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 0146 AM CST Mon Dec 18 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will amplify along the East Coast as a second mid-level trough impinges on California, with abundant rainfall expected in both regions today. Meanwhile, surface high pressure and associated cooler air will overspread the central CONUS. The net result will be quiescent fire weather conditions across the U.S., especially considering that fuels will be poorly receptive to wildfire spread for many locales. ..Squitieri.. 12/18/2023 ...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 0146 AM CST Mon Dec 18 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will amplify along the East Coast as a second mid-level trough impinges on California, with abundant rainfall expected in both regions today. Meanwhile, surface high pressure and associated cooler air will overspread the central CONUS. The net result will be quiescent fire weather conditions across the U.S., especially considering that fuels will be poorly receptive to wildfire spread for many locales. ..Squitieri.. 12/18/2023 ...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 0146 AM CST Mon Dec 18 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will amplify along the East Coast as a second mid-level trough impinges on California, with abundant rainfall expected in both regions today. Meanwhile, surface high pressure and associated cooler air will overspread the central CONUS. The net result will be quiescent fire weather conditions across the U.S., especially considering that fuels will be poorly receptive to wildfire spread for many locales. ..Squitieri.. 12/18/2023 ...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 0146 AM CST Mon Dec 18 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level trough will amplify along the East Coast as a second mid-level trough impinges on California, with abundant rainfall expected in both regions today. Meanwhile, surface high pressure and associated cooler air will overspread the central CONUS. The net result will be quiescent fire weather conditions across the U.S., especially considering that fuels will be poorly receptive to wildfire spread for many locales. ..Squitieri.. 12/18/2023 ...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 1252 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... Upper low initially centered over the PA/western NY vicinity is forecast to progress eastward throughout the day, moving off the northern Mid-Atlantic coast by Tuesday evening. This upper low will be characterized by cold mid-level temperatures and strong mid-level flow, particularly throughout its eastern periphery. Even so, low-level moisture will have been scoured well offshore by a previous frontal intrusion, and the dry continental air mass expected to be in place will be hostile to deep convection. Farther west, an upper low is expected to drift southward off the West Coast, ending the period centered off the central CA Coast. Persistent southwesterly flow aloft is anticipated across central CA ahead of this upper low, contributing to showers throughout the day. A few deeper updrafts capable of lightning flashes are possible within these showers. A higher probability lightning potential is expected early Wednesday morning as the primary frontal band associated with the upper low approaches the central CA Coast. A low-amplitude shortwave trough is forecast to move through the westerly flow aloft south of the upper low across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/18/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... Upper low initially centered over the PA/western NY vicinity is forecast to progress eastward throughout the day, moving off the northern Mid-Atlantic coast by Tuesday evening. This upper low will be characterized by cold mid-level temperatures and strong mid-level flow, particularly throughout its eastern periphery. Even so, low-level moisture will have been scoured well offshore by a previous frontal intrusion, and the dry continental air mass expected to be in place will be hostile to deep convection. Farther west, an upper low is expected to drift southward off the West Coast, ending the period centered off the central CA Coast. Persistent southwesterly flow aloft is anticipated across central CA ahead of this upper low, contributing to showers throughout the day. A few deeper updrafts capable of lightning flashes are possible within these showers. A higher probability lightning potential is expected early Wednesday morning as the primary frontal band associated with the upper low approaches the central CA Coast. A low-amplitude shortwave trough is forecast to move through the westerly flow aloft south of the upper low across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/18/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... Upper low initially centered over the PA/western NY vicinity is forecast to progress eastward throughout the day, moving off the northern Mid-Atlantic coast by Tuesday evening. This upper low will be characterized by cold mid-level temperatures and strong mid-level flow, particularly throughout its eastern periphery. Even so, low-level moisture will have been scoured well offshore by a previous frontal intrusion, and the dry continental air mass expected to be in place will be hostile to deep convection. Farther west, an upper low is expected to drift southward off the West Coast, ending the period centered off the central CA Coast. Persistent southwesterly flow aloft is anticipated across central CA ahead of this upper low, contributing to showers throughout the day. A few deeper updrafts capable of lightning flashes are possible within these showers. A higher probability lightning potential is expected early Wednesday morning as the primary frontal band associated with the upper low approaches the central CA Coast. A low-amplitude shortwave trough is forecast to move through the westerly flow aloft south of the upper low across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/18/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... Upper low initially centered over the PA/western NY vicinity is forecast to progress eastward throughout the day, moving off the northern Mid-Atlantic coast by Tuesday evening. This upper low will be characterized by cold mid-level temperatures and strong mid-level flow, particularly throughout its eastern periphery. Even so, low-level moisture will have been scoured well offshore by a previous frontal intrusion, and the dry continental air mass expected to be in place will be hostile to deep convection. Farther west, an upper low is expected to drift southward off the West Coast, ending the period centered off the central CA Coast. Persistent southwesterly flow aloft is anticipated across central CA ahead of this upper low, contributing to showers throughout the day. A few deeper updrafts capable of lightning flashes are possible within these showers. A higher probability lightning potential is expected early Wednesday morning as the primary frontal band associated with the upper low approaches the central CA Coast. A low-amplitude shortwave trough is forecast to move through the westerly flow aloft south of the upper low across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/18/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1252 AM CST Mon Dec 18 2023 Valid 191200Z - 201200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... Upper low initially centered over the PA/western NY vicinity is forecast to progress eastward throughout the day, moving off the northern Mid-Atlantic coast by Tuesday evening. This upper low will be characterized by cold mid-level temperatures and strong mid-level flow, particularly throughout its eastern periphery. Even so, low-level moisture will have been scoured well offshore by a previous frontal intrusion, and the dry continental air mass expected to be in place will be hostile to deep convection. Farther west, an upper low is expected to drift southward off the West Coast, ending the period centered off the central CA Coast. Persistent southwesterly flow aloft is anticipated across central CA ahead of this upper low, contributing to showers throughout the day. A few deeper updrafts capable of lightning flashes are possible within these showers. A higher probability lightning potential is expected early Wednesday morning as the primary frontal band associated with the upper low approaches the central CA Coast. A low-amplitude shortwave trough is forecast to move through the westerly flow aloft south of the upper low across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/18/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1159 PM CST Sun Dec 17 2023 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF COASTAL SOUTHERN NEW ENGLAND... ...SUMMARY... A damaging gust or two is possible from the eastern shore of New Jersey into southern New England this morning and afternoon. A few isolated lightning flashes are possible along the northern/central California coast. ...Synopsis... A broad mid-level trough will amplify across the East Coast as a 500 mb jet max overspreads portions of southern New England today, supporting the rapid northeastward ejection of a 986 mb surface low into Quebec by evening. Intense low-level wind fields will be in place ahead of the surface low, supporting conditional damaging gust potential with any storms that can root into an unstable boundary layer. Meanwhile, another trough will impinge on the West Coast, supporting appreciable rainfall accumulations and at least isolated thunderstorms. ...Portions of southern New England... The surface low will overspread southern New England, immediately preceded by a 70+ kt 850 mb southerly jet. Tropospheric flow will be unidirectional, supporting straight hodographs. 6 C/km lapse rates above 850 mb may boost MUCAPE to 500 J/kg, which will support at least elevated convection. The primary mitigating factor for a robust severe thunderstorm wind threat is the likelihood for a stable boundary layer, which should dampen downward momentum transport in stronger storm cores. Modified forecast soundings suggest surface temperatures would need to reach the mid 60s F amid 60+ F dewpoints to support 100+ J/kg SBCAPE. However, ensemble guidance suggests that maximum high surface temperatures will struggle to reach the lower 60s F, casting doubt on the potential for organized severe storms. Nonetheless, the intense low-level wind fields suggest that any downward momentum transport within thunderstorm cores that can occur may support a damaging gust threat during the late morning and afternoon hours. A Category 1/Marginal Risk has been maintained for coastal portions of southern New England to address the conditional damaging gust threat. ..Squitieri/Darrow.. 12/18/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1159 PM CST Sun Dec 17 2023 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF COASTAL SOUTHERN NEW ENGLAND... ...SUMMARY... A damaging gust or two is possible from the eastern shore of New Jersey into southern New England this morning and afternoon. A few isolated lightning flashes are possible along the northern/central California coast. ...Synopsis... A broad mid-level trough will amplify across the East Coast as a 500 mb jet max overspreads portions of southern New England today, supporting the rapid northeastward ejection of a 986 mb surface low into Quebec by evening. Intense low-level wind fields will be in place ahead of the surface low, supporting conditional damaging gust potential with any storms that can root into an unstable boundary layer. Meanwhile, another trough will impinge on the West Coast, supporting appreciable rainfall accumulations and at least isolated thunderstorms. ...Portions of southern New England... The surface low will overspread southern New England, immediately preceded by a 70+ kt 850 mb southerly jet. Tropospheric flow will be unidirectional, supporting straight hodographs. 6 C/km lapse rates above 850 mb may boost MUCAPE to 500 J/kg, which will support at least elevated convection. The primary mitigating factor for a robust severe thunderstorm wind threat is the likelihood for a stable boundary layer, which should dampen downward momentum transport in stronger storm cores. Modified forecast soundings suggest surface temperatures would need to reach the mid 60s F amid 60+ F dewpoints to support 100+ J/kg SBCAPE. However, ensemble guidance suggests that maximum high surface temperatures will struggle to reach the lower 60s F, casting doubt on the potential for organized severe storms. Nonetheless, the intense low-level wind fields suggest that any downward momentum transport within thunderstorm cores that can occur may support a damaging gust threat during the late morning and afternoon hours. A Category 1/Marginal Risk has been maintained for coastal portions of southern New England to address the conditional damaging gust threat. ..Squitieri/Darrow.. 12/18/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1159 PM CST Sun Dec 17 2023 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF COASTAL SOUTHERN NEW ENGLAND... ...SUMMARY... A damaging gust or two is possible from the eastern shore of New Jersey into southern New England this morning and afternoon. A few isolated lightning flashes are possible along the northern/central California coast. ...Synopsis... A broad mid-level trough will amplify across the East Coast as a 500 mb jet max overspreads portions of southern New England today, supporting the rapid northeastward ejection of a 986 mb surface low into Quebec by evening. Intense low-level wind fields will be in place ahead of the surface low, supporting conditional damaging gust potential with any storms that can root into an unstable boundary layer. Meanwhile, another trough will impinge on the West Coast, supporting appreciable rainfall accumulations and at least isolated thunderstorms. ...Portions of southern New England... The surface low will overspread southern New England, immediately preceded by a 70+ kt 850 mb southerly jet. Tropospheric flow will be unidirectional, supporting straight hodographs. 6 C/km lapse rates above 850 mb may boost MUCAPE to 500 J/kg, which will support at least elevated convection. The primary mitigating factor for a robust severe thunderstorm wind threat is the likelihood for a stable boundary layer, which should dampen downward momentum transport in stronger storm cores. Modified forecast soundings suggest surface temperatures would need to reach the mid 60s F amid 60+ F dewpoints to support 100+ J/kg SBCAPE. However, ensemble guidance suggests that maximum high surface temperatures will struggle to reach the lower 60s F, casting doubt on the potential for organized severe storms. Nonetheless, the intense low-level wind fields suggest that any downward momentum transport within thunderstorm cores that can occur may support a damaging gust threat during the late morning and afternoon hours. A Category 1/Marginal Risk has been maintained for coastal portions of southern New England to address the conditional damaging gust threat. ..Squitieri/Darrow.. 12/18/2023 Read more