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SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0646 AM CST Sun Dec 17 2023 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT ACROSS THE COASTAL CAROLINAS... ...SUMMARY... Isolated damaging gusts and a tornado or two will be possible through tonight across the coastal Carolinas. ...Coastal Carolinas through tonight... A deepening cyclone will progress from north FL this morning to eastern NC by 09-12z Monday, in response to gradual phasing of Gulf of Mexico shortwave troughs with a larger-scale trough over the eastern CONUS. Midlevel drying with the passage of a lead shortwave trough and diminished ascent have acted to limit deep convection across FL overnight. Any lingering severe threat will end across southeast FL by mid-late morning as drying occurs from the west and vertical shear continues to weaken. The cyclone will skirt the GA coast during the day and then approach SC this afternoon and NC tonight. A narrow portion of the surface warm sector could spread far enough inland to support some threat for near-surface-based convection across the coastal Carolinas, where vertical shear will be strong. However, poor lapse rates aloft will tend to limit buoyancy in the zone of stronger forcing for ascent where vertical shear will be strongest, and cool shelf waters will likely maintain a shallow stable layer near the coast. Will maintain the outlook area given the conditional potential for isolated damaging gusts and a tornado or two, but it is not clear how much of the potential will be realized inland. ...Northern CA coast... To the east of a closed low over the eastern Pacific, isolated lightning flashes will be possible with embedded/elevated convection. ..Thompson/Broyles.. 12/17/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0646 AM CST Sun Dec 17 2023 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT ACROSS THE COASTAL CAROLINAS... ...SUMMARY... Isolated damaging gusts and a tornado or two will be possible through tonight across the coastal Carolinas. ...Coastal Carolinas through tonight... A deepening cyclone will progress from north FL this morning to eastern NC by 09-12z Monday, in response to gradual phasing of Gulf of Mexico shortwave troughs with a larger-scale trough over the eastern CONUS. Midlevel drying with the passage of a lead shortwave trough and diminished ascent have acted to limit deep convection across FL overnight. Any lingering severe threat will end across southeast FL by mid-late morning as drying occurs from the west and vertical shear continues to weaken. The cyclone will skirt the GA coast during the day and then approach SC this afternoon and NC tonight. A narrow portion of the surface warm sector could spread far enough inland to support some threat for near-surface-based convection across the coastal Carolinas, where vertical shear will be strong. However, poor lapse rates aloft will tend to limit buoyancy in the zone of stronger forcing for ascent where vertical shear will be strongest, and cool shelf waters will likely maintain a shallow stable layer near the coast. Will maintain the outlook area given the conditional potential for isolated damaging gusts and a tornado or two, but it is not clear how much of the potential will be realized inland. ...Northern CA coast... To the east of a closed low over the eastern Pacific, isolated lightning flashes will be possible with embedded/elevated convection. ..Thompson/Broyles.. 12/17/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0646 AM CST Sun Dec 17 2023 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT ACROSS THE COASTAL CAROLINAS... ...SUMMARY... Isolated damaging gusts and a tornado or two will be possible through tonight across the coastal Carolinas. ...Coastal Carolinas through tonight... A deepening cyclone will progress from north FL this morning to eastern NC by 09-12z Monday, in response to gradual phasing of Gulf of Mexico shortwave troughs with a larger-scale trough over the eastern CONUS. Midlevel drying with the passage of a lead shortwave trough and diminished ascent have acted to limit deep convection across FL overnight. Any lingering severe threat will end across southeast FL by mid-late morning as drying occurs from the west and vertical shear continues to weaken. The cyclone will skirt the GA coast during the day and then approach SC this afternoon and NC tonight. A narrow portion of the surface warm sector could spread far enough inland to support some threat for near-surface-based convection across the coastal Carolinas, where vertical shear will be strong. However, poor lapse rates aloft will tend to limit buoyancy in the zone of stronger forcing for ascent where vertical shear will be strongest, and cool shelf waters will likely maintain a shallow stable layer near the coast. Will maintain the outlook area given the conditional potential for isolated damaging gusts and a tornado or two, but it is not clear how much of the potential will be realized inland. ...Northern CA coast... To the east of a closed low over the eastern Pacific, isolated lightning flashes will be possible with embedded/elevated convection. ..Thompson/Broyles.. 12/17/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0646 AM CST Sun Dec 17 2023 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT ACROSS THE COASTAL CAROLINAS... ...SUMMARY... Isolated damaging gusts and a tornado or two will be possible through tonight across the coastal Carolinas. ...Coastal Carolinas through tonight... A deepening cyclone will progress from north FL this morning to eastern NC by 09-12z Monday, in response to gradual phasing of Gulf of Mexico shortwave troughs with a larger-scale trough over the eastern CONUS. Midlevel drying with the passage of a lead shortwave trough and diminished ascent have acted to limit deep convection across FL overnight. Any lingering severe threat will end across southeast FL by mid-late morning as drying occurs from the west and vertical shear continues to weaken. The cyclone will skirt the GA coast during the day and then approach SC this afternoon and NC tonight. A narrow portion of the surface warm sector could spread far enough inland to support some threat for near-surface-based convection across the coastal Carolinas, where vertical shear will be strong. However, poor lapse rates aloft will tend to limit buoyancy in the zone of stronger forcing for ascent where vertical shear will be strongest, and cool shelf waters will likely maintain a shallow stable layer near the coast. Will maintain the outlook area given the conditional potential for isolated damaging gusts and a tornado or two, but it is not clear how much of the potential will be realized inland. ...Northern CA coast... To the east of a closed low over the eastern Pacific, isolated lightning flashes will be possible with embedded/elevated convection. ..Thompson/Broyles.. 12/17/2023 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0321 AM CST Sun Dec 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range guidance is in good agreement that a low-amplitude upper pattern, free of any larger disturbances, and a dry continental air mass will be in place over the CONUS early D4/Wednesday. Some modification of the portion of this air mass over the Plains will begin on D4/Wednesday, ahead of a low-amplitude shortwave expected to gradually move across the Southwest. This shortwave will likely interact with the returning low-level moisture late D5/Thursday and early D6/Friday, but buoyancy and shear will be modest, limiting the severe potential. This shortwave will likely continue eastward into the Lower/Mid MS Valley on D6/Friday. At the same time, upper low off the southern CA coast is expected to start progressing more eastward, potentially moving across southern CA on D6/Friday and into northern Mexico/Southwest on D7/Saturday. Modest low-level moisture is forecast to be in place over the southern Plains ahead of this wave, but warm mid-level temperatures and resultant poor lapse rates should keep the severe potential low. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0321 AM CST Sun Dec 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range guidance is in good agreement that a low-amplitude upper pattern, free of any larger disturbances, and a dry continental air mass will be in place over the CONUS early D4/Wednesday. Some modification of the portion of this air mass over the Plains will begin on D4/Wednesday, ahead of a low-amplitude shortwave expected to gradually move across the Southwest. This shortwave will likely interact with the returning low-level moisture late D5/Thursday and early D6/Friday, but buoyancy and shear will be modest, limiting the severe potential. This shortwave will likely continue eastward into the Lower/Mid MS Valley on D6/Friday. At the same time, upper low off the southern CA coast is expected to start progressing more eastward, potentially moving across southern CA on D6/Friday and into northern Mexico/Southwest on D7/Saturday. Modest low-level moisture is forecast to be in place over the southern Plains ahead of this wave, but warm mid-level temperatures and resultant poor lapse rates should keep the severe potential low. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0321 AM CST Sun Dec 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range guidance is in good agreement that a low-amplitude upper pattern, free of any larger disturbances, and a dry continental air mass will be in place over the CONUS early D4/Wednesday. Some modification of the portion of this air mass over the Plains will begin on D4/Wednesday, ahead of a low-amplitude shortwave expected to gradually move across the Southwest. This shortwave will likely interact with the returning low-level moisture late D5/Thursday and early D6/Friday, but buoyancy and shear will be modest, limiting the severe potential. This shortwave will likely continue eastward into the Lower/Mid MS Valley on D6/Friday. At the same time, upper low off the southern CA coast is expected to start progressing more eastward, potentially moving across southern CA on D6/Friday and into northern Mexico/Southwest on D7/Saturday. Modest low-level moisture is forecast to be in place over the southern Plains ahead of this wave, but warm mid-level temperatures and resultant poor lapse rates should keep the severe potential low. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0321 AM CST Sun Dec 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range guidance is in good agreement that a low-amplitude upper pattern, free of any larger disturbances, and a dry continental air mass will be in place over the CONUS early D4/Wednesday. Some modification of the portion of this air mass over the Plains will begin on D4/Wednesday, ahead of a low-amplitude shortwave expected to gradually move across the Southwest. This shortwave will likely interact with the returning low-level moisture late D5/Thursday and early D6/Friday, but buoyancy and shear will be modest, limiting the severe potential. This shortwave will likely continue eastward into the Lower/Mid MS Valley on D6/Friday. At the same time, upper low off the southern CA coast is expected to start progressing more eastward, potentially moving across southern CA on D6/Friday and into northern Mexico/Southwest on D7/Saturday. Modest low-level moisture is forecast to be in place over the southern Plains ahead of this wave, but warm mid-level temperatures and resultant poor lapse rates should keep the severe potential low. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0321 AM CST Sun Dec 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range guidance is in good agreement that a low-amplitude upper pattern, free of any larger disturbances, and a dry continental air mass will be in place over the CONUS early D4/Wednesday. Some modification of the portion of this air mass over the Plains will begin on D4/Wednesday, ahead of a low-amplitude shortwave expected to gradually move across the Southwest. This shortwave will likely interact with the returning low-level moisture late D5/Thursday and early D6/Friday, but buoyancy and shear will be modest, limiting the severe potential. This shortwave will likely continue eastward into the Lower/Mid MS Valley on D6/Friday. At the same time, upper low off the southern CA coast is expected to start progressing more eastward, potentially moving across southern CA on D6/Friday and into northern Mexico/Southwest on D7/Saturday. Modest low-level moisture is forecast to be in place over the southern Plains ahead of this wave, but warm mid-level temperatures and resultant poor lapse rates should keep the severe potential low. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0321 AM CST Sun Dec 17 2023 Valid 201200Z - 251200Z ...DISCUSSION... Medium-range guidance is in good agreement that a low-amplitude upper pattern, free of any larger disturbances, and a dry continental air mass will be in place over the CONUS early D4/Wednesday. Some modification of the portion of this air mass over the Plains will begin on D4/Wednesday, ahead of a low-amplitude shortwave expected to gradually move across the Southwest. This shortwave will likely interact with the returning low-level moisture late D5/Thursday and early D6/Friday, but buoyancy and shear will be modest, limiting the severe potential. This shortwave will likely continue eastward into the Lower/Mid MS Valley on D6/Friday. At the same time, upper low off the southern CA coast is expected to start progressing more eastward, potentially moving across southern CA on D6/Friday and into northern Mexico/Southwest on D7/Saturday. Modest low-level moisture is forecast to be in place over the southern Plains ahead of this wave, but warm mid-level temperatures and resultant poor lapse rates should keep the severe potential low. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0209 AM CST Sun Dec 17 2023 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... An upper cyclone will likely be centered over PA early Tuesday morning, accompanied by cold mid-level temperatures and strong mid-level flow (i.e. 90-100 kt at 500 mb) throughout its eastern periphery. This system is forecast to gradually move eastward through the Northeast and Mid-Atlantic during the period, with largely zonal flow in its wake across the CONUS. High surface pressure associated with dry continental airmass will dominant the sensible weather east of the Rockies, limiting low-level moisture and precluding thunderstorm development. An upper low is expected to drift southward off the West Coast, ending the period centered well off the central CA Coast. A low-amplitude shortwave trough moving through the base of this upper low may move across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/17/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0209 AM CST Sun Dec 17 2023 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... An upper cyclone will likely be centered over PA early Tuesday morning, accompanied by cold mid-level temperatures and strong mid-level flow (i.e. 90-100 kt at 500 mb) throughout its eastern periphery. This system is forecast to gradually move eastward through the Northeast and Mid-Atlantic during the period, with largely zonal flow in its wake across the CONUS. High surface pressure associated with dry continental airmass will dominant the sensible weather east of the Rockies, limiting low-level moisture and precluding thunderstorm development. An upper low is expected to drift southward off the West Coast, ending the period centered well off the central CA Coast. A low-amplitude shortwave trough moving through the base of this upper low may move across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/17/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0209 AM CST Sun Dec 17 2023 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... An upper cyclone will likely be centered over PA early Tuesday morning, accompanied by cold mid-level temperatures and strong mid-level flow (i.e. 90-100 kt at 500 mb) throughout its eastern periphery. This system is forecast to gradually move eastward through the Northeast and Mid-Atlantic during the period, with largely zonal flow in its wake across the CONUS. High surface pressure associated with dry continental airmass will dominant the sensible weather east of the Rockies, limiting low-level moisture and precluding thunderstorm development. An upper low is expected to drift southward off the West Coast, ending the period centered well off the central CA Coast. A low-amplitude shortwave trough moving through the base of this upper low may move across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/17/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0209 AM CST Sun Dec 17 2023 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... An upper cyclone will likely be centered over PA early Tuesday morning, accompanied by cold mid-level temperatures and strong mid-level flow (i.e. 90-100 kt at 500 mb) throughout its eastern periphery. This system is forecast to gradually move eastward through the Northeast and Mid-Atlantic during the period, with largely zonal flow in its wake across the CONUS. High surface pressure associated with dry continental airmass will dominant the sensible weather east of the Rockies, limiting low-level moisture and precluding thunderstorm development. An upper low is expected to drift southward off the West Coast, ending the period centered well off the central CA Coast. A low-amplitude shortwave trough moving through the base of this upper low may move across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/17/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0209 AM CST Sun Dec 17 2023 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... An upper cyclone will likely be centered over PA early Tuesday morning, accompanied by cold mid-level temperatures and strong mid-level flow (i.e. 90-100 kt at 500 mb) throughout its eastern periphery. This system is forecast to gradually move eastward through the Northeast and Mid-Atlantic during the period, with largely zonal flow in its wake across the CONUS. High surface pressure associated with dry continental airmass will dominant the sensible weather east of the Rockies, limiting low-level moisture and precluding thunderstorm development. An upper low is expected to drift southward off the West Coast, ending the period centered well off the central CA Coast. A low-amplitude shortwave trough moving through the base of this upper low may move across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/17/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0209 AM CST Sun Dec 17 2023 Valid 191200Z - 201200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected on Tuesday. ...Synopsis... An upper cyclone will likely be centered over PA early Tuesday morning, accompanied by cold mid-level temperatures and strong mid-level flow (i.e. 90-100 kt at 500 mb) throughout its eastern periphery. This system is forecast to gradually move eastward through the Northeast and Mid-Atlantic during the period, with largely zonal flow in its wake across the CONUS. High surface pressure associated with dry continental airmass will dominant the sensible weather east of the Rockies, limiting low-level moisture and precluding thunderstorm development. An upper low is expected to drift southward off the West Coast, ending the period centered well off the central CA Coast. A low-amplitude shortwave trough moving through the base of this upper low may move across southern CA. However, thermodynamic conditions in the vicinity of this shortwave are not conducive to lightning production. ..Mosier.. 12/17/2023 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0140 AM CST Sun Dec 17 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Upper ridging will become established across the western and central CONUS as a mid-level trough amplifies over the Appalachians tomorrow/Monday. Surface high pressure and cooler air will continue to overspread the Rockies to East Coast areas, as appreciable precipitation accumulates over much of California. When also considering marginal fuel statuses across the U.S., the threat for significant wildfire-spread potential currently appears negligible. ..Squitieri.. 12/17/2023 ...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 0140 AM CST Sun Dec 17 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Upper ridging will become established across the western and central CONUS as a mid-level trough amplifies over the Appalachians tomorrow/Monday. Surface high pressure and cooler air will continue to overspread the Rockies to East Coast areas, as appreciable precipitation accumulates over much of California. When also considering marginal fuel statuses across the U.S., the threat for significant wildfire-spread potential currently appears negligible. ..Squitieri.. 12/17/2023 ...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 0140 AM CST Sun Dec 17 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Upper ridging will become established across the western and central CONUS as a mid-level trough amplifies over the Appalachians tomorrow/Monday. Surface high pressure and cooler air will continue to overspread the Rockies to East Coast areas, as appreciable precipitation accumulates over much of California. When also considering marginal fuel statuses across the U.S., the threat for significant wildfire-spread potential currently appears negligible. ..Squitieri.. 12/17/2023 ...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 0140 AM CST Sun Dec 17 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... ...Synopsis... Upper ridging will become established across the western and central CONUS as a mid-level trough amplifies over the Appalachians tomorrow/Monday. Surface high pressure and cooler air will continue to overspread the Rockies to East Coast areas, as appreciable precipitation accumulates over much of California. When also considering marginal fuel statuses across the U.S., the threat for significant wildfire-spread potential currently appears negligible. ..Squitieri.. 12/17/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more