Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0638 AM CST Sat Dec 16 2023 Valid 161300Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FL PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase by tonight into Sunday morning across the Florida peninsula and Keys. ...FL through Sunday morning... No changes to previous outlook area. Cyclogenesis is underway across the central Gulf of Mexico in association with a southern stream shortwave trough. The cyclone is expected to consolidate/deepen and move toward central/north FL by the end of the period, as a result of phasing with an upstream trough now near the TX coast, and due to convective feedback. These processes will result in strengthening wind fields and northward moisture transport across the FL peninsula, especially tonight into Sunday morning. As boundary-layer dewpoints of 68-72 F spread northward, destabilization should be sufficient for surface-based storms later today through Sunday morning. Isolated, weakly rotating storms will be possible today in the warm advection zone, starting late this morning across the Keys and spreading northward along the Atlantic coast this afternoon. The primary ascent band/convection and associated wind shift are expected to approach the FL Gulf coast near or after 03z and continue eastward across the peninsula through 09-12z Sunday. A somewhat broken band of storms is expected just ahead of the wind shift in an environment of 500-1000 J/kg MLCAPE, modest lapse rates aloft and strengthening vertical shear. Forecast profiles show large, curved hodographs in the low levels and sufficient hodograph length/deep-layer vertical shear for supercells. Assuming moisture advection and overnight mechanical mixing are strong enough inland, the potential for damaging gusts and a few tornadoes will spread inland from the Gulf coast. Other supercells with the potential for damaging gusts and tornadoes could also form in the convergence zone and somewhat richer low-level moisture along the east-central and southeast FL coasts overnight. The main uncertainties in this forecast will be the magnitude of the mass response/vertical shear, and the degree of low-level warming/moistening inland overnight. Both will be a function of how quickly the Gulf cyclone consolidates and deepens in a data sparse area. Given the modest lapse rates aloft, maintenance of surface-based convection will be sensitive to a few degrees of temperature/dewpoint up to the cyclone track. ..Thompson/Broyles.. 12/16/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0638 AM CST Sat Dec 16 2023 Valid 161300Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FL PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase by tonight into Sunday morning across the Florida peninsula and Keys. ...FL through Sunday morning... No changes to previous outlook area. Cyclogenesis is underway across the central Gulf of Mexico in association with a southern stream shortwave trough. The cyclone is expected to consolidate/deepen and move toward central/north FL by the end of the period, as a result of phasing with an upstream trough now near the TX coast, and due to convective feedback. These processes will result in strengthening wind fields and northward moisture transport across the FL peninsula, especially tonight into Sunday morning. As boundary-layer dewpoints of 68-72 F spread northward, destabilization should be sufficient for surface-based storms later today through Sunday morning. Isolated, weakly rotating storms will be possible today in the warm advection zone, starting late this morning across the Keys and spreading northward along the Atlantic coast this afternoon. The primary ascent band/convection and associated wind shift are expected to approach the FL Gulf coast near or after 03z and continue eastward across the peninsula through 09-12z Sunday. A somewhat broken band of storms is expected just ahead of the wind shift in an environment of 500-1000 J/kg MLCAPE, modest lapse rates aloft and strengthening vertical shear. Forecast profiles show large, curved hodographs in the low levels and sufficient hodograph length/deep-layer vertical shear for supercells. Assuming moisture advection and overnight mechanical mixing are strong enough inland, the potential for damaging gusts and a few tornadoes will spread inland from the Gulf coast. Other supercells with the potential for damaging gusts and tornadoes could also form in the convergence zone and somewhat richer low-level moisture along the east-central and southeast FL coasts overnight. The main uncertainties in this forecast will be the magnitude of the mass response/vertical shear, and the degree of low-level warming/moistening inland overnight. Both will be a function of how quickly the Gulf cyclone consolidates and deepens in a data sparse area. Given the modest lapse rates aloft, maintenance of surface-based convection will be sensitive to a few degrees of temperature/dewpoint up to the cyclone track. ..Thompson/Broyles.. 12/16/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0638 AM CST Sat Dec 16 2023 Valid 161300Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FL PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase by tonight into Sunday morning across the Florida peninsula and Keys. ...FL through Sunday morning... No changes to previous outlook area. Cyclogenesis is underway across the central Gulf of Mexico in association with a southern stream shortwave trough. The cyclone is expected to consolidate/deepen and move toward central/north FL by the end of the period, as a result of phasing with an upstream trough now near the TX coast, and due to convective feedback. These processes will result in strengthening wind fields and northward moisture transport across the FL peninsula, especially tonight into Sunday morning. As boundary-layer dewpoints of 68-72 F spread northward, destabilization should be sufficient for surface-based storms later today through Sunday morning. Isolated, weakly rotating storms will be possible today in the warm advection zone, starting late this morning across the Keys and spreading northward along the Atlantic coast this afternoon. The primary ascent band/convection and associated wind shift are expected to approach the FL Gulf coast near or after 03z and continue eastward across the peninsula through 09-12z Sunday. A somewhat broken band of storms is expected just ahead of the wind shift in an environment of 500-1000 J/kg MLCAPE, modest lapse rates aloft and strengthening vertical shear. Forecast profiles show large, curved hodographs in the low levels and sufficient hodograph length/deep-layer vertical shear for supercells. Assuming moisture advection and overnight mechanical mixing are strong enough inland, the potential for damaging gusts and a few tornadoes will spread inland from the Gulf coast. Other supercells with the potential for damaging gusts and tornadoes could also form in the convergence zone and somewhat richer low-level moisture along the east-central and southeast FL coasts overnight. The main uncertainties in this forecast will be the magnitude of the mass response/vertical shear, and the degree of low-level warming/moistening inland overnight. Both will be a function of how quickly the Gulf cyclone consolidates and deepens in a data sparse area. Given the modest lapse rates aloft, maintenance of surface-based convection will be sensitive to a few degrees of temperature/dewpoint up to the cyclone track. ..Thompson/Broyles.. 12/16/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0638 AM CST Sat Dec 16 2023 Valid 161300Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FL PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase by tonight into Sunday morning across the Florida peninsula and Keys. ...FL through Sunday morning... No changes to previous outlook area. Cyclogenesis is underway across the central Gulf of Mexico in association with a southern stream shortwave trough. The cyclone is expected to consolidate/deepen and move toward central/north FL by the end of the period, as a result of phasing with an upstream trough now near the TX coast, and due to convective feedback. These processes will result in strengthening wind fields and northward moisture transport across the FL peninsula, especially tonight into Sunday morning. As boundary-layer dewpoints of 68-72 F spread northward, destabilization should be sufficient for surface-based storms later today through Sunday morning. Isolated, weakly rotating storms will be possible today in the warm advection zone, starting late this morning across the Keys and spreading northward along the Atlantic coast this afternoon. The primary ascent band/convection and associated wind shift are expected to approach the FL Gulf coast near or after 03z and continue eastward across the peninsula through 09-12z Sunday. A somewhat broken band of storms is expected just ahead of the wind shift in an environment of 500-1000 J/kg MLCAPE, modest lapse rates aloft and strengthening vertical shear. Forecast profiles show large, curved hodographs in the low levels and sufficient hodograph length/deep-layer vertical shear for supercells. Assuming moisture advection and overnight mechanical mixing are strong enough inland, the potential for damaging gusts and a few tornadoes will spread inland from the Gulf coast. Other supercells with the potential for damaging gusts and tornadoes could also form in the convergence zone and somewhat richer low-level moisture along the east-central and southeast FL coasts overnight. The main uncertainties in this forecast will be the magnitude of the mass response/vertical shear, and the degree of low-level warming/moistening inland overnight. Both will be a function of how quickly the Gulf cyclone consolidates and deepens in a data sparse area. Given the modest lapse rates aloft, maintenance of surface-based convection will be sensitive to a few degrees of temperature/dewpoint up to the cyclone track. ..Thompson/Broyles.. 12/16/2023 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0638 AM CST Sat Dec 16 2023 Valid 161300Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FL PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase by tonight into Sunday morning across the Florida peninsula and Keys. ...FL through Sunday morning... No changes to previous outlook area. Cyclogenesis is underway across the central Gulf of Mexico in association with a southern stream shortwave trough. The cyclone is expected to consolidate/deepen and move toward central/north FL by the end of the period, as a result of phasing with an upstream trough now near the TX coast, and due to convective feedback. These processes will result in strengthening wind fields and northward moisture transport across the FL peninsula, especially tonight into Sunday morning. As boundary-layer dewpoints of 68-72 F spread northward, destabilization should be sufficient for surface-based storms later today through Sunday morning. Isolated, weakly rotating storms will be possible today in the warm advection zone, starting late this morning across the Keys and spreading northward along the Atlantic coast this afternoon. The primary ascent band/convection and associated wind shift are expected to approach the FL Gulf coast near or after 03z and continue eastward across the peninsula through 09-12z Sunday. A somewhat broken band of storms is expected just ahead of the wind shift in an environment of 500-1000 J/kg MLCAPE, modest lapse rates aloft and strengthening vertical shear. Forecast profiles show large, curved hodographs in the low levels and sufficient hodograph length/deep-layer vertical shear for supercells. Assuming moisture advection and overnight mechanical mixing are strong enough inland, the potential for damaging gusts and a few tornadoes will spread inland from the Gulf coast. Other supercells with the potential for damaging gusts and tornadoes could also form in the convergence zone and somewhat richer low-level moisture along the east-central and southeast FL coasts overnight. The main uncertainties in this forecast will be the magnitude of the mass response/vertical shear, and the degree of low-level warming/moistening inland overnight. Both will be a function of how quickly the Gulf cyclone consolidates and deepens in a data sparse area. Given the modest lapse rates aloft, maintenance of surface-based convection will be sensitive to a few degrees of temperature/dewpoint up to the cyclone track. ..Thompson/Broyles.. 12/16/2023 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0314 AM CST Sat Dec 16 2023 Valid 191200Z - 241200Z ...DISCUSSION... An upper trough will likely extend from southwest Quebec into the Mid-Atlantic early D4/Tuesday, before then progressing eastward throughout the day. Zonal flow is expected across much of the CONUS in its wake on D5/Wednesday, before a slow-moving upper low initially off the southern CA coast introduces some amplitude into the southern stream. This upper low will likely remain off the southern CA coast through the period, but a preceding low-amplitude shortwave may move through the Southwest on D5/Wednesday and into Plains on D6/Thursday. Modest low-level moisture return should precede this shortwave, and some interaction between this shortwave (and attendant cold front) with this buoyancy is possible on D7/Friday. However, weak buoyancy is currently expected to limit the overall severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0314 AM CST Sat Dec 16 2023 Valid 191200Z - 241200Z ...DISCUSSION... An upper trough will likely extend from southwest Quebec into the Mid-Atlantic early D4/Tuesday, before then progressing eastward throughout the day. Zonal flow is expected across much of the CONUS in its wake on D5/Wednesday, before a slow-moving upper low initially off the southern CA coast introduces some amplitude into the southern stream. This upper low will likely remain off the southern CA coast through the period, but a preceding low-amplitude shortwave may move through the Southwest on D5/Wednesday and into Plains on D6/Thursday. Modest low-level moisture return should precede this shortwave, and some interaction between this shortwave (and attendant cold front) with this buoyancy is possible on D7/Friday. However, weak buoyancy is currently expected to limit the overall severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0314 AM CST Sat Dec 16 2023 Valid 191200Z - 241200Z ...DISCUSSION... An upper trough will likely extend from southwest Quebec into the Mid-Atlantic early D4/Tuesday, before then progressing eastward throughout the day. Zonal flow is expected across much of the CONUS in its wake on D5/Wednesday, before a slow-moving upper low initially off the southern CA coast introduces some amplitude into the southern stream. This upper low will likely remain off the southern CA coast through the period, but a preceding low-amplitude shortwave may move through the Southwest on D5/Wednesday and into Plains on D6/Thursday. Modest low-level moisture return should precede this shortwave, and some interaction between this shortwave (and attendant cold front) with this buoyancy is possible on D7/Friday. However, weak buoyancy is currently expected to limit the overall severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0314 AM CST Sat Dec 16 2023 Valid 191200Z - 241200Z ...DISCUSSION... An upper trough will likely extend from southwest Quebec into the Mid-Atlantic early D4/Tuesday, before then progressing eastward throughout the day. Zonal flow is expected across much of the CONUS in its wake on D5/Wednesday, before a slow-moving upper low initially off the southern CA coast introduces some amplitude into the southern stream. This upper low will likely remain off the southern CA coast through the period, but a preceding low-amplitude shortwave may move through the Southwest on D5/Wednesday and into Plains on D6/Thursday. Modest low-level moisture return should precede this shortwave, and some interaction between this shortwave (and attendant cold front) with this buoyancy is possible on D7/Friday. However, weak buoyancy is currently expected to limit the overall severe potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0314 AM CST Sat Dec 16 2023 Valid 191200Z - 241200Z ...DISCUSSION... An upper trough will likely extend from southwest Quebec into the Mid-Atlantic early D4/Tuesday, before then progressing eastward throughout the day. Zonal flow is expected across much of the CONUS in its wake on D5/Wednesday, before a slow-moving upper low initially off the southern CA coast introduces some amplitude into the southern stream. This upper low will likely remain off the southern CA coast through the period, but a preceding low-amplitude shortwave may move through the Southwest on D5/Wednesday and into Plains on D6/Thursday. Modest low-level moisture return should precede this shortwave, and some interaction between this shortwave (and attendant cold front) with this buoyancy is possible on D7/Friday. However, weak buoyancy is currently expected to limit the overall severe potential. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0212 AM CST Sat Dec 16 2023 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few lightning flashes are possible from the eastern shore of New Jersey into southern New England Monday morning. A few isolated flashes are also possible along the northern California coast. ...Synopsis... Upper troughing is expected to cover much of the central and eastern CONUS early Monday morning. A pair of shortwave troughs are forecast to be embedded within this troughing, one over the Mid-Atlantic and the other extending from northwestern Ontario into the Mid MS Valley. The eastern wave is expected to progress quickly northward across the Northeast while the western wave moves southeastward across the Upper Great Lakes and OH Valley. The western wave is then forecast to continue more eastward, ending the period extending from the Lower Great Lakes into the Mid-Atlantic. Strong wind fields will accompany this wave, with a belt of 90 to 100 kt 500-mb flow likely across the Mid MS Valley throughout the day. However, a dry continental air mass will be in place east of the Rockies, with its limited low-level moisture precluding thunderstorm development. There is a low probability that some limited low-level moisture reaches NJ, Long Island, and portions of southern New England early Monday morning, just ahead of a surface low associated with the eastern shortwave. If this occurs, some convective structures are possible. Most of this convection would be shallow, but the potential exists for a few cores to become deep enough for lightning. Strong kinematic fields suggests any deeper, more sustained cores could produce damaging gusts, but the overall uncertainty of the scenario merits leaving the area free of severe probabilities for this outlook. Farther west, a series of shortwave troughs are expected to move across northern CA and the Pacific Northwest on Monday. The lead shortwave is forecast to move from northern California into ID during the first half of the period while another shortwave moves along the Pacific Northwest coast during the second half. Strong forcing for ascent and cold mid-level temperatures could support a few isolated flashes along the northern CA coast. ..Mosier.. 12/16/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0212 AM CST Sat Dec 16 2023 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few lightning flashes are possible from the eastern shore of New Jersey into southern New England Monday morning. A few isolated flashes are also possible along the northern California coast. ...Synopsis... Upper troughing is expected to cover much of the central and eastern CONUS early Monday morning. A pair of shortwave troughs are forecast to be embedded within this troughing, one over the Mid-Atlantic and the other extending from northwestern Ontario into the Mid MS Valley. The eastern wave is expected to progress quickly northward across the Northeast while the western wave moves southeastward across the Upper Great Lakes and OH Valley. The western wave is then forecast to continue more eastward, ending the period extending from the Lower Great Lakes into the Mid-Atlantic. Strong wind fields will accompany this wave, with a belt of 90 to 100 kt 500-mb flow likely across the Mid MS Valley throughout the day. However, a dry continental air mass will be in place east of the Rockies, with its limited low-level moisture precluding thunderstorm development. There is a low probability that some limited low-level moisture reaches NJ, Long Island, and portions of southern New England early Monday morning, just ahead of a surface low associated with the eastern shortwave. If this occurs, some convective structures are possible. Most of this convection would be shallow, but the potential exists for a few cores to become deep enough for lightning. Strong kinematic fields suggests any deeper, more sustained cores could produce damaging gusts, but the overall uncertainty of the scenario merits leaving the area free of severe probabilities for this outlook. Farther west, a series of shortwave troughs are expected to move across northern CA and the Pacific Northwest on Monday. The lead shortwave is forecast to move from northern California into ID during the first half of the period while another shortwave moves along the Pacific Northwest coast during the second half. Strong forcing for ascent and cold mid-level temperatures could support a few isolated flashes along the northern CA coast. ..Mosier.. 12/16/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0212 AM CST Sat Dec 16 2023 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few lightning flashes are possible from the eastern shore of New Jersey into southern New England Monday morning. A few isolated flashes are also possible along the northern California coast. ...Synopsis... Upper troughing is expected to cover much of the central and eastern CONUS early Monday morning. A pair of shortwave troughs are forecast to be embedded within this troughing, one over the Mid-Atlantic and the other extending from northwestern Ontario into the Mid MS Valley. The eastern wave is expected to progress quickly northward across the Northeast while the western wave moves southeastward across the Upper Great Lakes and OH Valley. The western wave is then forecast to continue more eastward, ending the period extending from the Lower Great Lakes into the Mid-Atlantic. Strong wind fields will accompany this wave, with a belt of 90 to 100 kt 500-mb flow likely across the Mid MS Valley throughout the day. However, a dry continental air mass will be in place east of the Rockies, with its limited low-level moisture precluding thunderstorm development. There is a low probability that some limited low-level moisture reaches NJ, Long Island, and portions of southern New England early Monday morning, just ahead of a surface low associated with the eastern shortwave. If this occurs, some convective structures are possible. Most of this convection would be shallow, but the potential exists for a few cores to become deep enough for lightning. Strong kinematic fields suggests any deeper, more sustained cores could produce damaging gusts, but the overall uncertainty of the scenario merits leaving the area free of severe probabilities for this outlook. Farther west, a series of shortwave troughs are expected to move across northern CA and the Pacific Northwest on Monday. The lead shortwave is forecast to move from northern California into ID during the first half of the period while another shortwave moves along the Pacific Northwest coast during the second half. Strong forcing for ascent and cold mid-level temperatures could support a few isolated flashes along the northern CA coast. ..Mosier.. 12/16/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0212 AM CST Sat Dec 16 2023 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few lightning flashes are possible from the eastern shore of New Jersey into southern New England Monday morning. A few isolated flashes are also possible along the northern California coast. ...Synopsis... Upper troughing is expected to cover much of the central and eastern CONUS early Monday morning. A pair of shortwave troughs are forecast to be embedded within this troughing, one over the Mid-Atlantic and the other extending from northwestern Ontario into the Mid MS Valley. The eastern wave is expected to progress quickly northward across the Northeast while the western wave moves southeastward across the Upper Great Lakes and OH Valley. The western wave is then forecast to continue more eastward, ending the period extending from the Lower Great Lakes into the Mid-Atlantic. Strong wind fields will accompany this wave, with a belt of 90 to 100 kt 500-mb flow likely across the Mid MS Valley throughout the day. However, a dry continental air mass will be in place east of the Rockies, with its limited low-level moisture precluding thunderstorm development. There is a low probability that some limited low-level moisture reaches NJ, Long Island, and portions of southern New England early Monday morning, just ahead of a surface low associated with the eastern shortwave. If this occurs, some convective structures are possible. Most of this convection would be shallow, but the potential exists for a few cores to become deep enough for lightning. Strong kinematic fields suggests any deeper, more sustained cores could produce damaging gusts, but the overall uncertainty of the scenario merits leaving the area free of severe probabilities for this outlook. Farther west, a series of shortwave troughs are expected to move across northern CA and the Pacific Northwest on Monday. The lead shortwave is forecast to move from northern California into ID during the first half of the period while another shortwave moves along the Pacific Northwest coast during the second half. Strong forcing for ascent and cold mid-level temperatures could support a few isolated flashes along the northern CA coast. ..Mosier.. 12/16/2023 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0212 AM CST Sat Dec 16 2023 Valid 181200Z - 191200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few lightning flashes are possible from the eastern shore of New Jersey into southern New England Monday morning. A few isolated flashes are also possible along the northern California coast. ...Synopsis... Upper troughing is expected to cover much of the central and eastern CONUS early Monday morning. A pair of shortwave troughs are forecast to be embedded within this troughing, one over the Mid-Atlantic and the other extending from northwestern Ontario into the Mid MS Valley. The eastern wave is expected to progress quickly northward across the Northeast while the western wave moves southeastward across the Upper Great Lakes and OH Valley. The western wave is then forecast to continue more eastward, ending the period extending from the Lower Great Lakes into the Mid-Atlantic. Strong wind fields will accompany this wave, with a belt of 90 to 100 kt 500-mb flow likely across the Mid MS Valley throughout the day. However, a dry continental air mass will be in place east of the Rockies, with its limited low-level moisture precluding thunderstorm development. There is a low probability that some limited low-level moisture reaches NJ, Long Island, and portions of southern New England early Monday morning, just ahead of a surface low associated with the eastern shortwave. If this occurs, some convective structures are possible. Most of this convection would be shallow, but the potential exists for a few cores to become deep enough for lightning. Strong kinematic fields suggests any deeper, more sustained cores could produce damaging gusts, but the overall uncertainty of the scenario merits leaving the area free of severe probabilities for this outlook. Farther west, a series of shortwave troughs are expected to move across northern CA and the Pacific Northwest on Monday. The lead shortwave is forecast to move from northern California into ID during the first half of the period while another shortwave moves along the Pacific Northwest coast during the second half. Strong forcing for ascent and cold mid-level temperatures could support a few isolated flashes along the northern CA coast. ..Mosier.. 12/16/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST SOUTH CAROLINA INTO EASTERN NORTH CAROLINA AND THE OUTER BANKS... ...SUMMARY... Severe thunderstorms are possible Sunday from northeast South Carolina into eastern North Carolina and the Outer Banks. Primary severe hazard is damaging wind gusts. ...Synopsis and Discussion... Surface low likely over the northern FL/southeast GA vicinity early Sunday morning is forecast to undergo robust deepening throughout the day at it moves rapidly northward. This low is expected to further occlude during this period as well, particularly from Sunday evening onward through early Monday morning. General expectation is for this low to be in the NJ vicinity by 12Z Monday. Given the orientation of the coastline and largely meridional motion of the low, subtle changes to the track of the low could have an outsized influence on the severe risk. A more easterly track will keep much of the higher theta-e air offshore, likely confining the severe risk to the immediate coastal areas and the NC Outer Bank. However, a more westerly track, even by just 50-75 miles, could place significantly more land area within the warm sector, particularly across eastern NC. Shear across the warm sector is expected to be very strong, supported by robust low to mid-level southeasterly flow east of the center of the deepening cyclone. The warm sector will likely feature low to mid 60s dewpoints, but surface heating will be minimal and mid-level lapse rates will be poor, owing to widespread cloud cover and precipitation. Even so, the very strong large-scale forcing for ascent associated with this system will likely lead to the development of narrow, but strongly forced convective line. Current expectation is for this line to impact land areas from northeastern SC across eastern NC and the Outer Banks. Primary threat within this line would be damaging wind gusts, but a brief tornado or two is also possible. A low-probability severe threat may linger during the morning hours farther south over the FL Peninsula. Here, some deep convection is still possible along the primary surface trough before it moves offshore. ..Mosier.. 12/16/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST SOUTH CAROLINA INTO EASTERN NORTH CAROLINA AND THE OUTER BANKS... ...SUMMARY... Severe thunderstorms are possible Sunday from northeast South Carolina into eastern North Carolina and the Outer Banks. Primary severe hazard is damaging wind gusts. ...Synopsis and Discussion... Surface low likely over the northern FL/southeast GA vicinity early Sunday morning is forecast to undergo robust deepening throughout the day at it moves rapidly northward. This low is expected to further occlude during this period as well, particularly from Sunday evening onward through early Monday morning. General expectation is for this low to be in the NJ vicinity by 12Z Monday. Given the orientation of the coastline and largely meridional motion of the low, subtle changes to the track of the low could have an outsized influence on the severe risk. A more easterly track will keep much of the higher theta-e air offshore, likely confining the severe risk to the immediate coastal areas and the NC Outer Bank. However, a more westerly track, even by just 50-75 miles, could place significantly more land area within the warm sector, particularly across eastern NC. Shear across the warm sector is expected to be very strong, supported by robust low to mid-level southeasterly flow east of the center of the deepening cyclone. The warm sector will likely feature low to mid 60s dewpoints, but surface heating will be minimal and mid-level lapse rates will be poor, owing to widespread cloud cover and precipitation. Even so, the very strong large-scale forcing for ascent associated with this system will likely lead to the development of narrow, but strongly forced convective line. Current expectation is for this line to impact land areas from northeastern SC across eastern NC and the Outer Banks. Primary threat within this line would be damaging wind gusts, but a brief tornado or two is also possible. A low-probability severe threat may linger during the morning hours farther south over the FL Peninsula. Here, some deep convection is still possible along the primary surface trough before it moves offshore. ..Mosier.. 12/16/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST SOUTH CAROLINA INTO EASTERN NORTH CAROLINA AND THE OUTER BANKS... ...SUMMARY... Severe thunderstorms are possible Sunday from northeast South Carolina into eastern North Carolina and the Outer Banks. Primary severe hazard is damaging wind gusts. ...Synopsis and Discussion... Surface low likely over the northern FL/southeast GA vicinity early Sunday morning is forecast to undergo robust deepening throughout the day at it moves rapidly northward. This low is expected to further occlude during this period as well, particularly from Sunday evening onward through early Monday morning. General expectation is for this low to be in the NJ vicinity by 12Z Monday. Given the orientation of the coastline and largely meridional motion of the low, subtle changes to the track of the low could have an outsized influence on the severe risk. A more easterly track will keep much of the higher theta-e air offshore, likely confining the severe risk to the immediate coastal areas and the NC Outer Bank. However, a more westerly track, even by just 50-75 miles, could place significantly more land area within the warm sector, particularly across eastern NC. Shear across the warm sector is expected to be very strong, supported by robust low to mid-level southeasterly flow east of the center of the deepening cyclone. The warm sector will likely feature low to mid 60s dewpoints, but surface heating will be minimal and mid-level lapse rates will be poor, owing to widespread cloud cover and precipitation. Even so, the very strong large-scale forcing for ascent associated with this system will likely lead to the development of narrow, but strongly forced convective line. Current expectation is for this line to impact land areas from northeastern SC across eastern NC and the Outer Banks. Primary threat within this line would be damaging wind gusts, but a brief tornado or two is also possible. A low-probability severe threat may linger during the morning hours farther south over the FL Peninsula. Here, some deep convection is still possible along the primary surface trough before it moves offshore. ..Mosier.. 12/16/2023 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1239 AM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST SOUTH CAROLINA INTO EASTERN NORTH CAROLINA AND THE OUTER BANKS... ...SUMMARY... Severe thunderstorms are possible Sunday from northeast South Carolina into eastern North Carolina and the Outer Banks. Primary severe hazard is damaging wind gusts. ...Synopsis and Discussion... Surface low likely over the northern FL/southeast GA vicinity early Sunday morning is forecast to undergo robust deepening throughout the day at it moves rapidly northward. This low is expected to further occlude during this period as well, particularly from Sunday evening onward through early Monday morning. General expectation is for this low to be in the NJ vicinity by 12Z Monday. Given the orientation of the coastline and largely meridional motion of the low, subtle changes to the track of the low could have an outsized influence on the severe risk. A more easterly track will keep much of the higher theta-e air offshore, likely confining the severe risk to the immediate coastal areas and the NC Outer Bank. However, a more westerly track, even by just 50-75 miles, could place significantly more land area within the warm sector, particularly across eastern NC. Shear across the warm sector is expected to be very strong, supported by robust low to mid-level southeasterly flow east of the center of the deepening cyclone. The warm sector will likely feature low to mid 60s dewpoints, but surface heating will be minimal and mid-level lapse rates will be poor, owing to widespread cloud cover and precipitation. Even so, the very strong large-scale forcing for ascent associated with this system will likely lead to the development of narrow, but strongly forced convective line. Current expectation is for this line to impact land areas from northeastern SC across eastern NC and the Outer Banks. Primary threat within this line would be damaging wind gusts, but a brief tornado or two is also possible. A low-probability severe threat may linger during the morning hours farther south over the FL Peninsula. Here, some deep convection is still possible along the primary surface trough before it moves offshore. ..Mosier.. 12/16/2023 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1228 AM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...NO CRITICAL AREAS... ...Synopsis... A series of mid-level troughs will traverse the eastern CONUS as a mid-level trough approaches the West Coast tomorrow/Sunday. Cool conditions will overspread much of the U.S. east of the Rockies, with appreciable precipitation accumulations possible over California with the approaching West Coast mid-level trough. As such, significant, widespread wildfire-growth potential appears negligible across the CONUS. ..Squitieri.. 12/16/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more