Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0145 PM CST Fri Dec 15 2023 Valid 152000Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. through tonight. ...20Z Update... Lightning has diminished with convection embedded within a band of precipitation, ahead of mid-level troughing slowly progressing across the Great Plains. Stronger mid/upper support and colder air aloft, associated with a remnant embedded low, appear to be shifting northeast of the better low-level moisture return off the northwestern Gulf, and potential for renewed thunderstorm activity may be low in the near term. However, as the trailing flank of the mid-level troughing begins to dig across central Texas, toward the coastal plain, guidance suggests that probabilities for scattered weak thunderstorm activity may increase across parts of eastern/southeastern Texas later this evening or overnight. ..Kerr.. 12/15/2023 .PREV DISCUSSION... /ISSUED 1020 AM CST Fri Dec 15 2023/ ...Discussion... A central U.S. upper trough -- flanked by ridging over both eastern and western portions of the country -- will shift slowly eastward today and tonight. In response, very weak surface cyclogenesis will occur, with a low expected to reside over the southern Iowa/northwestern Missouri area early Saturday morning. Ahead of this low, and the associated/trailing weak surface trough/front, very little in the way of moisture return is expected, given the northeasterly/northerly cyclonic flow over the northern and western Gulf of Mexico. As such, an overall lack of buoyancy with this system suggests only occasional/sporadic lightning through tonight -- primarily across the eastern Texas/western Louisiana/Arklatex area. A few flashes may also occur across southern Florida and the Keys later in the period, within easterly low-level flow east of the weak southern Gulf surface low. Elsewhere, thunderstorms are not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0145 PM CST Fri Dec 15 2023 Valid 152000Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. through tonight. ...20Z Update... Lightning has diminished with convection embedded within a band of precipitation, ahead of mid-level troughing slowly progressing across the Great Plains. Stronger mid/upper support and colder air aloft, associated with a remnant embedded low, appear to be shifting northeast of the better low-level moisture return off the northwestern Gulf, and potential for renewed thunderstorm activity may be low in the near term. However, as the trailing flank of the mid-level troughing begins to dig across central Texas, toward the coastal plain, guidance suggests that probabilities for scattered weak thunderstorm activity may increase across parts of eastern/southeastern Texas later this evening or overnight. ..Kerr.. 12/15/2023 .PREV DISCUSSION... /ISSUED 1020 AM CST Fri Dec 15 2023/ ...Discussion... A central U.S. upper trough -- flanked by ridging over both eastern and western portions of the country -- will shift slowly eastward today and tonight. In response, very weak surface cyclogenesis will occur, with a low expected to reside over the southern Iowa/northwestern Missouri area early Saturday morning. Ahead of this low, and the associated/trailing weak surface trough/front, very little in the way of moisture return is expected, given the northeasterly/northerly cyclonic flow over the northern and western Gulf of Mexico. As such, an overall lack of buoyancy with this system suggests only occasional/sporadic lightning through tonight -- primarily across the eastern Texas/western Louisiana/Arklatex area. A few flashes may also occur across southern Florida and the Keys later in the period, within easterly low-level flow east of the weak southern Gulf surface low. Elsewhere, thunderstorms are not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0145 PM CST Fri Dec 15 2023 Valid 152000Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. through tonight. ...20Z Update... Lightning has diminished with convection embedded within a band of precipitation, ahead of mid-level troughing slowly progressing across the Great Plains. Stronger mid/upper support and colder air aloft, associated with a remnant embedded low, appear to be shifting northeast of the better low-level moisture return off the northwestern Gulf, and potential for renewed thunderstorm activity may be low in the near term. However, as the trailing flank of the mid-level troughing begins to dig across central Texas, toward the coastal plain, guidance suggests that probabilities for scattered weak thunderstorm activity may increase across parts of eastern/southeastern Texas later this evening or overnight. ..Kerr.. 12/15/2023 .PREV DISCUSSION... /ISSUED 1020 AM CST Fri Dec 15 2023/ ...Discussion... A central U.S. upper trough -- flanked by ridging over both eastern and western portions of the country -- will shift slowly eastward today and tonight. In response, very weak surface cyclogenesis will occur, with a low expected to reside over the southern Iowa/northwestern Missouri area early Saturday morning. Ahead of this low, and the associated/trailing weak surface trough/front, very little in the way of moisture return is expected, given the northeasterly/northerly cyclonic flow over the northern and western Gulf of Mexico. As such, an overall lack of buoyancy with this system suggests only occasional/sporadic lightning through tonight -- primarily across the eastern Texas/western Louisiana/Arklatex area. A few flashes may also occur across southern Florida and the Keys later in the period, within easterly low-level flow east of the weak southern Gulf surface low. Elsewhere, thunderstorms are not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0145 PM CST Fri Dec 15 2023 Valid 152000Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. through tonight. ...20Z Update... Lightning has diminished with convection embedded within a band of precipitation, ahead of mid-level troughing slowly progressing across the Great Plains. Stronger mid/upper support and colder air aloft, associated with a remnant embedded low, appear to be shifting northeast of the better low-level moisture return off the northwestern Gulf, and potential for renewed thunderstorm activity may be low in the near term. However, as the trailing flank of the mid-level troughing begins to dig across central Texas, toward the coastal plain, guidance suggests that probabilities for scattered weak thunderstorm activity may increase across parts of eastern/southeastern Texas later this evening or overnight. ..Kerr.. 12/15/2023 .PREV DISCUSSION... /ISSUED 1020 AM CST Fri Dec 15 2023/ ...Discussion... A central U.S. upper trough -- flanked by ridging over both eastern and western portions of the country -- will shift slowly eastward today and tonight. In response, very weak surface cyclogenesis will occur, with a low expected to reside over the southern Iowa/northwestern Missouri area early Saturday morning. Ahead of this low, and the associated/trailing weak surface trough/front, very little in the way of moisture return is expected, given the northeasterly/northerly cyclonic flow over the northern and western Gulf of Mexico. As such, an overall lack of buoyancy with this system suggests only occasional/sporadic lightning through tonight -- primarily across the eastern Texas/western Louisiana/Arklatex area. A few flashes may also occur across southern Florida and the Keys later in the period, within easterly low-level flow east of the weak southern Gulf surface low. Elsewhere, thunderstorms are not expected. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0145 PM CST Fri Dec 15 2023 Valid 152000Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. through tonight. ...20Z Update... Lightning has diminished with convection embedded within a band of precipitation, ahead of mid-level troughing slowly progressing across the Great Plains. Stronger mid/upper support and colder air aloft, associated with a remnant embedded low, appear to be shifting northeast of the better low-level moisture return off the northwestern Gulf, and potential for renewed thunderstorm activity may be low in the near term. However, as the trailing flank of the mid-level troughing begins to dig across central Texas, toward the coastal plain, guidance suggests that probabilities for scattered weak thunderstorm activity may increase across parts of eastern/southeastern Texas later this evening or overnight. ..Kerr.. 12/15/2023 .PREV DISCUSSION... /ISSUED 1020 AM CST Fri Dec 15 2023/ ...Discussion... A central U.S. upper trough -- flanked by ridging over both eastern and western portions of the country -- will shift slowly eastward today and tonight. In response, very weak surface cyclogenesis will occur, with a low expected to reside over the southern Iowa/northwestern Missouri area early Saturday morning. Ahead of this low, and the associated/trailing weak surface trough/front, very little in the way of moisture return is expected, given the northeasterly/northerly cyclonic flow over the northern and western Gulf of Mexico. As such, an overall lack of buoyancy with this system suggests only occasional/sporadic lightning through tonight -- primarily across the eastern Texas/western Louisiana/Arklatex area. A few flashes may also occur across southern Florida and the Keys later in the period, within easterly low-level flow east of the weak southern Gulf surface low. Elsewhere, thunderstorms are not expected. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0142 PM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Southern CA... Locally elevated offshore winds and low humidity are possible early Saturday and into early Sunday across parts of southern CA. High pressure over the interior West will continue to support moderate offshore pressure gradients and dry conditions. A few hours of breezy winds greater than 15-20 mph and RH below 20% are possible. However, weak upper-level support and spotty fuels should keep broader concerns limited. Elsewhere across the country, seasonably cool and moist conditions will negate fire-weather concerns. ..Lyons.. 12/15/2023 .PREV DISCUSSION... /ISSUED 0146 AM CST Fri Dec 15 2023/ ...Synopsis... A mid-level trough will deepen across the eastern CONUS as a surface cyclone deepens across the eastern Gulf of Mexico and traverses the Florida Peninsula. Surface high pressure should overspread most of the rest of the CONUS, promoting relatively cooler surface conditions amid poorly receptive fuels, dampening significant wildfire-spread potential. ...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 0142 PM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Southern CA... Locally elevated offshore winds and low humidity are possible early Saturday and into early Sunday across parts of southern CA. High pressure over the interior West will continue to support moderate offshore pressure gradients and dry conditions. A few hours of breezy winds greater than 15-20 mph and RH below 20% are possible. However, weak upper-level support and spotty fuels should keep broader concerns limited. Elsewhere across the country, seasonably cool and moist conditions will negate fire-weather concerns. ..Lyons.. 12/15/2023 .PREV DISCUSSION... /ISSUED 0146 AM CST Fri Dec 15 2023/ ...Synopsis... A mid-level trough will deepen across the eastern CONUS as a surface cyclone deepens across the eastern Gulf of Mexico and traverses the Florida Peninsula. Surface high pressure should overspread most of the rest of the CONUS, promoting relatively cooler surface conditions amid poorly receptive fuels, dampening significant wildfire-spread potential. ...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 0142 PM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Southern CA... Locally elevated offshore winds and low humidity are possible early Saturday and into early Sunday across parts of southern CA. High pressure over the interior West will continue to support moderate offshore pressure gradients and dry conditions. A few hours of breezy winds greater than 15-20 mph and RH below 20% are possible. However, weak upper-level support and spotty fuels should keep broader concerns limited. Elsewhere across the country, seasonably cool and moist conditions will negate fire-weather concerns. ..Lyons.. 12/15/2023 .PREV DISCUSSION... /ISSUED 0146 AM CST Fri Dec 15 2023/ ...Synopsis... A mid-level trough will deepen across the eastern CONUS as a surface cyclone deepens across the eastern Gulf of Mexico and traverses the Florida Peninsula. Surface high pressure should overspread most of the rest of the CONUS, promoting relatively cooler surface conditions amid poorly receptive fuels, dampening significant wildfire-spread potential. ...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 0142 PM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Southern CA... Locally elevated offshore winds and low humidity are possible early Saturday and into early Sunday across parts of southern CA. High pressure over the interior West will continue to support moderate offshore pressure gradients and dry conditions. A few hours of breezy winds greater than 15-20 mph and RH below 20% are possible. However, weak upper-level support and spotty fuels should keep broader concerns limited. Elsewhere across the country, seasonably cool and moist conditions will negate fire-weather concerns. ..Lyons.. 12/15/2023 .PREV DISCUSSION... /ISSUED 0146 AM CST Fri Dec 15 2023/ ...Synopsis... A mid-level trough will deepen across the eastern CONUS as a surface cyclone deepens across the eastern Gulf of Mexico and traverses the Florida Peninsula. Surface high pressure should overspread most of the rest of the CONUS, promoting relatively cooler surface conditions amid poorly receptive fuels, dampening significant wildfire-spread potential. ...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 0142 PM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...NO CRITICAL AREAS... ...Southern CA... Locally elevated offshore winds and low humidity are possible early Saturday and into early Sunday across parts of southern CA. High pressure over the interior West will continue to support moderate offshore pressure gradients and dry conditions. A few hours of breezy winds greater than 15-20 mph and RH below 20% are possible. However, weak upper-level support and spotty fuels should keep broader concerns limited. Elsewhere across the country, seasonably cool and moist conditions will negate fire-weather concerns. ..Lyons.. 12/15/2023 .PREV DISCUSSION... /ISSUED 0146 AM CST Fri Dec 15 2023/ ...Synopsis... A mid-level trough will deepen across the eastern CONUS as a surface cyclone deepens across the eastern Gulf of Mexico and traverses the Florida Peninsula. Surface high pressure should overspread most of the rest of the CONUS, promoting relatively cooler surface conditions amid poorly receptive fuels, dampening significant wildfire-spread potential. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SATURDAY EVENING THROUGH SATURDAY NIGHT ACROSS MUCH OF THE CENTRAL AND SOUTHERN FLORIDA PENINSULA AND KEYS... ...SUMMARY... Strong thunderstorms may impact the Florida Peninsula and Keys Saturday night, with a few possibly becoming severe and posing a risk for tornadoes and damaging wind gusts. ...Synopsis... Stronger, more zonal westerlies will remain confined to the northern mid-latitudes through this period, while flow remains more amplified in lower latitudes. The latter regime will include a broad and deep, occluded cyclone over the southern mid-latitude eastern Pacific and prominent downstream mid/upper ridging across the Pacific coast and much of the Intermountain West. Farther downstream, developments, particularly in the shorter wavelengths, remain more unclear. The axis of mean larger-scale mid-level troughing is forecast to dig across and east-southeast of the Mississippi Valley Saturday through Saturday night. This may include one embedded short wave perturbation digging across the Texas Gulf coast, before coming in phase with amplifying short wave troughing in a branch of westerlies emanating from the subtropical eastern Pacific, across the northwestern into central Gulf of Mexico. Surface cyclogenesis may already be underway along a remnant frontal zone across the south central Gulf of Mexico at the outset of the period, associated with a preceding subtropical perturbation. Substantive further deepening of this cyclone appears probable, but notable differences in its evolution remain apparent within the various model output, particularly as it approaches and crosses the central through northeastern Florida vicinity during the evening and overnight hours. ...Florida Peninsula... Given the model spread concerning the cyclone evolution, coupled with initially dry and stable boundary-layer conditions across much of the peninsula early Saturday and potential increasing inhibition associated with pronounced mid/upper warming Saturday into Saturday night, the risk for severe weather still appears largely conditional at this point. However, destabilization associated with rapid low-level moistening within the inland spreading warm sector, coincident with strengthening deep-layer shear and enlarging, clockwise-curved low-level hodographs, could become sufficient for organized convection, including supercells, with potential to produce tornadoes and damaging wind gusts. Given this concern, slight risk probabilities will be maintained, and extended southward through the remainder of the peninsula and Florida Keys. However, highest severe probabilities may ultimately become focused near and just inland of coastal areas between Tampa and Fort Myers Saturday evening, and near/offshore east central and southeast coastal areas overnight, where low-level forcing and destabilization will be most favorable. ..Kerr.. 12/15/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SATURDAY EVENING THROUGH SATURDAY NIGHT ACROSS MUCH OF THE CENTRAL AND SOUTHERN FLORIDA PENINSULA AND KEYS... ...SUMMARY... Strong thunderstorms may impact the Florida Peninsula and Keys Saturday night, with a few possibly becoming severe and posing a risk for tornadoes and damaging wind gusts. ...Synopsis... Stronger, more zonal westerlies will remain confined to the northern mid-latitudes through this period, while flow remains more amplified in lower latitudes. The latter regime will include a broad and deep, occluded cyclone over the southern mid-latitude eastern Pacific and prominent downstream mid/upper ridging across the Pacific coast and much of the Intermountain West. Farther downstream, developments, particularly in the shorter wavelengths, remain more unclear. The axis of mean larger-scale mid-level troughing is forecast to dig across and east-southeast of the Mississippi Valley Saturday through Saturday night. This may include one embedded short wave perturbation digging across the Texas Gulf coast, before coming in phase with amplifying short wave troughing in a branch of westerlies emanating from the subtropical eastern Pacific, across the northwestern into central Gulf of Mexico. Surface cyclogenesis may already be underway along a remnant frontal zone across the south central Gulf of Mexico at the outset of the period, associated with a preceding subtropical perturbation. Substantive further deepening of this cyclone appears probable, but notable differences in its evolution remain apparent within the various model output, particularly as it approaches and crosses the central through northeastern Florida vicinity during the evening and overnight hours. ...Florida Peninsula... Given the model spread concerning the cyclone evolution, coupled with initially dry and stable boundary-layer conditions across much of the peninsula early Saturday and potential increasing inhibition associated with pronounced mid/upper warming Saturday into Saturday night, the risk for severe weather still appears largely conditional at this point. However, destabilization associated with rapid low-level moistening within the inland spreading warm sector, coincident with strengthening deep-layer shear and enlarging, clockwise-curved low-level hodographs, could become sufficient for organized convection, including supercells, with potential to produce tornadoes and damaging wind gusts. Given this concern, slight risk probabilities will be maintained, and extended southward through the remainder of the peninsula and Florida Keys. However, highest severe probabilities may ultimately become focused near and just inland of coastal areas between Tampa and Fort Myers Saturday evening, and near/offshore east central and southeast coastal areas overnight, where low-level forcing and destabilization will be most favorable. ..Kerr.. 12/15/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SATURDAY EVENING THROUGH SATURDAY NIGHT ACROSS MUCH OF THE CENTRAL AND SOUTHERN FLORIDA PENINSULA AND KEYS... ...SUMMARY... Strong thunderstorms may impact the Florida Peninsula and Keys Saturday night, with a few possibly becoming severe and posing a risk for tornadoes and damaging wind gusts. ...Synopsis... Stronger, more zonal westerlies will remain confined to the northern mid-latitudes through this period, while flow remains more amplified in lower latitudes. The latter regime will include a broad and deep, occluded cyclone over the southern mid-latitude eastern Pacific and prominent downstream mid/upper ridging across the Pacific coast and much of the Intermountain West. Farther downstream, developments, particularly in the shorter wavelengths, remain more unclear. The axis of mean larger-scale mid-level troughing is forecast to dig across and east-southeast of the Mississippi Valley Saturday through Saturday night. This may include one embedded short wave perturbation digging across the Texas Gulf coast, before coming in phase with amplifying short wave troughing in a branch of westerlies emanating from the subtropical eastern Pacific, across the northwestern into central Gulf of Mexico. Surface cyclogenesis may already be underway along a remnant frontal zone across the south central Gulf of Mexico at the outset of the period, associated with a preceding subtropical perturbation. Substantive further deepening of this cyclone appears probable, but notable differences in its evolution remain apparent within the various model output, particularly as it approaches and crosses the central through northeastern Florida vicinity during the evening and overnight hours. ...Florida Peninsula... Given the model spread concerning the cyclone evolution, coupled with initially dry and stable boundary-layer conditions across much of the peninsula early Saturday and potential increasing inhibition associated with pronounced mid/upper warming Saturday into Saturday night, the risk for severe weather still appears largely conditional at this point. However, destabilization associated with rapid low-level moistening within the inland spreading warm sector, coincident with strengthening deep-layer shear and enlarging, clockwise-curved low-level hodographs, could become sufficient for organized convection, including supercells, with potential to produce tornadoes and damaging wind gusts. Given this concern, slight risk probabilities will be maintained, and extended southward through the remainder of the peninsula and Florida Keys. However, highest severe probabilities may ultimately become focused near and just inland of coastal areas between Tampa and Fort Myers Saturday evening, and near/offshore east central and southeast coastal areas overnight, where low-level forcing and destabilization will be most favorable. ..Kerr.. 12/15/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SATURDAY EVENING THROUGH SATURDAY NIGHT ACROSS MUCH OF THE CENTRAL AND SOUTHERN FLORIDA PENINSULA AND KEYS... ...SUMMARY... Strong thunderstorms may impact the Florida Peninsula and Keys Saturday night, with a few possibly becoming severe and posing a risk for tornadoes and damaging wind gusts. ...Synopsis... Stronger, more zonal westerlies will remain confined to the northern mid-latitudes through this period, while flow remains more amplified in lower latitudes. The latter regime will include a broad and deep, occluded cyclone over the southern mid-latitude eastern Pacific and prominent downstream mid/upper ridging across the Pacific coast and much of the Intermountain West. Farther downstream, developments, particularly in the shorter wavelengths, remain more unclear. The axis of mean larger-scale mid-level troughing is forecast to dig across and east-southeast of the Mississippi Valley Saturday through Saturday night. This may include one embedded short wave perturbation digging across the Texas Gulf coast, before coming in phase with amplifying short wave troughing in a branch of westerlies emanating from the subtropical eastern Pacific, across the northwestern into central Gulf of Mexico. Surface cyclogenesis may already be underway along a remnant frontal zone across the south central Gulf of Mexico at the outset of the period, associated with a preceding subtropical perturbation. Substantive further deepening of this cyclone appears probable, but notable differences in its evolution remain apparent within the various model output, particularly as it approaches and crosses the central through northeastern Florida vicinity during the evening and overnight hours. ...Florida Peninsula... Given the model spread concerning the cyclone evolution, coupled with initially dry and stable boundary-layer conditions across much of the peninsula early Saturday and potential increasing inhibition associated with pronounced mid/upper warming Saturday into Saturday night, the risk for severe weather still appears largely conditional at this point. However, destabilization associated with rapid low-level moistening within the inland spreading warm sector, coincident with strengthening deep-layer shear and enlarging, clockwise-curved low-level hodographs, could become sufficient for organized convection, including supercells, with potential to produce tornadoes and damaging wind gusts. Given this concern, slight risk probabilities will be maintained, and extended southward through the remainder of the peninsula and Florida Keys. However, highest severe probabilities may ultimately become focused near and just inland of coastal areas between Tampa and Fort Myers Saturday evening, and near/offshore east central and southeast coastal areas overnight, where low-level forcing and destabilization will be most favorable. ..Kerr.. 12/15/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SATURDAY EVENING THROUGH SATURDAY NIGHT ACROSS MUCH OF THE CENTRAL AND SOUTHERN FLORIDA PENINSULA AND KEYS... ...SUMMARY... Strong thunderstorms may impact the Florida Peninsula and Keys Saturday night, with a few possibly becoming severe and posing a risk for tornadoes and damaging wind gusts. ...Synopsis... Stronger, more zonal westerlies will remain confined to the northern mid-latitudes through this period, while flow remains more amplified in lower latitudes. The latter regime will include a broad and deep, occluded cyclone over the southern mid-latitude eastern Pacific and prominent downstream mid/upper ridging across the Pacific coast and much of the Intermountain West. Farther downstream, developments, particularly in the shorter wavelengths, remain more unclear. The axis of mean larger-scale mid-level troughing is forecast to dig across and east-southeast of the Mississippi Valley Saturday through Saturday night. This may include one embedded short wave perturbation digging across the Texas Gulf coast, before coming in phase with amplifying short wave troughing in a branch of westerlies emanating from the subtropical eastern Pacific, across the northwestern into central Gulf of Mexico. Surface cyclogenesis may already be underway along a remnant frontal zone across the south central Gulf of Mexico at the outset of the period, associated with a preceding subtropical perturbation. Substantive further deepening of this cyclone appears probable, but notable differences in its evolution remain apparent within the various model output, particularly as it approaches and crosses the central through northeastern Florida vicinity during the evening and overnight hours. ...Florida Peninsula... Given the model spread concerning the cyclone evolution, coupled with initially dry and stable boundary-layer conditions across much of the peninsula early Saturday and potential increasing inhibition associated with pronounced mid/upper warming Saturday into Saturday night, the risk for severe weather still appears largely conditional at this point. However, destabilization associated with rapid low-level moistening within the inland spreading warm sector, coincident with strengthening deep-layer shear and enlarging, clockwise-curved low-level hodographs, could become sufficient for organized convection, including supercells, with potential to produce tornadoes and damaging wind gusts. Given this concern, slight risk probabilities will be maintained, and extended southward through the remainder of the peninsula and Florida Keys. However, highest severe probabilities may ultimately become focused near and just inland of coastal areas between Tampa and Fort Myers Saturday evening, and near/offshore east central and southeast coastal areas overnight, where low-level forcing and destabilization will be most favorable. ..Kerr.. 12/15/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CST Fri Dec 15 2023 Valid 161200Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE SATURDAY EVENING THROUGH SATURDAY NIGHT ACROSS MUCH OF THE CENTRAL AND SOUTHERN FLORIDA PENINSULA AND KEYS... ...SUMMARY... Strong thunderstorms may impact the Florida Peninsula and Keys Saturday night, with a few possibly becoming severe and posing a risk for tornadoes and damaging wind gusts. ...Synopsis... Stronger, more zonal westerlies will remain confined to the northern mid-latitudes through this period, while flow remains more amplified in lower latitudes. The latter regime will include a broad and deep, occluded cyclone over the southern mid-latitude eastern Pacific and prominent downstream mid/upper ridging across the Pacific coast and much of the Intermountain West. Farther downstream, developments, particularly in the shorter wavelengths, remain more unclear. The axis of mean larger-scale mid-level troughing is forecast to dig across and east-southeast of the Mississippi Valley Saturday through Saturday night. This may include one embedded short wave perturbation digging across the Texas Gulf coast, before coming in phase with amplifying short wave troughing in a branch of westerlies emanating from the subtropical eastern Pacific, across the northwestern into central Gulf of Mexico. Surface cyclogenesis may already be underway along a remnant frontal zone across the south central Gulf of Mexico at the outset of the period, associated with a preceding subtropical perturbation. Substantive further deepening of this cyclone appears probable, but notable differences in its evolution remain apparent within the various model output, particularly as it approaches and crosses the central through northeastern Florida vicinity during the evening and overnight hours. ...Florida Peninsula... Given the model spread concerning the cyclone evolution, coupled with initially dry and stable boundary-layer conditions across much of the peninsula early Saturday and potential increasing inhibition associated with pronounced mid/upper warming Saturday into Saturday night, the risk for severe weather still appears largely conditional at this point. However, destabilization associated with rapid low-level moistening within the inland spreading warm sector, coincident with strengthening deep-layer shear and enlarging, clockwise-curved low-level hodographs, could become sufficient for organized convection, including supercells, with potential to produce tornadoes and damaging wind gusts. Given this concern, slight risk probabilities will be maintained, and extended southward through the remainder of the peninsula and Florida Keys. However, highest severe probabilities may ultimately become focused near and just inland of coastal areas between Tampa and Fort Myers Saturday evening, and near/offshore east central and southeast coastal areas overnight, where low-level forcing and destabilization will be most favorable. ..Kerr.. 12/15/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1020 AM CST Fri Dec 15 2023 Valid 151630Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the United States through tonight. ...Discussion... A central U.S. upper trough -- flanked by ridging over both eastern and western portions of the country -- will shift slowly eastward today and tonight. In response, very weak surface cyclogenesis will occur, with a low expected to reside over the southern Iowa/northwestern Missouri area early Saturday morning. Ahead of this low, and the associated/trailing weak surface trough/front, very little in the way of moisture return is expected, given the northeasterly/northerly cyclonic flow over the northern and western Gulf of Mexico. As such, an overall lack of buoyancy with this system suggests only occasional/sporadic lightning through tonight -- primarily across the eastern Texas/western Louisiana/Arklatex area. A few flashes may also occur across southern Florida and the Keys later in the period, within easterly low-level flow east of the weak southern Gulf surface low. Elsewhere, thunderstorms are not expected. ..Goss/Thornton.. 12/15/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1020 AM CST Fri Dec 15 2023 Valid 151630Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the United States through tonight. ...Discussion... A central U.S. upper trough -- flanked by ridging over both eastern and western portions of the country -- will shift slowly eastward today and tonight. In response, very weak surface cyclogenesis will occur, with a low expected to reside over the southern Iowa/northwestern Missouri area early Saturday morning. Ahead of this low, and the associated/trailing weak surface trough/front, very little in the way of moisture return is expected, given the northeasterly/northerly cyclonic flow over the northern and western Gulf of Mexico. As such, an overall lack of buoyancy with this system suggests only occasional/sporadic lightning through tonight -- primarily across the eastern Texas/western Louisiana/Arklatex area. A few flashes may also occur across southern Florida and the Keys later in the period, within easterly low-level flow east of the weak southern Gulf surface low. Elsewhere, thunderstorms are not expected. ..Goss/Thornton.. 12/15/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1020 AM CST Fri Dec 15 2023 Valid 151630Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the United States through tonight. ...Discussion... A central U.S. upper trough -- flanked by ridging over both eastern and western portions of the country -- will shift slowly eastward today and tonight. In response, very weak surface cyclogenesis will occur, with a low expected to reside over the southern Iowa/northwestern Missouri area early Saturday morning. Ahead of this low, and the associated/trailing weak surface trough/front, very little in the way of moisture return is expected, given the northeasterly/northerly cyclonic flow over the northern and western Gulf of Mexico. As such, an overall lack of buoyancy with this system suggests only occasional/sporadic lightning through tonight -- primarily across the eastern Texas/western Louisiana/Arklatex area. A few flashes may also occur across southern Florida and the Keys later in the period, within easterly low-level flow east of the weak southern Gulf surface low. Elsewhere, thunderstorms are not expected. ..Goss/Thornton.. 12/15/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1020 AM CST Fri Dec 15 2023 Valid 151630Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the United States through tonight. ...Discussion... A central U.S. upper trough -- flanked by ridging over both eastern and western portions of the country -- will shift slowly eastward today and tonight. In response, very weak surface cyclogenesis will occur, with a low expected to reside over the southern Iowa/northwestern Missouri area early Saturday morning. Ahead of this low, and the associated/trailing weak surface trough/front, very little in the way of moisture return is expected, given the northeasterly/northerly cyclonic flow over the northern and western Gulf of Mexico. As such, an overall lack of buoyancy with this system suggests only occasional/sporadic lightning through tonight -- primarily across the eastern Texas/western Louisiana/Arklatex area. A few flashes may also occur across southern Florida and the Keys later in the period, within easterly low-level flow east of the weak southern Gulf surface low. Elsewhere, thunderstorms are not expected. ..Goss/Thornton.. 12/15/2023 Read more