Severe Storms

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1153 PM CST Sun Dec 29 2024 Valid 301200Z - 311200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected to develop in the U.S. today or tonight. ...DISCUSSION... A large-scale mid-level trough will move northeastward across the Northeast today, as another mid-level trough moves through the central U.S. At the surface, a relatively dry airmass will be in place across much of the nation. For this reason, thunderstorms are not expected to develop across the continental U.S. today or tonight. ..Broyles/Thornton.. 12/30/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1153 PM CST Sun Dec 29 2024 Valid 301200Z - 311200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected to develop in the U.S. today or tonight. ...DISCUSSION... A large-scale mid-level trough will move northeastward across the Northeast today, as another mid-level trough moves through the central U.S. At the surface, a relatively dry airmass will be in place across much of the nation. For this reason, thunderstorms are not expected to develop across the continental U.S. today or tonight. ..Broyles/Thornton.. 12/30/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1153 PM CST Sun Dec 29 2024 Valid 301200Z - 311200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected to develop in the U.S. today or tonight. ...DISCUSSION... A large-scale mid-level trough will move northeastward across the Northeast today, as another mid-level trough moves through the central U.S. At the surface, a relatively dry airmass will be in place across much of the nation. For this reason, thunderstorms are not expected to develop across the continental U.S. today or tonight. ..Broyles/Thornton.. 12/30/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1153 PM CST Sun Dec 29 2024 Valid 301200Z - 311200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are not expected to develop in the U.S. today or tonight. ...DISCUSSION... A large-scale mid-level trough will move northeastward across the Northeast today, as another mid-level trough moves through the central U.S. At the surface, a relatively dry airmass will be in place across much of the nation. For this reason, thunderstorms are not expected to develop across the continental U.S. today or tonight. ..Broyles/Thornton.. 12/30/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 PM CST Sun Dec 29 2024 Valid 300100Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible this evening in parts of the Atlantic Coastal states, in the Ohio and Tennessee Valleys, Intermountain West and Pacific Northwest. No severe weather is expected. ...DISCUSSION... A large-scale mid-level trough will move quickly northeastward across the Ohio Valley, central Appalachians and Carolinas this evening. An associated surface low will move through southwest Ontario, as a cold front advances toward the southern and middle Atlantic Coast. Thunderstorm development will be possible near or ahead of the front this evening. Additional storms will be possible near a pocket of cold air aloft in the Ohio and Tennessee Valleys. Isolated storms may also occur ahead of a low-amplitude shortwave trough in the Intermountain West and near a trough in the Pacific Northwest. No severe threat is expected across the continental U.S. this evening and tonight. ..Broyles.. 12/30/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 PM CST Sun Dec 29 2024 Valid 300100Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible this evening in parts of the Atlantic Coastal states, in the Ohio and Tennessee Valleys, Intermountain West and Pacific Northwest. No severe weather is expected. ...DISCUSSION... A large-scale mid-level trough will move quickly northeastward across the Ohio Valley, central Appalachians and Carolinas this evening. An associated surface low will move through southwest Ontario, as a cold front advances toward the southern and middle Atlantic Coast. Thunderstorm development will be possible near or ahead of the front this evening. Additional storms will be possible near a pocket of cold air aloft in the Ohio and Tennessee Valleys. Isolated storms may also occur ahead of a low-amplitude shortwave trough in the Intermountain West and near a trough in the Pacific Northwest. No severe threat is expected across the continental U.S. this evening and tonight. ..Broyles.. 12/30/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0655 PM CST Sun Dec 29 2024 Valid 300100Z - 301200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible this evening in parts of the Atlantic Coastal states, in the Ohio and Tennessee Valleys, Intermountain West and Pacific Northwest. No severe weather is expected. ...DISCUSSION... A large-scale mid-level trough will move quickly northeastward across the Ohio Valley, central Appalachians and Carolinas this evening. An associated surface low will move through southwest Ontario, as a cold front advances toward the southern and middle Atlantic Coast. Thunderstorm development will be possible near or ahead of the front this evening. Additional storms will be possible near a pocket of cold air aloft in the Ohio and Tennessee Valleys. Isolated storms may also occur ahead of a low-amplitude shortwave trough in the Intermountain West and near a trough in the Pacific Northwest. No severe threat is expected across the continental U.S. this evening and tonight. ..Broyles.. 12/30/2024 Read more

No watches are valid as of Sun Dec 29 23:14:02 UTC 2024.

No Mesoscale Discussions are in effect as of Sun Dec 29 23:14:02 UTC 2024.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0336 PM CST Sun Dec 29 2024 Valid 311200Z - 061200Z An upper-level ridge will build over the West from Day 4/Wednesday into Day 6/Friday before an upper-level trough moves into the West late Day 6/Friday and over the weekend. An offshore pressure gradient will continue into Day 5/Thursday across coastal southern California, while an upper-level trough deepens over the eastern US mid to late this week. ...Day 3/Tuesday - Day 5/Thursday: Southern California... A weak to moderate Santa Ana wind event will peak Day 3/Tuesday into Day 4/Wednesday across portions of southern California. North-northeast offshore winds amid lowering RH will create elevated to locally critical fire weather conditions in portions of the Transverse Ranges, with ocean facing/southern slopes of Ventura County and western Los Angeles County favored. Above normal temperatures and critically low RH are expected with weaker offshore flow across the rest of the Transverse and Peninsular Ranges, but winds should remain below critical thresholds with locally elevated conditions possible. As more of the event comes into the range of the broader suite of high-resolution guidance, modifications to the forecast are likely. ...Day 7/Saturday - Day 8: Southwest onto southern High Plains... An upper-level trough is forecast to move into the West Day 6/Friday - Day 7/Saturday, with strong flow aloft overspreading portions of the Southwest and southern High Plains this weekend. If this pattern develops, downslope flow and lee troughing will likely create an environment conducive for elevated/critical fire weather conditions. However, there is too much uncertainty to introduce probabilities at this time. ..Nauslar.. 12/29/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0336 PM CST Sun Dec 29 2024 Valid 311200Z - 061200Z An upper-level ridge will build over the West from Day 4/Wednesday into Day 6/Friday before an upper-level trough moves into the West late Day 6/Friday and over the weekend. An offshore pressure gradient will continue into Day 5/Thursday across coastal southern California, while an upper-level trough deepens over the eastern US mid to late this week. ...Day 3/Tuesday - Day 5/Thursday: Southern California... A weak to moderate Santa Ana wind event will peak Day 3/Tuesday into Day 4/Wednesday across portions of southern California. North-northeast offshore winds amid lowering RH will create elevated to locally critical fire weather conditions in portions of the Transverse Ranges, with ocean facing/southern slopes of Ventura County and western Los Angeles County favored. Above normal temperatures and critically low RH are expected with weaker offshore flow across the rest of the Transverse and Peninsular Ranges, but winds should remain below critical thresholds with locally elevated conditions possible. As more of the event comes into the range of the broader suite of high-resolution guidance, modifications to the forecast are likely. ...Day 7/Saturday - Day 8: Southwest onto southern High Plains... An upper-level trough is forecast to move into the West Day 6/Friday - Day 7/Saturday, with strong flow aloft overspreading portions of the Southwest and southern High Plains this weekend. If this pattern develops, downslope flow and lee troughing will likely create an environment conducive for elevated/critical fire weather conditions. However, there is too much uncertainty to introduce probabilities at this time. ..Nauslar.. 12/29/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0336 PM CST Sun Dec 29 2024 Valid 311200Z - 061200Z An upper-level ridge will build over the West from Day 4/Wednesday into Day 6/Friday before an upper-level trough moves into the West late Day 6/Friday and over the weekend. An offshore pressure gradient will continue into Day 5/Thursday across coastal southern California, while an upper-level trough deepens over the eastern US mid to late this week. ...Day 3/Tuesday - Day 5/Thursday: Southern California... A weak to moderate Santa Ana wind event will peak Day 3/Tuesday into Day 4/Wednesday across portions of southern California. North-northeast offshore winds amid lowering RH will create elevated to locally critical fire weather conditions in portions of the Transverse Ranges, with ocean facing/southern slopes of Ventura County and western Los Angeles County favored. Above normal temperatures and critically low RH are expected with weaker offshore flow across the rest of the Transverse and Peninsular Ranges, but winds should remain below critical thresholds with locally elevated conditions possible. As more of the event comes into the range of the broader suite of high-resolution guidance, modifications to the forecast are likely. ...Day 7/Saturday - Day 8: Southwest onto southern High Plains... An upper-level trough is forecast to move into the West Day 6/Friday - Day 7/Saturday, with strong flow aloft overspreading portions of the Southwest and southern High Plains this weekend. If this pattern develops, downslope flow and lee troughing will likely create an environment conducive for elevated/critical fire weather conditions. However, there is too much uncertainty to introduce probabilities at this time. ..Nauslar.. 12/29/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0336 PM CST Sun Dec 29 2024 Valid 311200Z - 061200Z An upper-level ridge will build over the West from Day 4/Wednesday into Day 6/Friday before an upper-level trough moves into the West late Day 6/Friday and over the weekend. An offshore pressure gradient will continue into Day 5/Thursday across coastal southern California, while an upper-level trough deepens over the eastern US mid to late this week. ...Day 3/Tuesday - Day 5/Thursday: Southern California... A weak to moderate Santa Ana wind event will peak Day 3/Tuesday into Day 4/Wednesday across portions of southern California. North-northeast offshore winds amid lowering RH will create elevated to locally critical fire weather conditions in portions of the Transverse Ranges, with ocean facing/southern slopes of Ventura County and western Los Angeles County favored. Above normal temperatures and critically low RH are expected with weaker offshore flow across the rest of the Transverse and Peninsular Ranges, but winds should remain below critical thresholds with locally elevated conditions possible. As more of the event comes into the range of the broader suite of high-resolution guidance, modifications to the forecast are likely. ...Day 7/Saturday - Day 8: Southwest onto southern High Plains... An upper-level trough is forecast to move into the West Day 6/Friday - Day 7/Saturday, with strong flow aloft overspreading portions of the Southwest and southern High Plains this weekend. If this pattern develops, downslope flow and lee troughing will likely create an environment conducive for elevated/critical fire weather conditions. However, there is too much uncertainty to introduce probabilities at this time. ..Nauslar.. 12/29/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0336 PM CST Sun Dec 29 2024 Valid 311200Z - 061200Z An upper-level ridge will build over the West from Day 4/Wednesday into Day 6/Friday before an upper-level trough moves into the West late Day 6/Friday and over the weekend. An offshore pressure gradient will continue into Day 5/Thursday across coastal southern California, while an upper-level trough deepens over the eastern US mid to late this week. ...Day 3/Tuesday - Day 5/Thursday: Southern California... A weak to moderate Santa Ana wind event will peak Day 3/Tuesday into Day 4/Wednesday across portions of southern California. North-northeast offshore winds amid lowering RH will create elevated to locally critical fire weather conditions in portions of the Transverse Ranges, with ocean facing/southern slopes of Ventura County and western Los Angeles County favored. Above normal temperatures and critically low RH are expected with weaker offshore flow across the rest of the Transverse and Peninsular Ranges, but winds should remain below critical thresholds with locally elevated conditions possible. As more of the event comes into the range of the broader suite of high-resolution guidance, modifications to the forecast are likely. ...Day 7/Saturday - Day 8: Southwest onto southern High Plains... An upper-level trough is forecast to move into the West Day 6/Friday - Day 7/Saturday, with strong flow aloft overspreading portions of the Southwest and southern High Plains this weekend. If this pattern develops, downslope flow and lee troughing will likely create an environment conducive for elevated/critical fire weather conditions. However, there is too much uncertainty to introduce probabilities at this time. ..Nauslar.. 12/29/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0336 PM CST Sun Dec 29 2024 Valid 311200Z - 061200Z An upper-level ridge will build over the West from Day 4/Wednesday into Day 6/Friday before an upper-level trough moves into the West late Day 6/Friday and over the weekend. An offshore pressure gradient will continue into Day 5/Thursday across coastal southern California, while an upper-level trough deepens over the eastern US mid to late this week. ...Day 3/Tuesday - Day 5/Thursday: Southern California... A weak to moderate Santa Ana wind event will peak Day 3/Tuesday into Day 4/Wednesday across portions of southern California. North-northeast offshore winds amid lowering RH will create elevated to locally critical fire weather conditions in portions of the Transverse Ranges, with ocean facing/southern slopes of Ventura County and western Los Angeles County favored. Above normal temperatures and critically low RH are expected with weaker offshore flow across the rest of the Transverse and Peninsular Ranges, but winds should remain below critical thresholds with locally elevated conditions possible. As more of the event comes into the range of the broader suite of high-resolution guidance, modifications to the forecast are likely. ...Day 7/Saturday - Day 8: Southwest onto southern High Plains... An upper-level trough is forecast to move into the West Day 6/Friday - Day 7/Saturday, with strong flow aloft overspreading portions of the Southwest and southern High Plains this weekend. If this pattern develops, downslope flow and lee troughing will likely create an environment conducive for elevated/critical fire weather conditions. However, there is too much uncertainty to introduce probabilities at this time. ..Nauslar.. 12/29/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2321 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF FAR EASTERN IN AND CENTRAL OH
Mesoscale Discussion 2321 NWS Storm Prediction Center Norman OK 1241 PM CST Sun Dec 29 2024 Areas affected...portions of far eastern IN and central OH Concerning...Severe potential...Watch unlikely Valid 291841Z - 292045Z Probability of Watch Issuance...20 percent SUMMARY...Low-topped thunderstorms may pose a risk for occasional damaging gusts and perhaps a brief tornado this afternoon. Weak buoyancy suggests the threat is limited and a WW is unlikely. DISCUSSION...As of 1830 UTC, afternoon analysis showed an impressive negative tilt, 500 mb trough centered over IN and western OH. Near the center of the upper trough, cold 500 mb temperatures (-20C to -23C) were advecting over the northern fringes of returning surface moisture across the upper OH Valley. East of a deepening sub 1000 mb surface cyclone, differential temperature advection and strong DPVA were aiding in steepening low and mid-level lapse rates to 6-7 C/km. In combination with marginal surface moisture (50s F dewpoints) weak buoyancy (100-400 J/kg MUCAPE) has developed, and is supporting a band of low-topped convective showers/weak thunderstorms across southeastern IN into southern OH/KY. Despite meager buoyancy, very strong mid and low-level wind fields are present, and should continue to intensify as the surface low and upper trough deepen. Deep-layer shear in excess of 70 kt (ILN VAD) will allow for some organization of the low-topped storms into a broken band or QLCS structure. Downward mixing of the stronger mid-level flow within the convective line could support sporadic damaging gusts across parts of central OH this afternoon. Additionally, the distribution of the weak buoyancy concentrated near the surface, along with strong shear and ample vertical voritcity suggest a brief tornado is possible within the stronger convective elements. The primary limiting factor remains the marginal buoyancy and limited moisture. Dense cloud cover is in place over much of north-central and eastern OH/PA which will further limit seasonally muted diurnal heating. Thus, while sporadic gusts and perhaps a brief tornado cannot be ruled out a WW appears unlikely. ..Lyons/Hart.. 12/29/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PBZ...RLX...CLE...ILN...IWX...IND... LAT...LON 40808131 39848122 39038247 39138404 39598503 40228505 40668437 41188295 41438199 41368173 40808131 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0202 PM CST Sun Dec 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE UPPER OHIO VALLEY AND IN PARTS OF THE CAROLINAS/VIRGINIA... ...SUMMARY... Isolated wind damage remains possible in parts of Carolinas into southern Virginia into the early evening. A brief tornado and isolated wind damage is also possible in the upper Ohio Valley vicinity. ...20Z... With continued downward trend in intensity of convection in the Carolinas. Severe probabilities have been reduced. Recent model trends have shown less potential for additional development in central North Carolina/Virginia; however, given the large-scale ascent, have opted to maintain low severe wind probabilities. More recent model trends would suggest develop, if it occurs, may in eastern North Carolina/Virginia. A shortwave trough now in Missouri may spur convective development late this afternoon in parts of western/central Kentucky into northern Middle Tennessee. Very cold temperature aloft and lingering upper 40s F dewpoints may allow for a stronger storm or two. Small hail and strong wind gusts are possible. The threat appears too conditional for severe probabilities, however. The forecast in the upper Ohio Valley remains unchanged. Isolated wind damage and a brief tornado remain possible with convection along the leading edge of the upper-level trough. ..Wendt.. 12/29/2024 .PREV DISCUSSION... /ISSUED 1020 AM CST Sun Dec 29 2024/ ...Carolinas... A large and negatively-tilted shortwave trough is rotating northeastward across the TN/OH Valleys today, with intense low and mid-level wind fields overspreading much of the eastern US. A pre-frontal squall line has advanced eastward into central NC and eastern SC, well ahead of the primary surface cold front and considerably faster than model guidance had predicted. This line is moving through weak instability, with very limited lightning being observed. Nevertheless, low-level winds and convergence along the line are quite strong, leading to gusty and occasional damaging winds. This trend will continue through the afternoon across the eastern Carolinas. ...NC/VA This Evening... Behind this line, widespread clouds and dewpoints in the 50s will result in continued weak thermodynamic profiles for deep convection. However, given the large-scale ascent and strong winds aloft, there remains some chance of re-development of showers and occasional thunderstorms from central NC into VA this evening. If this scenario unfolds, isolated damaging wind gusts could occur. ...OH/PA... A deep surface low currently over southern IN will track into northwest OH today, with a occluded front extending eastward from the low across OH. Widespread cloud cover will limit CAPE to 100-200 J/kg this afternoon ahead of the front. However, very strong winds aloft and large scale forcing for ascent is expected to result in scattered showers and thunderstorms. This fast-moving convection may result in locally damaging wind gusts or a brief tornado as it affects much of OH and western PA through early evening. ...FL Keys... An east-west band of thunderstorms is sagging southward across the FL Keys today. Several areas of rotation have been noted all morning along the line, which may pose a risk of gusty winds or waterspout/brief tornado activity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0202 PM CST Sun Dec 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE UPPER OHIO VALLEY AND IN PARTS OF THE CAROLINAS/VIRGINIA... ...SUMMARY... Isolated wind damage remains possible in parts of Carolinas into southern Virginia into the early evening. A brief tornado and isolated wind damage is also possible in the upper Ohio Valley vicinity. ...20Z... With continued downward trend in intensity of convection in the Carolinas. Severe probabilities have been reduced. Recent model trends have shown less potential for additional development in central North Carolina/Virginia; however, given the large-scale ascent, have opted to maintain low severe wind probabilities. More recent model trends would suggest develop, if it occurs, may in eastern North Carolina/Virginia. A shortwave trough now in Missouri may spur convective development late this afternoon in parts of western/central Kentucky into northern Middle Tennessee. Very cold temperature aloft and lingering upper 40s F dewpoints may allow for a stronger storm or two. Small hail and strong wind gusts are possible. The threat appears too conditional for severe probabilities, however. The forecast in the upper Ohio Valley remains unchanged. Isolated wind damage and a brief tornado remain possible with convection along the leading edge of the upper-level trough. ..Wendt.. 12/29/2024 .PREV DISCUSSION... /ISSUED 1020 AM CST Sun Dec 29 2024/ ...Carolinas... A large and negatively-tilted shortwave trough is rotating northeastward across the TN/OH Valleys today, with intense low and mid-level wind fields overspreading much of the eastern US. A pre-frontal squall line has advanced eastward into central NC and eastern SC, well ahead of the primary surface cold front and considerably faster than model guidance had predicted. This line is moving through weak instability, with very limited lightning being observed. Nevertheless, low-level winds and convergence along the line are quite strong, leading to gusty and occasional damaging winds. This trend will continue through the afternoon across the eastern Carolinas. ...NC/VA This Evening... Behind this line, widespread clouds and dewpoints in the 50s will result in continued weak thermodynamic profiles for deep convection. However, given the large-scale ascent and strong winds aloft, there remains some chance of re-development of showers and occasional thunderstorms from central NC into VA this evening. If this scenario unfolds, isolated damaging wind gusts could occur. ...OH/PA... A deep surface low currently over southern IN will track into northwest OH today, with a occluded front extending eastward from the low across OH. Widespread cloud cover will limit CAPE to 100-200 J/kg this afternoon ahead of the front. However, very strong winds aloft and large scale forcing for ascent is expected to result in scattered showers and thunderstorms. This fast-moving convection may result in locally damaging wind gusts or a brief tornado as it affects much of OH and western PA through early evening. ...FL Keys... An east-west band of thunderstorms is sagging southward across the FL Keys today. Several areas of rotation have been noted all morning along the line, which may pose a risk of gusty winds or waterspout/brief tornado activity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0202 PM CST Sun Dec 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE UPPER OHIO VALLEY AND IN PARTS OF THE CAROLINAS/VIRGINIA... ...SUMMARY... Isolated wind damage remains possible in parts of Carolinas into southern Virginia into the early evening. A brief tornado and isolated wind damage is also possible in the upper Ohio Valley vicinity. ...20Z... With continued downward trend in intensity of convection in the Carolinas. Severe probabilities have been reduced. Recent model trends have shown less potential for additional development in central North Carolina/Virginia; however, given the large-scale ascent, have opted to maintain low severe wind probabilities. More recent model trends would suggest develop, if it occurs, may in eastern North Carolina/Virginia. A shortwave trough now in Missouri may spur convective development late this afternoon in parts of western/central Kentucky into northern Middle Tennessee. Very cold temperature aloft and lingering upper 40s F dewpoints may allow for a stronger storm or two. Small hail and strong wind gusts are possible. The threat appears too conditional for severe probabilities, however. The forecast in the upper Ohio Valley remains unchanged. Isolated wind damage and a brief tornado remain possible with convection along the leading edge of the upper-level trough. ..Wendt.. 12/29/2024 .PREV DISCUSSION... /ISSUED 1020 AM CST Sun Dec 29 2024/ ...Carolinas... A large and negatively-tilted shortwave trough is rotating northeastward across the TN/OH Valleys today, with intense low and mid-level wind fields overspreading much of the eastern US. A pre-frontal squall line has advanced eastward into central NC and eastern SC, well ahead of the primary surface cold front and considerably faster than model guidance had predicted. This line is moving through weak instability, with very limited lightning being observed. Nevertheless, low-level winds and convergence along the line are quite strong, leading to gusty and occasional damaging winds. This trend will continue through the afternoon across the eastern Carolinas. ...NC/VA This Evening... Behind this line, widespread clouds and dewpoints in the 50s will result in continued weak thermodynamic profiles for deep convection. However, given the large-scale ascent and strong winds aloft, there remains some chance of re-development of showers and occasional thunderstorms from central NC into VA this evening. If this scenario unfolds, isolated damaging wind gusts could occur. ...OH/PA... A deep surface low currently over southern IN will track into northwest OH today, with a occluded front extending eastward from the low across OH. Widespread cloud cover will limit CAPE to 100-200 J/kg this afternoon ahead of the front. However, very strong winds aloft and large scale forcing for ascent is expected to result in scattered showers and thunderstorms. This fast-moving convection may result in locally damaging wind gusts or a brief tornado as it affects much of OH and western PA through early evening. ...FL Keys... An east-west band of thunderstorms is sagging southward across the FL Keys today. Several areas of rotation have been noted all morning along the line, which may pose a risk of gusty winds or waterspout/brief tornado activity. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0202 PM CST Sun Dec 29 2024 Valid 292000Z - 301200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE UPPER OHIO VALLEY AND IN PARTS OF THE CAROLINAS/VIRGINIA... ...SUMMARY... Isolated wind damage remains possible in parts of Carolinas into southern Virginia into the early evening. A brief tornado and isolated wind damage is also possible in the upper Ohio Valley vicinity. ...20Z... With continued downward trend in intensity of convection in the Carolinas. Severe probabilities have been reduced. Recent model trends have shown less potential for additional development in central North Carolina/Virginia; however, given the large-scale ascent, have opted to maintain low severe wind probabilities. More recent model trends would suggest develop, if it occurs, may in eastern North Carolina/Virginia. A shortwave trough now in Missouri may spur convective development late this afternoon in parts of western/central Kentucky into northern Middle Tennessee. Very cold temperature aloft and lingering upper 40s F dewpoints may allow for a stronger storm or two. Small hail and strong wind gusts are possible. The threat appears too conditional for severe probabilities, however. The forecast in the upper Ohio Valley remains unchanged. Isolated wind damage and a brief tornado remain possible with convection along the leading edge of the upper-level trough. ..Wendt.. 12/29/2024 .PREV DISCUSSION... /ISSUED 1020 AM CST Sun Dec 29 2024/ ...Carolinas... A large and negatively-tilted shortwave trough is rotating northeastward across the TN/OH Valleys today, with intense low and mid-level wind fields overspreading much of the eastern US. A pre-frontal squall line has advanced eastward into central NC and eastern SC, well ahead of the primary surface cold front and considerably faster than model guidance had predicted. This line is moving through weak instability, with very limited lightning being observed. Nevertheless, low-level winds and convergence along the line are quite strong, leading to gusty and occasional damaging winds. This trend will continue through the afternoon across the eastern Carolinas. ...NC/VA This Evening... Behind this line, widespread clouds and dewpoints in the 50s will result in continued weak thermodynamic profiles for deep convection. However, given the large-scale ascent and strong winds aloft, there remains some chance of re-development of showers and occasional thunderstorms from central NC into VA this evening. If this scenario unfolds, isolated damaging wind gusts could occur. ...OH/PA... A deep surface low currently over southern IN will track into northwest OH today, with a occluded front extending eastward from the low across OH. Widespread cloud cover will limit CAPE to 100-200 J/kg this afternoon ahead of the front. However, very strong winds aloft and large scale forcing for ascent is expected to result in scattered showers and thunderstorms. This fast-moving convection may result in locally damaging wind gusts or a brief tornado as it affects much of OH and western PA through early evening. ...FL Keys... An east-west band of thunderstorms is sagging southward across the FL Keys today. Several areas of rotation have been noted all morning along the line, which may pose a risk of gusty winds or waterspout/brief tornado activity. Read more