SPC Sep 26, 2024 Day 4-8 Severe Weather Outlook

2 months ago
Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0316 AM CDT Thu Sep 26 2024 Valid 291200Z - 041200Z ...DISCUSSION... The upper low over the OH Valley will weaken and become an open wave early next week. Meanwhile, upper troughing across the east will be reinforced through midweek by a shortwave trough developing east/southeast across the Great Lakes. A surface cold front will develop east/southeast across much of the Plains and Midwest through Day 6/Tue. However stronger deep-layer flow will remain displaced well to the north and behind the front. Meanwhile, low-amplitude upper ridging will prevail across the Southwest/Four Corner, while a series of shortwave troughs migrate through more progressive northern stream flow near the international border in the vicinity of the Pacific Northwest and northern Rockies. Overall severe thunderstorm potential appears low during the Day 4-8 period. Read more

SPC Sep 26, 2024 0730 UTC Day 3 Severe Thunderstorm Outlook

2 months ago
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CDT Thu Sep 26 2024 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Synopsis... The closed mid/upper low will progress east across the OH/TN Valleys on Saturday, weakening with time. Enhanced southwesterly flow will prevail on the eastern periphery of this system, from parts of northern FL to the Mid-Atlantic. A moist boundary layer will also prevail across parts of the Southeast and Mid-Atlantic vicinity. However, dry midlevels and poor lapse rates will limit instability across much of the region, with the exception being parts of the FL Peninsula. Isolated thunderstorms will be possible across the FL Peninsula, but poor lapse rates, weak instability and only modest effective shear will limit severe thunderstorm potential. ..Leitman.. 09/26/2024 Read more

SPC Sep 26, 2024 0730 UTC Day 3 Severe Thunderstorm Outlook

2 months ago
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0152 AM CDT Thu Sep 26 2024 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Saturday. ...Synopsis... The closed mid/upper low will progress east across the OH/TN Valleys on Saturday, weakening with time. Enhanced southwesterly flow will prevail on the eastern periphery of this system, from parts of northern FL to the Mid-Atlantic. A moist boundary layer will also prevail across parts of the Southeast and Mid-Atlantic vicinity. However, dry midlevels and poor lapse rates will limit instability across much of the region, with the exception being parts of the FL Peninsula. Isolated thunderstorms will be possible across the FL Peninsula, but poor lapse rates, weak instability and only modest effective shear will limit severe thunderstorm potential. ..Leitman.. 09/26/2024 Read more

SPC Sep 26, 2024 0600 UTC Day 2 Convective Outlook

2 months ago
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Thu Sep 26 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CAROLINAS... ...SUMMARY... A risk for a few tornadoes and damaging thunderstorm wind gusts exists from the central Appalachians into the Carolinas and southern Virginia on Friday. ...Central Appalachians and Southern Mid-Atlantic... The expansive, enhanced low/midlevel flow field on the eastern periphery of the remnants of Hurricane Helene will impact the central Appalachians east to portions of coastal SC/NC/southern VA through Friday afternoon/evening. Convective bands will likely be ongoing Friday morning across the Pee Dee region of SC, and lift northward through the afternoon. As a dry slot punches quickly north/northeast behind this band of convection, the severe risk will quickly come to an end from south to north by late afternoon or early evening. Supercell wind profiles, with enlarged, looping low-level hodographs are evident in forecast soundings around the region. Strong 0-1 km SRH and surface dewpoints in the mid 70s F (resulting in favorable low-level instability) will support a tornado risk with cells within the northward moving convective bands. Furthermore, given the already strong low-level flow field, strong thunderstorm wind gusts also will be possible. ...TN/OH Valley vicinity... Strong winds will likely occur from the central Appalachians westward across the OH/TN Valley vicinity as Helene tracks north/northwest and becomes absorbed by the mid/upper cyclone over the Mid-South region. However, these gusty winds will be tied to the transitioning tropical system, and less influenced by convective processes, precluding severe probabilities. ..Leitman.. 09/26/2024 Read more

SPC Sep 26, 2024 0600 UTC Day 2 Convective Outlook

2 months ago
SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Thu Sep 26 2024 Valid 271200Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CAROLINAS... ...SUMMARY... A risk for a few tornadoes and damaging thunderstorm wind gusts exists from the central Appalachians into the Carolinas and southern Virginia on Friday. ...Central Appalachians and Southern Mid-Atlantic... The expansive, enhanced low/midlevel flow field on the eastern periphery of the remnants of Hurricane Helene will impact the central Appalachians east to portions of coastal SC/NC/southern VA through Friday afternoon/evening. Convective bands will likely be ongoing Friday morning across the Pee Dee region of SC, and lift northward through the afternoon. As a dry slot punches quickly north/northeast behind this band of convection, the severe risk will quickly come to an end from south to north by late afternoon or early evening. Supercell wind profiles, with enlarged, looping low-level hodographs are evident in forecast soundings around the region. Strong 0-1 km SRH and surface dewpoints in the mid 70s F (resulting in favorable low-level instability) will support a tornado risk with cells within the northward moving convective bands. Furthermore, given the already strong low-level flow field, strong thunderstorm wind gusts also will be possible. ...TN/OH Valley vicinity... Strong winds will likely occur from the central Appalachians westward across the OH/TN Valley vicinity as Helene tracks north/northwest and becomes absorbed by the mid/upper cyclone over the Mid-South region. However, these gusty winds will be tied to the transitioning tropical system, and less influenced by convective processes, precluding severe probabilities. ..Leitman.. 09/26/2024 Read more

SPC Sep 26, 2024 0600 UTC Day 1 Convective Outlook

2 months ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Sep 26 2024 Valid 261200Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR COASTAL AREAS OF NORTHEAST FLORIDA...GEORGIA...AND SOUTH CAROLINA... ...SUMMARY... Several tornadoes will be possible later today into tonight, in association with Hurricane Helene. The greatest threat is expected from parts of Florida into southeast Georgia, the Midlands and Low Country of South Carolina, and southern North Carolina. ...FL/GA into the Carolinas... Hurricane Helene is forecast to move north to north-northeast and accelerate across the eastern Gulf of Mexico today, with landfall expected in the Florida Big Bend region this evening. See NHC forecasts and advisories for more information. Increasing low-level flow/shear associated with Helene's large wind field will overspread the Florida Peninsula this morning, southeast Georgia and parts of SC by this afternoon, and eventually into parts of NC later tonight. Low-level hodographs will become quite large, with 0-1 km SRH increasing into at least the 250-500 m2/s2 range. This will support tornado potential with any low-topped supercells that are able to develop and persist within Helene's rain bands. Due to Helene's large size and fast forward speed, a broad region from Florida and Georgia northward into the Carolinas will see some risk for tornadoes. During the day, Helene's rain bands will overspread the FL Peninsula, with other outer bands potentially moving inland across parts of GA/SC and eventually NC through tonight. The Enhanced Risk has been maintained and expanded somewhat from extreme northeast FL into coastal GA/SC, where multiple low-topped supercells will be possible within an increasingly favorable environment. Some tornado potential will spread into parts of NC later tonight, with the northern extent of the primary tornado threat still somewhat uncertain and dependent on Helene's forward speed and track. ...Hudson Valley vicinity into southern New England... An upper low will move eastward across southern Quebec and adjacent portions of New England today. Strong large-scale ascent will aid in the development of convection during the afternoon from southern New England into the Hudson Valley. Lapse rates will be weak and buoyancy modest at best, but enhanced mid-level flow through the base of the upper low will support moderate to strong deep-layer vertical shear. Consequently, a few stronger storms capable of gusty winds are possible, but confidence in sufficient destabilization is too low for severe probabilities at this time. ..Dean.. 09/26/2024 Read more

SPC Sep 26, 2024 0600 UTC Day 1 Convective Outlook

2 months ago
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Sep 26 2024 Valid 261200Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR COASTAL AREAS OF NORTHEAST FLORIDA...GEORGIA...AND SOUTH CAROLINA... ...SUMMARY... Several tornadoes will be possible later today into tonight, in association with Hurricane Helene. The greatest threat is expected from parts of Florida into southeast Georgia, the Midlands and Low Country of South Carolina, and southern North Carolina. ...FL/GA into the Carolinas... Hurricane Helene is forecast to move north to north-northeast and accelerate across the eastern Gulf of Mexico today, with landfall expected in the Florida Big Bend region this evening. See NHC forecasts and advisories for more information. Increasing low-level flow/shear associated with Helene's large wind field will overspread the Florida Peninsula this morning, southeast Georgia and parts of SC by this afternoon, and eventually into parts of NC later tonight. Low-level hodographs will become quite large, with 0-1 km SRH increasing into at least the 250-500 m2/s2 range. This will support tornado potential with any low-topped supercells that are able to develop and persist within Helene's rain bands. Due to Helene's large size and fast forward speed, a broad region from Florida and Georgia northward into the Carolinas will see some risk for tornadoes. During the day, Helene's rain bands will overspread the FL Peninsula, with other outer bands potentially moving inland across parts of GA/SC and eventually NC through tonight. The Enhanced Risk has been maintained and expanded somewhat from extreme northeast FL into coastal GA/SC, where multiple low-topped supercells will be possible within an increasingly favorable environment. Some tornado potential will spread into parts of NC later tonight, with the northern extent of the primary tornado threat still somewhat uncertain and dependent on Helene's forward speed and track. ...Hudson Valley vicinity into southern New England... An upper low will move eastward across southern Quebec and adjacent portions of New England today. Strong large-scale ascent will aid in the development of convection during the afternoon from southern New England into the Hudson Valley. Lapse rates will be weak and buoyancy modest at best, but enhanced mid-level flow through the base of the upper low will support moderate to strong deep-layer vertical shear. Consequently, a few stronger storms capable of gusty winds are possible, but confidence in sufficient destabilization is too low for severe probabilities at this time. ..Dean.. 09/26/2024 Read more

SPC Day 2 Fire Weather Outlook

2 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Thu Sep 26 2024 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns are expected to remain low on Friday. High pressure will continue to build in across the western US with warming temperatures and some drying of fuels. Overall, high pressure will keep winds light and fire concerns low. Across the eastern US, remnants of Hurricane Helene will bring strong winds but also widespread heavy rainfall. Overall, no overlap of Elevated/Critical conditions with receptive fuels is expected on Friday. ..Thornton.. 09/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook

2 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Thu Sep 26 2024 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... Fire weather concerns are expected to remain low on Friday. High pressure will continue to build in across the western US with warming temperatures and some drying of fuels. Overall, high pressure will keep winds light and fire concerns low. Across the eastern US, remnants of Hurricane Helene will bring strong winds but also widespread heavy rainfall. Overall, no overlap of Elevated/Critical conditions with receptive fuels is expected on Friday. ..Thornton.. 09/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook

2 months ago
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1220 AM CDT Thu Sep 26 2024 Valid 261200Z - 271200Z ...Synopsis... The pattern across the US on Thursday will be characterized by Hurricane Helene moving inland and becoming absorbed into the upper-level flow across the eastern US as a ridge of high pressure continues to be in place across the western US. Across the northern Rockies, a shortwave trough will traverse the northern periphery of the ridge with a dry cold front sagging southward into the northern Plains through the period. Ahead of the front, relative humidity around 15-20 percent will be possible across portions of eastern Wyoming into South Dakota. The frontal passage will bring an increase in surface winds, with sustained winds around 20-25 mph. There is some question as to what the duration of overlap will be between the lower relative humidity and stronger wind speeds. HREF probabilities of Elevated to Critical conditions remain generally around 30-40 percent. Fuels across much of eastern Wyoming into South Dakota are critically dry. Taking into account the possibility of briefly Elevated to locally Critical conditions, an Elevated area was included with this outlook given the uncertainty. ..Thornton.. 09/26/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Sep 26, 2024 0100 UTC Day 1 Convective Outlook

2 months ago
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Wed Sep 25 2024 Valid 260100Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN APPALACHIANS INTO PARTS OF THE SOUTHEAST AND FLORIDA... ...SUMMARY... Isolated strong to severe storms are possible this evening from the southern Appalachians into parts of the Southeast. Some tornado threat may develop later tonight over Florida, in association with Hurricane Helene. ...Florida... Hurricane Helene is forecast to intensify and move north to north-northeastward across the southeast Gulf of Mexico tonight; see NHC forecasts/advisories for more information. Helene's large wind field will continue to overspread the Florida Peninsula and Keys tonight, with low-level shear/SRH becoming increasingly favorable for low-topped supercells with a potential tornado threat. Low-topped supercell potential prior to 12Z Thursday morning remains uncertain, with inland instability expected to remain relatively limited. Outer rain bands could begin to affect the western Peninsula later tonight, while convection may persist near a convergence zone near the east coast. ...Southern Appalachians vicinity into parts of the Southeast... Widespread precipitation is ongoing this evening within a corridor from the FL Panhandle into western NC/VA, but weak to locally moderate buoyancy persists east of this band, with regional VWPs and the 00Z RNK sounding depicting vertically veering wind profiles favorable for organized convection. Generally weak low/midlevel lapse rates will tend to limit storm intensity, but marginal supercell potential may persist through the evening, with a threat of isolated damaging gusts and possibly a tornado. ...Northern ID/northeast WA/northwest MT... While low-level moisture is limited, steep lapse rates and ascent attendant to an approaching mid/upper-level shortwave trough are supporting a high-based storm cluster currently moving across the ID Panhandle. This cluster has a history of 60-65 mph gusts, and will move across northwest MT early this evening, with a continued threat of strong to locally severe gusts. ..Dean.. 09/26/2024 Read more

SPC Sep 26, 2024 0100 UTC Day 1 Convective Outlook

2 months ago
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Wed Sep 25 2024 Valid 260100Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN APPALACHIANS INTO PARTS OF THE SOUTHEAST AND FLORIDA... ...SUMMARY... Isolated strong to severe storms are possible this evening from the southern Appalachians into parts of the Southeast. Some tornado threat may develop later tonight over Florida, in association with Hurricane Helene. ...Florida... Hurricane Helene is forecast to intensify and move north to north-northeastward across the southeast Gulf of Mexico tonight; see NHC forecasts/advisories for more information. Helene's large wind field will continue to overspread the Florida Peninsula and Keys tonight, with low-level shear/SRH becoming increasingly favorable for low-topped supercells with a potential tornado threat. Low-topped supercell potential prior to 12Z Thursday morning remains uncertain, with inland instability expected to remain relatively limited. Outer rain bands could begin to affect the western Peninsula later tonight, while convection may persist near a convergence zone near the east coast. ...Southern Appalachians vicinity into parts of the Southeast... Widespread precipitation is ongoing this evening within a corridor from the FL Panhandle into western NC/VA, but weak to locally moderate buoyancy persists east of this band, with regional VWPs and the 00Z RNK sounding depicting vertically veering wind profiles favorable for organized convection. Generally weak low/midlevel lapse rates will tend to limit storm intensity, but marginal supercell potential may persist through the evening, with a threat of isolated damaging gusts and possibly a tornado. ...Northern ID/northeast WA/northwest MT... While low-level moisture is limited, steep lapse rates and ascent attendant to an approaching mid/upper-level shortwave trough are supporting a high-based storm cluster currently moving across the ID Panhandle. This cluster has a history of 60-65 mph gusts, and will move across northwest MT early this evening, with a continued threat of strong to locally severe gusts. ..Dean.. 09/26/2024 Read more

SPC Day 3-8 Fire Weather Outlook

2 months ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0442 PM CDT Wed Sep 25 2024 Valid 271200Z - 031200Z Hurricane Helene will pull tropical moisture northward and absorb into a cutoff upper low in the Tennessee Valley region on Friday. This cutoff low will remain through at least Saturday before the pattern becomes more progressive. The combination of cool and moist conditions associated with this upper pattern will alleviate most fire weather concerns across the eastern CONUS through the extended period. Ridging will result in warm and dry conditions across much of the western CONUS during the period. While critically dry fuels are mostly sparse across the western CONUS presently, this extended warm/dry period may result in larger regions of critically dry fuels (particularly fine fuels) by the end of the weekend when the next trough crosses the western CONUS. At this time the forecast winds/relative humidity are not strong/dry enough to warrant any Critical probabilities, especially given the questionable/sparse dry fuels presently. ..Bentley.. 09/25/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook

2 months ago
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0442 PM CDT Wed Sep 25 2024 Valid 271200Z - 031200Z Hurricane Helene will pull tropical moisture northward and absorb into a cutoff upper low in the Tennessee Valley region on Friday. This cutoff low will remain through at least Saturday before the pattern becomes more progressive. The combination of cool and moist conditions associated with this upper pattern will alleviate most fire weather concerns across the eastern CONUS through the extended period. Ridging will result in warm and dry conditions across much of the western CONUS during the period. While critically dry fuels are mostly sparse across the western CONUS presently, this extended warm/dry period may result in larger regions of critically dry fuels (particularly fine fuels) by the end of the weekend when the next trough crosses the western CONUS. At this time the forecast winds/relative humidity are not strong/dry enough to warrant any Critical probabilities, especially given the questionable/sparse dry fuels presently. ..Bentley.. 09/25/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Sep 25, 2024 2000 UTC Day 1 Convective Outlook

2 months ago
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Wed Sep 25 2024 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE GULF COAST INTO THE SOUTHERN/CENTRAL APPALACHIANS AND FLORIDA PENINSULA... ...SUMMARY... Isolated severe storms remain possible this afternoon from parts of the Southeast and central/southern Appalachians to the Texas/Louisiana Gulf Coast. Some tornado threat may still develop across the Florida Peninsula by this evening, in association with Hurricane Helene. ...20Z Update... The only changes made to the Day 1 Convective Outlook were to trim thunder and severe contours across the Gulf Coast into the OH Valley, where lightning and strong wind gust coverage should become increasingly sparse through the day. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 09/25/2024 .PREV DISCUSSION... /ISSUED 1143 AM CDT Wed Sep 25 2024/ ..Southeast and southern Appalachians... The influence of the upstream mid/upper-level trough and moisture streaming north from the Gulf of Mexico and Helene will lead to widespread precipitation across parts of the Southeast and southern Appalachians. This will tend to limit available buoyancy in some areas, but strong to locally severe storms may occur. Favorable deep-layer winds/shear exist, especially across the southern Appalachians vicinity where a few semi-discrete supercells could occur aside from more prevalent quasi-linear convective bands. Locally damaging wind gusts and perhaps a tornado could accompany the strongest storms, before low/mid-level lapse rates and buoyancy become increasingly weak with time, and an outflow-reinforced effective front sags southward across the region. ...Texas Gulf Coast/Middle Gulf Coast... Somewhat stronger diurnal destabilization will be possible from parts of central/east Texas into Louisiana, and perhaps into Mississippi, with MLCAPE potentially increasing above 1500 J/kg. Isolated to widely scattered thunderstorm development will be possible near a southward-moving cold front. Effective shear will generally range from 25-35 kt, and a few modestly organized storms are possible. Isolated damaging gusts could accompany the strongest storms within this regime. ...Florida Peninsula and Keys... Hurricane Helene's wind field is forecast to be rather large, especially on the east side of the circulation, associated with a strengthening Helene through the afternoon and tonight. Reference the National Hurricane Center for the latest Helene details. This scenario will result in modestly strengthening low-level shear/SRH across the Florida Peninsula during the day, but more so into the evening and overnight after the peak diurnal instability cycle. Instability will likely remain rather weak overall, and details regarding the intensity of any outer rain bands remain uncertain. However, some tropical-cyclone tornado threat could evolve across parts of the Florida Peninsula and Keys, mainly into tonight. ...Eastern Washington/northern Idaho/northwest Montana... While buoyancy is expected to remain quite weak, relatively steep mid-level lapse rates will support thunderstorm potential late this afternoon through early evening from eastern Washington into northern Idaho and northwest Montana, in advance of the approaching shortwave trough. Strong deep-layer flow/shear could support a locally severe storm or two with gusty winds and possibly some hail. Read more

SPC Day 2 Fire Weather Outlook

2 months ago
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Wed Sep 25 2024 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 09/25/2024 .PREV DISCUSSION... /ISSUED 0143 AM CDT Wed Sep 25 2024/ ...Synopsis... Fire weather concerns are expected to be low on Thursday. Hurricane Helene will be absorbed into the upper-level flow across the eastern US with widespread rainfall anticipated. Across the central and western US, a ridge of high pressure will remain in place with generally light winds. As such, no overlap of critically dry fuels with Elevated/Critical conditions is expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Sep 25, 2024 1930 UTC Day 3 Severe Thunderstorm Outlook

2 months ago
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0211 PM CDT Wed Sep 25 2024 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL APPALACHIANS INTO THE CAROLINAS AND SOUTHERN VIRGINIA... ...SUMMARY... A risk for a couple of tornadoes and damaging thunderstorm wind gusts exists from the central Appalachians into the Carolinas and southern Virginia. ...Synopsis... Upper ridging centered over the Southwest/northern Mexico is forecast to remain in place on Friday, with some modest northward expansion possible. To the east of this ridging, complex interaction is expected between a cold-core upper low initially over the Mid-South and Tropical Cyclone Helene, which will likely be centered over northern GA. Strong westerlies will remain along and north of the US/Canada border, and stable conditions will persist west of the Mississippi River. As such, tornadoes and strong convective gusts associated with Helene will constitute the only severe risk across the CONUS on Friday. ...Central Appalachians into the Carolinas and southern VA... Strong low to mid level flow will persist throughout the eastern periphery of Helene on Friday, over an area characterized by low to mid 70s dewpoints and modest buoyancy. This modest buoyancy could support some deeper convective cores, particularly within any rainbands. The combination of deeper, more persistent updrafts with the strong low to mid level flow could support strong, convectively augmented gusts and/or a few tornadoes. ..Mosier.. 09/25/2024 Read more
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