Aggregator

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Fri Jan 12 2024 Valid 121700Z - 131200Z The previous forecast (see below) remains unchanged. ..Squitieri.. 01/12/2024 .PREV DISCUSSION... /ISSUED 0156 AM CST Fri Jan 12 2024/ ...Synopsis... An amplified large-scale trough accompanied by strong flow aloft will advance eastward from the Great Plains into the eastern CONUS. An attendant surface low initially over the Mid-MS Valley will deepen as it moves northeastward into the Great Lakes, while a southward-extending cold front continues eastward across the Gulf of Mexico. On the backside of the surface low and midlevel wave, a tight pressure gradient will yield strong northwesterly surface winds across much of TX. Along the Lower Rio Grande Valley, 20-30 mph sustained northwesterly surface winds (with higher gusts) are expected during the morning into early afternoon hours. During this time, boundary-layer heating/mixing into very dry air aloft will favor 10-15 percent minimum RH. These dry/windy conditions will support elevated to locally/briefly critical fire-weather conditions given modestly receptive fine fuels over the area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Fri Jan 12 2024 Valid 121700Z - 131200Z The previous forecast (see below) remains unchanged. ..Squitieri.. 01/12/2024 .PREV DISCUSSION... /ISSUED 0156 AM CST Fri Jan 12 2024/ ...Synopsis... An amplified large-scale trough accompanied by strong flow aloft will advance eastward from the Great Plains into the eastern CONUS. An attendant surface low initially over the Mid-MS Valley will deepen as it moves northeastward into the Great Lakes, while a southward-extending cold front continues eastward across the Gulf of Mexico. On the backside of the surface low and midlevel wave, a tight pressure gradient will yield strong northwesterly surface winds across much of TX. Along the Lower Rio Grande Valley, 20-30 mph sustained northwesterly surface winds (with higher gusts) are expected during the morning into early afternoon hours. During this time, boundary-layer heating/mixing into very dry air aloft will favor 10-15 percent minimum RH. These dry/windy conditions will support elevated to locally/briefly critical fire-weather conditions given modestly receptive fine fuels over the area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Fri Jan 12 2024 Valid 121700Z - 131200Z The previous forecast (see below) remains unchanged. ..Squitieri.. 01/12/2024 .PREV DISCUSSION... /ISSUED 0156 AM CST Fri Jan 12 2024/ ...Synopsis... An amplified large-scale trough accompanied by strong flow aloft will advance eastward from the Great Plains into the eastern CONUS. An attendant surface low initially over the Mid-MS Valley will deepen as it moves northeastward into the Great Lakes, while a southward-extending cold front continues eastward across the Gulf of Mexico. On the backside of the surface low and midlevel wave, a tight pressure gradient will yield strong northwesterly surface winds across much of TX. Along the Lower Rio Grande Valley, 20-30 mph sustained northwesterly surface winds (with higher gusts) are expected during the morning into early afternoon hours. During this time, boundary-layer heating/mixing into very dry air aloft will favor 10-15 percent minimum RH. These dry/windy conditions will support elevated to locally/briefly critical fire-weather conditions given modestly receptive fine fuels over the area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Fri Jan 12 2024 Valid 121700Z - 131200Z The previous forecast (see below) remains unchanged. ..Squitieri.. 01/12/2024 .PREV DISCUSSION... /ISSUED 0156 AM CST Fri Jan 12 2024/ ...Synopsis... An amplified large-scale trough accompanied by strong flow aloft will advance eastward from the Great Plains into the eastern CONUS. An attendant surface low initially over the Mid-MS Valley will deepen as it moves northeastward into the Great Lakes, while a southward-extending cold front continues eastward across the Gulf of Mexico. On the backside of the surface low and midlevel wave, a tight pressure gradient will yield strong northwesterly surface winds across much of TX. Along the Lower Rio Grande Valley, 20-30 mph sustained northwesterly surface winds (with higher gusts) are expected during the morning into early afternoon hours. During this time, boundary-layer heating/mixing into very dry air aloft will favor 10-15 percent minimum RH. These dry/windy conditions will support elevated to locally/briefly critical fire-weather conditions given modestly receptive fine fuels over the area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Fri Jan 12 2024 Valid 121700Z - 131200Z The previous forecast (see below) remains unchanged. ..Squitieri.. 01/12/2024 .PREV DISCUSSION... /ISSUED 0156 AM CST Fri Jan 12 2024/ ...Synopsis... An amplified large-scale trough accompanied by strong flow aloft will advance eastward from the Great Plains into the eastern CONUS. An attendant surface low initially over the Mid-MS Valley will deepen as it moves northeastward into the Great Lakes, while a southward-extending cold front continues eastward across the Gulf of Mexico. On the backside of the surface low and midlevel wave, a tight pressure gradient will yield strong northwesterly surface winds across much of TX. Along the Lower Rio Grande Valley, 20-30 mph sustained northwesterly surface winds (with higher gusts) are expected during the morning into early afternoon hours. During this time, boundary-layer heating/mixing into very dry air aloft will favor 10-15 percent minimum RH. These dry/windy conditions will support elevated to locally/briefly critical fire-weather conditions given modestly receptive fine fuels over the area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Fri Jan 12 2024 Valid 121700Z - 131200Z The previous forecast (see below) remains unchanged. ..Squitieri.. 01/12/2024 .PREV DISCUSSION... /ISSUED 0156 AM CST Fri Jan 12 2024/ ...Synopsis... An amplified large-scale trough accompanied by strong flow aloft will advance eastward from the Great Plains into the eastern CONUS. An attendant surface low initially over the Mid-MS Valley will deepen as it moves northeastward into the Great Lakes, while a southward-extending cold front continues eastward across the Gulf of Mexico. On the backside of the surface low and midlevel wave, a tight pressure gradient will yield strong northwesterly surface winds across much of TX. Along the Lower Rio Grande Valley, 20-30 mph sustained northwesterly surface winds (with higher gusts) are expected during the morning into early afternoon hours. During this time, boundary-layer heating/mixing into very dry air aloft will favor 10-15 percent minimum RH. These dry/windy conditions will support elevated to locally/briefly critical fire-weather conditions given modestly receptive fine fuels over the area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Fri Jan 12 2024 Valid 121700Z - 131200Z The previous forecast (see below) remains unchanged. ..Squitieri.. 01/12/2024 .PREV DISCUSSION... /ISSUED 0156 AM CST Fri Jan 12 2024/ ...Synopsis... An amplified large-scale trough accompanied by strong flow aloft will advance eastward from the Great Plains into the eastern CONUS. An attendant surface low initially over the Mid-MS Valley will deepen as it moves northeastward into the Great Lakes, while a southward-extending cold front continues eastward across the Gulf of Mexico. On the backside of the surface low and midlevel wave, a tight pressure gradient will yield strong northwesterly surface winds across much of TX. Along the Lower Rio Grande Valley, 20-30 mph sustained northwesterly surface winds (with higher gusts) are expected during the morning into early afternoon hours. During this time, boundary-layer heating/mixing into very dry air aloft will favor 10-15 percent minimum RH. These dry/windy conditions will support elevated to locally/briefly critical fire-weather conditions given modestly receptive fine fuels over the area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1015 AM CST Fri Jan 12 2024 Valid 121700Z - 131200Z The previous forecast (see below) remains unchanged. ..Squitieri.. 01/12/2024 .PREV DISCUSSION... /ISSUED 0156 AM CST Fri Jan 12 2024/ ...Synopsis... An amplified large-scale trough accompanied by strong flow aloft will advance eastward from the Great Plains into the eastern CONUS. An attendant surface low initially over the Mid-MS Valley will deepen as it moves northeastward into the Great Lakes, while a southward-extending cold front continues eastward across the Gulf of Mexico. On the backside of the surface low and midlevel wave, a tight pressure gradient will yield strong northwesterly surface winds across much of TX. Along the Lower Rio Grande Valley, 20-30 mph sustained northwesterly surface winds (with higher gusts) are expected during the morning into early afternoon hours. During this time, boundary-layer heating/mixing into very dry air aloft will favor 10-15 percent minimum RH. These dry/windy conditions will support elevated to locally/briefly critical fire-weather conditions given modestly receptive fine fuels over the area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No Mesoscale Discussions are in effect as of Fri Jan 12 15:31:02 UTC 2024.

MD 0053 CONCERNING TORNADO WATCH 10... FOR CENTRAL/NORTHERN MS...NORTHEAST LA...EXTREME SOUTHWEST TN
Mesoscale Discussion 0053 NWS Storm Prediction Center Norman OK 0755 AM CST Fri Jan 12 2024 Areas affected...Central/northern MS...Northeast LA...extreme southwest TN Concerning...Tornado Watch 10... Valid 121355Z - 121530Z The severe weather threat for Tornado Watch 10 continues. SUMMARY...The threat for severe gusts and a couple tornadoes will move eastward through mid morning. DISCUSSION...A convective line, which earlier produced measured severe gusts across AR, has shown signs of weakening across far northern MS into western TN, within an increasingly cool and less unstable environment. Farther south, convection has evolved into multiple bands of semi-discrete storms, with occasional stronger midlevel rotation noted with the strongest cells. While storms across TN may continue to outpace stronger moistening/destabilization, storms across central/northern MS will continue will have greater access to richer low-level moisture and modest instability (MLCAPE of 500-1000 J/kg). A notable increase in low-level flow has been noted on the KDGX VWP, with 60-80 kt noted in the lowest 1-3 km AGL, so any organized storm structures within this regime will pose a threat for both severe gusts (potentially 65+ kt) and a couple tornadoes. Recent surface observations indicate strong pressure falls associated with a deepening cyclone near the TN/AR border, which may help to sustain organized convection into mid/late morning as it moves northeastward, with some potential for later downstream watch issuance into parts of northwest AL. Some southward expansion of WW 10 may also be needed to account for increasing convection into south-central MS. ..Dean/Edwards.. 01/12/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BMX...HUN...MEG...JAN... LAT...LON 32159187 33559066 34389016 35139007 35428990 35568948 35358875 35028812 34738793 34068795 33338816 32108892 31778936 31768996 31799051 31829097 31889118 31869144 32159187 Read more

WW 0010 Status Updates
STATUS REPORT ON WW 10 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NE HEZ TO 60 S GLH TO 40 S GWO TO 30 E GWO TO 15 ESE UOX TO 35 S MKL TO 15 NNW MKL. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0053 ..JEWELL..01/12/24 ATTN...WFO...LZK...JAN...SHV...MEG... STATUS REPORT FOR WT 10 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MSC003-007-009-013-017-019-021-023-025-029-031-035-037-049-051- 057-061-063-065-067-069-073-075-077-079-081-085-087-089-091-095- 097-099-101-103-105-115-117-121-123-127-129-139-141-145-149-155- 159-163-121540- MS . MISSISSIPPI COUNTIES INCLUDED ARE ALCORN ATTALA BENTON CALHOUN CHICKASAW CHOCTAW CLAIBORNE CLARKE CLAY COPIAH COVINGTON FORREST FRANKLIN HINDS HOLMES ITAWAMBA JASPER JEFFERSON JEFFERSON DAVIS JONES KEMPER LAMAR LAUDERDALE LAWRENCE LEAKE LEE LINCOLN LOWNDES MADISON MARION MONROE MONTGOMERY NESHOBA NEWTON NOXUBEE OKTIBBEHA PONTOTOC PRENTISS RANKIN SCOTT SIMPSON SMITH Read more

WW 0010 Status Updates
STATUS REPORT ON WW 10 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NE HEZ TO 60 S GLH TO 40 S GWO TO 30 E GWO TO 15 ESE UOX TO 35 S MKL TO 15 NNW MKL. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0053 ..JEWELL..01/12/24 ATTN...WFO...LZK...JAN...SHV...MEG... STATUS REPORT FOR WT 10 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MSC003-007-009-013-017-019-021-023-025-029-031-035-037-049-051- 057-061-063-065-067-069-073-075-077-079-081-085-087-089-091-095- 097-099-101-103-105-115-117-121-123-127-129-139-141-145-149-155- 159-163-121540- MS . MISSISSIPPI COUNTIES INCLUDED ARE ALCORN ATTALA BENTON CALHOUN CHICKASAW CHOCTAW CLAIBORNE CLARKE CLAY COPIAH COVINGTON FORREST FRANKLIN HINDS HOLMES ITAWAMBA JASPER JEFFERSON JEFFERSON DAVIS JONES KEMPER LAMAR LAUDERDALE LAWRENCE LEAKE LEE LINCOLN LOWNDES MADISON MARION MONROE MONTGOMERY NESHOBA NEWTON NOXUBEE OKTIBBEHA PONTOTOC PRENTISS RANKIN SCOTT SIMPSON SMITH Read more

WW 0010 Status Updates
STATUS REPORT ON WW 10 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 NE HEZ TO 60 S GLH TO 40 S GWO TO 30 E GWO TO 15 ESE UOX TO 35 S MKL TO 15 NNW MKL. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0053 ..JEWELL..01/12/24 ATTN...WFO...LZK...JAN...SHV...MEG... STATUS REPORT FOR WT 10 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MSC003-007-009-013-017-019-021-023-025-029-031-035-037-049-051- 057-061-063-065-067-069-073-075-077-079-081-085-087-089-091-095- 097-099-101-103-105-115-117-121-123-127-129-139-141-145-149-155- 159-163-121540- MS . MISSISSIPPI COUNTIES INCLUDED ARE ALCORN ATTALA BENTON CALHOUN CHICKASAW CHOCTAW CLAIBORNE CLARKE CLAY COPIAH COVINGTON FORREST FRANKLIN HINDS HOLMES ITAWAMBA JASPER JEFFERSON JEFFERSON DAVIS JONES KEMPER LAMAR LAUDERDALE LAWRENCE LEAKE LEE LINCOLN LOWNDES MADISON MARION MONROE MONTGOMERY NESHOBA NEWTON NOXUBEE OKTIBBEHA PONTOTOC PRENTISS RANKIN SCOTT SIMPSON SMITH Read more

WW 10 TORNADO AR LA MS TN TX 120955Z - 121700Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 10 NWS Storm Prediction Center Norman OK 355 AM CST Fri Jan 12 2024 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southern, central and eastern Arkansas Northern Louisiana Northern and central Mississippi Southwestern Tennessee Northeast Texas * Effective this Friday morning from 355 AM until 1100 AM CST. * Primary threats include... A few tornadoes possible Scattered damaging winds and isolated significant gusts to 80 mph likely Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A line of severe thunderstorms is expected to become better organized the next few hours and sweep eastward across the watch area through the remainder of the morning, offering severe gusts (some potentially over 70 mph), a few tornadoes, and isolated hail. Isolated severe thunderstorms also may form ahead of the line, with all the same hazards possible. The tornado watch area is approximately along and 95 statute miles either side of a line from 30 miles southwest of Texarkana AR to 25 miles east of Tupelo MS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...This tornado watch replaces tornado watch number 9. Watch number 9 will not be in effect after 355 AM CST. AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 70 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 25040. ...Edwards Read more

MD 0051 CONCERNING HEAVY SNOW FOR NORTHERN IL...SOUTHERN WI...EASTERN IA
Mesoscale Discussion 0051 NWS Storm Prediction Center Norman OK 0423 AM CST Fri Jan 12 2024 Areas affected...Northern IL...Southern WI...Eastern IA Concerning...Heavy snow Valid 121023Z - 121430Z SUMMARY...Snow rates of 1+ inch per hour will spread northward this morning. DISCUSSION...At 1015 UTC, a broad region of moderate precipitation is ongoing within the warm conveyor belt of a deepening cyclone currently centered near the Ozark Plateau. Within this region, an area of locally heavier precipitation is noted from eastern IA into northern IL, where some enhancement is likely being provided by a midlevel shortwave trough that is moving across southern IL in advance of the primary shortwave across the central/southern Plains. Some increase in moderate to heavy snow observations has been noted over the last hour across northwest/north-central IL, and this trend is likely to continue as heavier precipitation spreads into northeast IL and southern WI. Favorable moistening and ascent within a deep layer (including the dendritic growth zone) will support snow rates of 1+ inch per hour for at least a few hours this morning. Continued strong low-level warm advection will eventually result in a snow-to-rain transition along the southern periphery of the ongoing precipitation shield, with the rain/snow line expected to gradually advance northward into parts of northern IL later this morning. ..Dean.. 01/12/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...MKX...DVN...ARX... LAT...LON 42928774 42298769 41908757 41638752 41418749 41158750 41068777 41168948 41229053 41269132 41499156 42109160 43069064 43208884 42928774 Read more

MD 0052 CONCERNING TORNADO WATCH 10... FOR EASTERN AR...NORTHWEST MS...EXTREME SOUTHWEST TN...EXTREME NORTHEAST LA
Mesoscale Discussion 0052 NWS Storm Prediction Center Norman OK 0614 AM CST Fri Jan 12 2024 Areas affected...Eastern AR...Northwest MS...Extreme southwest TN...Extreme northeast LA Concerning...Tornado Watch 10... Valid 121214Z - 121345Z The severe weather threat for Tornado Watch 10 continues. SUMMARY...The threat for 70-80 mph winds and a couple tornadoes will continue through sunrise. DISCUSSION...A fast-moving convective line has recently increased in organization across eastern AR, with several mesovortices noted along the leading edge of the line. Shortly after 1130 UTC, 64-kt and 63-kt gusts were noted at Pine Bluff (KPBF) and Stuttgart, AR (KSGT), respectively, as the line moved through those observing sites. Very strong low/midlevel flow in advance of a powerful shortwave trough moving across the southern Plains will continue to support severe-gust potential (with 65+ kt gusts possible) as this convective line moves quickly eastward toward northwest MS and extreme southwest TN. A couple brief line-embedded tornadoes will also be possible. The northward extent of the severe threat will be limited by increasingly cool/stable near-surface conditions, though some severe-gust potential could extend into regions were convection remains somewhat elevated. In advance of the convective line described above, semi-discrete storms have intensified from northeast LA/southeast AR into northwest MS. It remains uncertain regarding whether supercells can mature within the weakly unstable and strongly sheared environment across this region, but very strong low-level shear/SRH (as noted on regional VWPs) will support a conditional tornado risk with any sustained supercell ahead of the primary convective line this morning. ..Dean.. 01/12/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MEG...JAN...LZK...SHV... LAT...LON 35409093 35459031 35399001 35038985 34458984 33938989 32779082 32609111 32609161 32619201 32789212 33029209 33169200 33349191 33509187 33879165 34379143 35409093 Read more

WW 0010 Status Updates
STATUS REPORT ON WW 10 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 N ESF TO 50 NNW GWO TO 30 E JBR. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0052 ..DEAN..01/12/24 ATTN...WFO...LZK...JAN...SHV...MEG... STATUS REPORT FOR WT 10 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC017-121440- AR . ARKANSAS COUNTIES INCLUDED ARE CHICOT LAC035-041-065-083-107-123-121440- LA . LOUISIANA PARISHES INCLUDED ARE EAST CARROLL FRANKLIN MADISON RICHLAND TENSAS WEST CARROLL MSC003-007-009-013-015-017-019-021-025-033-043-049-051-053-055- 057-069-071-075-079-081-083-087-089-093-095-097-099-101-103-105- 107-115-117-119-121-123-125-133-135-137-139-141-145-149-151-155- 159-161-163-121440- MS Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0650 AM CST Fri Jan 12 2024 Valid 121300Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF CENTRAL/NORTHERN MISSISSIPPI AND WESTERN ALABAMA... ...SUMMARY... Severe thunderstorm winds and a few tornadoes are possible across a large part of the Southeast through early this evening. The most intense gusts (potentially above 70 mph) are possible through midday over parts of the Mid-South and Tennessee Valley regions. ...Synopsis... Broadly cyclonic flow in mid/upper levels will cover most of the CONUS through the period, except for shortwave ridging on either side of a strong lead trough now over the central/southern Plains. That perturbation will be the primary upper-air influence on convection today. The southern part -- initially located over portions of OK and north TX -- should eject northeastward to the IN/MI border area by 00Z, while the northern part moves more slowly across IA toward the Quad Cities. Overnight, these will combine into a 500-mb cyclone over Lower MI to Lake Huron, increasingly stacked on the surface cyclone described below. The 11Z surface analysis showed an area of low pressure over central MO, along the northern segment of a cold front extending across parts of central/western AR to central TX. A synoptic warm front was drawn from the low across the lower Ohio Valley. A prefrontal trough/wind shift and remnant of a Pacific front was evident over central LA southwestward to deep south TX. The surface low should occlude and move northeastward to near ORD by 00Z, then across Lower MI overnight. The main/Arctic cold front is forecast by 00Z to overtake the Pacific boundary and reach WV, the western Carolinas, northern/western GA, central/eastern FL Panhandle, and the central Gulf. The front should move offshore from the Mid-Atlantic, Carolinas and GA by 12Z, extending southwestward over central/ southwestern peninsular FL. ...Southeastern CONUS... Ongoing lines of strong to severe thunderstorms near the Mississippi River should consolidate and sweep eastward across parts of the Mid South toward the Tennessee Valley region through midday -- in and near the 30% wind/"enhanced" area. This activity will pose a threat for severe gusts (some significant/65+ kt), a few embedded tornadoes, and isolated, marginally severe hail. See SPC tornado watch 10 and related mesoscale discussions for near-term coverage of this convective stage. Though peak intensity of the main thunderstorm line is likely to be in the next several hours, as it encounters the greatest warm-sector theta-e, some severe-wind and tornado threat may persist eastward across portions of AL/GA today and into the Carolinas this evening following very strong low-level warm/theta-e advection. Additional strong-severe thunderstorm development is possible over the warm sector throughout today into this evening, as convergence lines produce showers that can grow gradually deeper and upscale. Given the strength of the wind fields projected to spread over the warm sector and ahead of the main line, some of this activity may become supercellular, also with a tornado/damaging-wind/marginal-hail threat. Dewpoints generally reaching the 50s to mid 60s F just prior to cold frontal passage, and sufficient surface-based instability, should develop today in the warm sector to offset weak midlevel lapse rates and support 500-1500 J/kg MLCAPE -- more southward, and mainly south of I-20 in AL/GA and from the Piedmont eastward in SC/NC. Forecast soundings suggest hodographs will be straightening/losing size, but remaining very long, as the buoyant layer lowers closer to the surface and the main belt of convection approaches. Still, that supports effective SRH locally exceeding 400 J/kg, amidst 60-80-kt effective-shear magnitudes. The main limiting factor for areal severe potential will be lack of greater instability. Given the strength of ambient flow, a broad 15% wind area is maintained, with the understanding that localized pockets of denser wind/tornado potential may quickly evolve within. Farther north across northern TN/KY to southern VA, though MLCAPE will be weak, intense wind fields and associated convective momentum transfer still will support some potential for convective gusts to penetrate near-neutral stability layers and reach the surface. A broad area of 60-110-kt winds in the 850-700-mb layer will shift northeastward across parts of TN/KY and the southern Appalachians today. The severe potential in such scenarios is rather spotty and nebulous, and may extend well northward within cool surface air on an isolated basis. ..Edwards/Dean.. 01/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0650 AM CST Fri Jan 12 2024 Valid 121300Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF CENTRAL/NORTHERN MISSISSIPPI AND WESTERN ALABAMA... ...SUMMARY... Severe thunderstorm winds and a few tornadoes are possible across a large part of the Southeast through early this evening. The most intense gusts (potentially above 70 mph) are possible through midday over parts of the Mid-South and Tennessee Valley regions. ...Synopsis... Broadly cyclonic flow in mid/upper levels will cover most of the CONUS through the period, except for shortwave ridging on either side of a strong lead trough now over the central/southern Plains. That perturbation will be the primary upper-air influence on convection today. The southern part -- initially located over portions of OK and north TX -- should eject northeastward to the IN/MI border area by 00Z, while the northern part moves more slowly across IA toward the Quad Cities. Overnight, these will combine into a 500-mb cyclone over Lower MI to Lake Huron, increasingly stacked on the surface cyclone described below. The 11Z surface analysis showed an area of low pressure over central MO, along the northern segment of a cold front extending across parts of central/western AR to central TX. A synoptic warm front was drawn from the low across the lower Ohio Valley. A prefrontal trough/wind shift and remnant of a Pacific front was evident over central LA southwestward to deep south TX. The surface low should occlude and move northeastward to near ORD by 00Z, then across Lower MI overnight. The main/Arctic cold front is forecast by 00Z to overtake the Pacific boundary and reach WV, the western Carolinas, northern/western GA, central/eastern FL Panhandle, and the central Gulf. The front should move offshore from the Mid-Atlantic, Carolinas and GA by 12Z, extending southwestward over central/ southwestern peninsular FL. ...Southeastern CONUS... Ongoing lines of strong to severe thunderstorms near the Mississippi River should consolidate and sweep eastward across parts of the Mid South toward the Tennessee Valley region through midday -- in and near the 30% wind/"enhanced" area. This activity will pose a threat for severe gusts (some significant/65+ kt), a few embedded tornadoes, and isolated, marginally severe hail. See SPC tornado watch 10 and related mesoscale discussions for near-term coverage of this convective stage. Though peak intensity of the main thunderstorm line is likely to be in the next several hours, as it encounters the greatest warm-sector theta-e, some severe-wind and tornado threat may persist eastward across portions of AL/GA today and into the Carolinas this evening following very strong low-level warm/theta-e advection. Additional strong-severe thunderstorm development is possible over the warm sector throughout today into this evening, as convergence lines produce showers that can grow gradually deeper and upscale. Given the strength of the wind fields projected to spread over the warm sector and ahead of the main line, some of this activity may become supercellular, also with a tornado/damaging-wind/marginal-hail threat. Dewpoints generally reaching the 50s to mid 60s F just prior to cold frontal passage, and sufficient surface-based instability, should develop today in the warm sector to offset weak midlevel lapse rates and support 500-1500 J/kg MLCAPE -- more southward, and mainly south of I-20 in AL/GA and from the Piedmont eastward in SC/NC. Forecast soundings suggest hodographs will be straightening/losing size, but remaining very long, as the buoyant layer lowers closer to the surface and the main belt of convection approaches. Still, that supports effective SRH locally exceeding 400 J/kg, amidst 60-80-kt effective-shear magnitudes. The main limiting factor for areal severe potential will be lack of greater instability. Given the strength of ambient flow, a broad 15% wind area is maintained, with the understanding that localized pockets of denser wind/tornado potential may quickly evolve within. Farther north across northern TN/KY to southern VA, though MLCAPE will be weak, intense wind fields and associated convective momentum transfer still will support some potential for convective gusts to penetrate near-neutral stability layers and reach the surface. A broad area of 60-110-kt winds in the 850-700-mb layer will shift northeastward across parts of TN/KY and the southern Appalachians today. The severe potential in such scenarios is rather spotty and nebulous, and may extend well northward within cool surface air on an isolated basis. ..Edwards/Dean.. 01/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0650 AM CST Fri Jan 12 2024 Valid 121300Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF CENTRAL/NORTHERN MISSISSIPPI AND WESTERN ALABAMA... ...SUMMARY... Severe thunderstorm winds and a few tornadoes are possible across a large part of the Southeast through early this evening. The most intense gusts (potentially above 70 mph) are possible through midday over parts of the Mid-South and Tennessee Valley regions. ...Synopsis... Broadly cyclonic flow in mid/upper levels will cover most of the CONUS through the period, except for shortwave ridging on either side of a strong lead trough now over the central/southern Plains. That perturbation will be the primary upper-air influence on convection today. The southern part -- initially located over portions of OK and north TX -- should eject northeastward to the IN/MI border area by 00Z, while the northern part moves more slowly across IA toward the Quad Cities. Overnight, these will combine into a 500-mb cyclone over Lower MI to Lake Huron, increasingly stacked on the surface cyclone described below. The 11Z surface analysis showed an area of low pressure over central MO, along the northern segment of a cold front extending across parts of central/western AR to central TX. A synoptic warm front was drawn from the low across the lower Ohio Valley. A prefrontal trough/wind shift and remnant of a Pacific front was evident over central LA southwestward to deep south TX. The surface low should occlude and move northeastward to near ORD by 00Z, then across Lower MI overnight. The main/Arctic cold front is forecast by 00Z to overtake the Pacific boundary and reach WV, the western Carolinas, northern/western GA, central/eastern FL Panhandle, and the central Gulf. The front should move offshore from the Mid-Atlantic, Carolinas and GA by 12Z, extending southwestward over central/ southwestern peninsular FL. ...Southeastern CONUS... Ongoing lines of strong to severe thunderstorms near the Mississippi River should consolidate and sweep eastward across parts of the Mid South toward the Tennessee Valley region through midday -- in and near the 30% wind/"enhanced" area. This activity will pose a threat for severe gusts (some significant/65+ kt), a few embedded tornadoes, and isolated, marginally severe hail. See SPC tornado watch 10 and related mesoscale discussions for near-term coverage of this convective stage. Though peak intensity of the main thunderstorm line is likely to be in the next several hours, as it encounters the greatest warm-sector theta-e, some severe-wind and tornado threat may persist eastward across portions of AL/GA today and into the Carolinas this evening following very strong low-level warm/theta-e advection. Additional strong-severe thunderstorm development is possible over the warm sector throughout today into this evening, as convergence lines produce showers that can grow gradually deeper and upscale. Given the strength of the wind fields projected to spread over the warm sector and ahead of the main line, some of this activity may become supercellular, also with a tornado/damaging-wind/marginal-hail threat. Dewpoints generally reaching the 50s to mid 60s F just prior to cold frontal passage, and sufficient surface-based instability, should develop today in the warm sector to offset weak midlevel lapse rates and support 500-1500 J/kg MLCAPE -- more southward, and mainly south of I-20 in AL/GA and from the Piedmont eastward in SC/NC. Forecast soundings suggest hodographs will be straightening/losing size, but remaining very long, as the buoyant layer lowers closer to the surface and the main belt of convection approaches. Still, that supports effective SRH locally exceeding 400 J/kg, amidst 60-80-kt effective-shear magnitudes. The main limiting factor for areal severe potential will be lack of greater instability. Given the strength of ambient flow, a broad 15% wind area is maintained, with the understanding that localized pockets of denser wind/tornado potential may quickly evolve within. Farther north across northern TN/KY to southern VA, though MLCAPE will be weak, intense wind fields and associated convective momentum transfer still will support some potential for convective gusts to penetrate near-neutral stability layers and reach the surface. A broad area of 60-110-kt winds in the 850-700-mb layer will shift northeastward across parts of TN/KY and the southern Appalachians today. The severe potential in such scenarios is rather spotty and nebulous, and may extend well northward within cool surface air on an isolated basis. ..Edwards/Dean.. 01/12/2024 Read more