Severe Storms

MD 1994 CONCERNING HEAVY SNOW FOR NORTHERN SIERRA NEVADA
Mesoscale Discussion 1994 NWS Storm Prediction Center Norman OK 1154 AM CST Thu Dec 01 2022 Areas affected...northern Sierra Nevada Concerning...Heavy snow Valid 011754Z - 012200Z SUMMARY...Heavy snow is likely to continue through this afternoon along the western slopes of the Sierra Nevada, to the west and southwest of Lake Tahoe, with rates perhaps peaking on the order of 2-3+ inches per hour during the 1-4 PM PST time frame. DISCUSSION...In advance of a significant short wave trough still digging near the northern Pacific coast, a surface cold front is already in the process of advancing southward across northern into central California. This includes the northern Sierra Nevada, with a continued gradual progress across the higher terrain to the west and southwest of Lake Tahoe during the next several hours. As lower-levels gradually cool in the wake of the cold front, models indicate that strong warm advection will be maintained aloft (around/above the 700 mb level) into the 21-00Z time frame along/west of the Sierra Nevada, before the upstream mid-level troughing turns inland of the Pacific coast. The latest Rapid Refresh suggests that heaviest snow rates will be maintained in a corridor along the higher terrain to the west and southwest of Lake Tahoe, and may intensify further late this afternoon as lift in the dendritic growth layer maximizes. As low-levels cool, forecast soundings suggest that snow levels may lower toward and below 3000 ft. ..Kerr.. 12/01/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...REV...STO... LAT...LON 39982148 40012074 39082025 38632031 38622070 39052096 39392122 39982148 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1054 AM CST Thu Dec 01 2022 Valid 021200Z - 031200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Friday. ...Synopsis... A mid/upper-level trough is forecast to move from the central/northern Rockies across the Great Plains during the day on Friday, and into parts of the Midwest/Great Lakes by early Saturday morning. In conjunction with this trough, a surface cyclone is forecast to deepen over the upper MS Valley and then move northeastward into northern Ontario, as an attendant cold front moves through the central/northern Plains and Midwest. Surface-based buoyancy is expected to remain negligible across the CONUS, which should help to limit any threat of severe thunderstorms. A rather strong southwesterly low-level jet will support stronger moisture return above the surface into parts of the lower/mid MS Valley and OH Valley. This will result in the development of modest elevated buoyancy, and may support the potential for sporadic lightning flashes as precipitation expands through the afternoon/evening within a low-level warm advection regime. ..Dean.. 12/01/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1042 AM CST Thu Dec 01 2022 Valid 011700Z - 021200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 12/01/2022 .PREV DISCUSSION... /ISSUED 0131 AM CST Thu Dec 01 2022/ ...Synopsis... Falling heights and increasing mid-level flow will lead to lee cyclogenesis across eastern Colorado today. Strengthening surface winds will develop across portions of the central Plains. However, these winds of 15 to 20 mph will likely occur with relative humidity in the 25 to 30 percent range. Therefore, borderline relative humidity amid only moderately dry fuels precludes the need for an Elevated fire weather delineation. However, these dry and breezy conditions will help cure fuels for stronger winds on Friday. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1027 AM CST Thu Dec 01 2022 Valid 011630Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected through tonight. ...Synopsis... Water-vapor imagery early today shows a mid-level trough moving ashore the West Coast with quasi-zonal flow downstream over the central U.S. The mid-level trough over the West will move east into the northern Rockies/Great Basin by early morning Friday. A few thunderstorms are possible from near the mouth of the Columbia River southward into far northern parts of coastal CA, due in part to -35 deg C 500 mb temperatures and scant buoyancy. Elsewhere, a few thunderstorms may develop and perhaps move ashore in parts of South FL and the upper Keys this afternoon. ..Smith.. 12/01/2022 Read more

No watches are valid as of Wed Nov 30 17:58:02 UTC 2022.

No Mesoscale Discussions are in effect as of Wed Nov 30 17:58:02 UTC 2022.

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1122 AM CST Wed Nov 30 2022 Valid 011200Z - 021200Z ...NO CRITICAL AREAS... The previous forecast (see below) remains on track, and no changes/additions were made with this update. Locally elevated conditions are possible over southeast CO, northeast NM, and southwest KS during peak heating. However, these conditions appear too marginal/localized for Elevated highlights at this time. With that said, downslope warming/drying will continue to precondition fine fuels for a potential critical fire-weather event on Day 3/Friday. ..Weinman.. 11/30/2022 .PREV DISCUSSION... /ISSUED 1140 PM CST Tue Nov 29 2022/ ...Synopsis... An upper trough will rapidly traverse the Intermountain West tomorrow/Thursday, encouraging the deepening of a surface low and associated strong southerly low-level flow over the Plains. Modestly dry conditions may accompany the stronger southerly flow. However, several guidance members struggle to show RH dipping below 25 percent by afternoon peak heating. When also taking mediocre fuel status into account, fire weather highlights have been withheld. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1040 AM CST Wed Nov 30 2022 Valid 011200Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not expected on Thursday. ...Synopsis... One amplified mid/upper-level trough will move eastward from the Mid Atlantic/New England to the Canadian Maritimes on Thursday, while another mid/upper-level trough will move into and across the western CONUS through the period. A large surface ridge will persist from the south-central into the eastern CONUS, while a surface cyclone will move from the interior Northwest into the northern High Plains. Generally dry and stable conditions will dominate over most of the CONUS through the period. Isolated thunderstorms will be possible across parts of south FL, within a moist and moderately unstable environment. Cold midlevel temperatures will support weak convection capable of sporadic lightning flashes near the OR and northern CA coasts. Some weak elevated convection will be possible across parts of the southern Plains into the Ozarks within a warm advection regime, but midlevel lapse rates and buoyancy appear too weak to support thunderstorm development. Weak convection will also be possible across parts of the Great Basin in association with the mid/upper-level trough passing through the region, though lightning potential appears limited at this time. ..Dean.. 11/30/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1019 AM CST Wed Nov 30 2022 Valid 301630Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WITHIN THE FLORIDA BIG BEND AND PARTS OF SOUTHEAST GEORGIA... ...SUMMARY... Strong to marginally severe thunderstorms are possible for another hour or two within the Florida Big Bend region and parts of southeast Georgia. ...Synopsis... A broad mid-level trough is centered over the northern Great Lakes this morning. This feature will continue north and east through the day. At the surface, a cold front continues to move through the Southeast. Some pre-frontal convection continues in far southeast Georgia into north Florida. Convection from the Florida Big Bend into southeast Georgia will have decreasing mid-level support with time as well as encounter more stable air in northern/central Florida. A marginal threat for a damaging wind gust and brief, weak tornado may continue for another hour or two. For additional mesoscale details, see MCD 1993. ..Wendt.. 11/30/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1021 AM CST Wed Nov 30 2022 Valid 301700Z - 011200Z ...NO CRITICAL AREAS... The forecast remains on track, and no changes/additions were needed with this update. For details, see the previous discussion below. ..Weinman.. 11/30/2022 .PREV DISCUSSION... /ISSUED 1139 PM CST Tue Nov 29 2022/ ...Synopsis... An upper trough will eject into the Atlantic as a second upper trough impinges on the Pacific Northwest today. In between both upper troughs, surface high pressure and associated cold temperatures will sweep across much of the CONUS, limiting significant wildfire-spread potential. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0572 Status Updates
STATUS FOR WATCH 0572 HAS NOT BEEN ISSUED YET Read more

WW 572 TORNADO AR LA MS 291810Z - 300100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 572 NWS Storm Prediction Center Norman OK 1210 PM CST Tue Nov 29 2022 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southeast Arkansas Northern and Central Louisiana Central Mississippi * Effective this Tuesday afternoon and evening from 1210 PM until 700 PM CST. ...THIS IS A PARTICULARLY DANGEROUS SITUATION... * Primary threats include... Numerous tornadoes expected with a few intense tornadoes likely Scattered large hail and isolated very large hail events to 2 inches in diameter likely Scattered damaging wind gusts to 70 mph likely SUMMARY...Supercells are expected to develop this afternoon and track northeastward across much of northeast Louisiana and central Mississippi. Parameters appear favorable for strong and long-tracked tornadoes this afternoon and early evening. The tornado watch area is approximately along and 80 statute miles north and south of a line from 25 miles north of Fort Polk LA to 55 miles south of Tupelo MS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). 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. && AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 24035. ...Hart Read more

MD 1978 CONCERNING SEVERE POTENTIAL...TORNADO WATCH LIKELY FOR NORTHERN LA...EXTREME SOUTHEAST ARKANSAS AND INTO CENTRAL MS
Mesoscale Discussion 1978 NWS Storm Prediction Center Norman OK 1120 AM CST Tue Nov 29 2022 Areas affected...northern LA...extreme southeast Arkansas and into central MS Concerning...Severe potential...Tornado Watch likely Valid 291720Z - 291945Z Probability of Watch Issuance...95 percent SUMMARY...A PDS tornado watch will be needed by 19z/1pm CT for portions of northern Louisiana, extreme southeast Arkansas and into central Mississippi. Tornadoes, a couple potentially long-track and strong, large hail and damaging gusts will be possible into the evening hours. DISCUSSION...Rich Gulf boundary-layer moisture continues to rapidly return northward across the Lower MS Valley vicinity. Surface dewpoints near 65 F have developed as far north as south-central MS and northern LA late this morning. Meanwhile, the marine warm front, roughly delineating 70 F dewpoints, extends west-to east from southeast TX through central LA into southern MS. Moisture should continue to rapidly increase across northern LA into far southeast AR and MS through the afternoon. A plume of steep midlevel lapse rates will continue to overspread the region, aiding in MLCAPE increasing to 1000-2000 J/kg by mid-afternoon. Breaks in cloud cover across northeast LA into central MS will further aid in destabilization as greater heating occurs within these cloud breaks. Strong vertical shear, with effective shear magnitudes greater than 45 kt is already in place across the region. Regional VWPs and profilers already show enlarged, favorably curved low-level hodographs with 0-1 km SRH values greater than 250 m2/s. Large-scale ascent will remain modest across the region, resulting in a large warm sector supporting discrete supercells. One or more bands of supercells will be possible within low-level confluence zones. A particular dangerous situation is expected to develop across northeast LA into central MS through this evening as multiple supercells track across the area. Tornadoes, a couple strong and long-track, will be possible, in addition to large hail (scattered 2+ inch) and damaging gusts. ..Leitman/Hart.. 11/29/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MEG...JAN...LZK...LCH...SHV... LAT...LON 31979322 32349307 32839272 33529153 33769082 33869032 33888967 33648891 33408865 32828846 32448861 32038886 31728928 31628956 31509045 31369186 31379278 31599318 31979322 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1110 AM CST Tue Nov 29 2022 Valid 301200Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHEAST... ...SUMMARY... Thunderstorms capable of locally damaging winds and a tornado or two will be possible across parts of the Southeast on Wednesday, with the primary threat expected during the morning hours. ...Southeast... Extensive convection will likely be ongoing at 12Z Wednesday morning, from near the mouth of the Mississippi River northeastward into parts of GA/SC. Initially strong low-level shear and sufficient buoyancy will support a threat of locally damaging gusts and a brief tornado or two with these storms during the morning hours. A gradual weakening trend is expected with time as the stronger large-scale ascent moves northeastward away from the region, and deep-layer flow/shear gradually weakens. Some threat for locally strong gusts could persist into the early afternoon across parts of southwest GA and the FL Peninsula, before convection diminishes across north FL. ...Northeast/New England... The strong and progressive mid/upper-level trough initially over the Great Lakes/Ohio Valley will move eastward into New England by Wednesday evening. A strong cold front will move through Mid Atlantic and Northeast through the day, with very modest low-level moisture return expected along/ahead of the front. Increasing moisture and favorable low-level convergence and large-scale ascent may support development of a somewhat organized frontal band within the larger precipitation shield. Strong wind gusts could accompany any such frontal band, but with SBCAPE currently forecast to be negligible across the region, the potential for convectively enhanced gusts appears too limited for wind probabilities at this time. ..Dean.. 11/29/2022 Read more

MD 1977 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHERN MISSISSIPPI...NORTHERN ALABAMA...FAR SOUTHERN MIDDLE TENNESSEE
Mesoscale Discussion 1977 NWS Storm Prediction Center Norman OK 1056 AM CST Tue Nov 29 2022 Areas affected...Northern Mississippi...northern Alabama...far southern Middle Tennessee Concerning...Severe potential...Watch unlikely Valid 291656Z - 291900Z Probability of Watch Issuance...20 percent SUMMARY...Marginally severe hail will be possible with elevated storms early this afternoon. No watch is expected for this activity. More intense activity is expected later this afternoon/evening. DISCUSSION...As moisture rapidly returns north and east, a few elevated storms have developed along the leading edge. Current storm motions may keep this activity at least loosely tied to modest elevated instability. Given the strongly sheared environment, some potential for marginally severe hail will exist with the more intense storms as they move northeast. It does not appear likely that enough downstream destabilization will occur to support surface-based updrafts. With that said, strong/damaging wind gust potential is low. No watch is anticipated for this activity. Stronger storms are expected to impact some of these same areas later in the afternoon and evening. ..Wendt/Hart.. 11/29/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OHX...BMX...HUN...MEG... LAT...LON 34368716 34068856 33998949 34098975 34318995 34778970 35148907 35478680 35438612 34908603 34368716 Read more

Public Severe Weather Outlook
PUBLIC SEVERE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1049 AM CST TUE NOV 29 2022 ...Severe thunderstorms expected over parts of the lower Mississippi Valley this afternoon and tonight... * LOCATIONS... Central and northern Mississippi Northern Alabama Northeast Louisiana Southeast Arkansas Southern Tennessee * HAZARDS... Several tornadoes, a few intense Scattered large hail, some baseball size Scattered damaging winds * SUMMARY... Strong tornadoes, very large hail, and severe wind gusts are forecast this afternoon into the overnight period across parts of the lower to mid Mississippi Valley, Mid-South and parts of the Southeast. Preparedness actions... Review your severe weather safety procedures for the possibility of dangerous weather today. Stay tuned to NOAA Weather Radio, weather.gov, or other media for watches and warnings. A tornado watch means that conditions are favorable for tornadoes to form during the next several hours. If a tornado warning is issued for your area, move to a place of safety, ideally in a basement or interior room on the lowest floor of a sturdy building. && Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1036 AM CST Tue Nov 29 2022 Valid 301200Z - 011200Z ...NO CRITICAL AREAS... The forecast remains on track, and no changes were needed with this update. For details, see the previous discussion below. ..Weinman.. 11/29/2022 .PREV DISCUSSION... /ISSUED 1148 PM CST Mon Nov 28 2022/ ...Synopsis... Upper ridging will follow the mid-level trough from Day 1, which is poised to move offshore during the Day 2/Wednesday period. Behind a surface cold front, high pressure and associated cooler temperatures will overspread much of the CONUS, limiting concerns for widespread, significant wildfire-spread potential. ...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 1036 AM CST Tue Nov 29 2022 Valid 291700Z - 301200Z ...NO CRITICAL AREAS... The previous forecast reasoning (see below) remains the same, therefore, no changes/additions were made with this update. ..Weinman.. 11/29/2022 .PREV DISCUSSION... /ISSUED 1147 PM CST Mon Nov 28 2022/ ...Synopsis... A mid-level trough will overspread the Plains states while a surface cyclone will intensify and surge northeast towards the Great Lakes today. A surface cold front will sweep southeastward across the central Plains, with a dryline also surging eastward across far eastern New Mexico into western Texas during the afternoon. Dry and windy conditions are expected in the post-dryline environment. However, several guidance members still struggle to show RH dropping below 20 percent across the southern High Plains. When also factoring in fuels that are marginally receptive (at best) to fire spread, fire weather highlights have been withheld. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1021 AM CST Tue Nov 29 2022 Valid 291630Z - 301200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND TONIGHT OVER PARTS OF NORTHEAST LOUISIANA...EXTREME SOUTHEAST ARKANSAS...CENTRAL AND NORTHERN MISSISSIPPI...AND NORTHWEST ALABAMA... ...SUMMARY... Strong tornadoes, very large hail, and severe wind gusts are forecast this afternoon into the overnight period across parts of the lower to mid Mississippi Valley, Mid-South and parts of the Southeast. ...Regional Outbreak of severe thunderstorms and tornadoes is forecast today and tonight for parts of the lower Mississippi Valley... ...Lower MS Valley... Morning water vapor imagery shows a broad upper trough over much of the CONUS this morning, with several fast moving shortwave troughs moving across the southwest into the southern Plains. Strong southerly low-level winds have developed across the lower MS Valley, aiding in the rapid return of rich Gulf moisture. Dewpoints in the mid/upper 60s have spread into much of east TX and LA, and should extend into central MS by mid-afternoon. Plentiful low clouds are present, limiting daytime heating. But relatively steep mid-level lapse rates and returning moisture will lead to widespread MLCAPE values of 1000-1500 J/kg later today, with only a weak cap. Vertical shear profiles are very strong throughout the region, with effective SRH values of 200-400 m2/s2 beneath 50+ knots of deep-layer shear. Given the subtle forcing today, relatively long-lived discrete supercell storms are expected with an attendant threat of intense and long-track tornadoes. Present indications are that primary thunderstorm development will begin early this afternoon over parts of LA, spreading quickly into MS. This corridor may see multiple waves of severe convection as storms redevelop upstream through the evening. Along with the strong tornado threat, very large hail and damaging wind gusts may occur with these storms. Consideration was made to introduce a small HIGH risk, but still too much uncertainty in the exact corridor of highest risk since moisture is not yet in place and there is no surface boundary to focus on. ..Hart/Wendt.. 11/29/2022 Read more

MD 1976 CONCERNING HEAVY SNOW FOR PORTIONS OF EASTERN MINNESOTA INTO NORTHWEST WISCONSIN
Mesoscale Discussion 1976 NWS Storm Prediction Center Norman OK 0945 AM CST Tue Nov 29 2022 Areas affected...Portions of eastern Minnesota into northwest Wisconsin Concerning...Heavy snow Valid 291545Z - 292145Z SUMMARY...Areas of 1 inch per hour snow rates are possible in eastern Minnesota into northwest Wisconsin this afternoon. The heaviest snowfall rates should occur from 12 PM to 4 PM CST. DISCUSSION...A band of snow within the Upper Midwest has produced generally light to moderate snowfall rates from southwestern Minnesota into far northwest Wisconsin. Recent observations within the last hour near the Twin Cities indicate snowfall rates of 1 inch per hour are occurring. This broad area of snow is being driven by 850-700 mb frontogenesis. Through the afternoon, the upper trough over the northern Plains is expected to become more negatively tilted as it progresses into the Upper Midwest and Great Lakes regions. At the surface, a low currently in northwest Missouri should track northeastward and deepen. This should act to increase the frontogenetic forcing and lead to snowfall rates of 1 inch per hour, particularly within locally heavier snow bands. Heavier snowfall rates will move from southwest to northeast along with the better low/mid-level ascent from about 12 PM to 4 PM CST. ..Wendt.. 11/29/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MQT...DLH...ARX...MPX...DMX... LAT...LON 45009388 46029320 46809251 47489153 47539062 47139000 46308993 45059125 44269203 43489320 43549365 44109440 45009388 Read more