Severe Storms

WW 491 SEVERE TSTM IA MN WI 231635Z - 240000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 491 NWS Storm Prediction Center Norman OK 1135 AM CDT Sat Jul 23 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern Iowa Southeast Minnesota Western Wisconsin * Effective this Saturday morning and evening from 1135 AM until 700 PM CDT. * Primary threats include... Widespread damaging winds likely with isolated significant gusts to 75 mph possible Scattered large hail and isolated very large hail events to 2 inches in diameter possible A tornado or two possible SUMMARY...A cluster of storms will likely continue to intensify and progress east-southeastward across the region through the afternoon, with additional near-frontal development possible across southern Minnesota/northern Iowa this afternoon. The severe thunderstorm watch area is approximately along and 70 statute miles north and south of a line from 50 miles south southwest of Minneapolis MN to 50 miles east southeast of La Crosse WI. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for 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. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 488...WW 489...WW 490... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 29030. ...Guyer Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1050 AM CDT Sat Jul 23 2022 Valid 231700Z - 241200Z ...NO CRITICAL AREAS... The previous forecast (see below) remains on track. ..Squitieri.. 07/23/2022 .PREV DISCUSSION... /ISSUED 0200 AM CDT Sat Jul 23 2022/ ...Synopsis... A strong midlevel shortwave trough will track east-southeastward across the northern Plains, while an attendant cold front sweeps southward across the central Plains during the afternoon. Ahead of the approaching cold front, southerly surface winds will strengthen across the central and southern Plains, where 20-25 percent minimum RH is expected. Given receptive fuels across the region, elevated conditions will be possible -- especially from the northern TX Panhandle northward through western KS and western NE. Behind the cold front, breezy/gusty northerly surface winds and low RH will persist across western NE and western KS into the evening hours. However, scattered showers/thunderstorms along/ahead of the southward-advancing cold front casts uncertainty on the duration of elevated conditions across the aforementioned areas, precluding Elevated highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0487 Status Updates
STATUS REPORT ON WW 487 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NE PIA TO RFD TO 30 WNW BEH. ..MOORE..07/23/22 ATTN...WFO...LOT...DVN...MKX... STATUS REPORT FOR WS 487 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC037-043-063-089-091-093-197-231640- IL . ILLINOIS COUNTIES INCLUDED ARE DE KALB DUPAGE GRUNDY KANE KANKAKEE KENDALL WILL THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

No watches are valid as of Fri Jul 22 18:00:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Fri Jul 22 2022 Valid 231200Z - 241200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN MINNESOTA...CENTRAL/SOUTHERN WISCONSIN AND NORTHERN IOWA... ...SUMMARY... Severe thunderstorms are expected Saturday across parts of the Upper Midwest. A few tornadoes, significant damaging winds, and large to very large hail will accompany these storms. ...Upper Midwest Vicinity... A compact but strong midlevel shortwave trough will develop eastward across the Upper MS Valley and Great Lakes on Saturday. An associated band of enhanced westerly mid/upper level flow will overspread the region as a surface low migrates from SD toward the lower MO Valley. A cold front will shift east across the Dakotas/NE during the afternoon, while a warm front lifts northward across southern MN into central WI. Morning showers and cloud cover may limit northward progression of the front, and some minor trimming of higher severe probabilities across northern WI reflects this trend with the Day 2 update. Ahead of the cold front and south of the warm front, surface dewpoints in the upper 60s to low 70s are forecast beneath steep midlevel lapse rates, fostering a corridor of moderate to strong instability. As large-scale ascent increases by midday, ongoing thunderstorms across west-central MN will increase in intensity and coverage. Effective shear magnitudes greater than 45 kt will favor initial supercells capable of very large hail and damaging gusts. Forecast soundings depict favorably curved low-level hodographs with a deep inflow layer and moderate to strong low-level shear. A couple of tornadoes will be possible with any supercell that can maintain discrete storm mode as convection shifts eastward. A southwesterly low-level jet is expected to increase by late afternoon into the evening. This will foster upscale developing into a bowing MCS across southeast MN/northern IA and central/southern WI. The MCS should develop east/southeast along the strong instability gradient draped across the region. A risk for damaging gusts, some greater than 65 kt, will increase as this occurs and a swatch of wind damage is expected across the Enhanced (level 3 of 5) risk area. Additionally, low-level shear will remain favorable for mesovortex formation along the leading edge of the east/southeastward-advancing convection and a few tornadoes will remain possible into northern IA and across central/southern WI. ...Nebraska into western IA... Isolated to widely scattered thunderstorms are expected to develop ahead of the surface cold front in a deeply mixed and strongly unstable airmass. Very steep low-level lapse rates and modest vertical shear will support strong to locally damaging gust potential and perhaps a few instances of hail. ...OH...IN...Northern KY... Strong storms may be ongoing Saturday morning, producing gusty winds and small hail. An outflow boundary associated with this weakening activity may become a focus for redevelopment during the afternoon amid a moist and unstable airmass across parts of IN into southwest OH/northern KY. These storms could produce gusty winds and marginally severe hail during the afternoon before diminishing by evening. ..Leitman.. 07/22/2022 Read more

MD 1548 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN OHIO TO SOUTHERN NEW YORK
Mesoscale Discussion 1548 NWS Storm Prediction Center Norman OK 1150 AM CDT Fri Jul 22 2022 Areas affected...Eastern Ohio to southern New York Concerning...Severe potential...Watch unlikely Valid 221650Z - 221845Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorm development is expected in the coming hours, and a few storms may intensify enough to pose a damaging wind risk. This potential is expected to remain isolated, and a watch is not anticipated. DISCUSSION...Latest GOES visible imagery continues to show building cumulus across eastern OH to southern NY ahead of a broad surface trough that is approaching from the west. Low-level water vapor imagery reveals a few deeper towers developing in the vicinity of a decaying MCV over southern NY/northern PA as well as across eastern OH. A recent ACARs sounding from Buffalo, NY revealed minimal inhibition, which supports trends noted in recent RAP mesoanalyses. These trends, combined with the noted signatures in low-level water vapor imagery, suggest that convective initiation appears likely in the next 1-2 hours. Additional convection is expected to develop through the early and mid afternoon hours. As thunderstorms mature, 30-40 knot mid-level flow may support a few organized cells and/or clusters. Poor mid-level lapse rates will hinder the potential for severe hail, but steepening boundary-layer lapse rates will support a damaging wind potential for the afternoon. Thunderstorm coverage will likely remain isolated to widely scattered given the modest forcing for ascent, which appears at this time to mitigate the need for a watch. ..Moore/Goss.. 07/22/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ALY...PHI...BGM...BUF...CTP...PBZ...CLE... LAT...LON 40958196 41778017 42667768 42887654 42817534 42527463 41797452 41147524 40387711 40117965 40008095 40028161 40288204 40958196 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Fri Jul 22 2022 Valid 221700Z - 231200Z ...CRITICAL FIRE WEATHER AREA FOR PARTS OF THE SNAKE RIVER PLAIN... Critical conditions are still expected across portions of the Snake River Plain (see previous forecast below for more details). At least locally Elevated conditions may extend as far east as the northern High Plains this afternoon in tandem with surface low development as a mid-level trough traverses the northern Rockies through the period. The primary factor in withholding fire weather highlights was the lack of a more widespread 15+ mph sustained wind field. Deep-layer ascent accompanying the mid-level trough will also trigger isolated thunderstorms across the central and northern Rockies by afternoon peak heating given the presence of adequate mid-level moisture. Isolated dry thunderstorm highlights have been added where coverage of fast-moving high-based storms is expected to be greatest, and where fuels are receptive to fire spread. In addition, brief but erratic wind gusts may accompany the stronger storms, potentially exacerbating the spread of ongoing fires, or agitating lightning-induced ignitions. Otherwise, locally Elevated conditions are still expected this afternoon across portions of the Great Basin, and within a confined area of southern California (Tejon Pass into the Tehachapi mountains). ..Squitieri.. 07/22/2022 .PREV DISCUSSION... /ISSUED 0202 AM CDT Fri Jul 22 2022/ ...Synopsis... A midlevel shortwave trough and enhanced west-southwesterly flow aloft will track eastward across the Northern Great Basin into the northern Rockies during peak heating, while a secondary shortwave impulse crosses the Sierra late in the period. ...Northern Great Basin into the central/northern Rockies... As the strong/deep west-southwesterly flow overspreads portions of the Northern Great Basin, deep boundary-layer mixing will result in single-digit to lower teens RH amid breezy westerly surface winds. The best overlap of strong winds and low RH is expected along portions of the Snake River Plain -- where 20-25 mph sustained westerly surface winds (with higher gusts) will overspread critically dry fuels. Therefore, Critical highlights have been maintained over this area. Farther west in the lee of the Sierra, dry/breezy conditions will be possible as modest west-southwesterly flow preceding the second midlevel impulse crosses the area. However, these conditions appear too brief/localized for highlights. ...Parts of Southern California... Enhanced onshore flow peripheral to the midlevel trough will result in warming/drying over parts of inland southern California -- where widespread single-digit to lower teens RH is expected. These dry conditions, coupled with breezy/terrain-enhanced surface winds, will support locally enhanced fire-weather conditions along the I-5 corridor. Highlights have been withheld owing to the localized nature of the fire-weather threat. ...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 1119 AM CDT Fri Jul 22 2022 Valid 221630Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS CENTRAL PLAINS TO THE UPPER MIDWEST...NORTHERN PLAINS...UPPER OH RIVER VALLEY...AND NORTHERN UTAH... ...SUMMARY... Isolated strong to severe thunderstorms may occur from parts of the central and northern Plains into the Upper Midwest, separately over parts of northern Utah, and the upper Ohio Valley/north-central Appalachians region. ...Synopsis... Mid-morning water vapor imagery continues to track a stout upper ridge over AZ as well as several shortwave perturbations embedded within a swath of relatively strong zonal flow across the northern tier of the CONUS. Of these, the shortwave troughs translating across the Pacific Northwest and across the upper Midwest/Great Lakes regions are notable and will likely drive severe weather potential for parts of the Northern Plains and upper OH River Valley this afternoon and/or tonight. Other notable surface features (outlined below) will support additional severe weather concerns this afternoon. ...Central Plains into the Midwest... A residual outflow boundary from overnight and early-morning convection is noted across eastern IA with a weak surface trough/warm front draped across NE into eastern CO/western KS. Although gradual clearing is noted in latest visible imagery across parts of eastern NE and IA, weakening convection and showers are stunting daytime heating with temperatures struggling to climb past the mid-70s. A region of dry, subsident air is gradually moving into the region behind the Midwest/Great Lakes shortwave trough, and should aid in continued clearing and gradual destabilization through the day. Thunderstorm potential will likely be greatest this evening as the low-level jet increases in response to the approaching disturbance from the Pacific Northwest, boosting isentropic ascent over the residual boundary/weak warm front in the process. Thunderstorm coverage remains somewhat unclear given spread in latest hi-res guidance, though 30-40 knot northwesterly flow aloft should support some storm organization and the potential for wind/hail. Severe wind potential may be locally maximized across northern IL into northern IN overnight if an organized cluster/line can become established and propagate east along the outflow/warm frontal boundary. However, this potential remains too conditional to warrant higher probabilities at this time. ...Upper OH River Valley/Central Appalachians... Building cumulus is noted across eastern OH into northern PA ahead of an upper level disturbance and weak surface pressure trough approaching from the west. Destabilization will continue through the late morning/early afternoon as temperatures climb into the upper 80s. Although mid-level lapse rates sampled by regional 12 UTC soundings are modest, rich boundary-layer moisture combined with diurnal heating should yield 1000-1500 J/kg MLCAPE by early afternoon with limited inhibition. 30 knot winds in the lowest 3 km (sampled by regional VWPs) coupled with steep low-level lapse rates should support a damaging wind potential across the region as isolated to scattered thunderstorms develop through the afternoon. ...Northern Plains... Surface pressure falls are noted across the northern High Plains this morning as the Pacific Northwest disturbance approaches the northern Rockies. This trend will continue through the day and help consolidate a broad frontal zone draped along the international border. Thunderstorm development remains possible in the vicinity of a developing triple point this evening as the upper low shifts into the Plains. Warm temperatures between 850-700 mb sampled by the 12 UTC BIS and GGW soundings and modest boundary-layer moisture will act as a mitigating factors for storm coverage and intensity despite strong dynamic ascent. However, storms that can mature may become organized given the elongated forecast hodographs, and could support a hail/wind threat. A zone of enhanced ascent appears probable early Saturday morning along the ND/SD border either along the surface cold front, along an outflow boundary from tonight's convection, within a zone of strong isentropic ascent, or a combination of these factors. Regardless, many CAMs show this potential for additional development, which may pose a severe risk prior to sunrise for parts of the lower Red River Valley. ...Northern Utah... The 12 UTC soundings from SLC sampled a dry boundary layer along with adequate mid-level moisture and lapse rates to support around 100 J/kg MUCAPE. Mostly clear skies will support deep boundary-layer mixing and inverted-v profiles favorable for strong to severe downbursts by mid/late afternoon. Isolated to scattered thunderstorms are expected across the region as ascent from the passing Pacific Northwest disturbance glances the region to the north, supporting the severe wind potential. ..Moore/Goss.. 07/22/2022 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0808 AM CDT Fri Jul 22 2022 Valid 251200Z - 301200Z ...DISCUSSION... A broad upper cyclone will move east over southern Canada during much of the Day 4-8 time frame as upper-level high pressure extends across the south-central and southeast U.S. A cold front will move east across the northeast U.S. on Monday/Day 4 accompanied by some risk for strong/severe storms. At least low severe probabilities may eventually be warranted as frontal location/timing uncertainties are resolved. As the cold front moves offshore across New England late Monday, the western portion of the front will extend from the mid-Atlantic west across the OH/TN Valley region and central Plains on Tuesday/Day 5 and Wednesday/Day 6. Thunderstorms will be possible in the vicinity of the front each day, however variability regarding the overlap of favorable shear/instability remains too great to delineate daily severe risk areas/probabilities. By Day 7/8, the upper low sharpens over Ontario Province south across the Great Lakes/northeast states, resulting in stronger mid-level flow from the OH/TN Valley region into the northeast. Although daily predictability remains low at this extended range, some severe threat may ultimately exist in these areas in the vicinity of a surface cold front. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Thu Jul 21 2022 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN PLAINS...CENTRAL PLAINS INTO THE MIDWEST...AND PARTS OF THE NORTHEAST... ...SUMMARY... Isolated strong to severe thunderstorms may occur Friday into Friday night from parts of the central and northern Plains into the Upper Midwest, and over portions of the Northeast. ...Central Plains/Midwest... Considerable uncertainty remains regarding convective evolution from the central Plains into the Midwest Friday into Friday night. The most likely area of surface-based storm development appears to be across southwest NE into northwest KS, where strong heating and moderate destabilization is expected near/east of a weak surface low. Any development in this area could evolve into a multicell cluster capable of locally severe gusts and perhaps some hail. Other late afternoon/early evening development cannot be ruled out farther east, where one or more outflow boundaries may be left over from morning convection. Moderate instability and modest deep-layer shear would support an isolated severe hail/wind threat with any such development. Finally, one or more elevated clusters may develop late Friday night, in response to an increasing low-level jet and a vigorous mid/upper-level shortwave trough moving through the Dakotas. Should this occur, some threat for isolated severe hail/wind may persist into the overnight hours into parts of the Midwest. ...Dakotas into northwest MN... A vigorous mid/upper-level shortwave trough is forecast to move from the northern Rockies towards the Dakotas by Friday evening. In conjunction with this system, a surface low is forecast to develop somewhere over northeast MT/southern SK and move southeastward over the Dakotas. Guidance varies regarding the extent of destabilization near/north of a surface boundary that will be draped near the international border, but there is some potential for vigorous convection to develop across southeast SK/southwest MB and spread southeastward into parts of ND/northwest MN during the afternoon/early evening, potentially posing some threat of hail and strong wind gusts. Late Friday night into Saturday morning, an elevated cluster of storms may develop across southeast ND/northeast SD and begin moving east-southeastward, with a threat of isolated hail and strong/locally severe gusts. ...Northeast... Diurnal heating and sufficient low-level moisture will result in moderate destabilization across parts of the Northeast on Friday. Midlevel flow is expected to gradually weaken through the day, but remain sufficient to support 30-40 kt of effective shear, which will support a conditional threat of organized convection. With generally weak large-scale ascent and the lack of any notable focusing mechanisms, coverage and intensity of storm development remain uncertain, but storms capable of isolated damaging winds will be possible, primarily during the afternoon into the early evening. ..Dean.. 07/21/2022 Read more

WW 0480 Status Updates
STATUS FOR WATCH 0480 HAS NOT BEEN ISSUED YET Read more

WW 480 SEVERE TSTM MD NC VA CW 211705Z - 220000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 480 NWS Storm Prediction Center Norman OK 105 PM EDT Thu Jul 21 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Maryland Eastern Shore Central and Northeast North Carolina Southern and Southeast Virginia Coastal Waters * Effective this Thursday afternoon and evening from 105 PM until 800 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A cluster of thunderstorms developing over north-central North Carolina will track east-northeastward across the watch area through the afternoon. Damaging winds are the main threat. The severe thunderstorm watch area is approximately along and 60 statute miles north and south of a line from 25 miles south of Greensboro NC to 20 miles south of Wallops VA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for 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. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 479... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25025. ...Hart Read more

MD 1534 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF CENTRAL AND EASTERN VIRGINIA AND CENTRAL NORTH CAROLINA
Mesoscale Discussion 1534 NWS Storm Prediction Center Norman OK 1138 AM CDT Thu Jul 21 2022 Areas affected...parts of central and eastern Virginia and central North Carolina Concerning...Severe potential...Watch possible Valid 211638Z - 211845Z Probability of Watch Issuance...60 percent SUMMARY...Thunderstorms are forecast to develop this afternoon across central portions of North Carolina and Virginia. Potential for locally damaging winds with these storms may warrant WW consideration. DISCUSSION...Latest visible satellite loop shows a relative minimum in cloud cover from portions of central North Carolina northward across central Virginia, south of the northern Virginia cold front and northeast of an MCV crossing west-central North Carolina. With surface dewpoints in the mid to upper 70s across this region, heating has pushed mixed-layer CAPE values into the 2000 to 2500 J/kg range. Initial development of storms within this destabilizing environment is occurring near the aforementioned MCV. With time, storm coverage is expected to expand northeastward to the vicinity of the slowly southeastward-advancing cold front. Given moderate westerly flow at low to mid levels, and some increase in the mid-level winds with time, organized storms -- and some later upscale growth into bands -- is expected. Given accompanying/increasing potential for locally damaging wind gusts, WW may become needed over the next hour or so. ..Goss/Hart.. 07/21/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...LWX...RAH...RNK...GSP... LAT...LON 35398098 36198016 36397956 36997906 37817891 38057885 38867715 38647624 37717624 36577687 35427899 35398098 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu Jul 21 2022 Valid 211630Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF NEW ENGLAND...THE MID-ATLANTIC...AND SOUTHEAST STATES... ...SUMMARY... Scattered severe thunderstorms capable of producing mainly damaging wind gusts appear possible over parts of the Northeast and Southeast, today through this evening. ...Northeast States... An upper low is tracking across southern Quebec today, with strong westerly flow aloft across all of NY and New England. Hot/humid surface conditions are prevalent across this region with dewpoints in the upper 60s and 70s, and temperatures near 90F. This will yield afternoon MLCAPE values of over 2000 J/kg. Scattered thunderstorms have begun to develop ahead of an approaching cold front, and multiple lines/clusters of storms are expected through the afternoon. Damaging wind gusts will be the main threat, although the strongest cells may occasionally produce hail. An isolated tornado is also possible. Storms will spread eastward toward the coast by late afternoon/evening, where marine influences should temper convective intensity. ...NC/VA... A weak upper trough is noted in water vapor imagery over WV/western VA. This feature and its associated 30+ kt mid level speed max will track eastward across VA/NC this afternoon. Strong heating and ample low-level moisture will lead to scattered thunderstorm development, with a few severe storms expected. Damaging winds will be the main threat, mainly 18-01z. ...GA/AL/MS/LA/AR... A very moist and potentially unstable air mass is present today from northern LA/southern AR eastward across into MS/AL/GA. Forecast soundings across this region show relatively steep mid-level lapse rates and some dry air aloft, along max-heating MLCAPE values of 3000-4000 J/kg. Most 12z CAM solutions indicate considerable coverage of afternoon and evening thunderstorms across the SLGT risk area. Winds aloft are weak, which should limit convective organization/maintenance. However, thermodynamic conditions are quite favorable for pulse/multicell storms capable of damaging downburst winds. Thunderstorms will build/propagate southward during the evening before weakening due to diurnal cooling after dark. ..Hart/Broyles.. 07/21/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1115 AM CDT Thu Jul 21 2022 Valid 211700Z - 221200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 07/21/2022 .PREV DISCUSSION... /ISSUED 0153 AM CDT Thu Jul 21 2022/ ...Synopsis... A mid-level shortwave trough is forecast to move onshore across the northwestern periphery of a strong mid-level ridge centered over the Four Corners. Southwesterly flow aloft will increase accordingly, supporting locally gusty surface winds across much of the West. Beneath the ridge, very hot temperatures and isolated storms may produce locally elevated fire weather concerns across the southern Plains. ...Northern Great Basin into the central Rockies... Increasing southwesterly flow aloft ahead of the advancing trough should support an uptick in downslope winds off the higher terrain of the Great Basin and central Rockies this afternoon and evening. While not particularly strong, enhanced momentum transport and local terrain effects will aid occasional gusts to 20 mph. Given afternoon RH values below 15% and very dry fuels across much of the West, some localized fire weather threat will likely develop. The greatest confidence in a few hours of locally elevated conditions will remain across portions of southern OR, ID, into central WY. Elsewhere across the West, periodic dry and gusty conditions will be possible, but sustained elevated fire weather conditions are not expected. ...Southern Plains... Warm temperatures and low surface RH are again forecast beneath the strong upper ridge. Winds are forecast to be weak but may occasionally reach near 15 mph through the afternoon. These conditions may contribute to locally elevated fire weather concerns given drought-stricken fuels. The strong daytime heating will also support isolated afternoon thunderstorms across much of the southern Plains. While not dry given PWAT values of 1.8 inches, occasional lightning strikes may result in ignitions of highly receptive fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0479 Status Updates
STATUS FOR WATCH 0479 HAS NOT BEEN ISSUED YET Read more

WW 479 SEVERE TSTM CT MA ME NH NY RI VT CW 211540Z - 220000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 479 NWS Storm Prediction Center Norman OK 1140 AM EDT Thu Jul 21 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Connecticut Western and Central Massachusetts Maine New Hampshire Eastern New York Northern Rhode Island Vermont Coastal Waters * Effective this Thursday morning and evening from 1140 AM until 800 PM EDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Multiple waves and clusters of strong to severe storms are expected to spread across New York and much of New England this afternoon. Strong winds aloft and hot/humid conditions will result in a risk of damaging wind gusts and some hail in the strongest cells. The severe thunderstorm watch area is approximately along and 95 statute miles east and west of a line from 165 miles north northeast of Berlin NH to 40 miles south southwest of Windsor Locks CT. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for 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. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25035. ...Hart Read more

No Mesoscale Discussions are in effect as of Wed Jul 20 17:57:21 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Wed Jul 20 2022 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND SOUTHEAST/CAROLINAS... ...SUMMARY... Scattered severe thunderstorms capable of producing mainly damaging wind gusts appear possible over parts of the Northeast and Southeast on Thursday. ...Northeast... A weakening mid/upper-level trough and attendant cold front will move through parts of the Northeast and New England on Thursday. In advance of the front, diurnal heating of a relatively moist airmass will result in moderate destabilization, with MLCAPE rising into the 1500-2000 J/kg range. Initial development may occur as early as late morning, with an increase in storm coverage and intensity expected as convection spreads eastward through the afternoon. Effective shear in the 30-40 kt range will support the potential for organized multicell clusters and a few supercells. Damaging wind gusts are expected to be the most prominent threat, as low-level lapse rates steepen across the region prior to storm arrival. Modestly enhanced low-level flow/shear (0-1 km SRH potentially increasing to 100+ m2/s2) will also support a potential for a tornado or two with any sustained supercells. Despite relatively weak midlevel lapse rates, isolated hail will also be possible, especially with any discrete cells. ...Southeast into the Carolinas... Rich low-level moisture and strong diurnal heating will support moderate-to-strong destabilization across much of the Southeast by afternoon. The details of storm development and evolution remain somewhat uncertain, and will depend to some extent on the impact of prior-day convection, which may persist into the early morning across some areas. However, multiple storm clusters are likely to evolve by afternoon. Deep-layer shear will generally remain rather weak, though slightly enhanced midlevel flow on the fringe of the mid/upper-level trough passing to the north will influence the region, and potentially support some modest storm organization. The primary threat is expected to be damaging wind gusts resulting from wet microbursts and/or outflow-driven clusters, though the magnitude of instability may support some isolated hail as well. ..Dean.. 07/20/2022 Read more

WW 0477 Status Updates
STATUS FOR WATCH 0477 HAS NOT BEEN ISSUED YET Read more