Severe Storms

MD 1575 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR NORTHEAST OHIO TO SOUTHWESTERN NEW YORK
Mesoscale Discussion 1575 NWS Storm Prediction Center Norman OK 1210 PM CDT Sun Jul 24 2022 Areas affected...Northeast Ohio to southwestern New York Concerning...Severe potential...Watch likely Valid 241710Z - 241915Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms will continue to develop through the afternoon hours and will pose a threat for strong to severe winds. A watch is likely within the next hour. DISCUSSION...A field of growing cumulus is noted from northeast OH into northwest PA with a few deeper convective towers becoming evident, one of which has rapidly intensified within the past 20 minutes. In the absence of stronger surface/low-level forcing, this activity is likely being fostered by broad ascent ahead of a mid-level perturbation across the Great Lakes, aided by rapidly decreasing MLCIN as surface temperatures warm into the mid 80s (based on a modified 15 UTC BUF sounding). While thunderstorm coverage in the near-term is somewhat uncertain given the weak/broad forcing for ascent, continued destabilization through the day should support the maintenance of the deepening convection. Strong winds (upwards of 40-50 knots) are noted within the lowest 3 km of regional soundings and VWP observations, which suggests that any developing storm will pose a strong to severe wind risk. 0-6 km bulk shear values near 35-40 knots will support storm organization, including the potential for supercells capable of large hail. A watch will likely be needed within the hour to address this concern as addition thunderstorms mature through the early afternoon. ..Moore/Guyer.. 07/24/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BGM...BUF...CTP...PBZ...CLE... LAT...LON 41298220 41928080 42707883 42897742 42567674 41897643 41327665 40967736 40797928 40788068 40898179 41048215 41298220 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Sun Jul 24 2022 Valid 241630Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHEAST/LOWER GREAT LAKES... ...SUMMARY... Severe thunderstorms are expected to develop across the lower Great Lakes vicinity into St. Lawrence Valley by late this afternoon, with a threat for damaging wind gusts and a couple tornadoes. ...Lower Great Lakes and vicinity... Scattered thunderstorms are expected to develop this afternoon ahead of a southeastward-moving cold front. This will be influenced by an eastward-ejecting shortwave trough over Michigan/Upper Great Lakes, with corresponding enhancements to forcing for ascent and an increase in deep-layer wind profiles. Modest low/middle-level lapse rates will offset favorable low-level moisture enough to keep MLCAPE maximized at 1000-1500 J/kg in a narrow corridor east of the Lower Great Lakes, but with 40-50-kt effective-shear magnitudes and 150-300 m2/s2 effective SRH in support of mixed supercell/multicell modes and possible some bowing segments. Damaging winds will be the most common hazard, but some hail and/or a tornado risk may also exist as well. Farther southwest, stronger heating (especially outside of a residual cluster/cloud debris across northeast Illinois into northern Indiana) and higher moisture content will also support severe storms within a somewhat weaker deep-layer shear environment across Illinois/Indiana and vicinity. Multicell clusters should be the most prevalent severe mode with wind damage as the most common hazard. ...Central/northern Rockies and adjoining High Plains... Isolated to scattered thunderstorms are forecast to develop this afternoon, along a lengthy expanse of the interface between the eastern Rockies front and the High Plains. Activity should move roughly eastward onto the Plains, with more longevity/persistence likely in middle and southern segments of the outlook area with the main severe concern being isolated severe wind gusts. Diurnal heating will steepen lower/middle-tropospheric lapse rates in the presence of sufficient/residual low-level moisture advecting into the region in the post-frontal boundary layer. This should lead to a well-mixed low-level thermodynamic profile, beneath minimal MLCINH, with a plume of 500-1000 J/kg peak/preconvective MLCAPE that generally narrows northward. Though low-level moisture and theta-e should be somewhat lower on the northwest end, large-scale ascent ahead of the northern Rockies perturbation should overlie surface heating to contribute to very steep low/middle-level lapse rates. Continued easterly flow component north of the front/low should contribute to both favorable storm-relative boundary-layer winds for activity moving off the higher terrain, and strong veering of flow with height. Several loosely organized bands or clusters of convection may aggregate cold pools for a few hours in support of gust potential. Depending on subsequent mesoscale trends and convective guidance, some subset of this area may gain enough spatial certainty to warrant greater probabilities. ...Arizona... A cluster of storms continues to generally dissipate and move westward across the southern Arizona desert this morning. A relatively moist air mass persists across southeast Arizona in its wake where post-MCS insolation will be strong. Widely scattered storms should redevelop later this afternoon with slow westward movement off the mountains/higher terrain. The hot/well-mixed boundary layer could support some strong/potentially severe-caliber wind gusts later this afternoon through early evening. ..Guyer/Moore.. 07/24/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1108 AM CDT Sun Jul 24 2022 Valid 241700Z - 251200Z The previous forecast (see below) remains on track, with only minor changes made to the fire weather highlights to reflect the latest guidance consensus. ..Squitieri.. 07/24/2022 .PREV DISCUSSION... /ISSUED 0156 AM CDT Sun Jul 24 2022/ ...Synopsis... A compact midlevel shortwave trough will track eastward from the Northern Great Basin into the northern Rockies today. Within the base of the trough, deep/enhanced westerly flow will overspread parts of southern ID into western WY -- where single-digit to lower teens RH will develop during the afternoon. The combination of 15-20 mph sustained westerly surface winds, critically low RH, and receptive fuels will result in elevated to spotty critical fire-weather conditions this afternoon. In addition, increasing large-scale ascent ahead of the shortwave trough will encourage widely scattered, high-based thunderstorms over eastern ID into western MT. As these storms overspread a hot/deeply-mixed boundary layer and receptive fuels, isolated lightning-induced ignitions will be possible away from any precipitation cores. Farther south over the southern Plains, breezy southerly surface winds near 15 mph will develop in response to a weak surface low near northwest OK. The breezy surface winds, coupled with 20-25 percent minimum RH could lead to locally elevated conditions from the TX/OK Panhandles into western OK. However, these conditions appear too marginal/localized for Elevated highlights. ...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 1248 PM CDT Sat Jul 23 2022 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF NEW ENGLAND ACROSS THE MIDWEST... ...SUMMARY... Scattered severe storms will be possible Sunday from portions of New England west-southwestward across the Midwest/Ohio Valley. Damaging wind gusts will likely be the primary severe risk. Locally damaging wind gusts will also be possible across portions of southern Montana and into the northern and central High Plains. ...New England west-southwestward across the Midwest... A cold front initially stretching from the upper Great Lakes to Kansas is forecast to move eastward across the Lower Lakes (eventually reaching the Northeast), and southeastward across the Ohio Valley/Midwest/central Plains through the period. This will occur as mid-level height falls gradually expand southward across the Great Lakes region south of a mid-level low/short-wave trough crossing southern Ontario and eventually moving into western Quebec. Ahead of the front, a moist boundary layer will undergo heating/destabilization through the day. Storms -- and possibly some lingering severe potential -- may be ongoing early along the front across the parts of the Midwest/upper Great Lakes, but bands of afternoon storms are forecast to initiate near and ahead of the front, from western New England west-southwestward to Illinois/Missouri. The strongest flow aloft is forecast from the Great Lakes to New England, which warrants an expansion of severe probabilities across portions of New England in this update. Locally damaging winds are expected as multiple clusters/convective bands evolve with time, across the entire slight risk area. In addition, a tornado or two will also be possible -- particularly across the Lower Great Lakes region and into western New England, where with isolated/rotating storms will be possible, given veering low-level winds beneath stronger west-southwesterlies through the mid troposphere. Risk may continue through the evening, though gradually diminishing with time as the cold front shifts slowly southeastward. ...Southern Montana into the northern and central High Plains... A couple of short-wave troughs are forecast to shift east-southeastward across the northern Intermountain Region, with the lead disturbance expected to cross the central High Plains through the afternoon/evening. As heating/modest destabilization occurs, thunderstorm development is expected -- initially over the higher terrain from southern Montana into Colorado. Eventually, storms may congeal into clusters, moving off the higher terrain and into the northern and central High Plains. Given dry/deeply mixed subcloud layer, a few damaging wind gusts can be expected, warranting MRGL risk upgrade. Risk should diminish through the late evening in most areas. ...Arizona... As daytime heating/mixing/destabilization maximizes through the afternoon across Arizona, scattered convective development is expected. It appears that with low-level easterly flow beneath mid-level southeasterlies, some potential for propagation of storms off the higher terrain into the lower deserts could occur, with gusty/locally damaging winds not entirely out of the question. However, risk appears a bit uncertain/limited at this time, precluding an areal depiction at this time. ..Goss.. 07/23/2022 Read more

MD 1564 CONCERNING SEVERE THUNDERSTORM WATCH 490... FOR SOUTHERN AND EASTERN OHIO INTO SOUTHWEST PENNSYLVANIA AND WEST VIRGINIA
Mesoscale Discussion 1564 NWS Storm Prediction Center Norman OK 1244 PM CDT Sat Jul 23 2022 Areas affected...Southern and eastern Ohio into Southwest Pennsylvania and West Virginia Concerning...Severe Thunderstorm Watch 490... Valid 231744Z - 231945Z The severe weather threat for Severe Thunderstorm Watch 490 continues. SUMMARY...Isolated damaging to severe winds will remain possible through the afternoon hours as an MCS continues to move east. However, a downstream watch is not currently anticipated given the overall weakening trends of the system. DISCUSSION...An ongoing MCS continues to push east/southeast into eastern and southern OH. In general, satellite imagery and echo top data all show weakening trends over the past 60 minutes as the system becomes increasingly outflow dominant. While a few wind damage reports have been noted, most surface stations support this trend with recent observed wind gusts generally in the 30-45 mph range. Downstream into southwest PA and WV, mostly clear skies ahead of the line has allowed for MLCAPE to increase to around 2000-2500 J/kg with little inhibition. This is fostering some re-development along parts of the outflow boundary (new, but isolated, convective towers are noted in latest IR imagery along the line), and these storms may continue to support a sporadic wind threat into WV and PA. Modest deep-layer flow sampled in downstream VWPs is supporting upwards of 20-25 knots of effective shear, which should limit the potential for robust storm intensification. Given these observations, a downstream watch is not currently anticipated, though trends will continue to be monitored. ..Moore.. 07/23/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CTP...LWX...RNK...PBZ...RLX...CLE...JKL...ILN... LMK... LAT...LON 38718377 39238322 40068221 40718157 41078103 41087904 40357855 39567866 38837922 37958034 37898227 38028323 38278388 38718377 Read more

WW 0490 Status Updates
STATUS REPORT ON WW 490 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NNW UNI TO 20 NNE ZZV TO 15 N CAK. ..MOORE..07/23/22 ATTN...WFO...CLE...RLX...PBZ... STATUS REPORT FOR WS 490 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS OHC009-013-019-029-059-067-081-099-111-115-119-121-127-151-157- 167-231840- OH . OHIO COUNTIES INCLUDED ARE ATHENS BELMONT CARROLL COLUMBIANA GUERNSEY HARRISON JEFFERSON MAHONING MONROE MORGAN MUSKINGUM NOBLE PERRY STARK TUSCARAWAS WASHINGTON PAC003-007-059-073-125-231840- PA . PENNSYLVANIA COUNTIES INCLUDED ARE ALLEGHENY BEAVER GREENE LAWRENCE WASHINGTON WVC009-029-051-069-073-095-103-231840- Read more

WW 490 SEVERE TSTM OH PA WV 231540Z - 232200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 490 NWS Storm Prediction Center Norman OK 1140 AM EDT Sat Jul 23 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Ohio Western Pennsylvania Northern West Virginia * Effective this Saturday morning and evening from 1140 AM until 600 PM EDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible SUMMARY...A cluster of storms across central Ohio at late morning will continue to progress east-southeastward this afternoon toward eastern Ohio, northern West Virginia and far western Pennsylvania. Strong to severe wind gusts will remain a possibility this afternoon. The severe thunderstorm watch area is approximately along and 50 statute miles east and west of a line from 20 miles east northeast of Akron OH to 50 miles southeast of Zanesville OH. 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 488...WW 489... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28030. ...Guyer Read more

WW 0489 Status Updates
STATUS REPORT ON WW 489 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 S FRM TO 25 NW MKT TO 30 E MSP. ..LEITMAN..07/23/22 ATTN...WFO...ABR...MPX...FSD... STATUS REPORT FOR WS 489 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC013-037-079-103-131-139-147-161-231840- MN . MINNESOTA COUNTIES INCLUDED ARE BLUE EARTH DAKOTA LE SUEUR NICOLLET RICE SCOTT STEELE WASECA 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

WW 489 SEVERE TSTM MN SD 231130Z - 231900Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 489 NWS Storm Prediction Center Norman OK 630 AM CDT Sat Jul 23 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Minnesota Northeastern South Dakota * Effective this Saturday morning and afternoon from 630 AM until 200 PM CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph likely Scattered large hail and isolated very large hail events to 2 inches in diameter possible A tornado or two possible SUMMARY...Initially isolated severe thunderstorms over the western parts of the watch area, in SD, are expected to expand/organize into a complex of severe thunderstorms through the remainder of the morning and into the afternoon. As this activity moves east-southeastward over the next several hours, a threat exists for both severe wind and occasional damaging hail. The tornado potential may increase toward the later hours of the watch time in MN. The severe thunderstorm watch area is approximately along and 50 statute miles either side of a line from 30 miles west of Aberdeen SD to 45 miles east of Mankato MN. 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. && OTHER WATCH INFORMATION...CONTINUE...WW 487...WW 488... 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 600. Mean storm motion vector 29040. ...Edwards Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1153 AM CDT Sat Jul 23 2022 Valid 231630Z - 241200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MIDWEST AND GREAT LAKES... ...SUMMARY... Damaging thunderstorm gusts (some over 75 mph), a few tornadoes and large to very large hail will be possible today across parts of the Upper Midwest and southern Great Lakes regions. ...Upper Midwest and southern Great Lakes... Current MCS across southern Minnesota with a recent history of measured strong/severe wind gusts should continue to organize/grow upscale as it thrives along the instability gradient toward southern Wisconsin and far northeast Iowa and possibly far northern Illinois through the afternoon. Damaging winds will likely be the most common hazard, but isolated large hail may also occur along with at least some tornado risk. Additional severe storms are also likely to develop along the southeastward-moving front this afternoon/early evening across southern Minnesota/northern Iowa southwestward into the central Plains, including parts of Nebraska and northern Kansas, where severe-caliber wind gusts will be most probable risk. ...Midwest/Ohio Valley... A quasi-linear MCS persists at midday across Ohio with at least some persistent potential for wind gusts, with a bit of rejuvenation possible as the downstream air mass diurnally destabilizes. Additional isolated/episodic severe storms will remain possible across northern Illinois/northern Indiana into Ohio along the trailing boundary and atop the remnant surface cold pool. A secondary round of storms via the Minnesota/Wisconsin MCS could move into parts of the region later tonight, most probable in areas farther to the north toward the Lake Michigan vicinity. ..Guyer/Moore.. 07/23/2022 Read more

WW 0488 Status Updates
STATUS REPORT ON WW 488 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 SSE VPZ TO 25 NW MIE TO 35 SSW MIE TO 40 SW CMH TO CMH TO 25 SSW CLE. ..MOORE..07/23/22 ATTN...WFO...IWX...IND...ILN...CLE... STATUS REPORT FOR WS 488 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS INC011-015-023-057-059-065-095-097-157-159-171-181-231740- IN . INDIANA COUNTIES INCLUDED ARE BOONE CARROLL CLINTON HAMILTON HANCOCK HENRY MADISON MARION TIPPECANOE TIPTON WARREN WHITE OHC045-083-089-129-231740- OH . OHIO COUNTIES INCLUDED ARE FAIRFIELD KNOX LICKING PICKAWAY 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

WW 0491 Status Updates
STATUS FOR WATCH 0491 HAS NOT BEEN ISSUED YET Read more

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