Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Wed Jun 01 2022 Valid 011300Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHERN HIGH PLAINS TO MID-SOUTH AND THE NORTHEAST... ...SUMMARY... Scattered severe thunderstorms are possible from the southern High to the Mid-South and in parts of the Northeast. Damaging winds and large hail will be the primary hazards, although a tornado or two is possible. The most intense storms will likely occur in west Texas and southeast New Mexico between 3 to 9 PM CDT. ...West TX to southeast NM... A surface cold front will accelerate its southward push as surface ridging builds across the High Plains in the wake of a shortwave trough passage in the central Great Plains. The 00Z HRW-ARW has best handled this morning's regenerative convection in the TX Panhandle, along with the placement of convective outflow attendant to the decayed remnants of an overnight MCS in OK. Robust boundary-layer heating will be confined to the south of the outflow in TX with the western extent of upper 50s to mid 60s surface dew points holding in the Permian Basin and Trans-Pecos. Initial surface-based thunderstorm development is expected in the early afternoon over the higher terrain, spreading east-southeast into this evening. A corridor of around 2500 J/kg MLCAPE along the southern periphery of moderate mid-level westerlies will support initial supercells with a very large hail threat, especially in the southeast NM and TX South Plains area. The undercutting nature of the surface front and amalgamation of robust updrafts might yield forward-propagating clusters, increasing the potential for 60-80 mph severe wind gusts. But the lack of a stronger low-level jet this evening, suggests overall severe coverage may be confined. ...OK to the Mid-South... Regenerative convection is ongoing across the TX Panhandle to northwest OK, just north of a pronounced surface cold front slowly sinking south. Low-level isentropic ascent along the frontal zone should sustain elevated convection through at least midday, with a threat for mainly isolated severe hail. See MCD 998 for additional short-term discussion. Remnants of this activity could eventually intensify this afternoon as it impinges on a destabilizing air mass in southeast OK where low 70s surface dew points remain prevalent. Farther downstream, decaying morning convection still persists from southwest MO to central IL. Weakening low-level warm theta-e advection should result in much of this activity further weakening into midday. Differential heating is anticipated with scattered thunderstorms developing in the mid-late afternoon along residual outflows/MCVs. Much of this corridor will lie on the southeast periphery of moderate mid-level southwesterlies, suggesting that multicell clusters will dominate. But an MCV drifting east from northeast OK may help focus greater potential for multicell clustering into the Mid-South, which would offer a threat of scattered damaging winds, isolated severe hail, and a brief tornado. ...NY/PA... Scattered elevated thunderstorms are ongoing across parts of southeast Ontario and will spread across northern NY this morning. Intensifying boundary-layer heating to the southwest of this activity should yield pronounced differential heating, which will be further aided by a north/south-oriented quasi-stationary front from eastern NY to the Lower DE Valley. Suppression of a mid-level ridge with approach of an upstream shortwave trough should aid in scattered surface-based thunderstorms this afternoon. Westerly low-level winds will limit SRH in the warm sector, but will be locally enhanced along the surface boundaries. Adequate mid to upper-level speed shear will exist for a few supercells and organized clusters capable of producing damaging winds and marginally severe hail. ..Grams/Mosier.. 06/01/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1025 AM CDT Tue May 31 2022 Valid 311700Z - 011200Z A few minor adjustments based on current observations and expected afternoon conditions. The forecast is on track otherwise. See the previous discussion for more details. ..Wendt.. 05/31/2022 .PREV DISCUSSION... /ISSUED 0155 AM CDT Tue May 31 2022/ ...Synopsis... Within broad western US troughing, the main shortwave is forecast to continues across the upper Midwest and into southern Canada weakening overall troughing across the western CONUS. A second and weaker wave embedded within the residual southwesterly flow will pass over the central Rockies through the afternoon while a cold front approaches. While flow aloft is forecast to gradually weaken through the day, a few hours of gusty winds will likely remain across NM and the southern High Pains supporting brief elevated fire weather concerns. ...Northern New Mexico and southern Colorado... Lingering mid-level flow behind the departing trough should support gusty low-level winds near and south of a slow moving cold front across the Four Corners and southern High Plains. Ahead of the front, area soundings show a warm and well-mixed boundary layer with RH of 10-20%. With surface winds expected to peak near 15-20 mph elevated fire weather conditions appear possible through the afternoon. Fire weather concerns will quickly subside later in the evening with weakening winds and recovering humidity after the frontal passage. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Tue May 31 15:27:01 UTC 2022.

No Mesoscale Discussions are in effect as of Tue May 31 15:27:01 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0737 AM CDT Tue May 31 2022 Valid 311300Z - 011200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST TX PANHANDLE TO SOUTHEAST KS... ...SUMMARY... The most likely corridor for scattered severe thunderstorms during the late afternoon and evening will be from the southeast Texas Panhandle across western and northern Oklahoma into southeast Kansas. A couple tornadoes, significant severe wind gusts, and very large hail are all possible. ...Northwest TX to southeast KS... A slowly southward-sinking surface cold front will become quasi-stationary and should be draped from southeast KS to the southeast TX Panhandle by this afternoon. The dryline will extend southwest and south from this frontal zone, struggling to mix east of Far West TX. Surface temperatures will warm well through the 90s across southwest OK and west TX in the warm/moist sector ahead of the dryline and front. Late afternoon scattered thunderstorm development is likely along both the front and dryline. While strong mid-level southwesterlies will be centered from southeast CO to eastern NE, the southern influence of this jet will yield favorable deep-layer shear with effective values around 35-45 kts. However, mid to upper-level winds will largely parallel the surface front, suggesting that upscale growth into multiple clusters which amalgamate into a broader MCS appears plausible. Some guidance such as the 00Z HRW-ARW and HRW-NSSL indicate potential for a forward-propagating MCS especially with convection off the dryline merging with frontal convection near the southeast TX Panhandle/southwest OK vicinity. Still, 09Z RAP/06Z NAM guidance suggest 850-mb negative theta-e advection this evening which would likely curtail a more widespread severe wind event and yield a decaying MCS tonight. ...MO to Lower MI... Ongoing convection from eastern KS into northern MO within a low-level warm conveyor will likely persist through at least midday and may not entirely decay this afternoon. The effects of this early-day convection on the degree of downstream destabilization renders below-average confidence in more specific convective evolution during the afternoon and evening. Will maintain a broad cat 2-SLGT risk as areas undisturbed by early-day convection will warm through the 80s and should yield at least a moderately unstable air mass. 50-65 mph wind gusts, large hail, and a tornado or two all appear plausible. ...Southwest New England vicinity... Confidence in sustained convective development is low, but a conditionally favorable corridor exists for a few severe thunderstorms along a backdoor cold front. If isolated thunderstorms can develop, a threat for marginally severe hail and localized damaging wind gusts may become realized. ...Central to eastern Gulf Coast... Much of the region will lie within very weak effective shear around 10-15 kts. This suggests that organized severe thunderstorms are highly unlikely, although pulse storms along sea breezes might produce locally strong gusts in wet microbursts and small hail. ..Grams/Mosier.. 05/31/2022 Read more

No watches are valid as of Mon May 30 14:29:01 UTC 2022.

MD 0974 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF NORTHERN NE INTO SOUTHERN SD
Mesoscale Discussion 0974 NWS Storm Prediction Center Norman OK 0927 AM CDT Mon May 30 2022 Areas affected...portions of northern NE into southern SD Concerning...Severe potential...Watch possible Valid 301427Z - 301600Z Probability of Watch Issuance...60 percent SUMMARY...Initial convection this morning will pose a threat for hail. While a watch may not be needed in the next 1-2 hours, a quick transition toward increasing severe potential is expected by midday into early afternoon. DISCUSSION...Occasionally intense convection is developing/ongoing across north-central NE this morning within the left exit region of the ejecting midlevel trough over the central High Plains. This activity is elevated at this time and may pose a threat for hail. With time, a warm front extending eastward from a low over east-central NE will lift northward across northeast NE into southeast SD, allowing mid 60s surface dewpoints to spread northward. Elevated convection across southeast SD into western IA may continue in this low-level warm advection regime, with a threat for hail. As heating continues through the morning, increasing destabilization will occur and capping will erode as stronger large-scale ascent shifts east by early to mid afternoon. Any initially elevated convection may then become surface based with time and transition from merely a hail concern to also include a damaging gust and tornado concern. The timing of the evolution of threat transitioning from a more isolated/elevated thunderstorm threat to a surfaced-based all-hazards concern remains somewhat unclear. A watch may not be needed in the next 1-2 hours, but could quickly become necessary around midday. ..Leitman/Thompson.. 05/30/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...OAX...ABR...GID...LBF...UNR... LAT...LON 41809858 41869787 42069725 42989566 43189554 43539543 43839537 44129548 44259576 44389620 44409703 44249820 44149849 43179984 42560037 41980040 41719995 41729928 41809858 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 AM CDT Mon May 30 2022 Valid 301300Z - 311200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN SOUTH DAKOTA...EXTREME SOUTHEASTERN NORTH DAKOTA AND WESTERN TO NORTHERN MINNESOTA... ...SUMMARY... Numerous severe thunderstorms are forecast across parts of the Northern Plains and Upper Mississippi Valley, with more scattered to isolated activity southward into the central Plains today into tonight. Large to giant hail, 60-80 mph gusts, and tornadoes are probable, including the possibility for a couple strong/long-tracked tornadoes. ...Synopsis... A large field of mid/upper-level cyclonic flow covers most of the western/central CONUS, anchored by a broad, complex cyclone covering much of the northern/central Rockies and Intermountain region. Primary vorticity maxima are evident in moisture-channel imagery over ID and central/eastern CO. The latter will eject northeastward today, become a compact, closed cyclone in its own right, and deepen considerably, with the 500-mb low reaching east-central SD by 00Z. Meanwhile the western vorticity lobe will remain weaker and meander around southern ID/northern NV through the period. The 11Z surface analysis showed a low over extreme southeastern ND, with cold front across eastern SD, south-central NE, northwestern KS, and central CO. Another low was noted along the dryline between GCK-HYS. The southern low will move northward, merge onto the front, and intensify through the day as its mid/upper counterpart approaches, until the lows become stacked over east-central SD around 00Z. By then the surface low should be occluded, with a triple point over southwestern MN and cold front arching across western IA, southeastern NE and northern/western KS. An outflow boundary from prior MCS activity was drawn across southwestern MN, northwestern IA and northeastern NE. This boundary may maintain its identity for a few more hours before retreating northward and becoming more ill-defined amidst intense surface-850-mb warm advection and moisture transport. Both ongoing and future/intervening convective processes cast uncertainty over specific timing/location of these features across the northern Plains and Upper Midwest into the afternoon. A dryline -- drawn initially across western KS, the TX Panhandle and southward into the Big Bend region -- will shift eastward to central KS, western OK and west-central TX this afternoon, before being overtaken from north-south by the cold front over KS tonight. ...Northern Plains/Upper Midwest... Scattered to numerous thunderstorms, offering tornadoes (some potentially strong/EF2+), severe wind and occasional large/damaging hail, will be possible into this evening. The greatest coverage should be in and near the "moderate" and "enhanced" categorical areas, where low-level convergence and convective coverage each should be greatest. The main convective regime should develop as early as midday near the retreating outflow boundary across northern NE, southeastern SD and southwestern MN, growing upscale and sweeping north-northeastward through the remainder of the outlook area this afternoon and early evening. With the passage of such an intense prior-overnight/morning MCS to the south and east of the axis of the outlook area, and a well-defined outflow boundary currently entirely displaced from the greater severe probabilities, normally there would be great concern/uncertainty about airmass recovery. To some extent there is -- especially with northern extent across ND/MN. This is not a "normal" scenario, however, with higher-end kinematic/mass response to the approaching cyclone fostering very intense, deep-tropospheric meridional flow (the direction needed for favorable thermodynamic recovery) and related strong surface-850-mb warm advection. The remains of the outflow boundary accordingly should disperse through the day, and the stable air to its north will modify and advect northward out of at least some, perhaps most, of the outlook area. The probabilities supporting "enhanced" and "moderate" risks have been adjusted slightly eastward and compacted on the west side, to reflect the likely tight gradient between substantial and limited severe potential. Still, the axis of greatest probabilities remains somewhat uncertain and fluid, and may need further adjustment through the day as mesoscale trends warrant. Despite the component of mean-wind and deep-shear vectors off the axis of strongest low-level forcing, the intense deep-layer lift may compel a relatively quick transition from initial supercellular characteristics to mixed modes, then quasi-linear with embedded LEWPs/bows/mesocirculations. Forecast soundings suggest 2000-3000 J/kg MLCAPE can develop across the corridor from northeastern NE to central MN before the main round of convection, along with 55-70-kt effective-shear magnitudes, and effective SRH in the 150-300 J/kg range, with long, somewhat curved hodographs. ...Western IA to eastern/southern KS... Widely scattered to isolated thunderstorms may develop late this afternoon into evening in a northeast/southwest corridor related to the front and dryline. Though coverage may be limited by stronger EML-related capping, and weaker deep-layer forcing that farther north, the parameter space in the adjacent warm sector will be favorable for supercells. The stronger MLCINH also may favor longer-lasting, relatively discrete modes, further supporting the somewhat conditional tornado and significant-hail threats. Enough guidance indicates development of at least a few sustained cells in this regime that unconditional probabilities have been increased. This area will reside near the axis of the strongest 300-700-mb flow this afternoon and evening, enabling 55-65-kt effective-shear magnitudes, while low-level shear/hodographs enlarge with the LLJ intensification in the 00-03Z time frame. Surface dew points generally in the 60s F and steep low/middle-level lapse rates will support a plume of 2000-3000 J/kg MLCAPE parallel to and ahead of the front and dryline. ..Edwards/Mosier.. 05/30/2022 Read more

WW 0286 Status Updates
STATUS REPORT ON WW 286 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 S EAU TO 30 NW EAU TO 70 NNW EAU. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0960 ..GLEASON..05/29/22 ATTN...WFO...MPX...ARX... STATUS REPORT FOR WS 286 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS WIC005-033-291640- WI . WISCONSIN COUNTIES INCLUDED ARE BARRON DUNN 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

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1009 AM CDT Sun May 29 2022 Valid 291700Z - 301200Z ...CRITICAL FIRE WEATHER AREA FOR NEW MEXICO INTO THE SOUTHERN HIGH PLAINS... No changes to the previous forecast. See the previous discussion for more detail. ..Wendt.. 05/29/2022 .PREV DISCUSSION... /ISSUED 0158 AM CDT Sun May 29 2022/ ...Synopsis... Southwesterly flow aloft is forecast to increase ahead of a strengthening mid-level trough diving across the Southwest and Great Basin. At the surface, a cold front will stall across the southern Great Basin, while a lee low deepens in response to lift from the approaching trough. Widespread strong surface winds are expected ahead of the trough from the southern Great Basin to the High Plains. The strong winds will overlap with a warm and very dry airmass supporting widespread critical fire weather concerns within dry fuels. ...Southwest and southern Great Basin... Strong flow aloft associated with the fast moving upper trough/jet streak is forecast to overspread much of NM and the southern Four Corners early today. At the same time, a lee low across southeastern CO should intensify, bolstering low-level southwesterly winds to 25-35 mph. In addition to the strong boundary-layer flow, area soundings show very warm temperatures and low to very low relative humidity. The favorable overlap of strong surface winds, low humidity and dry fuels will support widespread critical fire weather concerns. A few hours of localized extremely critical conditions also appear possible mainly across portions of eastern and central NM where the greatest potential for 30+ mph winds and sub-10% humidity may briefly coexist. Confidence in prolonged extremely critical conditions remains low owing to limited spatial and temporal coverage and slightly moderated fuels due to recent precipitation. Across the southern Great Basin, model guidance shows a few hours of stronger surface winds of 15-20 mph overlapping with humidity of 10-15% south of the stalled cold front. While coverage and duration of the stronger winds and lower surface humidity is expected to be limited, a few hours of elevated to near critical fire weather conditions will likely develop within areas of dry fuels. ...Southern High Plains... As the lee low begins to move eastward into the central Plains, a trailing dryline and associated surface trough should aid in the strengthening southwesterly low-level winds across much of the southern High Plains. While widespread critical meteorological conditions are expected, recent precipitation has moderated some fuels. This will limit the potential for more vigorous fire weather activity, particularly across portions of the southern and eastern TX Panhandle. A Critical Area will be maintained where the best overlap in 20-25 mph surface winds, surface RH below 15% and the most supportive fuels exists. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 0960 CONCERNING SEVERE THUNDERSTORM WATCH 286... FOR PORTIONS OF FAR SOUTHEASTERN MN INTO WESTERN WI AND FAR NORTHEASTERN IA
Mesoscale Discussion 0960 NWS Storm Prediction Center Norman OK 1002 AM CDT Sun May 29 2022 Areas affected...Portions of far southeastern MN into western WI and far northeastern IA Concerning...Severe Thunderstorm Watch 286... Valid 291502Z - 291630Z The severe weather threat for Severe Thunderstorm Watch 286 continues. SUMMARY...An isolated severe hail threat appears to be diminishing. Downstream watch issuance is not expected. DISCUSSION...Elevated thunderstorms driven largely by low-level warm advection have struggled to intensity over the past couple of hours across southern MN. This activity is approaching the eastern bounds of meaningful MUCAPE based on latest mesoanalysis. Deep-layer shear is also marginal, around 25-30 kt. Current expectations are for the already marginal hail threat associated with these thunderstorms to continue diminishing as they move eastward across western WI over the next couple of hours. The remaining valid counties in Severe Thunderstorm Watch 286 should be able to be cleared shortly, and downstream watch issuance is not expected. ..Gleason.. 05/29/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ARX...MPX... LAT...LON 44609187 45239209 45499155 45429077 44959037 44029034 43409083 43049176 43329186 43869161 44609187 Read more

WW 286 SEVERE TSTM MN WI 291035Z - 291800Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 286 NWS Storm Prediction Center Norman OK 535 AM CDT Sun May 29 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern and Central Minnesota West-Central Wisconsin * Effective this Sunday morning and afternoon from 535 AM until 100 PM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible Isolated damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Ongoing thunderstorm cluster over southwest Minnesota is expected to continue northeastward into more of southern and central Minnesota and eventually west-central Wisconsin. Strong wind gusts and large to very large hail are possible with this storm cluster over the next several hours. The severe thunderstorm watch area is approximately along and 60 statute miles north and south of a line from 40 miles west of Mankato MN to 70 miles northeast of Rochester MN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). 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 285... AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 24040. ...Mosier/Edwards Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 AM CDT Sun May 29 2022 Valid 291300Z - 301200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM CENTRAL NEBRASKA TO CENTRAL MINNESOTA... ...SUMMARY... Severe thunderstorm gusts of 60 to 85 mph, hail over 2 inches in diameter, and a few tornadoes are possible this afternoon and tonight from parts of Nebraska northeastward into southwestern and central Minnesota. ...Synopsis... The dominant mid/upper-level feature for this forecast period will be a substantial, currently negatively tilted synoptic trough -- apparent in moisture-channel imagery from the BC coastal vicinity southeastward over the inland Pacific Northwest, Great Basin and AZ. A vorticity lobe now located over southeastern OR is forecast to evolve into a closed 500-mb cyclone over southern ID in the next few hours, then move slowly southeastward toward southwestern WY through the remainder of the period. Several weak perturbations/vorticity maxima will eject northeastward across the central/southern Rockies and central/northern Plains today in the associated cyclonic flow, which will become strongly difluent across the northern Plains overnight. At the surface, 11Z analysis showed a primary/occluded cyclone centered over west-central ND, occluded front to southeastern ND, warm front from there to western/southern WI, and slow-moving cold to quasistationary front across eastern SD, northeastern through south-central NE, northwestern KS, to a low in CO between LHX-LIC. By 00Z, the northern low should move slowly eastward to northeastward to northeastern ND, with front arching over the eastern Dakotas to northeastern and south-central NE, then to another low over northeastern CO. This evening, the central High Plains low will shift/redevelop over northwestern KS and move into south-central/central NE. By 12Z, the main surface low should be over central or south-central NE, with cold front extending southwestward across western KS and southeastern CO, and moving southeastward again. A dryline -- initially drawn across western KS, the TX Panhandle, to the Big Bend area of TX, should move eastward into western OK and west-central TX this afternoon before retreating northwestward tonight. Capping and lack of stronger lift should suppress substantial convective potential on the dryline. ...Central Plains to parts of SD/MN... Three primary convective episodes across this region cumulatively will offer the great majority of severe-thunderstorm threats through the period, and are covered chronologically below. 1. An ongoing, broken band of thunderstorms over central/southern MN, with potential for damaging gusts and hail the next few hours. See SPC severe-thunderstorm watch 286 and related/nearby mesoscale discussions for near-term coverage of the wind/hail threat from this activity. 2. Widely scattered to scattered thunderstorms should develop as soon as midday to midafternoon over the higher terrain of northwest/north-central CO and southern WY, as the strongest large-scale ascent ahead of the deepening cyclone spreads over at least marginal low/midlevel moisture and steep lapse rates in the region. Isolated strong-severe gusts and hail will be possible with this "early" activity as it continues to spread/build east- northeastward onto the adjoining High Plains of northeastern CO/eastern WY, western NE and perhaps southwestern SD. Upon leaving the mountains, this regime will encounter a favorable environment of upslope flow with a substantial headlong component relative to storm motion, with the resultant strong storm-relative low-level winds enabling optimized lift. These factors should help to sustain this activity toward the Sandhills and Badlands into evening. The southeastern part of this regime over NE and perhaps south-central SD will be in the most-favorable low-level moisture and instability north of the boundary, should last longer than farther north/ northwest, and may merge with the next process in NE. 3. Scattered thunderstorms should develop near the boundary late this afternoon and this evening over central/northeastern NE, with early-stage supercell mode possible. Convection should evolve upscale to a clustered, bowing, probably cold-pool-driven complex with time into parts of northwestern IA, southeastern SD and southern/central MN, moving astride the instability/buoyancy gradient related to the baroclinic zone. Damaging gusts, large to very large hail, and a tornado or two may occur with any supercells, especially along the boundary where low-level moisture, SRH, hodograph size, and vorticity will be maximized. In the adjoining warm sector, steep low/middle-level lapse rates, strong diurnal mixing, and related favorable DCAPE will support wind potential. 2500-4000 J/kg peak/preconvective MLCAPE is expected near the front, supported by surface dew points in the 60s. By 00-06Z, this corridor also will be near the axis of the strongest 500-250-mb layer flow, contributing to effective-shear magnitudes commonly in the 50-70-kt range. Descending rear-inflow jet(s) also may transport momentum downward from the strong flow aloft, augmenting the cold pools and wind potential, until activity encounters more-stable boundary-layer air late tonight across the upper Mississippi Valley. ..Edwards/Mosier.. 05/29/2022 Read more

No watches are valid as of Sat May 28 13:54:02 UTC 2022.

No Mesoscale Discussions are in effect as of Sat May 28 13:54:02 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Sat May 28 2022 Valid 281300Z - 291200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF SOUTH DAKOTA AND NORTHERN NEBRASKA... ...SUMMARY... Severe thunderstorm gusts (some over 70 mph) and large hail are expected today across parts of the central and northern Plains. A few severe storms may also occur across parts of the southern Plains and in the Northeast. ...Synopsis... A progressive, mid/upper-level synoptic pattern is forecast through the period, as one trough leaves the eastern CONUS and another crosses the West. The eastern trough is devolving from an open-wave cyclone over PA at this time, and extends south-southwestward across the Carolinas , GA and the western FL Panhandle. The primary vorticity lobe and former closed circulation will move off the coastal Mid-Atlantic and south of Long Island/southern New England by 00Z, with the trough south-southwestward over the Outer Banks. Out west, a broad area of cyclonic flow aloft -- with several embedded shortwaves -- will spread across the area from the High Plains westward, along with synoptic-scale height falls and general cooling aloft. The strongest shortwave trough -- now approaching 130W, west of the Pacific Northwest -- will move inland around 00Z. This perturbation then should dig southeastward to NV and eastern OR by the end of the period. Meanwhile, a weaker yet still well- evident perturbation -- spotted in moisture-channel imagery over northern NV -- will eject northeastward to portions of WY and eastern MT by 0)Z, then across ND by 12Z tomorrow. The surface analysis at 11Z showed weak lows connected by troughs over southwestern MB, eastern SD and near SHR. A cold front extended from the SHR low across northern UT and southern NV. By 00Z, the SHR low should relocate to western SD, with cold front southwestward across WY. Moist return flow across the lower southern/central Plains will sharpen a dryline, expected to extend from northern Coahuila north-northeastward to near CDS, then northward over the extreme eastern Panhandles, western KS and the NE Sandhills by 00Z. By 12Z, the low should occlude and reach northwestern ND, with a frontal triple point over southeastern ND, warm front over central MN/WI, and cold front over central NE, northwestern KS and south-central CO. A separate cold front -- analyzed initially from eastern NY to the central Carolinas and southern GA -- should move eastward over the Mid-Atlantic and New England today. The front is expected to reach (and decelerate over) the eastern Carolinas around the end of the period. ...Northern Plains... Scattered high-based thunderstorms should develop during mid/late afternoon, in a band of maximized deep-layer ascent from north- central/northeastern WY southeastward to the NE Sandhills. This activity is expected to offer severe wind (with some gusts above 65 kt possible) as it moves northeastward across eastern WY, extreme southeastern MT, western/central SD, and west-central/north-central NE from late afternoon into this evening. Strengthening low-level convergence is expected amidst the mass response to the approaching synoptic and shortwave troughs, and near the surface low. Storm-relative flow in the low-level/inflow layer also should increase with time, strengthening vertical shear and helping to organize and sustain the activity. A limiting factor will be lack of greater low-level moisture, though time series of forecast soundings suggest a balance appears likely between enough mixing/dryness to foster a deep boundary layer supporting downdraft acceleration, and too little moisture for organized convection. Mixing/heating will be muted somewhat by increasing mid/high cloud cover. Nonetheless, with surface dew points generally in the mid 40s to low 50s F, steep low/middle-level lapse rates will support 300-800 J/kg peak/preconvective MLCAPE (locally higher in NE where greater moisture will advect by late afternoon). Increases of both low-level moisture and MLCINH with time will be counterbalancing effects across central/eastern SD and northern NE for a few hours this evening. Activity then should weaken late this evening into tonight over the eastern Dakotas as it encounters progressively more-stable boundary-layer conditions, though marginal hail/wind potential will persist northeastward into portions of MN. ...Northeast CONUS... Near a prefrontal trough, a gradual increase in convective coverage and strength should occur over the next few hours, with isolated strong to marginally severe gusts possible by midday to early afternoon. This should occur behind a departing belt of morning clouds/precip, as a sliver of favorably moist, inland warm sector destabilizes from a combination of warm advection and insolation. Meanwhile, midlevels will destabilize slightly with increasing large-scale ascent preceding the mid/upper trough. The result should be around 500-1000 J/kg preconvective MLCAPE and negligible MLCINH over southeastern NY and southern New England, with MLCAPE decreasing northeastward to around 200-500 J/kg in a narrower, eastward- shifting corridor across ME. Low-level winds/shear will be modest, but strong mid/upper flow will contribute to favorable deep shear (e.g., 30-35-kt effective-shear magnitudes and up to about 90 kt of cloud-layer shear) for a few organized multicell clusters, transient supercells or small bows capable of damaging gusts. ...Southern Plains... Isolated to widely scattered thunderstorms may initiate near the dryline during mid/late afternoon and move into a hot, well-mixed boundary layer with steep lapse rates and large dewpoint depressions. The main concern will be severe gusts. A conditional risk of significant-severe downburst gusts exists; however, uncertainties regarding overall severe-thunderstorm coverage currently preclude a 15% unconditional wind upgrade that would allow a 10%-sig area within. Intense heating will boost surface temperatures along and east of the dryline to the upper 90s to mid 100s F over the outlook area, removing MLCINH and fostering pulses of updrafts up and down the dryline. MLCAPE in the 1000-2000 J/kg range should be common, locally/briefly higher, with similar magnitudes of DCAPE. Veering of winds with height will contribute to 30-40 kt effective-shear magnitudes, despite lack of stronger mid/upper-level flow -- supporting some organization potential for any convection that can survive some thermodynamic limitations. Dry entrainment will be a restricting factor for convective growth/maintenance, but a few cells may mature and last long enough to produce strong to severe gusts, before remaining activity diminishes in the cooling evening boundary layer. ..Edwards/Mosier.. 05/28/2022 Read more

WW 0276 Status Updates
STATUS REPORT ON WW 276 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 NW FLO TO 35 SE GSO TO 25 NE DAN TO 25 NE LYH TO 20 SSW AOO. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0936 ..DEAN..05/27/22 ATTN...WFO...LWX...RAH...RNK...AKQ... STATUS REPORT FOR WT 276 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS DCC001-271640- DC . DISTRICT OF COLUMBIA COUNTIES INCLUDED ARE DISTRICT OF COLUMBIA MDC003-005-009-013-017-021-027-031-033-037-043-510-271640- MD . MARYLAND COUNTIES INCLUDED ARE ANNE ARUNDEL BALTIMORE CALVERT CARROLL CHARLES FREDERICK HOWARD MONTGOMERY PRINCE GEORGES ST. MARYS WASHINGTON MARYLAND INDEPENDENT CITIES INCLUDED ARE BALTIMORE CITY Read more

MD 0936 CONCERNING TORNADO WATCH 276... FOR PARTS OF THE MID ATLANTIC
Mesoscale Discussion 0936 NWS Storm Prediction Center Norman OK 0959 AM CDT Fri May 27 2022 Areas affected...Parts of the Mid Atlantic Concerning...Tornado Watch 276... Valid 271459Z - 271630Z The severe weather threat for Tornado Watch 276 continues. SUMMARY...The threat for locally damaging wind and a brief tornado will continue through the morning. DISCUSSION...A QLCS is ongoing this morning from parts of VA into central NC. Convective intensity and organization has been relatively limited over the last 1-2 hours, but with filtered insolation and modest destabilization noted downstream, some intensification is possible through the remainder of the morning into early afternoon, with MLCAPE generally expected in the 1000-1500 J/kg range. The recent VWP from KLWX depicts a favorably veering wind profile, and a brief tornado or two will remain possible with the stronger embedded circulations, in addition to a threat of damaging wind gusts with any stronger bowing segments. ..Dean/Thompson.. 05/27/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...LWX...RAH... LAT...LON 35917835 36977784 38417782 39197789 39587749 39577645 39187613 37357675 35997744 35697787 35747823 35917835 Read more

MD 0935 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR EASTERN NC INTO SOUTHEAST VA
Mesoscale Discussion 0935 NWS Storm Prediction Center Norman OK 0944 AM CDT Fri May 27 2022 Areas affected...Eastern NC into southeast VA Concerning...Severe potential...Watch possible Valid 271444Z - 271615Z Probability of Watch Issuance...60 percent SUMMARY...The threat for locally damaging wind and a couple of tornadoes may increase with time into early afternoon. New watch issuance is possible. DISCUSSION...Ahead of a QLCS to the west, discrete convection is gradually increasing across parts of eastern NC into southeast VA, within a warming and destabilizing environment. MLCAPE is currently in the 1000-1500 J/kg range, with some modest increase possible as diurnal heating continues. Area VWPs show moderate low/midlevel flow across the region, with sufficient effective shear for some organized storm structures. A few marginal supercells may evolve with time within this environment. Rather unidirectional flow is not overly supportive of a tornado risk, but with rich low-level moisture in place and the potentially favorable discrete/cellular mode, a couple of tornadoes will be possible, in addition to a threat of locally damaging wind gusts and marginal hail. Watch issuance is possible sometime later this morning in order to address these threats. ..Dean/Thompson.. 05/27/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...MHX...RAH...ILM... LAT...LON 34577811 36057740 36797713 37547662 37387594 35837588 34617710 34357775 34577811 Read more

WW 276 TORNADO DC MD NC VA WV CW 271020Z - 271800Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 276 NWS Storm Prediction Center Norman OK 620 AM EDT Fri May 27 2022 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of District Of Columbia Central and northern Maryland Central and northern North Carolina Central and northern Virginia Extreme northeastern West Virginia Coastal Waters * Effective this Friday morning and afternoon from 620 AM until 200 PM EDT. * Primary threats include... A few tornadoes possible Scattered damaging wind gusts to 70 mph possible SUMMARY...A gradual ramp-up of thunderstorm intensity and coverage should continue through the remainder of the morning in a destabilizing, moist environment, with enough shear to support supercells and bowing segments. A few tornadoes and scattered damaging to locally severe gusts are possible. The tornado watch area is approximately along and 65 statute miles east and west of a line from 25 miles southwest of Southern Pines NC to 40 miles east northeast of Martinsburg WV. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). 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 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 22030. ...Edwards Read more