Severe Storms

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

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 AM CDT Fri May 27 2022 Valid 271300Z - 281200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE MID-ATLANTIC REGION AND NORTHERN HIGH PLAINS... ...SUMMARY... Damaging thunderstorm winds and a few tornadoes are possible today over parts of the Mid-Atlantic region. Thunderstorms may produce severe gusts this afternoon into early evening over portions of the northern High Plains. ...Synopsis... A progressive synoptic pattern in mid/upper levels will feature two dominant cyclones and their associated troughs: 1. A long-lived circulation now centered over the lower Wabash River area, with trough south-southwestward across southern MS to the north-central Gulf. As a closely phased, northern-stream perturbation amplifies across ON, the cyclone should move east-northeastward to PA and become an open-wave trough today. By 00Z, the combined trough should extend across north-central through south-central QC and southern New England, having moved offshore from the Mid-Atlantic a few hours prior. 2. A complex cyclone over the northeastern Pacific, covering much of the area from the southern Gulf of Alaska to the coastal Pacific Northwest. The main low -- evident in moisture-channel imagery west of Vancouver Island -- should move slowly northeastward to the mainland BC coastline north of Vancouver Island by 12Z. A series of mostly low-amplitude shortwave perturbations will be embedded in the cyclonic-flow field to its southeast, as heights fall across the Northwest, northern Rockies, and northern Plains. The 11Z surface analysis showed a complex, elongated area of low pressure from southwestern QC across Lake Huron to southwestern Lower MI. A cold front was drawn across western PA, WV, southwestern VA, the western Carolinas, and western FL Panhandle. The western part of the same boundary has become quasistationary approximately along the northern Gulf Coast to the middle TX Coast, to near DRT, and a low near FST. By 12Z tomorrow the cold front should reach western New England, the eastern Carolinas, southern GA, still quasistationary near the north-central Gulf Coast, and dissipating across south TX. ...Mid-Atlantic/Northeast/Carolinas... Scattered thunderstorms -- mainly in a north-northeast/south-southwest line already underway in western parts of the area -- are expected to offer sporadic damaging gusts and a few tornadoes. See tornado watch 276 and related mesoscale discussions for near-term details over portions of MD/VA/NC/DC and eastern WV Panhandle. Activity should move into a moist, low-LCL boundary layer that will destabilize from south to north via a combination of theta-e advection and diurnal heating tempered by cloud cover. MLCAPE of 1500-2000 J/kg already is apparent over eastern parts of the Carolinas, and may expand over southern/eastern VA in the preconvective sector. Values will decrease gradually northward to around 500 J/kg in southern/eastern NY and parts of New England. Meanwhile, height falls and strengthening mid/upper winds will overspread the area ahead of the progressive cyclone and trough aloft. Favorable deep shear (effective-shear magnitudes in the 40-55-kt range) will exist for supercells, though deep-shear and mean-wind vectors will have a substantial component parallel to the axis of convective lift. Hodographs will be long but not particular large in the low levels over most of the area. As such, predominantly quasi-linear mode, with embedded bows/LEWPs and related mesocirculations, will pose a threat for damaging gusts and brief tornadoes, while any relatively discrete supercells that still may form in the foregoing warm sector offer a cyclic tornado threat. The favorably unstable warm sector will narrow with weaker buoyancy northward extent toward southern NY and northern New England, beneath stronger upper-level winds. However, strong/isolated severe surface-based convection is possible as far north as northern New England. ...Northern High Plains, northern Rockies... Widely scattered to scattered thunderstorms are excepted to develop this afternoon over the southern MT/northern WY area, with the best-organized activity perhaps initiating over or near the northern Bighorns. Convection should move eastward astride a low-level moisture/instability axis, and atop a well-mixed boundary layer with upper 30s to mid 40s F surface dewpoints, supporting 500-800 J/kg MLCAPE, with even larger DCAPE values. Some upscale growth and cold-pool organization are possible. The main concern will be severe gusts, some of which may reach or exceed 65 kt. Activity should weaken this evening as it moves into a stabilizing boundary layer. Father southwest, isolated to widely scattered, high-based thunderstorms will develop today across parts of the northern Rockies into southern ID amidst weak MLCINH and marginal moisture. meanwhile cooling aloft and diurnal heating will steepen low/middle-level lapse rates and remove MLCINH, with just enough boundary-layer moisture to support 200-500 J/kg MLCAPE. With deep/well-mixed subcloud layers expected, strong/isolated severe gusts may be noted this afternoon into early evening. ..Edwards/Mosier.. 05/27/2022 Read more

MD 0923 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF WESTERN INTO CENTRAL ILLINOIS
Mesoscale Discussion 0923 NWS Storm Prediction Center Norman OK 0952 AM CDT Thu May 26 2022 Areas affected...portions of western into central Illinois Concerning...Severe potential...Watch possible Valid 261452Z - 261615Z Probability of Watch Issuance...40 percent SUMMARY...An increase in storm coverage and intensity is expected through the late morning into early afternoon. Large hail and damaging gusts are the main threats, though a tornado cannot be ruled out. Storm coverage and intensity trends are being monitored for the need of a WW issuance. DISCUSSION...A stacked low across western MO continues to gradually track eastward, with a cold front trailing the MO/IL border, where convection continues to gradually deepen. Ahead of the cold front/ intensifying storms, at least mid 60s F surface dewpoints reside beneath 7.5 C/km 700-500 mb lapse rates (per 12Z ILX observed sounding), contributing to over 500-1000 J/kg MLCAPE. 40 kts of effective bulk shear is also present, mainly driven by tropospheric speed shear given a unidirectional vertical wind profile. Any storms that can mature would most likely be multicellular or transient-supercellular. Modifying the 12Z ILX observed sounding to current surface temperatures/dewpoints yields dense CAPE around 500 mb, where temperatures are around -15C. As such, further surface heating/generation of buoyancy may support large-hail producing storms. The 14Z mesoanalysis also depicts nearly 200 J/kg CAPE and 7 C/km lapse rates in the 0-3 km layer, which suggests that further boundary-layer mixing will also favor strong/damaging gusts with the more intense storms that manage to form. The very strong low-level CAPE will enhance vorticity stretching potential and a supercell/landspout hybrid tornado cannot be completely ruled out. Nonetheless, buoyancy is expected to remain limited overall given the relatively narrow warm sector, with overall severe coverage still uncertain. Convective trends will continue to be monitored for the need of a WW issuance. ..Squitieri/Hart.. 05/26/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ILX...LSX...DVN... LAT...LON 38448930 38659003 38939032 39269055 39679087 39989121 40329152 40599164 41089096 40989026 40558947 39908888 39308867 38688875 38448930 Read more

WW 0274 Status Updates
STATUS REPORT ON WW 274 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0922 ..DEAN..05/26/22 ATTN...WFO...MOB...TAE...LIX... STATUS REPORT FOR WT 274 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ALC003-025-035-039-053-097-099-129-261540- AL . ALABAMA COUNTIES INCLUDED ARE BALDWIN CLARKE CONECUH COVINGTON ESCAMBIA MOBILE MONROE WASHINGTON FLC005-033-037-045-059-091-113-131-133-261540- FL . FLORIDA COUNTIES INCLUDED ARE BAY ESCAMBIA FRANKLIN GULF HOLMES OKALOOSA SANTA ROSA WALTON WASHINGTON MSC039-041-059-261540- MS . MISSISSIPPI COUNTIES INCLUDED ARE Read more

WW 274 TORNADO AL FL MS CW 261245Z - 261900Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 274 NWS Storm Prediction Center Norman OK 745 AM CDT Thu May 26 2022 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southern Alabama Panhandle of Florida Extreme southeastern Mississippi Coastal Waters * Effective this Thursday morning and afternoon from 745 AM until 200 PM CDT. * Primary threats include... A couple tornadoes possible Isolated damaging wind gusts to 70 mph possible SUMMARY...Several areas of thunderstorms, moving/expanding inland from the Gulf, will pose a threat for a couple tornadoes and some damaging gusts through midday. The tornado watch area is approximately along and 45 statute miles north and south of a line from 60 miles northwest of Mobile AL to 20 miles east northeast of Apalachicola FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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

MD 0922 CONCERNING TORNADO WATCH 274... FOR SOUTH AL...FL PANHANDLE
Mesoscale Discussion 0922 NWS Storm Prediction Center Norman OK 0946 AM CDT Thu May 26 2022 Areas affected...South AL...FL Panhandle Concerning...Tornado Watch 274... Valid 261446Z - 261615Z The severe weather threat for Tornado Watch 274 continues. SUMMARY...The threat for a brief tornado or two and locally damaging wind gusts will continue through the morning. DISCUSSION...Extensive convection has organized into multiple clusters across south AL into the FL Panhandle and northern Gulf of Mexico. Several embedded cells within the cluster offshore of Pensacola have shown periodic midlevel rotation, but thus far have weakened before moving onshore. Widespread cloudiness is noted over the FL Peninsula, limiting the potential for destabilization, but 0-1 km SRH in excess of 150 m2/s2 (as noted in KEVX VWP) will support a brief tornado threat near the coast, should any stronger cells make it onshore. Further west, a loosely organized, outflow-driven cluster is ongoing east of Mobile. Locally damaging wind gusts will be possible as this cluster moves eastward through the morning. A brief embedded tornado will also be possible with any embedded circulations, as this cluster merges with the storms ongoing near/south of Pensacola. To the east, another cluster of storms is ongoing near/south of the FL Big Bend. Increasing low-level flow/shear later this morning may result in an uptick in storm organization within this cluster, resulting in a threat of locally damaging wind gusts and/or a brief tornado with any stronger convection that is able to move onshore. ..Dean.. 05/26/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TAE...MOB... LAT...LON 31228785 31558736 31348631 30578486 30338406 30068359 29758364 29498427 29408530 29748676 30118784 30418831 31048820 31228785 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Thu May 26 2022 Valid 261300Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM OHIO TO PARTS OF SOUTHERN ALABAMA AND THE FLORIDA PANHANDLE... ...SUMMARY... Isolated to widely scattered severe thunderstorms are possible over parts of the inland Northwest, and from Ohio Valley region to the east-central Gulf Coast and southern Appalachians. ...Synopsis... A pronounced, slowly progressive, deep-layer cyclone was apparent in moisture-channel imagery over parts of KS, MO, OK, AR, southern IA and southeastern NE, centered roughly between JLN-TOP. The accompanying mid/upper-level trough extended southward across the Arklatex region to the northwestern Gulf. By 00Z, the 500-mb low should be over eastern MO, with trough roughly southward down the lower Mississippi Valley and offshore from LA. By 12Z, the low should reach the lower Wabash River area, with trough south-southwestward past BIX. Farther upstream, synoptic-scale ridging will cross the Rocky Mountain States, ahead of a complex, elongated mid/upper cyclone now located west of Vancouver Island and south of the Gulf of Alaska. Associated height falls and southwest flow aloft will spread inland over the Northwest. Embedded in that flow, a lead shortwave perturbation -- initially apparent with positive tilt from just west of the WA coast southwestward to about 600 nm W of SFO, will pivot inland across WA/OR around 00Z. The trough should weaken somewhat overnight as it accelerates toward the northern Rockies and the larger-scale ridge position. At the surface, 11Z analysis depicted a low near SZL, with cold front arching across southeastern MO, northwestern MS, and south-central LA. A warm front was drawn across northern IL, central Lower MI, and eastern OH, becoming quasistationary while wrapping around the Appalachians from Western WV to northeastern TN and northwestern SC. This front extended to another low offshore from HSE. By 00Z, the cold front should curve from the low near UIN across southern portions of IL/IN, middle TN, northern/southwestern AL, to near the mouth of the Mississippi River. By 12Z, it should reach eastern parts of KY/TN, the FL Panhandle, and the central Gulf. The eastern front should shift diffusely and slowly northward across the Carolinas later today. ...Ohio Valley region to Gulf Coast... Multiple rounds and areas of widely scattered to scattered thunderstorms are expected across the outlook area today into this evening -- both in the form of cold-frontal and prefrontal bands aligned roughly parallel to the cold front, and a blend of discrete cells and clusters in the weakly capped warm sector. Damaging to isolated severe gusts, a marginal overall tornado threat, and isolated severe hail are possible across a large swath from the Gulf Coast across the Ohio Valley and into the western Carolinas, with wind likely being the most common severe-report type. Convective coverage has been increasing gradually the last several hours near the Gulf Coast -- primarily over water, and may expand/develop inland with time this morning across AL and the FL Panhandle. This is occurring near a weak surface low between BVE-MOB and a related low-level convergence zone, within a richly moist air mass (low/mid 70s F surface dew points) supporting MLCAPE in the 1500-2500 J/kg range -- diminishing gradually with northward/inland extent across MS and western AL. Farther east, a baroclinic boundary is noted near or just off the FL Panhandle coastline between PAM and western Apalachee Bay, reinforced by precip from a complex extending well offshore (and which has contained occasional supercells appearing to be strengthened by vorticity in the baroclinic zone). That quasistationary boundary may limit inland penetration of favorable boundary-layer air in the near-term. Strongly difluent flow aloft also has been noted, rendering highly variable effective shear (magnitudes generally 25-50 kt, increasing inland into a currently less-unstable environment). See tornado watch 274 and related mesoscale discussions for more-updated near-term info on this region. Inland destabilization is expected later this morning into afternoon, related to both theta-e advection -- recovering west of the Panhandle/Gulf complex and its dissipated northward extension over eastern AL and GA. This may support both an inland growth of the Gulf activity over the next few hours, and later-morning/ afternoon development along/ahead of the front well inland across the Tennessee/Ohio Valleys. 35-50-kt effective-shear magnitudes (with shear and mean-wind vectors obliquely off the frontal alignment) will support mixed convective modes, but mainly linear. The "slight" areas have been connected accordingly, though a relative minimum in severe potential still may exist farther east near the mountains, where effects of the "wedge" front will be more persistent. Backed low-level winds preceding convection closer to the low, over IL/IN, also may support some hodograph enlargement, and marginal tornado probabilities have been expanded into those areas. Conditional, mesoscale to localized maxima in tornado potential also may exist near the Carolinas front (but with considerable uncertainty related to mode and cross-boundary cell motion), and in the weaker-instability arc along/ahead of the front over the IL/IN region. If any of those becomes better-focused and less conditional, an upgrade in those probabilities may be considered in a succeeding outlook. ...Interior Northwest... Isolated to scattered thunderstorms are expected to develop over western portions of OR/WA and central OR late this afternoon, then move northeastward into the evening. Meanwhile, the environment from central/eastern OR and southeastern WA, northeastward across western/northern ID, will best support severe potential, in the form of gusts and hail. Antecedent diurnal heating of lower terrain east of the Cascades will lead to a deep, well-mixed boundary layer beneath increasing midlevel moisture. Preconvective lapse rates aloft are expected to increase as well, related to large-scale DCVA/ascent preceding the shortwave trough. Pockets of MLCAPE near 500 J/kg are possible, with a broad area exceeding 100 J/kg -- nonetheless extending into thermal layers suitable for lightning generation. Although low- level hodograph size and shear-vector magnitudes will be limited by some westerly to northerly near-surface wind components, favorable deep shear will exist for either high-based supercells or organized bowing structures. Any hail associated with the former would be well-maintained to the surface through the subcloud layer, and large DCAPE will support the potential for cold pools to aggregate and produce a wind swath with a northeastward thrust into ID. ..Edwards/Kerr.. 05/26/2022 Read more

WW 0273 Status Updates
STATUS FOR WATCH 0273 HAS NOT BEEN ISSUED YET Read more

WW 273 SEVERE TSTM LA MS 251435Z - 252200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 273 NWS Storm Prediction Center Norman OK 935 AM CDT Wed May 25 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Louisiana Central and Southern Mississippi * Effective this Wednesday morning and afternoon from 935 AM until 500 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely A tornado or two possible SUMMARY...A line of thunderstorms and isolated cells ahead of the line will track northeastward across the watch area today. Locally damaging wind gusts and an isolated tornado or two are the main threats. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 45 miles east northeast of Greenwood MS to 30 miles west southwest of Slidell LA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). 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 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 23025. ...Hart Read more

MD 0912 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR EASTERN/SOUTHEASTERN LOUISIANA INTO SOUTHERN/CENTRAL MS
Mesoscale Discussion 0912 NWS Storm Prediction Center Norman OK 0923 AM CDT Wed May 25 2022 Areas affected...eastern/southeastern Louisiana into southern/central MS Concerning...Severe potential...Watch possible Valid 251423Z - 251600Z Probability of Watch Issuance...60 percent SUMMARY...Sporadic strong gusts and a tornado or two will be possible the remainder of the morning into the afternoon across parts of far eastern/southeastern Louisiana into southern/central Mississippi. DISCUSSION...A line of storms along a composite outflow and ahead of a surface cold front will continue to shift east/northeast through the remainder of the morning and into the afternoon. Pockets of heating ahead of the line and surface dewpoints in the upper 60s to low/mid 70s F is aiding in moderate destabilization this morning, with MLCAPE values around 1500-2500 J/kg. However, effective shear magnitudes are expected to remain modest through the day at around 30 kt. Furthermore, both low and midlevel lapse rates are expected to remain weak. This will limit storm intensity overall, but the parameter space will adequately support at least brief strong embedded cells or bows along the line. The main hazard with this activity will be strong gusts in the 40-50 kt range. Regional VWP data also shows enlarged, curved low-level hodograph, which could support rotation within the line or in cellular activity ahead of the line. While low-level lapse rates are poor, 0-3 km MLCAPE greater than 100 J/kg and some enhanced low-level vorticity could support a brief spin-up in more intense convection. Convective trends will be monitored and a watch may be needed. ..Leitman/Hart.. 05/25/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MOB...JAN...LIX...LCH... LAT...LON 30909181 31709177 32519159 32909123 33139038 33108988 32998940 32668896 32308870 31878854 30578846 29608870 29078906 28978977 28959038 29049109 29319143 29729171 30639171 30909181 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 AM CDT Wed May 25 2022 Valid 251300Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF EASTERN LOUISIANA...MISSISSIPPI...AND WESTERN ALABAMA... ...SUMMARY... Strong to severe thunderstorms are possible from the central Gulf Coast into parts of the lower/mid Mississippi Valley, Southeast, Midwest, and Ohio Valley. ...Synopsis... The main mid/upper-level feature for this forecast will be a well-defined synoptic trough now over the Plains States southward to northeastern MX, with a 500-mb low re-forming across western OK at this time. The low should move erratically northeastward to near the southern part of the KS/MO line by 12Z tomorrow, with trough southward across the Arklatex and western Gulf. Small, convectively induced/augmented vorticity maxima will eject northeastward to northward ahead of the trough, across parts of the lower/mid Mississippi and Ohio Valleys, Tennessee Valley and central Gulf Coast. At the surface, 11Z analysis showed a low over northeastern KS, with a cold front arching across the OK/MO border area, northeast TX, and east-central TX, to near LRD. The cold front was preceded by a convective/outflow boundary from northeastern MX and near BRO northeastward across western LA. A warm front was drawn over northern MO, north-central IL, and central portions of IN/OH, though several areas of convection have altered the sector south of the synoptic warm front. The cold front should move eastward slowly across much of AR and LA through the period, preceded at least into this evening by the convective boundary. Meanwhile, the low should split, with one part moving northeastward along the warm front to WI tonight, and the other stacking more vertically with the mid/upper cyclone center. ...Gulf Coast States, Delta region, Mid-South, TN Valley... Scattered thunderstorms are possible in multiple episodes through the period, the main one likely being associated with a band of convection now extending from western LA across the northwestern Gulf. Sporadic damaging winds and a few line-embedded tornadoes are possible. This activity, and the associated corridor of outflow- aided convective lift, are expected to shift eastward into a low-level air mass destabilized by a combination of: 1. Theta-e advection from the south, with 70s F surface dew points already common south of I-20 between western AL and western LA; 2. Patchy areas of diurnal surface heating, in relative breaks of cloud cover between the convective band and a separate area of thunderstorms initially over AL and the western FL Panhandle. These factors should offset modest midlevel lapse rates enough to support MLCAPE near 2000 J/kg over southern LA/MS, decreasing to around 500-1000 J/kg northward over parts of the Mid-South region. Mid/upper-level winds and deep speed shear will increase with time as the synoptic trough approaches, but with little change in direction in the vertical profile. As such, forecast soundings show peak effective-shear magnitudes only reaching the 30-40-kt range, supporting organized multicells, QLCS mode, short-lived supercell structures, and a few bow/LEWP formations with associated mesocirculations. Additional strong/isolated severe thunderstorms may persist this morning across the east-central Gulf Coast region from the FL Panhandle into AL, as well as develop behind the remnants of original convective line tonight across parts of LA/MS/southern AL. The severe potential with the overnight activity (wind, perhaps tornado) is more uncertain, and dependent on the extent of airmass recovery behind the daytime complex. However, the bulk of any such nocturnal threat should be contained within the upgraded outlook area as drawn. ...Eastern Ozarks, mid Mississippi/lower Ohio Valleys... Widely scattered to scattered thunderstorms are expected to form this afternoon in an arc along/ahead of the front, and northeast through east of the surface low, over parts of northeastern AR and eastern MO. This activity should shift into IL before weakening appreciably. Widely scattered thunderstorms also should develop today in a zone of increasing low-level moisture and slowly eroding MLCINH in the partially modified warm sector across parts of IL/IN/OH/KY ahead of the near-frontal arc. At least a marginal wind/tornado threat may develop, along with isolated hail. The convective arc will be located in a zone of relatively maximized deep-layer lift and low-level convergence ahead of the progressive mid/upper cyclone, with relatively backed near-surface flow aiding boundary-layer shear. However, weak middle-level lapse rates and muted surface heating due to cloud cover (limiting low-level lapse rates) will temper buoyancy in this regime, which will be located well north of the richest Gulf moisture. MLCAPE generally in the 300-800 J/kg range is expected with little to no MLCINH left by midafternoon, enabling development and maintenance of this activity, which may link up with the northern extent of the LA/MS convective band discussed above. If mesoscale trends and subsequent model guidance indicate more destabilization (surface or aloft), or stronger sustained lift, greater severe probabilities may need to be extended north into this region. ..Edwards/Kerr.. 05/25/2022 Read more

No watches are valid as of Tue May 24 14:51:02 UTC 2022.

MD 0897 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR UPPER TEXAS COAST VICINITY
Mesoscale Discussion 0897 NWS Storm Prediction Center Norman OK 0948 AM CDT Tue May 24 2022 Areas affected...Upper Texas Coast vicinity Concerning...Severe potential...Watch unlikely Valid 241448Z - 241615Z Probability of Watch Issuance...20 percent SUMMARY...Locally strong gusts may occur across portions of the Upper Texas Coast the next couple of hours. DISCUSSION...A band of strong storms is lifting northward near the Upper Texas Coast this morning at around 40 kt. Latest radar data indicates a pocket of 45-55 kt velocities around 1-2 kft. Deep-layer flow is rather weak, but some local enhancement is likely occurring as this activity is developing on the east side of an MCV/lead shortwave impulse shifting east toward the Middle Texas Coast. Surface dewpoints in the low 70s are supporting a corridor of 1500-2000 J/kg MLCAPE ahead of the line of convection. However, low and mid-level lapse rates remain weak, while DCAPE values are less than 1000 J/kg. Forecast RAP soundings do indicate a modest dry layer just above the surface, which could aid in stronger outflow as the convection advances quickly northward. Locally strong gusts may accompany this activity the remainder of the morning, but overall severe threat is expected to remain marginal and a watch is not expected at this time. ..Leitman/Hart.. 05/24/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LCH...HGX... LAT...LON 28779529 28969542 29839554 30149551 30329539 30429514 30519450 30479415 30319391 29949381 29409386 29099398 28919412 28799443 28759488 28779529 Read more