Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0731 AM CDT Mon May 16 2022 Valid 161300Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM LATE MORNING THROUGH THE AFTERNOON FROM CENTRAL/EASTERN NY TO THE MID-ATLANTIC... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY TONIGHT FROM EASTERN NM INTO THE TX PANHANDLE... ...SUMMARY... Scattered to numerous severe storms with damaging winds, a couple of tornadoes and isolated large hail are expected from late morning through the afternoon from central/eastern New York to the Mid_Atlantic. Damaging winds and isolated large hail will also be possible this afternoon and early tonight from eastern New Mexico into the Texas Panhandle. ...NY to the Mid-Atlantic from late morning to late afternoon... A midlevel shortwave trough over the OH Valley this morning will progress east-northeastward over the Mid-Atlantic and New England by tonight, as an associated surface cyclone deepens across the Saint Lawrence Valley and a trailing cold front likewise moves eastward and offshore overnight. Low-mid 60s boundary-layer dewpoints will spread northward ahead of the front, and pockets of surface heating will boost buoyancy by afternoon (MLCAPE of 1000-1500 J/kg). Deep-layer flow/vertical shear will increase with the approach of the midlevel trough from the west, contributing to an environment supportive of organized line segments and some supercell structures from late morning through the afternoon. Thunderstorms are expected to increase in coverage/intensity by late morning from the Finger Lakes region southward along the leading edge of the pre-frontal convective band moving into western PA this morning. These storms will subsequently spread eastward across NY and the Mid-Atlantic through late afternoon, and other storms could form farther west and southwest along the synoptic cold front, assuming sufficient cloud breaks occur by midday. The presence of organized convective bands and strengthening wind profiles suggest that wind damage with peak gusts of 55-70 mph will be a common threat this afternoon, west of any cooling marine influence. The threat for significant (75+ mph) gusts is more questionable given rather modest downdraft potential (DCAPE generally less than 500 J/kg) and low-midlevel flow no stronger than 30-40 kt. Otherwise, low-level shear may be strong enough to support a couple of tornadoes with pre-frontal supercells or circulations embedded in line segments, and the stronger storms may also produce isolated large hail of 1 to 1.5 inches in diameter. ...Southern High Plains this afternoon into early tonight... Low-level moisture has spread westward into eastern NM this morning on post-frontal easterly flow. Weak lee cyclogenesis and heating/mixing within the initially moist air mass will reduce convective inhibition this afternoon and allow scattered high-based thunderstorm development across eastern NM, and storms will gradually grow upscale and spread eastward on consolidating outflows. Inverted-V profiles with large DCAPE (near 1500 J/kg) will favor scattered severe outflow gusts, some of which may approach 75 mph prior to the convection slowly weakening early tonight across the TX Panhandle. ...Northern Rockies areas afternoon/evening... Subtle embedded speed maxima will continue to move from the northern Great Basin/Pacific Northwest to the northern Rockies, atop a weak baroclinic zone from central ID to southwest MT. A lingering low-midlevel moisture plume and surface heating in cloud breaks will support MLCAPE up to about 500 J/kg, within a corridor of effective bulk shear of 30-40 kt and largely straight hodographs. This environment will support widely scattered storms this afternoon/evening in the vicinity of the Beartooth Mountains, some of which could have low-end/splitting supercell characteristics with gusty outflow winds and marginally severe hail. Farther south, a few high-based storms may form this afternoon across extreme northeast NV and northwest UT, in advance of a subtle shortwave trough now near the northeast CA/NV border. Inverted-V profiles will favor strong outflow gusts with any deep convection in this corridor this afternoon/evening. ..Thompson/Leitman.. 05/16/2022 Read more

WW 0216 Status Updates
STATUS REPORT ON WW 216 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 WNW SLN TO 5 WNW TOP TO 15 NE SZL. ..MOSIER..05/15/22 ATTN...WFO...ICT...TOP...EAX... STATUS REPORT FOR WS 216 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC001-003-015-017-031-041-045-059-073-079-107-111-113-115-121- 127-139-169-177-197-207-151640- KS . KANSAS COUNTIES INCLUDED ARE ALLEN ANDERSON BUTLER CHASE COFFEY DICKINSON DOUGLAS FRANKLIN GREENWOOD HARVEY LINN LYON MCPHERSON MARION MIAMI MORRIS OSAGE SALINE SHAWNEE WABAUNSEE WOODSON MOC013-037-053-083-101-159-151640- MO . MISSOURI COUNTIES INCLUDED ARE BATES CASS COOPER HENRY JOHNSON PETTIS THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE Read more

WW 216 SEVERE TSTM KS MO 151150Z - 151800Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 216 NWS Storm Prediction Center Norman OK 650 AM CDT Sun May 15 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Kansas Western Missouri * Effective this Sunday morning and afternoon from 650 AM until 100 PM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Clusters of elevated thunderstorms will likely continue to grow in size while intensifying through the morning. Large hail will be possible with the strongest storms, and the threat for wind damage will increase through the morning from Topeka into the Kansas City area. The severe thunderstorm watch area is approximately along and 55 statute miles north and south of a line from 20 miles west northwest of Salina KS to 10 miles north northeast of Knob Noster MO. 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. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 30045. ...Thompson Read more

No Mesoscale Discussions are in effect as of Sun May 15 15:31:04 UTC 2022.

WW 0217 Status Updates
STATUS FOR WATCH 0217 HAS NOT BEEN ISSUED YET Read more

WW 217 SEVERE TSTM AR KS MO OK 151345Z - 152100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 217 NWS Storm Prediction Center Norman OK 845 AM CDT Sun May 15 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Far northwest Arkansas Southeast Kansas Central to southern Missouri Northeast Oklahoma * Effective this Sunday morning and afternoon from 845 AM until 400 PM CDT. * Primary threats include... Widespread damaging winds and isolated significant gusts to 80 mph likely Scattered large hail and isolated very large hail events to 2.5 inches in diameter likely A tornado or two possible SUMMARY...Multiple clusters with embedded bows and supercells will spread across the Ozark Plateau region into this afternoon. The severe thunderstorm watch area is approximately along and 70 statute miles north and south of a line from 35 miles east of Vichy MO to 25 miles west southwest of Bartlesville OK. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). 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 216... AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 70 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 30045. ...Grams Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0732 AM CDT Sun May 15 2022 Valid 151300Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THROUGH THIS EVENING FROM SOUTHEAST KS AND NORTHEAST OK INTO NORTHERN AR AND SOUTHERN MO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR THE INTERIOR PACIFIC NORTHWEST... ...SUMMARY... Scattered to numerous severe storms with very large hail and swaths of wind damage are expected from mid morning through this evening from eastern Kansas and western/southern Missouri into Oklahoma and Arkansas. Other isolated severe storms will be possible later this afternoon across the interior Pacific Northwest. ...Eastern KS/OK to MO/AR through late evening... Elevated convection is ongoing this morning across northeast KS, in advance of a midlevel shortwave trough moving east-southeastward over western/central NE. The convection will be maintained in a zone of ascent preceding the midlevel trough, and will likely intensify this morning while encountering increasing low-level moisture/buoyancy across eastern KS and western MO. Strengthening deep-layer, west-northwesterly shear (effective bulk shear in excess of 45 kt), midlevel lapse rates near 8 C/km, and MLCAPE increasing to near 3000 J/kg by midday will favor clusters/embedded supercells capable of producing very large hail up to 2.75 inches in diameter. Upscale growth into a larger cluster or two appears probable through the afternoon across southwest MO, southeast KS, and northeast OK, with an increasing threat for swaths of damaging winds of 60-75 mph. A deep mixed layer and relatively weak convective inhibition suggest that the storms could develop at least as far southwest as the I-35 corridor in central OK by this evening, where thermodynamic profiles will favor damaging outflow winds. The richer moisture/larger buoyancy suggest the eastern extent of the stronger/sustained MCS will likely be across AR, with more uncertainty with eastward extent from the MS River. Some form of the MCS(s) could make it as far as the Mid South and the Red River Valley of OK/TX, though the severe threat should be diminishing by this time (this evening/early tonight). ...OH Valley into PA/western NY this afternoon... A weak midlevel trough/vorticity lobe will move eastward from the upper OH Valley across WV/PA/NY today. A diffuse surface trough is expected from central NY southward in the lee of the Appalachians. These features could help focus scattered thunderstorm development by midday into this afternoon, and a few of the storms could produce strong outflow winds and minor damage, along with marginally severe hail in an environment characterized by weak vertical shear and moderate buoyancy (MLCAPE of 1000-1500 J/kg). It appears there will be a relative gap in any severe threat across far western NY/PA and eastern OH, to the west of the weak shortwave trough. Additional convection will form farther west toward the lower OH Valley into southeast Lower MI later this afternoon in advance of the stronger shortwave trough (now over NE) and an associated surface cold front. The stronger vertical shear will remain farther to the west during the day, with the larger buoyancy farther southwest. However, the strongest storms will be capable of producing at least isolated wind damage and marginally severe hail, and some low-end severe threat may persist into the OH Valley as the convection spreads east into tonight. ...Interior Pacific Northwest/northern Rockies this afternoon... A compact shortwave trough now off the OR coast will move east-northeastward over OR/WA and the ID Panhandle by this evening. Boundary-layer dewpoints in the upper 40s to lower 50s, daytime heating in cloud breaks, and increasing ascent with the approaching shortwave trough/front will support thunderstorm development this afternoon across northeast OR. Though buoyancy will not be particularly large (MLCAPE of 500-750 J/kg), strengthening wind profiles/deep-layer shear will support the potential for organized convection, including isolated supercells and/or short line segments with an attendant threat for large hail, damaging winds, and perhaps an isolated tornado. ..Thompson/Leitman.. 05/15/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0732 AM CDT Sun May 15 2022 Valid 151300Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THROUGH THIS EVENING FROM SOUTHEAST KS AND NORTHEAST OK INTO NORTHERN AR AND SOUTHERN MO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR THE INTERIOR PACIFIC NORTHWEST... ...SUMMARY... Scattered to numerous severe storms with very large hail and swaths of wind damage are expected from mid morning through this evening from eastern Kansas and western/southern Missouri into Oklahoma and Arkansas. Other isolated severe storms will be possible later this afternoon across the interior Pacific Northwest. ...Eastern KS/OK to MO/AR through late evening... Elevated convection is ongoing this morning across northeast KS, in advance of a midlevel shortwave trough moving east-southeastward over western/central NE. The convection will be maintained in a zone of ascent preceding the midlevel trough, and will likely intensify this morning while encountering increasing low-level moisture/buoyancy across eastern KS and western MO. Strengthening deep-layer, west-northwesterly shear (effective bulk shear in excess of 45 kt), midlevel lapse rates near 8 C/km, and MLCAPE increasing to near 3000 J/kg by midday will favor clusters/embedded supercells capable of producing very large hail up to 2.75 inches in diameter. Upscale growth into a larger cluster or two appears probable through the afternoon across southwest MO, southeast KS, and northeast OK, with an increasing threat for swaths of damaging winds of 60-75 mph. A deep mixed layer and relatively weak convective inhibition suggest that the storms could develop at least as far southwest as the I-35 corridor in central OK by this evening, where thermodynamic profiles will favor damaging outflow winds. The richer moisture/larger buoyancy suggest the eastern extent of the stronger/sustained MCS will likely be across AR, with more uncertainty with eastward extent from the MS River. Some form of the MCS(s) could make it as far as the Mid South and the Red River Valley of OK/TX, though the severe threat should be diminishing by this time (this evening/early tonight). ...OH Valley into PA/western NY this afternoon... A weak midlevel trough/vorticity lobe will move eastward from the upper OH Valley across WV/PA/NY today. A diffuse surface trough is expected from central NY southward in the lee of the Appalachians. These features could help focus scattered thunderstorm development by midday into this afternoon, and a few of the storms could produce strong outflow winds and minor damage, along with marginally severe hail in an environment characterized by weak vertical shear and moderate buoyancy (MLCAPE of 1000-1500 J/kg). It appears there will be a relative gap in any severe threat across far western NY/PA and eastern OH, to the west of the weak shortwave trough. Additional convection will form farther west toward the lower OH Valley into southeast Lower MI later this afternoon in advance of the stronger shortwave trough (now over NE) and an associated surface cold front. The stronger vertical shear will remain farther to the west during the day, with the larger buoyancy farther southwest. However, the strongest storms will be capable of producing at least isolated wind damage and marginally severe hail, and some low-end severe threat may persist into the OH Valley as the convection spreads east into tonight. ...Interior Pacific Northwest/northern Rockies this afternoon... A compact shortwave trough now off the OR coast will move east-northeastward over OR/WA and the ID Panhandle by this evening. Boundary-layer dewpoints in the upper 40s to lower 50s, daytime heating in cloud breaks, and increasing ascent with the approaching shortwave trough/front will support thunderstorm development this afternoon across northeast OR. Though buoyancy will not be particularly large (MLCAPE of 500-750 J/kg), strengthening wind profiles/deep-layer shear will support the potential for organized convection, including isolated supercells and/or short line segments with an attendant threat for large hail, damaging winds, and perhaps an isolated tornado. ..Thompson/Leitman.. 05/15/2022 Read more

No watches are valid as of Sat May 14 13:53:01 UTC 2022.

No Mesoscale Discussions are in effect as of Sat May 14 13:53:02 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0744 AM CDT Sat May 14 2022 Valid 141300Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FROM THE GREAT LAKES TO THE LOWER MS VALLEY...AND THIS AFTERNOON INTO TONIGHT FOR PARTS OF WEST TX TO SOUTHEAST NE/NORTHEAST KS... ...SUMMARY... Strong to locally severe thunderstorms are possible across parts of the Great Plains, Mississippi Valley, and Great Lakes regions, mainly this afternoon and evening. Isolated hail and damaging wind gusts will be the primary threats. Some threat may redevelop late tonight across parts of Nebraska and Kansas. ...Synopsis... The persistent midlevel low over the Southeast is in the process of evolving into more of an open wave, and a primary embedded shortwave trough will eject north-northeastward from NC to southern New England by early Sunday. This pattern evolution will be in response to gradual upstream height falls across the upper Midwest and upper MS Valley, downstream from modest height rises over the northern Great Basin and northern Rockies. Within the primary jet, an embedded shortwave trough over MN/WI will eject northeastward toward ON, and an upstream shortwave trough over the northern High Plains will amplify some while digging southeastward over the middle MO Valley. The surface synoptic boundaries will remain rather diffuse today into early tonight, prior to some sharpening of a front near the KS/NE border by the end of the period. ...West TX to western KS this afternoon/evening... A somewhat diffuse dryline is expected this afternoon from western KS southward into west TX, where surface heating and deep mixing could allow isolated thunderstorm development by mid-late afternoon. A high-based supercell or two with isolated large hail and strong-severe outflow gusts will be possible, given sufficiently long hodographs with effective bulk shear greater than 40 kt. ...Lower MS Valley to the Great Lakes this afternoon/evening... Deep-layer flow/shear will be very weak from the lower OH River into MI, where surface heating will drive MLCAPE of 1000-2000 J/kg (weaker north) and DCAPE near 1000 J/kg. Weak low-level convergence and minimal convective inhibition should support widely-scattered to scattered thunderstorm development by mid-late afternoon, with the potential for isolated wind damage with downbursts. Somewhat richer low-level moisture and larger CAPE are expected farther south into the lower MS Valley region, though there is some uncertainty regarding the lingering influence of ongoing morning convection across the Ark-La-Miss. Where pockets of stronger surface heating occur, especially in conjunction with lingering outflow boundaries, a few multicell clusters with strong/isolated damaging downburst winds will be possible. ...Southeast NE/northeast KS 06-12z Sunday... The aforementioned shortwave trough and low-level frontogenesis, interacting with steep midlevel lapse rates and MUCAPE near 1500 J/kg, will likely result in the formation of elevated thunderstorm clusters early Sunday morning. This convection will pose mainly an isolated large hail threat during this forecast period, before evolving into more of a damaging wind threat during the day Sunday (D2). ..Thompson.. 05/14/2022 Read more

No watches are valid as of Fri May 13 14:02:02 UTC 2022.

No Mesoscale Discussions are in effect as of Fri May 13 14:02:02 UTC 2022.

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook RESENT 1 NWS Storm Prediction Center Norman OK 0816 AM CDT Fri May 13 2022 Valid 131300Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY TONIGHT FROM CENTRAL OK INTO MO... ...SUMMARY... Scattered afternoon and evening thunderstorms are expected Friday from the Upper Great Lakes to the southern Great Plains. The stronger storms will be capable of damaging gusts and hail. ...Upper MS Valley to the southern Plains through early tonight... Only small changes to the large-scale pattern are expected through early Saturday, as a weakening midlevel low will persist over the Southeast, and the primary belt of westerlies aloft will remain from the Pacific Northwest to the northern Plains/upper MS Valley. In the wake of an embedded shortwave trough and occluding cyclone moving north-northeastward to southern MB and western ON, a trailing cold front will make slow southeastward progress from WI to MO and OK. Despite some low-level drying the past few days as a result of retrogression of the Southeast midlevel low, boundary-layer dewpoints remain mostly in the mid 60s ahead of the slow-moving cold front and residual outflow boundaries. The corridor of richer pre-frontal moisture will be narrowest to the north toward WI, and somewhat broader to the south toward MO and OK. Overnight/morning convection raises some uncertainty in the forecast for this afternoon/evening. It appears some of the convection may persist long enough from northeast OK to northwest MO to influence later storm development through the stabilizing effects of lingering clouds into the afternoon. Any persistent differential heating zones and/or convective outflows could also serve to focus afternoon storm development. With MLCAPE near 3000 J/kg expected and modest vertical shear, a mix of multicell clusters and some supercells will be possible later this afternoon into early tonight from OK into MO. Occasional damaging gusts and isolated large hail will be the main threats. The window of opportunity for severe storms toward WI will be smaller and more marginal, given relatively weak vertical shear and weaker buoyancy in a narrower corridor compared to the MO-OK area. Farther southwest in TX, aside from isolated morning storms, deep mixing with strong surface heating should support at least isolated thunderstorm development later this afternoon along and immediately east of a remnant dryline/front. Inverted-V profiles will support high-based storms with the threat of strong downburst winds. Mid-upper westerly flow and straight hodographs could be sufficient for some splitting supercells with isolated large hail. ...Lower MS Valley this afternoon/evening... Along a diffuse front near the MS River and beneath modest (20-25 kt) northerly flow aloft, daytime heating and boundary-layer dewpoints in the 68-70 F range will contribute to MLCAPE of 2500-3000 J/kg. Scattered thunderstorm development is expected along the diffuse front by mid afternoon, and multicell clusters will subsequently spread southward across the Ark-La-Miss through this evening. Vertical shear will be relatively weak, but midlevel lapse rates/buoyancy will be sufficiently large to support marginally severe hail. Steep low-level lapse rates, DCAPE near 1000 J/kg, and precipitation loading suggest that strong outflow gusts will be the main concern. ..Thompson.. 05/13/2022 Read more

No watches are valid as of Thu May 12 14:46:01 UTC 2022.

No Mesoscale Discussions are in effect as of Thu May 12 14:46:01 UTC 2022.

Public Severe Weather Outlook
PUBLIC SEVERE WEATHER OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0758 AM CDT THU MAY 12 2022 ...Severe thunderstorms expected over parts of the northern/central Plains into the Upper Midwest this afternoon and evening... * LOCATIONS... Western Minnesota Eastern South Dakota Southeastern North Dakota * HAZARDS... Widespread damaging winds, some hurricane force A few tornadoes Scattered large hail, some baseball size * SUMMARY... Severe thunderstorm gusts (some near 75 mph), large hail and a few tornadoes are expected today over parts of the eastern Dakotas, eastern Nebraska, western Iowa, and central/southern Minnesota. Preparedness actions... Review your severe weather safety procedures for the possibility of dangerous weather today. Stay tuned to NOAA Weather Radio, weather.gov, or other media for watches and warnings. A watch means that conditions are favorable for severe thunderstorms over the next several hours. If a severe thunderstorm warning is issued for your area, move to a place of safety, ideally in an interior room on the lowest floor of a sturdy building. && ..Gleason.. 05/12/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0753 AM CDT Thu May 12 2022 Valid 121300Z - 131200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF EASTERN SOUTH DAKOTA...PARTS OF WESTERN MINNESOTA AND SOUTHEASTERN NORTH DAKOTA... ...SUMMARY... Severe thunderstorm gusts (some near 75 mph), large hail and a few tornadoes are expected today over parts of the eastern Dakotas, eastern Nebraska, western Iowa, and central/southern Minnesota. ...Synopsis... The mid/upper-level pattern will feature mean troughing over the western CONUS, a lengthy but weakening ridge from west-central MX across the Arklatex to southern ON, and a broad/retrograding Atlantic cyclone, forecast to move westward and ashore over much of the southeastern Atlantic Coast overnight. Within the southwest- flow field preceding the western larger-scale trough, an intense shortwave trough is apparent in moisture-channel imagery from near the ID/WY border across eastern UT. This perturbation, with a negative tilt and embedded low apparent near the southwest corner of WY -- is expected to eject northeastward through the period, reaching southeastern MT, western SD and the NE Panhandle by 00Z. By 12Z tomorrow, a well-defined 500-mb low should be apparent near the ND/SK/MB border confluence, with trough southeastward over southeastern SD. The 11Z surface analysis depicted a surface low over southwestern NE, with cold front across northern CO, and warm front over southeastern SD, extreme southern MN, and southern WI. The low should move northeastward to a frontal triple point over northeastern SD by 00Z, with an occluded low developing farther northwest and near the mid/upper cyclone center over northwestern SD/southwestern ND. By then, the warm front -- likely reinforced by outflow from earlier/morning convection to its north -- should extend from the triple point across southeastern ND, north-central MN, northern WI and the western U.P. of MI. The cold front should extend across eastern SD (likely behind a line of convection), south-central NE, western KS, and southeastern CO. A dryline will intersect the front over west-central KS, extending south-southwestward over the eastern TX Panhandle, the Permian Basin and the Big Bend region with isolated strong-severe convection possible late this afternoon. By 12Z, the triple-point low should lose definition, as the western low deepens and becomes nearly stacked with its midlevel counterpart. The cold front should extend across northern, central and southwestern MN, northwestern IA, southeastern NE, central KS, northwestern OK, the southern TX Panhandle, and southeastern NM. ...North-central Plains/Upper Midwest... Scattered to numerous thunderstorms are expected to develop in an arc near the surface low and cold front by mid/late afternoon, from eastern SD across central/eastern NE and into at least northern KS. A brief interval, early in the convective cycle, may support discrete to semi-discrete supercells before the convection becomes quasi-linear, and that accounts for potential for significant-severe hail in western parts of the outlook area. However, the most common severe type should evolve quickly to thunderstorm gusts -- some of which may be significant (65+ kt) strength, especially from parts of eastern SD and southeastern ND into western MN. The addition of the significant-wind area technically triggers a "moderate" categorical level, though the overall scenario hasn't changed in a major way from that discussed in the previous outlook. A few tornadoes also are possible -- especially near the surface warm front, where large buoyancy, backed near-surface winds and enlarged hodographs/SRH will yield the most favorable parameter space. The main uncertainty regarding the density and intensity of the tornado threat involves convective mode, which may be largely to entirely quasi-linear by the time activity encounters the largest combination of low-level buoyancy/shear with surface-based inflow parcels. The warm sector is forecast to destabilize throughout the day, with a combination of at least weak large-scale ascent (increasing northward), diurnal heating and related lift from below, and ultimately frontal convergence, eliminating a basal EML inversion and supporting convection initiation. Activity is expected to intensify quickly as it impinges on a narrow but very favorable prefrontal corridor where 60s to near 70 F surface dewpoints contribute to MLCAPE in the 3500-4500 J/kg range in and near the "moderate" area, decreasing gradually with southward extent as more low-level moisture is mixed out. Low-level and deep shear will be greatest near the triple point and warm front, with 300-500 J/kg effective SRH and 45-55-kt effective-shear magnitudes, also decreasing southward toward KS. A substantial component of mid/upper winds parallel to the axis of convective forcing indicates potential for fairly fast merging of early discrete and sporadically supercellular convection, forming a QLCS. Surges of wind from resulting LEWP/bowing segments will pose the greatest overall severe hazard, with line-embedded mesovortices and perhaps a few associated tornadoes also possible. With the warm sector's not being very broad, the convective event should diminish late this evening into early overnight hours as it outruns the most favorable instability. ...Central/southern MS and vicinity... Widely scattered thunderstorms should develop this afternoon into early evening, in a moist, well-heated and weakly capped environment, along and west of a nearly north-south low-level baroclinic zone separating the lower-theta-e air related to the cyclone from the ambient Gulf warm sector. Activity should move generally southwestward, offering isolated severe downbursts. As the mid/upper low moves toward the Atlantic Coast, and associated cyclonic flow spreads across more of the Southeast, a channel of enhanced northeast flow aloft (40-50 kt at 500 mb, 75-85 kt at 250 mb) will shift slowly westward across GA/AL. While the outlook area will be off the western rim of the strongest flow aloft, increasing winds are expected to support seasonally fast southwestward movement of multicellular clusters forming on the boundary and in the nearby warm sector. MLCAPE of 1500-2000 J/kg (locally higher) should develop atop a well-mixed boundary layer supporting downdraft- acceleration potential and strong/isolated severe gusts. ..Edwards/Gleason.. 05/12/2022 Read more

No watches are valid as of Wed May 11 14:56:01 UTC 2022.

MD 0720 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL AND WESTERN LOWER MICHIGAN
Mesoscale Discussion 0720 NWS Storm Prediction Center Norman OK 0954 AM CDT Wed May 11 2022 Areas affected...central and western Lower Michigan Concerning...Severe potential...Watch unlikely Valid 111454Z - 111730Z Probability of Watch Issuance...20 percent SUMMARY...A cluster of storms may persist today, with marginal wind or hail threat from central into southwest Lower Michigan. DISCUSSION...A cluster of storms is propagating slowly southward across central Lower MI, within the MLCAPE cape gradient and beneath the upper ridge. While shear will remain weak today, boundary-layer heating may aid continued redevelopment of updrafts along the south/southwestern flank of this cluster. Periodic strong cores with marginal hail may occur as midlevel lapse rates are steep, with isolated strong to severe gusts as well. ..Jewell/Mosier.. 05/11/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DTX...APX...GRR... LAT...LON 43758432 42788446 42118484 42078614 42428618 42998613 43578576 43768562 43918536 43948501 43828458 43758432 Read more