Severe Storms

WW 0229 Status Updates
STATUS FOR WATCH 0229 HAS NOT BEEN ISSUED YET Read more

WW 229 SEVERE TSTM TX 192020Z - 200300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 229 NWS Storm Prediction Center Norman OK 320 PM CDT Fri May 19 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of West to central Texas * Effective this Friday afternoon and evening from 320 PM until 1000 PM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible Isolated significant damaging wind gusts to 75 mph possible SUMMARY...Initial supercell development is expected over the eastern Edwards Plateau and parts of the Permian Basin with large hail from golf ball to baseball size possible. Storms may consolidate in the Hill Country vicinity this evening with a threat for isolated severe wind gusts as well. The severe thunderstorm watch area is approximately along and 80 statute miles north and south of a line from 75 miles east of Junction TX to 35 miles north northwest of Fort Stockton TX. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 227...WW 228... AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 30020. ...Grams Read more

WW 0228 Status Updates
STATUS REPORT ON WW 228 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..LEITMAN..05/19/23 ATTN...WFO...FWD... STATUS REPORT FOR WS 228 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS TXC027-035-085-093-099-113-121-133-139-143-193-213-217-221-251- 257-281-309-333-349-367-379-397-425-439-467-192140- TX . TEXAS COUNTIES INCLUDED ARE BELL BOSQUE COLLIN COMANCHE CORYELL DALLAS DENTON EASTLAND ELLIS ERATH HAMILTON HENDERSON HILL HOOD JOHNSON KAUFMAN LAMPASAS MCLENNAN MILLS NAVARRO PARKER RAINS ROCKWALL SOMERVELL TARRANT VAN ZANDT THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 228 SEVERE TSTM TX 191900Z - 200100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 228 NWS Storm Prediction Center Norman OK 200 PM CDT Fri May 19 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Central to north Texas * Effective this Friday afternoon and evening from 200 PM until 800 PM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Isolated damaging wind gusts to 70 mph possible SUMMARY...Initial storm development is underway around the Metroplex along an outflow boundary. Additional storms should form later southwest into central Texas. The severe thunderstorm watch area is approximately along and 65 statute miles east and west of a line from 40 miles northeast of Dallas TX to 55 miles west southwest of Waco TX. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). 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 227... 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 29020. ...Grams Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0252 PM CDT Fri May 19 2023 Valid 201200Z - 211200Z ...NO CRITICAL AREAS... No changes. Fire weather concern remains low for Saturday. ..Bentley.. 05/19/2023 .PREV DISCUSSION... /ISSUED 0155 AM CDT Fri May 19 2023/ ...Synopsis... The large scale pattern Saturday will encompass a weakening upper-low across the southwestern US, cooler post-frontal northerly flow across the Plains, and a trough exiting the far northeastern US. Overall, this pattern will yield light winds across the CONUS, limiting fire spread potential and precluding the need to include any areas. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0250 PM CDT Fri May 19 2023 Valid 192000Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN GREAT PLAINS INTO SOUTHWEST ARKANSAS... ...SUMMARY... Scattered severe thunderstorms are possible across parts of the southern Great Plains to southwest Arkansas through about 11 PM CDT. Large hail should be the main threat in terms of coverage, with damaging winds also possible. ...20Z Update... Minor changes to the general thunder area were made based on frontal progression. The remainder of the forecast remains on track and is unchanged. ..Wendt.. 05/19/2023 .PREV DISCUSSION... /ISSUED 1123 AM CDT Fri May 19 2023/ ...Southern Great Plains to AR... A surface cold front will continue to plunge down the Great Plains as ridging builds south through tonight. This boundary, along with a corridor of pre-frontal confluence ahead of it, and a post-frontal upslope regime behind it, will be the focus for scattered thunderstorm development during the mid to late afternoon. A decayed MCS along the OK/AR and its poor mid-level lapse rates/remnant cloud debris will serve as the northern/eastern limiter to the organized severe threat in AR later today. An MCV trailing to its west in central OK should aid in thunderstorm redevelopment across southeast OK to the Ark-La-Tex later this afternoon. This region will lie in the northeast gradient of surface-based instability with weakness in the wind profile above 500 mb. Nevertheless, modest low-level hodograph curvature should foster a few supercells that consolidate into a cluster across at least southwest AR before weakening. More favorable upper-level winds will exist farther southwest into central TX owing to a southern-stream sub-tropical jet downstream of a quasi-stationary low near the northern Gulf of CA. This combined with a corridor of large buoyancy (MLCAPE of 2500-3000 J/kg) and potential for pre-frontal development should favor a few supercells capable of producing significant severe hail. This threat may remain relatively confined owing to greater MLCIN and lack of ascent with southern extent, and eventual undercutting of the cold front. Storm-scale clustering should support a brief uptick in severe wind gust potential, but a broader MCS/greater wind coverage threat appears unlikely given weak to somewhat difluent low-level flow this evening. Finally, a corridor of post-frontal discrete supercell development is likely across the northern portion of the Permian Basin as convection develops off the higher terrain of southeast NM. Large hail will be the main threat here as well with the overall spatial extent limited by the undercutting nature of the cold front and diminishing of buoyancy from north to south behind it. ...Central OR... Modest low to mid-level moisture will persist in a south-southwesterly flow regime across OR/WA. Forcing for ascent appears to be nebulous, so terrain circulations will be the primary driver of thunderstorm development later this afternoon off the higher terrain of south-central OR. Vertical shear will be rather weak, but a couple multicell clusters could produce isolated, marginal severe gusts and small to marginally severe hail in the late afternoon to early evening. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Fri May 19 2023 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHEAST...NORTHWEST...AND SOUTH TEXAS.... ...SUMMARY... Isolated severe thunderstorms are possible Saturday across much of the Southeast, from the Edwards Plateau into the Rio Grande Valley in Texas, and parts of central Oregon and Washington. ...Synopsis... An upper-level trough across the Great Lakes region will pivot through the Northeast on Saturday. Modest mid-level flow enhancement will extend into parts of the Southeast. Upper-level ridging in the West will shift slowly eastward. A shortwave trough will also continue to approach the Northwest. At the surface, a cold front will progress farther southward through the southern Plains and Southeast. ...Southeast... A very moist airmass (likely upper 60s to low 70s F dewpoints) is expected across the region. An MCV currently in the Plains is forecast to move eastward into parts of the Mid-South. Some precipitation and cloud cover will be present across parts of northern MS/AL/GA associated with this feature. Farther to the south and west, at least filtered insolation will occur and lead to greater boundary-layer destabilization by the afternoon (nearing 2000 J/kg in some areas). Widely scattered to scattered storms do appear possible both near the MCV and along the front, though there is still variability in guidance as to where a greater concentration of storms would exist. Environmentally, a few more intense storms could occur in within the central AL/MS border vicinity. Here, greater surface heating would combine with modestly greater shear from larger-scale trough and MCV. ...Northwest... Little change in the pattern is expected between Friday and Saturday. Continued southwesterly flow aloft should help to maintain modest low-level moisture. With the approach of the trough, deep-layer shear will likely be slightly stronger on Saturday and storm coverage may also be greater as well. Storms will be capable of isolated damaging winds and perhaps marginally severe hail. ...South Texas... Uncertainty remains high in the exact convective evolution within the Rio Grande Valley/South Texas. Convection may be ongoing early in the period as overnight storms from the Edwards Plateau move southward. How far south such activity will reach is not certain. Two other possible scenarios are for storms to develop along outflow from that early morning activity as well as some potential for storms to move across the international border later in the afternoon. With the environment supportive of damaging winds and large hail, a Marginal risk area will be maintained for these possibilities. ..Wendt.. 05/19/2023 Read more

No watches are valid as of Thu May 18 21:37:01 UTC 2023.

MD 0816 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF SOUTHWEST TEXAS
Mesoscale Discussion 0816 NWS Storm Prediction Center Norman OK 0423 PM CDT Thu May 18 2023 Areas affected...portions of southwest Texas Concerning...Severe potential...Watch unlikely Valid 182123Z - 182330Z Probability of Watch Issuance...5 percent SUMMARY...Strong to briefly severe thunderstorms producing strong gusts and hail may persist another 1-2 hours before weakening. DISCUSSION...Widely scattered strong to briefly severe thunderstorms have developed in low-level confluence amid moderate instability late this afternoon. Vertical shear is very weak across the area and will remain so through the evening. This activity will shift generally east very slowly, within a narrow axis of instability before boundary-layer inhibition increases. Modestly steep midlevel lapse rates may support marginally severe hail, while a well-mixed boundary-layer contributing to steep low-level lapse rates, and weak low-level flow will foster strong outflow winds. Convective intensity should diminish this evening and with eastward extent. Further south, addition convection has developed west of the Rio Grande across northeast Mexico. This activity should weaken as it approaches the river and perhaps crosses into Texas. However, poor vertical shear and little forcing for ascent to maintain any organization/stronger intensity should preclude much severe potential. ..Leitman/Smith.. 05/18/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EWX...SJT...LUB...MAF... LAT...LON 29710211 32790130 32980060 32890002 32529978 31869998 31410007 28370041 29410138 29710211 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Thu May 18 2023 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TEXAS PANHANDLE VICINITY... ...SUMMARY... Generally isolated severe thunderstorms are expected across parts of the central to southern Great Plains, the Upper Midwest, and the Tennessee Valley this afternoon and evening. Relatively greater potential for severe hail and a tornado or two is apparent over the Texas Panhandle vicinity. ...20Z Update... Minor changes to the general thunderstorm lines were made based on observed trends. The outlook is otherwise unchanged. ..Wendt.. 05/18/2023 .PREV DISCUSSION... /ISSUED 1127 AM CDT Thu May 18 2023/ ...Southern/central High Plains... Relatively unfocused and generally marginal severe potential is anticipated this afternoon and evening as scattered thunderstorms develop from the Front Range to the Trans-Pecos and spread east. The broad cat 1-MRGL risk covers the bulk of the area with an embedded cat 2-SLGT in the TX Panhandle vicinity where a few supercells are most probable. Mid-level lapse rates should not be particularly steep east of the higher terrain. Weak deep-layer shear is anticipated south of the TX Panhandle, while weak buoyancy will be common north of the Panhandles. As such, the central High Plains portion should tend to favor an isolated/marginal severe hail threat initially, transitioning to more of a locally strong gust threat as storms congeal eastward. Most of the west TX portion should tend to be high-based initially and overall favor strong to locally severe wind gusts. The TX Panhandle vicinity will largely be driven by differential heating surrounding a persistent stratus deck that should slowly erode but may not completely dissipate. 12Z CAM consensus suggests an initial round of discrete cells may form around mid-afternoon, with a more probable later round of higher-based clusters spreading east from the Sangre de Cristos during the early evening. Low-level hodograph curvature should increase during the early evening and become moderately enlarged. These may support a few supercells as effective bulk shear increases to 30-35 kts. This could yield a relatively greater corridor of severe hail potential before storms further consolidate and gradually diminish after sunset. The tornado threat will be conditionally dependent on maintaining a discrete supercell mode during the early evening within the weakly focused baroclinic zone. ...Upper Midwest... A shortwave trough over southern Manitoba will slowly move southeast towards the Twin Ports area tonight. Leading and reinforcing surface cold fronts are expected to push southeast, with the lead one focusing isolated severe potential during the late afternoon to early evening. A plume of around 1 inch PW values characterized by mid to upper 50s surface dew points should be confined along the front and yield a corridor of weak buoyancy from northeast IA/southeast MN into central WI. While the strongest belt of mid-level flow will lag behind the leading front, moderate deep-layer shear will favor a few organized updrafts capable of isolated severe hail and damaging winds. This severe threat is expected to last up to around 3-4 hours due to the narrow instability axis and onset of nocturnal cooling. ...Southeast... Generally weak deep-layer flow will preclude organized convection across the Southeast this afternoon, but sporadic wet microbursts producing locally strong wind gusts will be possible. One area of somewhat more focused downburst and marginally severe hail threat remains apparent ahead of a slowly decaying mid-level trough drifting east from the Mid-South to the TN Valley. Here, relatively colder mid-level temperatures may compensate for the weak shear regime and support a marginal severe threat as scattered thunderstorms form and drift east through south. Read more

MD 0815 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF NORTHEASTERN NEW MEXICO...ADJACENT SOUTHEASTERN COLORADO...INTO THE TEXAS/OKLAHOMA PANHANDLES
Mesoscale Discussion 0815 NWS Storm Prediction Center Norman OK 0252 PM CDT Thu May 18 2023 Areas affected...parts of northeastern New Mexico...adjacent southeastern Colorado...into the Texas/Oklahoma Panhandles Concerning...Severe potential...Watch possible Valid 181952Z - 182215Z Probability of Watch Issuance...40 percent SUMMARY...Increasing thunderstorm development may gradually consolidate into a growing cluster of storms while spreading into the Oklahoma/Texas Panhandle vicinity through 5-7 PM CDT. The potential for severe weather appears relatively low in the near term, but could increase later this evening. DISCUSSION...Beneath weak mid-level troughing crossing the Rockies, orographic forcing for ascent is contributing to a gradual increase in thunderstorm activity near the Sangre de Cristo Mountains and along the Raton Mesa to the east. This appears to be occurring in the presence of modest deep-layer shear (largely due to veering of winds with height), but deep-layer mean ambient flow is weak (on the order of 15 kt) and south-southwesterly, which will support only a slow progression into the adjacent plains. As activity advects eastward, it does appear that southeasterly low-level inflow will gradually emanate from an increasingly moist and potentially unstable boundary-layer. This is expected to support further upscale growth and intensification through the remainder of the afternoon. Gradually, stronger convection may begin to focus along an increasingly better-defined zone of stronger differential surface heating southwest through south of Dalhart and Amarillo. Deep-layer shear may be marginally supportive of a supercell structure or two. Perhaps more substantively, various model output have been suggestive that a modest mesocale convective vortex could evolve in association with the persistent growing cluster of storms. If/when this occurs, strengthening rear inflow and downdrafts may be accompanied by increasing risk for strong surface gusts, but it is possible that this might not be until well after sunset. ..Kerr/Grams.. 05/18/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LUB...AMA...ABQ... LAT...LON 36350443 36980318 36890167 35810109 34930214 34410314 34250416 34900516 35500490 36350443 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0228 PM CDT Thu May 18 2023 Valid 191200Z - 201200Z ...NO CRITICAL AREAS... The previous forecast (see below) remains on track, with no changes or additions made. ..Squitieri.. 05/18/2023 .PREV DISCUSSION... /ISSUED 1045 PM CDT Wed May 17 2023/ ...Synopsis... A midlevel trough will track eastward across the Great Lakes region. Preceding the trough, enhanced deep-layer southwesterly flow will overspread the Northeast -- where a tightening surface pressure gradient is expected. As a result, breezy/gusty surface winds are possible; however, marginal RH reductions (35-40 percent) should generally limit the fire-weather threat. Elsewhere, the overlap of breezy surface winds and low RH over dry fuels should be minimal. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Thu May 18 2023 Valid 191200Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS INTO CENTRAL ARKANSAS... ...SUMMARY... Strong/locally severe storms are expected Friday from parts of the southern Plains eastward across Arkansas to parts of the Lower Mississippi Valley vicinity. ...Synopsis... A strong upper trough will move through the Upper Great Lakes on Friday. Attendant to this system, a surface cold front will extend from the Upper Midwest southwestward into the central/southern Plains. While upper-level ridging will be the primary feature across the West, a modest upper-level low will remain across the lower Colorado River Valley/Baja. Some mid-level flow enhancement across the southern High Plains into the Red River region will promote a weak, secondary surface low/dryline from perhaps southwest Oklahoma into parts of central Texas. ...Central Texas into Arkansas... Precipitation is expected to be ongoing during the morning in Oklahoma in association with an MCV from High Plains convection on Thursday. The location of this feature will determine the northward extent of severe potential. Along and south of the outflow/effective warm front, surface heating of low/mid 60s F dewpoints should promote 1000-1500 J/kg MLCAPE. While shear will not be overly strong, flow enhancement from the MCV will allow for modest storm organization. Initial storms would be capable of large hail before storm interactions and upscale growth occur and damaging wind become the primary concern. Along the dryline in Texas, there is less certainty in terms of storm initiation, particularly with southward extent. However, along the outflow/dryline intersection, enough convergence should exist to initiate thunderstorms. Steeper mid-level lapse rates and greater surface heating farther west should promote larger buoyancy (in excess of 2000 J/kg MLCAPE). Shear will be weaker as will anvil-level winds. Even so, initial storm development again will pose a risk of large hail (potentially up to 2 in.). The main uncertainty is where any potential clustering of storms may occur across the broader Slight risk area. Where this occurs, cold pool organization would bring potential for smaller corridors of greater wind damage potential. The spatial extent of the Slight risk intends to capture the envelope of solutions in guidance. ...South Plains into central New Mexico... Storm development is possible along the higher terrain in New Mexico and along the southward sagging cold front into the South Plains. Modest mid-level winds will be orthogonal to the boundary. A few semi-discrete cells are possible. Isolated large hail and damaging winds may occur before storms move north of the boundary and weaken. ...Arizona... Anomalous moisture in the region due to the upper low will promote widely scattered to scattered storms along the Mogollon Rim. Weak mid-level northeasterly flow could help push a cluster off the terrain, but such a scenario is uncertain. Should this occur, strong wind gusts would be possible. Confidence is too low for introducing unconditional severe probabilities. ..Wendt.. 05/18/2023 Read more

No watches are valid as of Wed May 17 21:31:01 UTC 2023.

No Mesoscale Discussions are in effect as of Wed May 17 21:31:01 UTC 2023.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Wed May 17 2023 Valid 172000Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON AND EVENING ACROSS PARTS OF THE SOUTHEAST AND THE GREAT PLAINS... ...SUMMARY... Localized damaging wind gusts remain possible in scattered storms across parts of the Southeast into early evening. Sporadic severe hail and wind gusts also remain possible with increasing thunderstorm activity across parts of the Dakotas into the southern High Plains through this early evening. ...20Z Update... Some adjustments have been made to the categorical and probabilistic lines, mostly to account for the progression of synoptic/sub-synoptic features and their influence on instability trends. Across the Southeast, the Gulf sea breeze and an assortment of outflow boundaries continue to spread inland of coastal areas. Deep-layer westerly ambient mean flow continues to weaken and (based on the latest Rapid Refresh), outside a broadening corridor across Georgia into the Carolinas, is now generally on the order of 15 kt or less. However, thermodynamic profiles with moderately steep low-level lapse rates may continue to support a risk for localized damaging wind gusts as thunderstorm activity becomes increasingly widespread through late afternoon. ..Kerr.. 05/17/2023 .PREV DISCUSSION... /ISSUED 1056 AM CDT Wed May 17 2023/ ...Southeast... Scattered thunderstorms are expected this afternoon from the Gulf Coast to a slow-moving cold front undergoing frontolysis across parts of the Deep South. Per 12Z observed soundings and visible satellite imagery, the strongest boundary-layer heating and MLCAPE should develop across southern portions of MS/AL/GA/SC, with more limited values to the north. Weak deep-layer shear and lapse rates (around 5.5-6 C/km from 700-500 mb) will mitigate organization potential and hail growth across much of the region. Pockets of marginally severe hail potential around 1 inch are possible in the most buoyant airmass over the central Gulf Coast and with somewhat greater deep shear across southern SC. Otherwise, sporadic wet microbursts producing strong gusts capable of tree damage should be the primary threat. ...Dakotas to southern High Plains... Isolated to scattered thunderstorms will be focused this afternoon along a southeast-moving cold front over the Dakotas, and southward along a lee trough to the southern High Plains. Mid-level west-northwesterlies will be weak, but strengthen with height into the upper-levels across the central High Plains and support potential for a few transient supercell structures. Though convective coverage here should be relatively less compared to farther north and south. Modest MLCAPE of 1000-1500 J/kg should develop over the southern High Plains along the northwest periphery of PW values around 1 inch, with weak buoyancy farther north. Overall setup should support sporadic instances of lower-end severe hail and wind. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0128 PM CDT Wed May 17 2023 Valid 181200Z - 191200Z ...NO CRITICAL AREAS... The previous forecast (see below) remains on track. ..Squitieri.. 05/17/2023 .PREV DISCUSSION... /ISSUED 0158 AM CDT Wed May 17 2023/ ...Synopsis... The overlap of breezy surface winds and low relative humidity over dry fuels should be minimal on Day 2/Thursday -- generally limiting the fire-weather risk. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 PM CDT Wed May 17 2023 Valid 181200Z - 191200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON AND EVENING ACROSS PARTS OF THE SOUTHERN HIGH PLAINS...AND PORTIONS OF THE UPPER MIDWEST... ...SUMMARY... Strong thunderstorms may impact parts of the southern Great Plains and the Upper Midwest on Thursday. Some of these may pose at least some risk for severe weather. ...Synopsis... Within the prevailing split flow across the Pacific, a broad and deep mid-level low is forecast to evolve in association with strong cyclogenesis to the southeast of the Aleutians during this period. Downstream of this feature, weak mid-level ridging is forecast to build inland of the U.S. and Canadian Pacific coast, while low amplitude troughing lingers in a separate stream near/west of Baja California. Farther east, weak, broadly confluent mid-level flow will generally prevail across much of the U.S. However, an initially vigorous mid-level low may continue digging south of the central Canadian/U.S. border, gradually elongating across the Upper Midwest into middle Missouri Valley by late Thursday night. Downstream of this feature low amplitude ridging is forecast to shift across and east of the lower Great Lakes, in the wake of a vigorous impulse accelerating east of the Canadian Maritimes. At the same time, downstream of the Baja mid-level troughing, short wave ridging may tend to build across the northern Mexican Plateau and southern Great Plains into the lower Mississippi Valley. However, this may be slowed by a smaller-scale perturbation of subtropical eastern Pacific origins, which is forecast to gradually progress around its northern periphery. Farther east, broad, weak mid-level troughing is forecast to continue slowly migrating eastward across the Southeast. In the wake of the stronger lead northern branch perturbation, and the weaker lead southern branch perturbation, boundary-layer moisture across the southern Great Plains into surface troughing to the lee of the southern Rockies will initially be seasonably modest. Substantive moisture advection appears unlikely, but evapotranspiration may contribute to moistening across this region during the day, as well as ahead of a significant cold front accompanying the northern branch low digging south of the international border. A significant preceding cold front appears likely to stall and weaken across parts of the southern Atlantic coast into Tennessee Valley vicinity. ...Southern High Plains... While models suggest that mid-level lapse rates will be initially modest across much of the region, some gradual steepening with lower/mid-tropospheric warming is forecast through the period. During the day, it appears that the boundary-layer, becoming deeply mixed with daytime heating, may become sufficiently unstable to support scattered thunderstorm posing a risk for marginally severe hail and wind. Deep-layer wind fields and shear appear likely to remain generally weak, but it is possible that a 30-40 kt west-southwesterly jet streak in the 700-500 mb layer (accompanying the subtropical perturbation) could enhance convection as it spreads across the southern Texas Panhandle/South Plains into Red River vicinity Thursday evening. An outflow boundary from prior convection, or at least a zone of stronger differential surface heating across the Texas Panhandle into southwestern Oklahoma/western North Texas, may become a focus for stronger lower/mid tropospheric warm advection by Thursday evening. This could support an isolated supercell structure or two, and eventually an upscale growing cluster which could be accompanied by strong surface gusts for a period late Thursday evening, before forcing shifts to the cool side of the boundary and convective intensities wane overnight. ...Upper Midwest... The cold core of the approaching mid-level low/trough is forecast to remain displaced to the northwest of the surface warm sector. Coupled with the modest warm sector boundary-layer moisture, maximum instability is forecast to remain weak and largely confined to a narrow pre-frontal corridor. However, it appears that this may be sufficient to support a developing line of storms by late Thursday afternoon across parts of north central through southwest Wisconsin and adjacent portions of Minnesota/Iowa, aided by favorable large-scale forcing for ascent. This may coincide with sufficient deep-layer shear beneath 40-50 kt southwesterly mid-level flow, to support a few supercell structures posing at least some risk for severe hail and wind gusts, before convection weakens after dark while spreading southeastward. ..Kerr.. 05/17/2023 Read more

No Mesoscale Discussions are in effect as of Tue May 16 21:42:06 UTC 2023.

WW 0225 Status Updates
STATUS REPORT ON WW 225 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NNE BNA TO 50 SE LOZ TO 20 S CRW. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0804 ..WEINMAN..05/16/23 ATTN...WFO...LMK...JKL...MRX...OHX...RLX... STATUS REPORT FOR WS 225 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KYC195-162240- KY . KENTUCKY COUNTIES INCLUDED ARE PIKE TNC001-009-013-025-029-035-049-057-063-067-073-087-089-093-105- 129-133-141-145-151-155-159-163-165-169-173-189-162240- TN . TENNESSEE COUNTIES INCLUDED ARE ANDERSON BLOUNT CAMPBELL CLAIBORNE COCKE CUMBERLAND FENTRESS GRAINGER HAMBLEN HANCOCK HAWKINS JACKSON JEFFERSON KNOX LOUDON MORGAN OVERTON PUTNAM ROANE SCOTT SEVIER SMITH SULLIVAN SUMNER TROUSDALE UNION WILSON Read more