Severe Storms

No watches are valid as of Sat May 20 21:41:02 UTC 2023.

No Mesoscale Discussions are in effect as of Sat May 20 21:41:02 UTC 2023.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Sat May 20 2023 Valid 202000Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHWEST...THE RIO GRANDE VALLEY AND THE DEEP SOUTH... ...SUMMARY... Isolated and marginally severe thunderstorms are possible through this evening across parts of the Deep South, the Northwest, and the Rio Grande Valley. ...20z Update... Only minor adjustments have been made to the Marginal risk (level 1 of 5) across Deep South Texas and MS/AL. These changes are based on currently location of ongoing convection and the position of the surface cold front. Otherwise, the previous forecast is on track. For more details, see the 1630z Day 1 discussion below. ..Leitman.. 05/20/2023 .PREV DISCUSSION... /ISSUED 1126 AM CDT Sat May 20 2023/ ...Deep South... A low-amplitude shortwave trough over the Mid-MS Valley will move southeast towards the southern Appalachians, and will be preceded by an MCV currently centered on middle TN. Abundant cloud coverage across northern portions of AL/GA will limit boundary-layer destabilization to the immediate southeast of lingering stratiform rain attendant to the MCV. Amid poor mid-level lapse rates (5-5.5 C/km between 700-500 mb) sampled by the 12Z BMX/BNA soundings, the lack of more robust boundary-layer heating will likely mitigate appreciable severe potential with north/east extent. With more robust insolation underway farther south-southwest and richer boundary-layer moisture, a plume of moderate MLCAPE from 1500-2000 J/kg is anticipated across southern MS to central AL. This should support convective development trailing southwestward along/ahead of a southeast-moving cold front in the next few hours. With a predominant westerly deep-layer wind profile, effective bulk shear should be limited to around 20-25 kts where buoyancy is greater. Given the poor mid-level lapse rates upstream, hail sizes will probably remain small to marginally severe. A threat for isolated damaging winds should be the main hazard with multicell clusters that spread east-southeast and largely weaken after sunset. ...OR/WA... Somewhat greater convective coverage is anticipated relative to yesterday during the late afternoon and evening within a modest south-southwesterly deep-layer flow regime. The most likely corridor for scattered storm development is off the higher terrain in southern OR east of the Cascades, with more isolated activity possible across central WA. Where adequate effective bulk shear is present, largely close to the Cascades, marginally severe hail will be possible. Otherwise, isolated strong gusts will be possible in eastern OR given deeper mixed thermodynamic profiles with eastern extent. ...Southwest NM vicinity... A minor upper low persists near the northwest Sonora/southeast AZ border area and will drift north-northeast today. With low 50s surface dew points having spread west of the Rio Grande following a recent cold front intrusion, a pocket of weak buoyancy should develop with MLCAPE of 500-1000 J/kg. Effective bulk shear will likely remain weak, from only 20-25 kts as stronger speed shear is confined to the very upper portion of the buoyancy profile. Small to marginally severe hail and a few locally strong gusts cannot be ruled out. ...Deep South TX... A few strong storms remain possible later this afternoon as a cold front continues to move slowly southward. Buoyancy should remain moderate owing to broken cloud coverage ahead of the front. 0-6 km winds will remain unremarkable with moderate southwesterlies above that. In addition, mid-level lapse rates peaked this morning and are consistently progged to weaken through the day. Small to marginally severe hail and a few locally strong gusts cannot be ruled out. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0215 PM CDT Sat May 20 2023 Valid 211200Z - 221200Z ...NO CRITICAL AREAS... No changes. See previous discussion below. ..Bentley.. 05/20/2023 .PREV DISCUSSION... /ISSUED 0109 AM CDT Sat May 20 2023/ ...Synopsis... On Sunday, a weak shortwave will rotate across the Central Plains as southerly flow returns moisture northward. Winds will increase but moisture return will keep relative humidity above critical thresholds. Drying conditions will be possible across the Southwest. However, winds will remain light with recent above normal rainfall leading to largely wet fuels. As such, fire weather concerns remain low with no areas included. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1235 PM CDT Sat May 20 2023 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF EASTERN OREGON AND WASHINGTON INTO NORTHERN IDAHO AND FAR NORTHWEST MONTANA... CORRECTED FOR SUMMARY TEXT ...SUMMARY... Severe thunderstorms are possible from eastern Oregon into far eastern Washington, northern Idaho, and far western Montana Sunday afternoon and evening. Large hail and isolated damaging gusts will be possible with these storms. ...Northern Rockies... An upper ridge will be oriented over the Great Basin and northern Rockies vicinity Sunday morning. However, a shortwave trough off the Pacific Northwest/British Columbia coast will dig southeast into the northern Rockies vicinity by the end of the period. Increasing southwesterly mid/upper-level flow will overspread eastern WA/OR into ID and western MT by afternoon. Cold temperatures aloft will support steep lapse rates over the region, with southwesterly flow increasing midlevel moisture. This will support destabilization, with MLCAPE values around 1000-2000 J/kg forecast. Low-level winds will remain somewhat light, but speed shear will create elongated hodographs and effective shear favorable for marginal supercells (around 30 kt). Large hail (to around 1.75 inch diameter) will be the main hazard, with environmental parameters supporting an upgrade to Slight risk (level 2 of 5). Some risk for strong outflow winds also will exist, especially over parts of eastern Oregon into adjacent portions of Idaho where stronger heating will support steeper low-level lapse rates. ...Southern High Plains... Thunderstorms are expected to develop over the higher terrain of central NM during the afternoon. As these storms shift east into the high Plains and interact with a weak surface trough, some strengthening of updrafts may occur. However, instability is expected to remain modest and vertical shear weak. This should limit storm organization and longevity of any stronger updrafts, and severe potential appears too limited for probabilities. ...Southeast... A weakening cold front will shift east/southeast across the region in a generally weak flow regime. Seasonal moisture ahead of the front and pockets of heating will allow for weak destabilization. A few storms could be strong enough to produce gusty winds. However, limited forcing, poor lapse rates and weak shear should limit severe potential. ..Leitman.. 05/20/2023 Read more

MD 0824 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL OREGON
Mesoscale Discussion 0824 NWS Storm Prediction Center Norman OK 0457 PM CDT Fri May 19 2023 Areas affected...central Oregon Concerning...Severe potential...Watch unlikely Valid 192157Z - 200000Z Probability of Watch Issuance...5 percent SUMMARY...Marginally severe gusts and hail possible as thunderstorm coverage increases through the afternoon. A watch is unlikely. DISCUSSION...Visible satellite shows maturing cumulus and developing thunderstorms activity across the Fremont Mountains and Oregon High Desert. Daytime heating has allowed MLCAPE around 500-1000 J/kg across the region. RAP soundings indicate profiles are fairly dry below 500 mb with large surface dew point depressions in current surface observations, especially within the High Desert east of the Cascades (around 40-45 F in some locations). Given fairly weak deep layer shear around 15 kts, storm mode will be largely multi-cell and clustered capable of marginally severe hail and downbursts. ..Thornton/Guyer.. 05/19/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PDT...MFR...PQR... LAT...LON 44232182 45242170 45762125 46002035 45821977 45121959 43402038 43262100 43262130 43292154 43292166 43692183 44232182 Read more

WW 0227 Status Updates
STATUS REPORT ON WW 227 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0823 ..LYONS..05/19/23 ATTN...WFO...LZK...SHV...TSA...OUN...FWD... STATUS REPORT FOR WS 227 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC019-051-057-059-061-073-081-091-097-099-109-113-127-131-133- 192140- AR . ARKANSAS COUNTIES INCLUDED ARE CLARK GARLAND HEMPSTEAD HOT SPRING HOWARD LAFAYETTE LITTLE RIVER MILLER MONTGOMERY NEVADA PIKE POLK SCOTT SEBASTIAN SEVIER OKC005-013-023-029-061-063-069-077-079-089-095-121-123-125-127- 133-192140- OK . OKLAHOMA COUNTIES INCLUDED ARE ATOKA BRYAN CHOCTAW COAL HASKELL HUGHES JOHNSTON LATIMER LE FLORE MCCURTAIN MARSHALL PITTSBURG PONTOTOC POTTAWATOMIE PUSHMATAHA Read more

WW 227 SEVERE TSTM AR OK TX 191810Z - 200100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 227 NWS Storm Prediction Center Norman OK 110 PM CDT Fri May 19 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southwest Arkansas Southeast Oklahoma Northeast Texas * Effective this Friday afternoon and evening from 110 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 A tornado or two possible SUMMARY...Initial thunderstorm development is underway along a west/east-oriented outflow boundary along the Red River. Additional storms will probably form to the northwest from central Oklahoma and intensify into southeast Oklahoma later this afternoon. The severe thunderstorm watch area is approximately along and 90 statute miles east and west of a line from 20 miles northeast of Poteau OK to 45 miles south southeast of Paris TX. 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. && 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 27030. ...Grams Read more

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