Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Fri May 12 2023 Valid 131200Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL/EASTERN IA INTO NORTHWEST IL...AND ACROSS PARTS OF SOUTH TX... ...SUMMARY... Scattered severe storms are possible across parts of Iowa and Illinois, with more isolated storms into the lower Ohio Valley. Scattered severe storms are also possible across parts of South Texas, with an isolated risk across a broader portion of the southern Plains. ...IA/IL into the lower OH Valley... A weakening deep-layer cyclone is forecast to move slowly eastward from the mid MO Valley across northern IA on Saturday. The evolution of convection during the D1/Friday period will influence the position of important surface features, but in general, a warm front is expected to extend east-southeastward from central IA into northwest IL, while a surface trough will extend south of the warm front and weakening cyclone. Midlevel lapse rates will be rather weak, but relatively rich low-level moisture will support moderate buoyancy by afternoon, and scattered thunderstorm development is possible near the surface low and along the warm front. Favorably veering wind profiles will support the potential for a few supercells initially, posing a threat of hail, locally damaging wind, and possibly a couple of tornadoes with any cells near/just north of the warm front, where low-level shear/SRH will be modestly enhanced. One or more clusters may eventually evolve and move southeastward into the evening, posing a continued threat of isolated hail and damaging wind that may spread into the lower OH Valley. ...South TX and vicinity... An MCS may be ongoing across parts of south/central TX at the start of the forecast period Saturday morning. Depending on the intensity/organization of the system overnight leading into D2/Saturday, some threat for severe wind/hail will be possible in the morning. The severe risk is expected to spread southeastward toward the lower TX coast with time, though guidance varies regarding whether this occurs early in the day, or if the morning MCS decays and allows for redevelopment during the afternoon. Regardless, rich low-level moisture will support moderate to strong buoyancy in the preconvective environment, which in turn will support a threat of severe wind/hail until storms move offshore. ...OK into north TX... An MCV is forecast to move northward across the TX South Plains/Panhandle during the day on Saturday. Scattered thunderstorms are expected east of the MCV track. Instability may remain rather modest due to weak midlevel lapse rates, but diurnal heating and modest deep-layer shear (effective shear generally 20-30 kt) may support a few strong storms during the afternoon, with a threat of isolated hail, locally damaging gusts, and perhaps a brief tornado. ..Dean.. 05/12/2023 Read more

WW 0213 Status Updates
STATUS REPORT ON WW 213 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..THORNTON..05/11/23 ATTN...WFO...OUN...FWD... STATUS REPORT FOR WT 213 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS OKC015-017-019-027-031-033-049-051-067-069-075-085-087-095-099- 109-123-125-133-137-141-149-112240- OK . OKLAHOMA COUNTIES INCLUDED ARE CADDO CANADIAN CARTER CLEVELAND COMANCHE COTTON GARVIN GRADY JEFFERSON JOHNSTON KIOWA LOVE MCCLAIN MARSHALL MURRAY OKLAHOMA PONTOTOC POTTAWATOMIE SEMINOLE STEPHENS TILLMAN WASHITA TXC009-077-097-181-337-485-112240- TX . TEXAS COUNTIES INCLUDED ARE ARCHER CLAY COOKE GRAYSON MONTAGUE WICHITA THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE Read more

WW 0213 Status Updates
STATUS REPORT ON WW 213 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..THORNTON..05/11/23 ATTN...WFO...OUN...FWD... STATUS REPORT FOR WT 213 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS OKC015-017-019-027-031-033-049-051-067-069-075-085-087-095-099- 109-123-125-133-137-141-149-112240- OK . OKLAHOMA COUNTIES INCLUDED ARE CADDO CANADIAN CARTER CLEVELAND COMANCHE COTTON GARVIN GRADY JEFFERSON JOHNSTON KIOWA LOVE MCCLAIN MARSHALL MURRAY OKLAHOMA PONTOTOC POTTAWATOMIE SEMINOLE STEPHENS TILLMAN WASHITA TXC009-077-097-181-337-485-112240- TX . TEXAS COUNTIES INCLUDED ARE ARCHER CLAY COOKE GRAYSON MONTAGUE WICHITA THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE Read more

WW 213 TORNADO OK TX 112045Z - 120400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 213 NWS Storm Prediction Center Norman OK 345 PM CDT Thu May 11 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southern and Central Oklahoma North Texas * Effective this Thursday afternoon and evening from 345 PM until 1100 PM CDT. * Primary threats include... A few tornadoes and a couple intense tornadoes possible Scattered large hail likely with isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Storms are expected to quickly develop and intensify through late afternoon, initially across southern Oklahoma and far north Texas in vicinity of a remnant boundary. Additional development will likely occur east-northeastward into central Oklahoma by early evening as the air mass continues to quickly moisten and destabilize. Supercells capable of very large hail and tornadoes can be expected through at least mid-evening as storms spread toward/east of the I-35 corridor. The tornado watch area is approximately along and 75 statute miles north and south of a line from 40 miles west of Fort Sill OK to 30 miles north of Durant OK. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 210...WW 211...WW 212... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 22025. ...Guyer Read more

WW 0211 Status Updates
STATUS REPORT ON WW 211 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 E LBL TO 15 S GCK TO 35 NW GCK TO 15 WNW LAA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0766 ..THORNTON..05/11/23 ATTN...WFO...GLD...PUB...DDC... STATUS REPORT FOR WT 211 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC017-061-063-125-112240- CO . COLORADO COUNTIES INCLUDED ARE CHEYENNE KIOWA KIT CARSON YUMA KSC023-025-033-039-047-051-055-057-063-065-069-071-083-097-101- 109-119-135-137-145-153-165-171-179-181-193-195-199-203- 112240- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE CLARK COMANCHE DECATUR EDWARDS ELLIS FINNEY FORD GOVE GRAHAM GRAY GREELEY HODGEMAN KIOWA LANE LOGAN MEADE NESS NORTON PAWNEE RAWLINS Read more

WW 0211 Status Updates
STATUS REPORT ON WW 211 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 E LBL TO 15 S GCK TO 35 NW GCK TO 15 WNW LAA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0766 ..THORNTON..05/11/23 ATTN...WFO...GLD...PUB...DDC... STATUS REPORT FOR WT 211 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC017-061-063-125-112240- CO . COLORADO COUNTIES INCLUDED ARE CHEYENNE KIOWA KIT CARSON YUMA KSC023-025-033-039-047-051-055-057-063-065-069-071-083-097-101- 109-119-135-137-145-153-165-171-179-181-193-195-199-203- 112240- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE CLARK COMANCHE DECATUR EDWARDS ELLIS FINNEY FORD GOVE GRAHAM GRAY GREELEY HODGEMAN KIOWA LANE LOGAN MEADE NESS NORTON PAWNEE RAWLINS Read more

WW 211 TORNADO CO KS NE 111720Z - 120000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 211 NWS Storm Prediction Center Norman OK 1220 PM CDT Thu May 11 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Far Eastern Colorado Western Kansas Southwest Nebraska * Effective this Thursday afternoon and evening from 1220 PM until 700 PM CDT. * Primary threats include... A few tornadoes possible Scattered large hail likely with isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Bands of storms in a northwest-to-southeast-oriented arc will continue to develop and intensify initially across far eastern Colorado and far western/southwest Kansas. This will include supercells capable of large hail and tornadoes, aside from an evolving damaging wind risk as the corridor storm development shifts east-northeastward through the afternoon across western Kansas/southwest Nebraska. The tornado watch area is approximately along and 85 statute miles north and south of a line from 25 miles west of Burlington CO to 45 miles northeast of Dodge City KS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 210... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 19020. ...Guyer Read more

WW 0212 Status Updates
STATUS REPORT ON WW 212 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 SSW HEZ TO 30 NW MCB TO 60 NNW PIB TO 35 W MEI TO 45 N MEI TO 35 WSW CBM. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0765 ..THORNTON..05/11/23 ATTN...WFO...LIX...JAN... STATUS REPORT FOR WT 212 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS LAC037-077-091-105-117-125-112240- LA . LOUISIANA PARISHES INCLUDED ARE EAST FELICIANA POINTE COUPEE ST. HELENA TANGIPAHOA WASHINGTON WEST FELICIANA MSC005-023-031-035-061-065-067-069-073-075-077-085-091-101-109- 113-127-129-147-157-112240- MS . MISSISSIPPI COUNTIES INCLUDED ARE AMITE CLARKE COVINGTON FORREST JASPER JEFFERSON DAVIS JONES KEMPER LAMAR LAUDERDALE LAWRENCE LINCOLN MARION NEWTON PEARL RIVER PIKE SIMPSON SMITH WALTHALL WILKINSON Read more

WW 0212 Status Updates
STATUS REPORT ON WW 212 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 SSW HEZ TO 30 NW MCB TO 60 NNW PIB TO 35 W MEI TO 45 N MEI TO 35 WSW CBM. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0765 ..THORNTON..05/11/23 ATTN...WFO...LIX...JAN... STATUS REPORT FOR WT 212 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS LAC037-077-091-105-117-125-112240- LA . LOUISIANA PARISHES INCLUDED ARE EAST FELICIANA POINTE COUPEE ST. HELENA TANGIPAHOA WASHINGTON WEST FELICIANA MSC005-023-031-035-061-065-067-069-073-075-077-085-091-101-109- 113-127-129-147-157-112240- MS . MISSISSIPPI COUNTIES INCLUDED ARE AMITE CLARKE COVINGTON FORREST JASPER JEFFERSON DAVIS JONES KEMPER LAMAR LAUDERDALE LAWRENCE LINCOLN MARION NEWTON PEARL RIVER PIKE SIMPSON SMITH WALTHALL WILKINSON Read more

WW 212 TORNADO LA MS 111745Z - 120100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 212 NWS Storm Prediction Center Norman OK 1245 PM CDT Thu May 11 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southeast Louisiana Southern and Central Mississippi * Effective this Thursday afternoon and evening from 1245 PM until 800 PM CDT. * Primary threats include... A couple tornadoes possible Scattered damaging wind gusts to 65 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...Clusters of storms capable of damaging winds and couple of tornadoes (mostly short-lived) will continue east-southeastward across southern/central Mississippi, with additional severe storm development possible this afternoon along the Mississippi/Louisiana border vicinity. The tornado watch area is approximately along and 60 statute miles east and west of a line from 60 miles north northwest of Meridian MS to 35 miles south southwest of Mc Comb MS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 210...WW 211... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27025. ...Guyer Read more

MD 0766 CONCERNING TORNADO WATCH 211... FOR WESTERN KANSAS INTO WESTERN NEBRASKA
Mesoscale Discussion 0766 NWS Storm Prediction Center Norman OK 0349 PM CDT Thu May 11 2023 Areas affected...western Kansas into western Nebraska Concerning...Tornado Watch 211... Valid 112049Z - 112215Z The severe weather threat for Tornado Watch 211 continues. SUMMARY...The severe risk persists over western Kansas, and may increase into western Nebraska with time. An additional watch could eventually be needed north of the existing watch 211, depending on storm trends. DISCUSSION...Bands of thunderstorms persist north of the surface low and ahead of midlevel cooling with the upper trough. Strong boundary layer easterlies continue to push moisture westward across northwest KS and into western NE toward an inverted surface trough. The easterly winds are also helping warm advection in general, as heating continues upstream from northern KS into central NE. Low-level shear is sufficient for a weak/brief tornado threat with 0-1 values around 100 m2/s2. As such, given the time of day, an additional watch could be needed into more of NE and perhaps north-central KS as the storms develop in that direction. In addition, a plume of steep lapse rates pushing into southwest KS ahead of the vort max could lead to locally severe gusts with activity developing over southeast CO currently. ..Jewell.. 05/11/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ICT...GID...LBF...DDC...GLD...BOU... LAT...LON 37489984 38120045 38940113 39630181 40110207 40640240 42030260 42630260 42720222 42540198 41680123 41080073 40340003 39099920 38369891 37559923 37489984 Read more

WW 0210 Status Updates
STATUS REPORT ON WW 210 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..BENTLEY..05/11/23 ATTN...WFO...JAN...SHV...LCH... STATUS REPORT FOR WT 210 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS LAC009-025-029-079-115-112140- LA . LOUISIANA PARISHES INCLUDED ARE AVOYELLES CATAHOULA CONCORDIA RAPIDES VERNON MSC001-021-063-149-112140- MS . MISSISSIPPI COUNTIES INCLUDED ARE ADAMS CLAIBORNE JEFFERSON WARREN 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 0210 Status Updates
STATUS REPORT ON WW 210 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..BENTLEY..05/11/23 ATTN...WFO...JAN...SHV...LCH... STATUS REPORT FOR WT 210 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS LAC009-025-029-079-115-112140- LA . LOUISIANA PARISHES INCLUDED ARE AVOYELLES CATAHOULA CONCORDIA RAPIDES VERNON MSC001-021-063-149-112140- MS . MISSISSIPPI COUNTIES INCLUDED ARE ADAMS CLAIBORNE JEFFERSON WARREN 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 210 TORNADO AR LA MS 111425Z - 112200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 210 NWS Storm Prediction Center Norman OK 925 AM CDT Thu May 11 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southeast Arkansas Northern and Central Louisiana Western Mississippi * Effective this Thursday morning and afternoon from 925 AM until 500 PM CDT. * Primary threats include... A couple tornadoes possible Scattered damaging wind gusts to 65 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...An environment supportive of supercells capable of a few mostly short-lived tornadoes is expected to continue into the afternoon across a broad portion of the ArkLaMiss region, with damaging wind potential also potentially increasing into the afternoon. The tornado watch area is approximately along and 65 statute miles east and west of a line from 30 miles east of Fort Polk LA to 55 miles north northeast of Monroe LA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 24020. ...Guyer Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Thu May 11 2023 Valid 112000Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS KANSAS INTO SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHEAST LOUISIANA INTO SOUTHERN MISSISSIPPI... ...SUMMARY... Scattered severe thunderstorms remain possible into this evening across parts of the Great Plains centered on Kansas and Oklahoma. The greatest threat for a couple strong tornadic supercells should exist across central and southern Oklahoma between 5 to 9 PM CDT. Isolated severe storms including a couple of tornadoes and damaging winds are also expected across the Lower Mississippi Valley. ...Kansas into Oklahoma... The severe threat continues across much of KS where an arcing band of convection has developed from northwest to southern/southwestern KS. Reflectivity/velocity data from regional radars show some cells taking on supercellular characteristics with persistent mesocyclones, including at least one reported tornado. So while the overall kinematic environment appears somewhat marginal based on latest RAP mesoanalyses (effective SRH values 100 m2/s2 or less), the environment is conducive for organized convection, and should remain so through the evening as the nocturnal jet strengthens after 00 UTC. Further south, a residual cold pool across central to northern OK from early-morning convection has introduced considerable uncertainty into the severe weather potential. While an intense storm or two remains possible across north-central OK to southern KS, confidence in the tornado potential has diminished due to the detrimental influence of the cold pool on low-level thermodynamics and questions regarding adequate air mass recovery into the evening. The 10% tornado risk probabilities have been bifurcated to reflect where confidence in the tornado threat is highest. See MCD #764 for additional information on recent observed trends and forecast expectations for southern/central OK. ...Lower MS Valley... An organized, but outflow-dominant, MCS has developed over the past several hours and continues to propagate eastward into southern MS. Latest radar trends and surface observations/analyses suggest that this feature may begin to take on a more southeasterly track through the late afternoon/early evening along a diffuse buoyancy/theta-e gradient into southeast MS. Although the system appears to be outflow dominant, damaging winds remain probable given recent measured wind speeds above 50 mph. ..Moore/Leitman.. 05/11/2023 .PREV DISCUSSION... /ISSUED 1141 AM CDT Thu May 11 2023/ ...Southern/Central Great Plains... A cluster of storms continues to persist at late morning across south-central Oklahoma, and remain somewhat strong in proximity to the Red River, with other more recent/initial arcing bands of thunderstorm development in a separate regime across southeast Colorado. This is occurring near/ahead of the largely stacked cyclone centered near the Raton Mesa vicinity of northeast New Mexico/southeast Colorado. 12z upper-air analysis features of a zone of stronger mid/high-level winds across the south-central High Plains immediately preceding this cyclone, while winds aloft (especially high level) are otherwise relatively weak across the region. A moist boundary layer is noted across the south-central High Plains, with relatively high PW values and 12+ C 850mb dewpoints observed at both Dodge City and Amarillo per 12z RAOBs, a northwestward extension of the rich low-level moist axis that otherwise extends across the middle part of Texas. The surface cyclone is expected to deepen as it develops toward southwest Kansas today, with the dryline mixing into western Oklahoma and arcing south-southwest into the Edwards Plateau. A north/south-oriented inverted trough/quasi-stationary front will extend north to the western Dakotas. Multiple corridors of increasing severe potential are expected this afternoon. As focused ascent overspreads southeast Colorado into western Kansas, low-topped supercells will become increasingly probable midday to early afternoon within a marginally buoyant environment initially. A smaller area of supercell development may also form in the wake of this activity near the Colorado/Kansas border later in the afternoon and yield a persistent severe threat into early evening. Farther south, the aforementioned early day persistent cluster of storms across south-central Oklahoma casts some uncertainty, particularly in regards to its north, with potential ramifications for areas such as northern Oklahoma/far southern Kansas with the possibility of somewhat more isolated storms. A volatile supercell environment should still evolve to the west of this cluster and ahead of the dryline, especially across southwest into west-central/south-central Oklahoma. A pronounced gradient in MLCAPE is likely by late afternoon to early evening as the most robust boundary-layer heating post-dryline occurs in Texas, while a plume of richer moisture advects north ahead of it. This should support MLCAPE approaching 1500 J/kg near the OK/KS border to around 3500 J/kg along the Red River. While a mid-level jetlet over the southern High Plains will be in an overall weakening state, its favorably timed eastward translation across the dryline should support sustained supercells. Upper-level wind fields will weaken with height and the bulk of hodograph structure will consist of enlarged curvature from 0-3 km. This suggests supercells should tend towards an HP character with a slow-moving cluster type evolution. A moderate increase in low-level flow early this evening could support a strong tornado risk, especially across southern/central Oklahoma with the most intense supercells. A small MCS/embedded supercell cluster will probably persist into eastern Oklahoma before eventually weakening during the overnight. ...ArkLaMiss/Lower Mississippi Valley to Southeast... The environment that potentially produced a couple of tornadoes this morning across northern Louisiana is expected to generally persist eastward across the ArkLaMiss into the afternoon, with a continued potential for mostly brief tornadoes. There will also likely be some increase in damaging wind potential as storm mergers occur and the downstream boundary layer warms and destabilizes. Other more localized/episodic strong to severe storms capable of damaging winds are possible farther east into Alabama, southwest Georgia, and northern Florida, primarily before sunset. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Thu May 11 2023 Valid 112000Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS KANSAS INTO SOUTHERN OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHEAST LOUISIANA INTO SOUTHERN MISSISSIPPI... ...SUMMARY... Scattered severe thunderstorms remain possible into this evening across parts of the Great Plains centered on Kansas and Oklahoma. The greatest threat for a couple strong tornadic supercells should exist across central and southern Oklahoma between 5 to 9 PM CDT. Isolated severe storms including a couple of tornadoes and damaging winds are also expected across the Lower Mississippi Valley. ...Kansas into Oklahoma... The severe threat continues across much of KS where an arcing band of convection has developed from northwest to southern/southwestern KS. Reflectivity/velocity data from regional radars show some cells taking on supercellular characteristics with persistent mesocyclones, including at least one reported tornado. So while the overall kinematic environment appears somewhat marginal based on latest RAP mesoanalyses (effective SRH values 100 m2/s2 or less), the environment is conducive for organized convection, and should remain so through the evening as the nocturnal jet strengthens after 00 UTC. Further south, a residual cold pool across central to northern OK from early-morning convection has introduced considerable uncertainty into the severe weather potential. While an intense storm or two remains possible across north-central OK to southern KS, confidence in the tornado potential has diminished due to the detrimental influence of the cold pool on low-level thermodynamics and questions regarding adequate air mass recovery into the evening. The 10% tornado risk probabilities have been bifurcated to reflect where confidence in the tornado threat is highest. See MCD #764 for additional information on recent observed trends and forecast expectations for southern/central OK. ...Lower MS Valley... An organized, but outflow-dominant, MCS has developed over the past several hours and continues to propagate eastward into southern MS. Latest radar trends and surface observations/analyses suggest that this feature may begin to take on a more southeasterly track through the late afternoon/early evening along a diffuse buoyancy/theta-e gradient into southeast MS. Although the system appears to be outflow dominant, damaging winds remain probable given recent measured wind speeds above 50 mph. ..Moore/Leitman.. 05/11/2023 .PREV DISCUSSION... /ISSUED 1141 AM CDT Thu May 11 2023/ ...Southern/Central Great Plains... A cluster of storms continues to persist at late morning across south-central Oklahoma, and remain somewhat strong in proximity to the Red River, with other more recent/initial arcing bands of thunderstorm development in a separate regime across southeast Colorado. This is occurring near/ahead of the largely stacked cyclone centered near the Raton Mesa vicinity of northeast New Mexico/southeast Colorado. 12z upper-air analysis features of a zone of stronger mid/high-level winds across the south-central High Plains immediately preceding this cyclone, while winds aloft (especially high level) are otherwise relatively weak across the region. A moist boundary layer is noted across the south-central High Plains, with relatively high PW values and 12+ C 850mb dewpoints observed at both Dodge City and Amarillo per 12z RAOBs, a northwestward extension of the rich low-level moist axis that otherwise extends across the middle part of Texas. The surface cyclone is expected to deepen as it develops toward southwest Kansas today, with the dryline mixing into western Oklahoma and arcing south-southwest into the Edwards Plateau. A north/south-oriented inverted trough/quasi-stationary front will extend north to the western Dakotas. Multiple corridors of increasing severe potential are expected this afternoon. As focused ascent overspreads southeast Colorado into western Kansas, low-topped supercells will become increasingly probable midday to early afternoon within a marginally buoyant environment initially. A smaller area of supercell development may also form in the wake of this activity near the Colorado/Kansas border later in the afternoon and yield a persistent severe threat into early evening. Farther south, the aforementioned early day persistent cluster of storms across south-central Oklahoma casts some uncertainty, particularly in regards to its north, with potential ramifications for areas such as northern Oklahoma/far southern Kansas with the possibility of somewhat more isolated storms. A volatile supercell environment should still evolve to the west of this cluster and ahead of the dryline, especially across southwest into west-central/south-central Oklahoma. A pronounced gradient in MLCAPE is likely by late afternoon to early evening as the most robust boundary-layer heating post-dryline occurs in Texas, while a plume of richer moisture advects north ahead of it. This should support MLCAPE approaching 1500 J/kg near the OK/KS border to around 3500 J/kg along the Red River. While a mid-level jetlet over the southern High Plains will be in an overall weakening state, its favorably timed eastward translation across the dryline should support sustained supercells. Upper-level wind fields will weaken with height and the bulk of hodograph structure will consist of enlarged curvature from 0-3 km. This suggests supercells should tend towards an HP character with a slow-moving cluster type evolution. A moderate increase in low-level flow early this evening could support a strong tornado risk, especially across southern/central Oklahoma with the most intense supercells. A small MCS/embedded supercell cluster will probably persist into eastern Oklahoma before eventually weakening during the overnight. ...ArkLaMiss/Lower Mississippi Valley to Southeast... The environment that potentially produced a couple of tornadoes this morning across northern Louisiana is expected to generally persist eastward across the ArkLaMiss into the afternoon, with a continued potential for mostly brief tornadoes. There will also likely be some increase in damaging wind potential as storm mergers occur and the downstream boundary layer warms and destabilizes. Other more localized/episodic strong to severe storms capable of damaging winds are possible farther east into Alabama, southwest Georgia, and northern Florida, primarily before sunset. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0113 PM CDT Thu May 11 2023 Valid 121200Z - 131200Z No changes to the ongoing forecast. ..Wendt.. 05/11/2023 .PREV DISCUSSION... /ISSUED 0112 AM CDT Thu May 11 2023/ ...Synopsis... The mid-level trough over the southern Plains is forecast to continue to drift northeastward and slowly weaken through Friday. Trialing the surface low, a cold front will move in from the northwest ushering in a cooler and more moist air mass across the Rockies and southern High Plains. Widespread precipitation is also expected starting Friday across the High Plains potentially limiting area fuels. With winds aloft weakening, increasing RH, and more limited fuels, widespread fire-weather concerns are not anticipated. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0113 PM CDT Thu May 11 2023 Valid 121200Z - 131200Z No changes to the ongoing forecast. ..Wendt.. 05/11/2023 .PREV DISCUSSION... /ISSUED 0112 AM CDT Thu May 11 2023/ ...Synopsis... The mid-level trough over the southern Plains is forecast to continue to drift northeastward and slowly weaken through Friday. Trialing the surface low, a cold front will move in from the northwest ushering in a cooler and more moist air mass across the Rockies and southern High Plains. Widespread precipitation is also expected starting Friday across the High Plains potentially limiting area fuels. With winds aloft weakening, increasing RH, and more limited fuels, widespread fire-weather concerns are not anticipated. ...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 1223 PM CDT Thu May 11 2023 Valid 121200Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THE MID-MISSOURI RIVER VALLEY AND ACROSS THE SOUTHERN PLAINS TO THE RIO GRANDE VALLEY... ...SUMMARY... Strong/severe storms are expected to begin during the afternoon, across a broad area extending from the Mid-Missouri Valley southward to the Rio Grande Valley. Very large hail and damaging wind gusts will likely be the primary severe threats over the southern half of the area into the overnight hours, while damaging winds and hail, and a couple of tornadoes, will be possible across the Mid Missouri Valley area through the evening. ...Synopsis... The upper-level wave currently migrating northeast across western KS is forecast to continue to the northeast over the next 48 hours, reaching the mid-MO Valley by mid/late afternoon. In general, this feature, and an attendant surface low, will de-amplify through the period with an associated weakening of mid/upper-level flow outside of the mid-MO Valley. A surface trough/dryline should be draped from eastern NE southward through central KS/OK and into TX by late afternoon and will act as a foci for convective initiation. To the south, mid-morning water-vapor imagery depicts a shortwave trough approaching Baja CA. This wave should reach the Big Bend region by tomorrow afternoon/evening, and will augment orographically-driven ascent, fostering scattered thunderstorm development along the Rio Grande. ...Mid Missouri River Valley... A reservoir of low 60s dewpoints is noted in morning surface observations across much of the central Plains. Persistent south/southeasterly flow over the next 36 hours ahead of the approaching surface low will maintain some poleward moisture advection, and some solutions suggest dewpoints may reach the mid-60s. Regardless, cool temperatures aloft associated with the upper-low will result in mid-level lapse rates near 7-7.5 C/km. Combined with the aforementioned low-level moisture, this should support MLCAPE values approaching 2000-3000 J/kg by late afternoon. Given the lack of an appreciable EML, diurnal warming should erode any mixed-layer inhibition and allow convective initiation along the surface trough/dryline. Initial convection will likely manifest as an arching band of discrete/semi-discrete cells with an attendant hail/wind risk. A few tornadoes are also possible given veered low-level winds and modest effective SRH ahead of the dryline. Upscale growth into one or more organized clusters is probable through the evening given deep-layer meridional flow oriented largely along the boundary - especially across southeast NE into adjacent areas of IA, KS, and MO. A corridor of several, perhaps longer-lived, supercells may emerge across portions of northeast NE where deep-layer shear orientations will be nearly orthogonal to the dryline. If this scenario occurs the large hail/tornado threat may be locally maximized. A significant hail area has been introduced to reflect the conditional nature of the threat. However, confidence in the spatial extent of this threat appears too limited in this forecast cycle for a categorical upgrade. ...Central OK to the Rio Grande... A migratory dryline should be draped from northeast KS through central OK and into western TX by late afternoon, though forecast uncertainty remains somewhat high in the exact placement of this feature by peak heating. This region will be well displaced from the stronger forcing for ascent to the north, but forecast soundings suggest residence time within the dryline circulation and strong diurnal warming will be sufficient for convective initiation along the boundary. Additional cells will likely develop off the terrain in northern Mexico, and should migrate east/northeast into southern TX. High-quality moisture return (dewpoints into the low 70s), coupled with temperatures in the low 80s will support strong buoyancy (MLCAPE near 4000 J/kg in some guidance). Mid and upper-level winds are forecast to be modest, only around 25-30 knots, but may be adequate for storm organization - especially across central/southern OK. Further south towards the Rio Grande, hodograph structure becomes more nebulous amid weak flow aloft, but the combination of ample buoyancy and a deep, well-mixed boundary layer will support the potential for strong downburst winds and large hail with initial updraft pulses. Through the evening, initially discrete/semi-discrete cells will likely see cold pool amalgamation/consolidation, resulting in upscale growth into a loosely organized, cold-pool driven MCS. As this occurs, the potential for severe winds should increase across central TX. The strengthening of a low-level jet over southern TX may allow for MCS maintenance overnight to near the TX Coastal Plain by 12 UTC Saturday (though the intensity of the MCS with eastward extent remains uncertain). ..Moore/Leitman.. 05/11/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 PM CDT Thu May 11 2023 Valid 121200Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THE MID-MISSOURI RIVER VALLEY AND ACROSS THE SOUTHERN PLAINS TO THE RIO GRANDE VALLEY... ...SUMMARY... Strong/severe storms are expected to begin during the afternoon, across a broad area extending from the Mid-Missouri Valley southward to the Rio Grande Valley. Very large hail and damaging wind gusts will likely be the primary severe threats over the southern half of the area into the overnight hours, while damaging winds and hail, and a couple of tornadoes, will be possible across the Mid Missouri Valley area through the evening. ...Synopsis... The upper-level wave currently migrating northeast across western KS is forecast to continue to the northeast over the next 48 hours, reaching the mid-MO Valley by mid/late afternoon. In general, this feature, and an attendant surface low, will de-amplify through the period with an associated weakening of mid/upper-level flow outside of the mid-MO Valley. A surface trough/dryline should be draped from eastern NE southward through central KS/OK and into TX by late afternoon and will act as a foci for convective initiation. To the south, mid-morning water-vapor imagery depicts a shortwave trough approaching Baja CA. This wave should reach the Big Bend region by tomorrow afternoon/evening, and will augment orographically-driven ascent, fostering scattered thunderstorm development along the Rio Grande. ...Mid Missouri River Valley... A reservoir of low 60s dewpoints is noted in morning surface observations across much of the central Plains. Persistent south/southeasterly flow over the next 36 hours ahead of the approaching surface low will maintain some poleward moisture advection, and some solutions suggest dewpoints may reach the mid-60s. Regardless, cool temperatures aloft associated with the upper-low will result in mid-level lapse rates near 7-7.5 C/km. Combined with the aforementioned low-level moisture, this should support MLCAPE values approaching 2000-3000 J/kg by late afternoon. Given the lack of an appreciable EML, diurnal warming should erode any mixed-layer inhibition and allow convective initiation along the surface trough/dryline. Initial convection will likely manifest as an arching band of discrete/semi-discrete cells with an attendant hail/wind risk. A few tornadoes are also possible given veered low-level winds and modest effective SRH ahead of the dryline. Upscale growth into one or more organized clusters is probable through the evening given deep-layer meridional flow oriented largely along the boundary - especially across southeast NE into adjacent areas of IA, KS, and MO. A corridor of several, perhaps longer-lived, supercells may emerge across portions of northeast NE where deep-layer shear orientations will be nearly orthogonal to the dryline. If this scenario occurs the large hail/tornado threat may be locally maximized. A significant hail area has been introduced to reflect the conditional nature of the threat. However, confidence in the spatial extent of this threat appears too limited in this forecast cycle for a categorical upgrade. ...Central OK to the Rio Grande... A migratory dryline should be draped from northeast KS through central OK and into western TX by late afternoon, though forecast uncertainty remains somewhat high in the exact placement of this feature by peak heating. This region will be well displaced from the stronger forcing for ascent to the north, but forecast soundings suggest residence time within the dryline circulation and strong diurnal warming will be sufficient for convective initiation along the boundary. Additional cells will likely develop off the terrain in northern Mexico, and should migrate east/northeast into southern TX. High-quality moisture return (dewpoints into the low 70s), coupled with temperatures in the low 80s will support strong buoyancy (MLCAPE near 4000 J/kg in some guidance). Mid and upper-level winds are forecast to be modest, only around 25-30 knots, but may be adequate for storm organization - especially across central/southern OK. Further south towards the Rio Grande, hodograph structure becomes more nebulous amid weak flow aloft, but the combination of ample buoyancy and a deep, well-mixed boundary layer will support the potential for strong downburst winds and large hail with initial updraft pulses. Through the evening, initially discrete/semi-discrete cells will likely see cold pool amalgamation/consolidation, resulting in upscale growth into a loosely organized, cold-pool driven MCS. As this occurs, the potential for severe winds should increase across central TX. The strengthening of a low-level jet over southern TX may allow for MCS maintenance overnight to near the TX Coastal Plain by 12 UTC Saturday (though the intensity of the MCS with eastward extent remains uncertain). ..Moore/Leitman.. 05/11/2023 Read more