Severe Storms

WW 0418 Status Updates
STATUS REPORT ON WW 418 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..THORNTON..06/29/23 ATTN...WFO...HUN... STATUS REPORT FOR WS 418 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ALC033-049-059-071-077-079-083-089-095-103-292240- AL . ALABAMA COUNTIES INCLUDED ARE COLBERT DEKALB FRANKLIN JACKSON LAUDERDALE LAWRENCE LIMESTONE MADISON MARSHALL MORGAN 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 418 SEVERE TSTM AL 291900Z - 300000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 418 NWS Storm Prediction Center Norman OK 200 PM CDT Thu Jun 29 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern Alabama * Effective this Thursday afternoon and evening from 200 PM until 700 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A cluster of storms will move southward from Middle Tennessee into northern Alabama through mid/late afternoon, while additional storms could develop behind it and intensify with a secondary round of storms. The severe thunderstorm watch area is approximately along and 20 statute miles north and south of a line from 25 miles west of Muscle Shoals AL to 65 miles east of Huntsville AL. 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 415...WW 416...WW 417... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 35030. ...Guyer Read more

WW 418 SEVERE TSTM AL 291900Z - 300000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 418 NWS Storm Prediction Center Norman OK 200 PM CDT Thu Jun 29 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern Alabama * Effective this Thursday afternoon and evening from 200 PM until 700 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A cluster of storms will move southward from Middle Tennessee into northern Alabama through mid/late afternoon, while additional storms could develop behind it and intensify with a secondary round of storms. The severe thunderstorm watch area is approximately along and 20 statute miles north and south of a line from 25 miles west of Muscle Shoals AL to 65 miles east of Huntsville AL. 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 415...WW 416...WW 417... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 35030. ...Guyer Read more

WW 0417 Status Updates
STATUS REPORT ON WW 417 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 E SLO TO 10 NNE EVV TO 35 WNW SDF TO 40 NNE SDF. ..THORNTON..06/29/23 ATTN...WFO...PAH...IND...IWX...LMK... STATUS REPORT FOR WS 417 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC047-055-065-081-191-193-292240- IL . ILLINOIS COUNTIES INCLUDED ARE EDWARDS FRANKLIN HAMILTON JEFFERSON WAYNE WHITE INC123-129-147-163-173-292240- IN . INDIANA COUNTIES INCLUDED ARE PERRY POSEY SPENCER VANDERBURGH WARRICK 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 417 SEVERE TSTM IL IN MI LM 291810Z - 300000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 417 NWS Storm Prediction Center Norman OK 210 PM EDT Thu Jun 29 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Illinois Western and Central Indiana Southwest Lower Michigan Lake Michigan * Effective this Thursday afternoon and evening from 210 PM until 800 PM EDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Isolated very large hail events to 2 inches in diameter possible A tornado or two possible SUMMARY...An intense/fast-moving squall line will continue generally eastward into Indiana, southern Illinois and possibly far southwest Lower Michigan this afternoon. It may eventually weaken as it moves across Indiana, but damaging winds, some hail, and possibly a brief tornado will all be possible, especially across western Indiana through early/mid-afternoon. The severe thunderstorm watch area is approximately along and 45 statute miles east and west of a line from 15 miles west northwest of South Bend IN to 10 miles east southeast of Evansville IN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 415...WW 416... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 28045. ...Guyer Read more

WW 417 SEVERE TSTM IL IN MI LM 291810Z - 300000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 417 NWS Storm Prediction Center Norman OK 210 PM EDT Thu Jun 29 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Illinois Western and Central Indiana Southwest Lower Michigan Lake Michigan * Effective this Thursday afternoon and evening from 210 PM until 800 PM EDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Isolated very large hail events to 2 inches in diameter possible A tornado or two possible SUMMARY...An intense/fast-moving squall line will continue generally eastward into Indiana, southern Illinois and possibly far southwest Lower Michigan this afternoon. It may eventually weaken as it moves across Indiana, but damaging winds, some hail, and possibly a brief tornado will all be possible, especially across western Indiana through early/mid-afternoon. The severe thunderstorm watch area is approximately along and 45 statute miles east and west of a line from 15 miles west northwest of South Bend IN to 10 miles east southeast of Evansville IN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 415...WW 416... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 28045. ...Guyer Read more

WW 0415 Status Updates
STATUS REPORT ON WW 415 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 N SLO TO 25 NNE SLO TO 10 E MTO TO 20 NE CMI TO 25 NNW MMO TO 30 E DBQ. ..THORNTON..06/29/23 ATTN...WFO...DVN...LSX...ILX...LOT... STATUS REPORT FOR WS 415 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC031-037-043-063-089-093-141-197-292140- IL . ILLINOIS COUNTIES INCLUDED ARE COOK DE KALB DUPAGE GRUNDY KANE KENDALL OGLE WILL INC089-127-292140- IN . INDIANA COUNTIES INCLUDED ARE LAKE PORTER LMZ741-742-743-744-745-292140- CW . ADJACENT COASTAL WATERS INCLUDED ARE WILMETTE HARBOR TO NORTHERLY ISLAND IL Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 29 2023 Valid 292000Z - 301200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO VALLEY...SOUTHEAST WYOMING AND NORTHEAST COLORADO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL PLAINS INTO THE OHIO/TENNESSEE VALLEYS... ...SUMMARY... Damaging wind and hail remain likely this afternoon over parts of southern Illinois and southern Indiana. Other severe storms with large hail and damaging winds gusts are expected across the Tennessee Valley, as well as the central High Plains. ...20Z Update... Only minor changes to the existing outlook include clearing probabilities from behind the IL/IN MCS where the air mass has stabilized. For more information see mesoscale discussions 1341. ..Jewell.. 06/29/2023 .PREV DISCUSSION... /ISSUED 1218 PM CDT Thu Jun 29 2023/ ...Midwest/Tennessee Valley including MO/IL/IN/KY/TN... An upper-ridge peripheral zone of locally intense/significant severe weather is expected today, especially across Illinois into western/southern Indiana and west-central Kentucky southward across the Tennessee Valley. A prominent/relatively large MCS across northeast Missouri and northwest Illinois at late morning will continue to progress eastward through a very unstable air mass, with potential for significant wind gusts, occasional hail, and some convective line-embedded tornado risk. The eastern extent of the most intense severe weather is a bit uncertain given current air mass characteristics across far eastern Illinois into Indiana in the wake of early day storms, but severe weather can nonetheless be expected through the afternoon into evening. Another focused corridor of severe weather will exist from the Lower Ohio Valley southward into the Tennessee Valley, highlighted with a leading south/southeastward-moving MCS, as well as regenerative potentially severe convection on its trailing west/northwest flanks. Bouts of damaging winds and severe hail will be possible into this evening in this corridor. ...Front Range/Central Plains this afternoon/evening... Have upgraded portions of the Front Range and southeast Wyoming/far western Nebraska and northeast Colorado to an Enhanced Risk. Severe storms are expected later this afternoon into tonight within the post-frontal upslope low-level flow across eastern Colorado/southeast Wyoming, with appreciable low-level moisture having spread westward to the Front Range overnight. Breaks in the low clouds will support moderate buoyancy by mid afternoon (MLCAPE of 1000-2000 J/kg), when thunderstorm development will become more probable on and immediately east of the higher terrain from Colorado into southeast Wyoming. The moderate buoyancy and relatively long hodographs with effective bulk shear in excess of 40 kt will support supercells capable of producing large hail of 2-3 inches in diameter, along with some tornado potential. Upscale growth into a few clusters will be possible this evening, with an attendant threat for isolated severe-caliber winds. Some of the evening convection may persist into the overnight hours across southern Nebraska/northern Kansas with some threat for isolated large hail and wind damage, potentially as far east as southwest Iowa/northwest Missouri. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0301 PM CDT Thu Jun 29 2023 Valid 292000Z - 301200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE OHIO VALLEY...SOUTHEAST WYOMING AND NORTHEAST COLORADO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL PLAINS INTO THE OHIO/TENNESSEE VALLEYS... ...SUMMARY... Damaging wind and hail remain likely this afternoon over parts of southern Illinois and southern Indiana. Other severe storms with large hail and damaging winds gusts are expected across the Tennessee Valley, as well as the central High Plains. ...20Z Update... Only minor changes to the existing outlook include clearing probabilities from behind the IL/IN MCS where the air mass has stabilized. For more information see mesoscale discussions 1341. ..Jewell.. 06/29/2023 .PREV DISCUSSION... /ISSUED 1218 PM CDT Thu Jun 29 2023/ ...Midwest/Tennessee Valley including MO/IL/IN/KY/TN... An upper-ridge peripheral zone of locally intense/significant severe weather is expected today, especially across Illinois into western/southern Indiana and west-central Kentucky southward across the Tennessee Valley. A prominent/relatively large MCS across northeast Missouri and northwest Illinois at late morning will continue to progress eastward through a very unstable air mass, with potential for significant wind gusts, occasional hail, and some convective line-embedded tornado risk. The eastern extent of the most intense severe weather is a bit uncertain given current air mass characteristics across far eastern Illinois into Indiana in the wake of early day storms, but severe weather can nonetheless be expected through the afternoon into evening. Another focused corridor of severe weather will exist from the Lower Ohio Valley southward into the Tennessee Valley, highlighted with a leading south/southeastward-moving MCS, as well as regenerative potentially severe convection on its trailing west/northwest flanks. Bouts of damaging winds and severe hail will be possible into this evening in this corridor. ...Front Range/Central Plains this afternoon/evening... Have upgraded portions of the Front Range and southeast Wyoming/far western Nebraska and northeast Colorado to an Enhanced Risk. Severe storms are expected later this afternoon into tonight within the post-frontal upslope low-level flow across eastern Colorado/southeast Wyoming, with appreciable low-level moisture having spread westward to the Front Range overnight. Breaks in the low clouds will support moderate buoyancy by mid afternoon (MLCAPE of 1000-2000 J/kg), when thunderstorm development will become more probable on and immediately east of the higher terrain from Colorado into southeast Wyoming. The moderate buoyancy and relatively long hodographs with effective bulk shear in excess of 40 kt will support supercells capable of producing large hail of 2-3 inches in diameter, along with some tornado potential. Upscale growth into a few clusters will be possible this evening, with an attendant threat for isolated severe-caliber winds. Some of the evening convection may persist into the overnight hours across southern Nebraska/northern Kansas with some threat for isolated large hail and wind damage, potentially as far east as southwest Iowa/northwest Missouri. Read more

WW 0416 Status Updates
STATUS REPORT ON WW 416 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 E MKL TO 35 NNW HSV TO 5 W CHA. ..THORNTON..06/29/23 ATTN...WFO...OHX...HUN... STATUS REPORT FOR WS 416 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS TNC031-061-099-181-292240- TN . TENNESSEE COUNTIES INCLUDED ARE COFFEE GRUNDY LAWRENCE WAYNE 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

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0128 PM CDT Thu Jun 29 2023 Valid 301200Z - 011200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 06/29/2023 .PREV DISCUSSION... /ISSUED 0149 AM CDT Thu Jun 29 2023/ ...Synopsis... Mid-level troughing over the Southwestern US will continue to weaken as the flow pattern gradually transitions to more zonal flow aloft. With the weakening winds over the Southwest, surface flow will weaken substantially. A weak cold front will move south from the Great Basin ushering in a cooler and slightly less dry air mass than the preceding days. The net result will be much more limited fire-weather potential, with only locally elevated conditions expected over portions of southern NM. ...Thunder... While the trough will be substantially weaker, lingering mid-level moisture ahead of the front, combined with subtle lift will allow for isolated thunderstorms across central and western CO. Likely high-based, owing to the limited moisture, there is some potential for dry lightning with these storms. However, the slowly unraveling forcing for ascent suggests uncertainty in the storm coverage. In addition, area fuels are driest in the lower terrain farther west where coverage is again questionable. While a few dry strikes are possible, uncertainty is too high for an IsoDryT area. ...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 0128 PM CDT Thu Jun 29 2023 Valid 301200Z - 011200Z ...NO CRITICAL AREAS... No changes to the ongoing forecast. ..Wendt.. 06/29/2023 .PREV DISCUSSION... /ISSUED 0149 AM CDT Thu Jun 29 2023/ ...Synopsis... Mid-level troughing over the Southwestern US will continue to weaken as the flow pattern gradually transitions to more zonal flow aloft. With the weakening winds over the Southwest, surface flow will weaken substantially. A weak cold front will move south from the Great Basin ushering in a cooler and slightly less dry air mass than the preceding days. The net result will be much more limited fire-weather potential, with only locally elevated conditions expected over portions of southern NM. ...Thunder... While the trough will be substantially weaker, lingering mid-level moisture ahead of the front, combined with subtle lift will allow for isolated thunderstorms across central and western CO. Likely high-based, owing to the limited moisture, there is some potential for dry lightning with these storms. However, the slowly unraveling forcing for ascent suggests uncertainty in the storm coverage. In addition, area fuels are driest in the lower terrain farther west where coverage is again questionable. While a few dry strikes are possible, uncertainty is too high for an IsoDryT area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0414 Status Updates
STATUS REPORT ON WW 414 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NNE EVV TO 35 ESE OWB TO 45 S SDF. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1337 ..THORNTON..06/29/23 ATTN...WFO...LMK...PAH... STATUS REPORT FOR WS 414 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS INC147-163-173-291840- IN . INDIANA COUNTIES INCLUDED ARE SPENCER VANDERBURGH WARRICK KYC003-009-031-047-059-061-085-099-101-107-141-149-177-183-213- 219-227-233-291840- KY . KENTUCKY COUNTIES INCLUDED ARE ALLEN BARREN BUTLER CHRISTIAN DAVIESS EDMONSON GRAYSON HART HENDERSON HOPKINS LOGAN MCLEAN MUHLENBERG OHIO SIMPSON TODD WARREN WEBSTER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Thu Jun 29 2023 Valid 301200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH CENTROIDS OVER THE OHIO VALLEY AND CENTRAL HIGH PLAINS... ...SUMMARY... Severe storms producing wind damage are expected Friday mainly from Illinois southeastward toward the southern Appalachians. Severe storms with large hail and wind are also forecast over eastern Colorado into parts of Kansas and Nebraska. ...Synopsis... An upper ridge will remain over the lower MS Valley, with moderate mid and high level flow from the central Plains into the OH Valley. A positive tilt upper trough will result in cooling aloft over the central Plains, while the upper high gradually weakens due to daily bouts of storms around the periphery. At the surface, substantial low-level moisture will remain across the MS and OH Valleys, with 70s F dewpoints and cool midlevel temperatures again resulting in very strong instability. Moisture will also linger along and north of a southwest/northeast surface trough over the central Plains, again with cool temperatures aloft maximizing instability. ...Mid MS Valley to the southern Appalachians... The potential will exist for corridors of damaging winds across portions of the region, as forecast soundings indicate very strong instability. Uncertainly exists given the potential for early day activity, and potential outflows. In general, extreme instability will exist over parts of southern IL, KY, and TN, with modest midlevel northwesterlies of 20-30 kt. Winds around 850 mb will be out of the northwest, but still within the deep-layer theta-e plume and favoring forward propagating MCSs. If a well-develop system can develop, it may spread farther south than forecast into much of northern GA and AL. ...Central Plains... Cooling aloft with the upper trough along with plentiful low-level moisture north of the boundary will lead to widespread thunderstorms over CO and extending into northeast NM during the afternoon. Directional shear will lead to hodographs favorable for large hail, and perhaps a brief tornado before storms eventually merge as they move into western KS during the evening. Additional late day storms are expected to form in the hotter air from southwest KS into west TX. Locally damaging gusts will be possible there. ..Jewell.. 06/29/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Thu Jun 29 2023 Valid 301200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH CENTROIDS OVER THE OHIO VALLEY AND CENTRAL HIGH PLAINS... ...SUMMARY... Severe storms producing wind damage are expected Friday mainly from Illinois southeastward toward the southern Appalachians. Severe storms with large hail and wind are also forecast over eastern Colorado into parts of Kansas and Nebraska. ...Synopsis... An upper ridge will remain over the lower MS Valley, with moderate mid and high level flow from the central Plains into the OH Valley. A positive tilt upper trough will result in cooling aloft over the central Plains, while the upper high gradually weakens due to daily bouts of storms around the periphery. At the surface, substantial low-level moisture will remain across the MS and OH Valleys, with 70s F dewpoints and cool midlevel temperatures again resulting in very strong instability. Moisture will also linger along and north of a southwest/northeast surface trough over the central Plains, again with cool temperatures aloft maximizing instability. ...Mid MS Valley to the southern Appalachians... The potential will exist for corridors of damaging winds across portions of the region, as forecast soundings indicate very strong instability. Uncertainly exists given the potential for early day activity, and potential outflows. In general, extreme instability will exist over parts of southern IL, KY, and TN, with modest midlevel northwesterlies of 20-30 kt. Winds around 850 mb will be out of the northwest, but still within the deep-layer theta-e plume and favoring forward propagating MCSs. If a well-develop system can develop, it may spread farther south than forecast into much of northern GA and AL. ...Central Plains... Cooling aloft with the upper trough along with plentiful low-level moisture north of the boundary will lead to widespread thunderstorms over CO and extending into northeast NM during the afternoon. Directional shear will lead to hodographs favorable for large hail, and perhaps a brief tornado before storms eventually merge as they move into western KS during the evening. Additional late day storms are expected to form in the hotter air from southwest KS into west TX. Locally damaging gusts will be possible there. ..Jewell.. 06/29/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1218 PM CDT Thu Jun 29 2023 Valid 291630Z - 301200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF ILLINOIS... ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT RANGE AND CENTRAL HIGH PLAINS... CORRECTED FOR IMPROPERLY FORMATTED HAIL POINTS PRODUCT ...SUMMARY... Swaths of damaging winds of 60-80 mph, large hail, and a couple of tornadoes are expected today across Illinois and western/southern Indiana. Other severe storms with large hail and damaging winds gusts are expected across the Tennessee Valley, as well as the central High Plains. ...Midwest/Tennessee Valley including MO/IL/IN/KY/TN... An upper-ridge peripheral zone of locally intense/significant severe weather is expected today, especially across Illinois into western/southern Indiana and west-central Kentucky southward across the Tennessee Valley. A prominent/relatively large MCS across northeast Missouri and northwest Illinois at late morning will continue to progress eastward through a very unstable air mass, with potential for significant wind gusts, occasional hail, and some convective line-embedded tornado risk. The eastern extent of the most intense severe weather is a bit uncertain given current air mass characteristics across far eastern Illinois into Indiana in the wake of early day storms, but severe weather can nonetheless be expected through the afternoon into evening. Another focused corridor of severe weather will exist from the Lower Ohio Valley southward into the Tennessee Valley, highlighted with a leading south/southeastward-moving MCS, as well as regenerative potentially severe convection on its trailing west/northwest flanks. Bouts of damaging winds and severe hail will be possible into this evening in this corridor. ...Front Range/Central Plains this afternoon/evening... Have upgraded portions of the Front Range and southeast Wyoming/far western Nebraska and northeast Colorado to an Enhanced Risk. Severe storms are expected later this afternoon into tonight within the post-frontal upslope low-level flow across eastern Colorado/southeast Wyoming, with appreciable low-level moisture having spread westward to the Front Range overnight. Breaks in the low clouds will support moderate buoyancy by mid afternoon (MLCAPE of 1000-2000 J/kg), when thunderstorm development will become more probable on and immediately east of the higher terrain from Colorado into southeast Wyoming. The moderate buoyancy and relatively long hodographs with effective bulk shear in excess of 40 kt will support supercells capable of producing large hail of 2-3 inches in diameter, along with some tornado potential. Upscale growth into a few clusters will be possible this evening, with an attendant threat for isolated severe-caliber winds. Some of the evening convection may persist into the overnight hours across southern Nebraska/northern Kansas with some threat for isolated large hail and wind damage, potentially as far east as southwest Iowa/northwest Missouri. ..Guyer/Smith.. 06/29/2023 Read more

No Mesoscale Discussions are in effect as of Wed Jun 28 22:15:22 UTC 2023.

WW 0408 Status Updates
STATUS REPORT ON WW 408 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1319 ..SMITH..06/28/23 ATTN...WFO...CYS...LBF...UNR... STATUS REPORT FOR WS 408 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC007-013-033-045-049-069-105-123-157-161-165-282230- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER BOX BUTTE CHEYENNE DAWES DEUEL GARDEN KIMBALL MORRILL SCOTTS BLUFF SHERIDAN SIOUX SDC033-047-081-093-102-103-282230- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE CUSTER FALL RIVER LAWRENCE MEADE OGLALA LAKOTA PENNINGTON WYC005-009-011-015-021-027-031-045-282230- WY . WYOMING COUNTIES INCLUDED ARE Read more

WW 408 SEVERE TSTM NE SD WY 281955Z - 290300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 408 NWS Storm Prediction Center Norman OK 155 PM MDT Wed Jun 28 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western Nebraska Southwest South Dakota Eastern Wyoming * Effective this Wednesday afternoon and evening from 155 PM until 900 PM MDT. * Primary threats include... Scattered large hail likely with isolated very large hail events to 3 inches in diameter possible Isolated damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Widely scattered storms will continue to develop across the region this afternoon, with conditions supportive of supercells capable of large to very large hail. Storms may eventually cluster by evening from southeast Wyoming into western Nebraska with an increased potential for severe-caliber wind gusts. The severe thunderstorm watch area is approximately along and 85 statute miles east and west of a line from 65 miles northwest of Rapid City SD to 30 miles west of Sidney NE. 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. && AVIATION...A few severe thunderstorms with hail surface and aloft to 3 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 26025. ...Guyer Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Jun 28 2023 Valid 282000Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHERN HIGH PLAINS...AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... Large hail, isolated damaging winds and a tornado or two are possible this afternoon/evening across northwest Wisconsin/eastern Minnesota as well as the central High Plains including southeast Wyoming and western Nebraska. Minor expansion of the Slight Risk over SD/NE at 20Z. Storms are just forming over the northern High Plains, and a severe thunderstorm watch has been issued. For more information see mesoscale discussion 1319. Additional severe storms remain possible later today from near the Twin Cities into western WI. The air mass continues to destabilize with gradual moisture advection from the south/southwest. ..Jewell.. 06/28/2023 .PREV DISCUSSION... /ISSUED 1152 AM CDT Wed Jun 28 2023/ ...Upper Mississippi Valley this afternoon through late evening... No outlook/forecast reasoning changes appear warranted. A shortwave trough (enhanced some by prior convection) will progress eastward over Minnesota/Wisconsin through evening. An associated/weak surface cold front will likewise move eastward across Minnesota, while low-level moistening occurs from the southwest during the day beneath a lingering plume of steep midlevel lapse rates. MLCAPE will increase to 2500-3000 J/kg with sufficiently long/curved hodographs for a supercell threat later this afternoon/evening from eastern Minnesota into northwest/western Wisconsin, along and just ahead of the front. Large hail will be the main threat, though isolated wind damage and a tornado or two will also be possible. ...Central High Plains this afternoon and tonight... Low-level flow will veer to easterly during the afternoon, with boundary-layer dewpoints from the mid 50s to lower 60s F in the upslope regime. Subtle speed maxima aloft and surface heating in cloud breaks should allow weakening of convective inhibition by mid-late afternoon, when at least isolated thunderstorm development is possible from eastern Wyoming into the Nebraska Panhandle, and possibly northeast Colorado and/or the South Dakota Black Hills vicinity. Moderate buoyancy and long, relatively straight hodographs will favor supercells capable of producing isolated very large hail, along with some potential for strong-severe outflow gusts and a tornado or two. A semi-organized cluster or two could evolve and progress east-southeastward this evening toward/across west/southwest Nebraska. ...Northern/central Illinois and eastern Iowa... The potential for deep convective development, and uncertain timing thereof, remains a key uncertainty for parts of Iowa/northwest Illinois. There appears to be a conditional potential for surface-based development late this afternoon/early evening in vicinity of the warm front and/or surface trough across west/central into southern Iowa. Strong deep-layer wind profiles, very steep mid-level lapse rates and ample buoyancy would support severe storms/supercells, although the degree of capping leads to uncertainty regarding the likelihood/extent of convective development around peak heating. Convective development will be more probable tonight as warm advection increases related to the strengthening of a west-southwesterly low-level jet. The chance for elevated thunderstorm development will increase overnight from eastern Iowa into Illinois. MUCAPE >2500 J/kg, steep mid-level lapse rates and effective bulk shear >50 kt will support the potential for elevated supercells to produce large hail, while DCAPE >1000 J/kg suggest some potential for strong gusts to reach the ground. There still remains substantial uncertainty regarding the specific corridor and timing of storm development late this afternoon into, so will continue to maintain the Marginal risk at this time. Read more