Severe Storms

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Mon May 20 2024 Valid 210100Z - 211200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN THE CENTRAL HIGH PLAINS ACROSS SOUTHERN NE... ...SUMMARY... Scattered severe thunderstorms are expected through tonight from the central High Plains to parts of the Upper Midwest. The greatest concentration of tornadoes, large hail, and severe wind is expected over northeast Colorado into southern Nebraska, and far northwest Kansas. This will include potential for a strong tornado, very large hail, and significant severe gusts. ...01Z Update... Primary concern is with ongoing convection developing across northeast CO into the southwest NE Panhandle. With a current of east to southeast 0-1 km winds expected to increase during the next few hours, afternoon CAM guidance along with recent WoFS runs are insistent on long-lived supercell development along the southern flank of the thunderstorm plume. This appears likely to emanate out of the Akron, CO vicinity and move east towards the CO/KS/NE border area. With low 60s surface dew points across northwest KS marking the northwest extent of MLCAPE in excess of 1500 J/kg, a supercell or two impinging on the increasingly buoyant airmass downstream, may become intense. In addition to the risk for very large hail, enlarging low-level hodographs will support potential for cyclic tornadogenesis, especially in the 02-05Z time frame. Transition from tornadic supercell to a bow will likely occur during the late evening to early morning, with probable movement along the pronounced MLCAPE gradient into at least south-central NE. Increasingly large MLCIN is anticipated overnight across KS, suggesting that the severe wind swath will remain latitudinally confined. Downstream convection, ongoing across southeast NE, suggests the upstream severe wind threat may wane somewhat near dawn as the MCS approaches the Mid-MO Valley. But the potential for a well-organized MCS to persist across much of southern NE is apparent and warrants expansion of the level 3-ENH risk. Elsewhere, scattered large hail and sporadic severe wind gusts should occur this evening into the early overnight from southeast NE to southeast MN. A lower-end QLCS across Lower MI into northwest IN may produce locally damaging winds with strong gusts through the rest of this evening. But this convection will likely diminish overnight. ..Grams.. 05/21/2024 Read more

MD 0857 CONCERNING SEVERE THUNDERSTORM WATCH 268... FOR CENTRAL MICHIGAN AND FAR NORTHERN INDIANA
Mesoscale Discussion 0857 NWS Storm Prediction Center Norman OK 0649 PM CDT Mon May 20 2024 Areas affected...Central Michigan and far northern Indiana Concerning...Severe Thunderstorm Watch 268... Valid 202349Z - 210115Z The severe weather threat for Severe Thunderstorm Watch 268 continues. SUMMARY...A bowing line segment or two capable of producing severe wind gusts near 60-70 mph remains possible across central MI. Further south into Lower MI, a few thunderstorms could produce marginally severe hail around 0.75 to 1.25" in diameter. DISCUSSION...A broken line of thunderstorms associated with an MCV moving east across central MI and northern IN is expected to maintain localized intensity through this evening. Although buoyancy across central MI is fairly limited and convective inhibition will continue to increase through nightfall, easterly surface flow downstream should continue to support a relatively balanced convergence zone. In addition, low-level shear vectors orthogonal to the line and magnitudes east of the MCV's center point may be favorable for a mesovortex or two. However, LCLs downstream of the line become increasingly unfavorable for tornadogenesis. ..Barnes/Thompson.. 05/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DTX...APX...GRR... LAT...LON 43638557 44158539 44128496 44168434 43818408 43408416 43288411 42738431 42548436 42168465 42158619 42558595 43638557 Read more

WW 0268 Status Updates
STATUS REPORT ON WW 268 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSE AZO TO 25 WSW LAN TO 35 WSW MBS TO 30 WNW MBS TO 25 S HTL. WW 268 WILL BE ALLOWED TO EXPIRE AT 210200Z. ..BENTLEY..05/21/24 ATTN...WFO...GRR... STATUS REPORT FOR WS 268 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC025-037-045-057-065-075-210200- MI . MICHIGAN COUNTIES INCLUDED ARE CALHOUN CLINTON EATON GRATIOT INGHAM JACKSON 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 0268 Status Updates
STATUS REPORT ON WW 268 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSE AZO TO 25 WSW LAN TO 35 WSW MBS TO 30 WNW MBS TO 25 S HTL. WW 268 WILL BE ALLOWED TO EXPIRE AT 210200Z. ..BENTLEY..05/21/24 ATTN...WFO...GRR... STATUS REPORT FOR WS 268 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC025-037-045-057-065-075-210200- MI . MICHIGAN COUNTIES INCLUDED ARE CALHOUN CLINTON EATON GRATIOT INGHAM JACKSON 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 0268 Status Updates
STATUS REPORT ON WW 268 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSE AZO TO 25 WSW LAN TO 35 WSW MBS TO 30 WNW MBS TO 25 S HTL. WW 268 WILL BE ALLOWED TO EXPIRE AT 210200Z. ..BENTLEY..05/21/24 ATTN...WFO...GRR... STATUS REPORT FOR WS 268 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC025-037-045-057-065-075-210200- MI . MICHIGAN COUNTIES INCLUDED ARE CALHOUN CLINTON EATON GRATIOT INGHAM JACKSON 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 0268 Status Updates
STATUS REPORT ON WW 268 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSE AZO TO 25 WSW LAN TO 35 WSW MBS TO 30 WNW MBS TO 25 S HTL. WW 268 WILL BE ALLOWED TO EXPIRE AT 210200Z. ..BENTLEY..05/21/24 ATTN...WFO...GRR... STATUS REPORT FOR WS 268 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC025-037-045-057-065-075-210200- MI . MICHIGAN COUNTIES INCLUDED ARE CALHOUN CLINTON EATON GRATIOT INGHAM JACKSON 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 0268 Status Updates
STATUS REPORT ON WW 268 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSE AZO TO 25 WSW LAN TO 35 WSW MBS TO 30 WNW MBS TO 25 S HTL. WW 268 WILL BE ALLOWED TO EXPIRE AT 210200Z. ..BENTLEY..05/21/24 ATTN...WFO...GRR... STATUS REPORT FOR WS 268 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC025-037-045-057-065-075-210200- MI . MICHIGAN COUNTIES INCLUDED ARE CALHOUN CLINTON EATON GRATIOT INGHAM JACKSON 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

MD 0855 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTHWESTERN IOWA AND FAR SOUTHERN MINNESOTA
Mesoscale Discussion 0855 NWS Storm Prediction Center Norman OK 0554 PM CDT Mon May 20 2024 Areas affected...Northwestern Iowa and far southern Minnesota Concerning...Severe potential...Watch possible Valid 202254Z - 210100Z Probability of Watch Issuance...40 percent SUMMARY...Scattered thunderstorm development is likely over the next 1-2 hours across portions of northwestern/northern IA and southern MN. Large hail up to 1 to 1.75 inches in diameter and wind gusts exceeding 60 mph may accompany a few of the thunderstorms. DISCUSSION...Recent satellite imagery indicates some upstream mid-level ascent, likely via PCVA, is beginning to impact locations east of the MO river valley over a stationary boundary. Elevated showers have developed over northern NE, and the cumulus field along and just north of the boundary is becoming agitated across northwestern IA and southern MN. The convective environment within this region is characterized by moderate instability, modest deep layer shear, and steep mid level lapse rates. As the evening progresses, a few organized updrafts may manage to develop with a threat of large hail and locally damaging wind gusts. There is some uncertainty regarding severe thunderstorm coverage across this region, however, so trends will be watched for a possible weather watch. ..Barnes/Thompson.. 05/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ARX...MPX...DMX...FSD...OAX... LAT...LON 42149452 42029497 41939575 42029627 42739661 43419632 43809554 44109495 44349428 44459386 44389296 44469241 44259207 43809196 42869309 42499374 42149452 Read more

MD 0856 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF SOUTH CENTRAL AND SOUTHEASTERN NEBRASKA
Mesoscale Discussion 0856 NWS Storm Prediction Center Norman OK 0606 PM CDT Mon May 20 2024 Areas affected...parts of south central and southeastern Nebraska Concerning...Severe potential...Watch possible Valid 202306Z - 210100Z Probability of Watch Issuance...60 percent SUMMARY...Scattered strong thunderstorm development is initiating across the region and probably will persist into mid/late evening. A few supercells are possible, primarily posing a risk for large hail. DISCUSSION...Deepening convective development is underway where boundary-layer destabilization has become maximized in a corridor from near the Hastings/Kearney vicinity into the Greater Omaha area. This is in advance of a slowly southeastward advancing cold front, where lower/mid-tropospheric warming across much of the central Great Plains may be offsetting weakening of inhibition associated with insolation. Still, roughly to the north of the Kansas/Nebraska border, temperatures in the 700-500 mb layer remain cooler relative to areas to south, and it appears inhibition is weak enough to allow for intensifying thunderstorm development during the next few hours. Mid/upper support for upward vertical motion remains uncertain, but strong southwesterly flow in mid/upper levels is contributing to sufficient deep-layer shear for supercell development. With mixed-layer CAPE in excess of 2000 J/kg beneath steep mid-level lapse rates, stronger storms may pose an initial risk for severe hail. Although boundary-layer cooling will contribute to increasing inhibition into and after sunset, modest strengthening of southerly 850 mb flow and associated warm advection may maintain stronger cells into mid/late evening. ..Kerr.. 05/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OAX...GID... LAT...LON 40829950 41519778 41609607 40759563 40129661 39959878 40219958 40829950 Read more

WW 0268 Status Updates
STATUS REPORT ON WW 268 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSE AZO TO 25 WSW LAN TO 35 WSW MBS TO 30 WNW MBS TO 25 S HTL. WW 268 WILL BE ALLOWED TO EXPIRE AT 210200Z. ..BENTLEY..05/21/24 ATTN...WFO...GRR... STATUS REPORT FOR WS 268 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC025-037-045-057-065-075-210200- MI . MICHIGAN COUNTIES INCLUDED ARE CALHOUN CLINTON EATON GRATIOT INGHAM JACKSON 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 268 SEVERE TSTM MI LM 202040Z - 210200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 268 NWS Storm Prediction Center Norman OK 440 PM EDT Mon May 20 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western and Central Lower Michigan Lake Michigan * Effective this Monday afternoon and evening from 440 PM until 1000 PM EDT. * Primary threats include... Isolated damaging wind gusts to 65 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms currently moving across Lake Michigan will spread into Lower Michigan soon. A few of the storms may pose a risk of locally damaging wind gusts and hail through early evening. The severe thunderstorm watch area is approximately along and 55 statute miles east and west of a line from 55 miles northeast of Muskegon MI to 15 miles southeast of Kalamazoo MI. 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 267... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 25030. ...Hart Read more

WW 0272 Status Updates
STATUS REPORT ON WW 272 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..BENTLEY..05/21/24 ATTN...WFO...FSD...DMX...ARX...MPX... STATUS REPORT FOR WS 272 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS IAC021-033-035-041-047-059-063-067-081-089-091-093-109-131-141- 143-147-149-151-161-167-189-193-195-197-210140- IA . IOWA COUNTIES INCLUDED ARE BUENA VISTA CERRO GORDO CHEROKEE CLAY CRAWFORD DICKINSON EMMET FLOYD HANCOCK HOWARD HUMBOLDT IDA KOSSUTH MITCHELL O'BRIEN OSCEOLA PALO ALTO PLYMOUTH POCAHONTAS SAC SIOUX WINNEBAGO WOODBURY WORTH WRIGHT MNC013-039-043-045-047-063-091-099-109-147-157-161-165-210140- MN . MINNESOTA COUNTIES INCLUDED ARE BLUE EARTH DODGE FARIBAULT FILLMORE FREEBORN JACKSON MARTIN MOWER OLMSTED STEELE WABASHA WASECA Read more

WW 0272 Status Updates
STATUS REPORT ON WW 272 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..BENTLEY..05/21/24 ATTN...WFO...FSD...DMX...ARX...MPX... STATUS REPORT FOR WS 272 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS IAC021-033-035-041-047-059-063-067-081-089-091-093-109-131-141- 143-147-149-151-161-167-189-193-195-197-210140- IA . IOWA COUNTIES INCLUDED ARE BUENA VISTA CERRO GORDO CHEROKEE CLAY CRAWFORD DICKINSON EMMET FLOYD HANCOCK HOWARD HUMBOLDT IDA KOSSUTH MITCHELL O'BRIEN OSCEOLA PALO ALTO PLYMOUTH POCAHONTAS SAC SIOUX WINNEBAGO WOODBURY WORTH WRIGHT MNC013-039-043-045-047-063-091-099-109-147-157-161-165-210140- MN . MINNESOTA COUNTIES INCLUDED ARE BLUE EARTH DODGE FARIBAULT FILLMORE FREEBORN JACKSON MARTIN MOWER OLMSTED STEELE WABASHA WASECA Read more

WW 0269 Status Updates
STATUS FOR WATCH 0269 HAS NOT BEEN ISSUED YET Read more

WW 0270 Status Updates
STATUS FOR WATCH 0270 HAS NOT BEEN ISSUED YET Read more

WW 0271 Status Updates
STATUS FOR WATCH 0271 HAS NOT BEEN ISSUED YET Read more

MD 0856 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF SOUTH CENTRAL AND SOUTHEASTERN NEBRASKA
Mesoscale Discussion 0856 NWS Storm Prediction Center Norman OK 0606 PM CDT Mon May 20 2024 Areas affected...parts of south central and southeastern Nebraska Concerning...Severe potential...Watch possible Valid 202306Z - 210100Z Probability of Watch Issuance...60 percent SUMMARY...Scattered strong thunderstorm development is initiating across the region and probably will persist into mid/late evening. A few supercells are possible, primarily posing a risk for large hail. DISCUSSION...Deepening convective development is underway where boundary-layer destabilization has become maximized in a corridor from near the Hastings/Kearney vicinity into the Greater Omaha area. This is in advance of a slowly southeastward advancing cold front, where lower/mid-tropospheric warming across much of the central Great Plains may be offsetting weakening of inhibition associated with insolation. Still, roughly to the north of the Kansas/Nebraska border, temperatures in the 700-500 mb layer remain cooler relative to areas to south, and it appears inhibition is weak enough to allow for intensifying thunderstorm development during the next few hours. Mid/upper support for upward vertical motion remains uncertain, but strong southwesterly flow in mid/upper levels is contributing to sufficient deep-layer shear for supercell development. With mixed-layer CAPE in excess of 2000 J/kg beneath steep mid-level lapse rates, stronger storms may pose an initial risk for severe hail. Although boundary-layer cooling will contribute to increasing inhibition into and after sunset, modest strengthening of southerly 850 mb flow and associated warm advection may maintain stronger cells into mid/late evening. ..Kerr.. 05/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OAX...GID... LAT...LON 40829950 41519778 41609607 40759563 40129661 39959878 40219958 40829950 Read more

MD 0855 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTHWESTERN IOWA AND FAR SOUTHERN MINNESOTA
Mesoscale Discussion 0855 NWS Storm Prediction Center Norman OK 0554 PM CDT Mon May 20 2024 Areas affected...Northwestern Iowa and far southern Minnesota Concerning...Severe potential...Watch possible Valid 202254Z - 210100Z Probability of Watch Issuance...40 percent SUMMARY...Scattered thunderstorm development is likely over the next 1-2 hours across portions of northwestern/northern IA and southern MN. Large hail up to 1 to 1.75 inches in diameter and wind gusts exceeding 60 mph may accompany a few of the thunderstorms. DISCUSSION...Recent satellite imagery indicates some upstream mid-level ascent, likely via PCVA, is beginning to impact locations east of the MO river valley over a stationary boundary. Elevated showers have developed over northern NE, and the cumulus field along and just north of the boundary is becoming agitated across northwestern IA and southern MN. The convective environment within this region is characterized by moderate instability, modest deep layer shear, and steep mid level lapse rates. As the evening progresses, a few organized updrafts may manage to develop with a threat of large hail and locally damaging wind gusts. There is some uncertainty regarding severe thunderstorm coverage across this region, however, so trends will be watched for a possible weather watch. ..Barnes/Thompson.. 05/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ARX...MPX...DMX...FSD...OAX... LAT...LON 42149452 42029497 41939575 42029627 42739661 43419632 43809554 44109495 44349428 44459386 44389296 44469241 44259207 43809196 42869309 42499374 42149452 Read more

WW 0272 Status Updates
STATUS FOR WATCH 0272 HAS NOT BEEN ISSUED YET Read more

WW 272 SEVERE TSTM IA MN 202345Z - 210500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 272 NWS Storm Prediction Center Norman OK 645 PM CDT Mon May 20 2024 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northwest and north central Iowa South central and southeast Minnesota * Effective this Monday night from 645 PM until Midnight CDT. * Primary threats include... Scattered damaging wind gusts to 60 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Scattered thunderstorm development is expected this evening along a slow moving front across southern Minnesota and northern Iowa. The storm environment will favor a mix of multicell clusters and storms with supercell structure capable of producing large hail of 1-1.5 inches in diameter and damaging outflow gusts up to 60 mph. The severe thunderstorm watch area is approximately along and 45 statute miles north and south of a line from 35 miles east of Rochester MN to 50 miles west of Storm Lake IA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). 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 268...WW 269...WW 270...WW 271... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 50 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27020. ...Thompson Read more