A few severe thunderstorms impacted southeast Michigan during the afternoon hours.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS DTX wrote it up.
A few severe thunderstorms impacted southeast Michigan during the afternoon hours.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Detroit, MI wrote its last area forecast discussion before the first event at May 20, 11:04 AM EST, 36 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1204 PM EDT Mon May 20 2024 .KEY MESSAGES... - Very warm and muggy conditions continue for the next several days. - Showers and thunderstorms develop this afternoon with highest confidence for broader coverage north of I-69. - Brief heavy downpours, gusty winds, and small hail are the main concerns today, although an isolated storm could approach severe wind or hail thresholds. - Additional storms are possible Tuesday afternoon followed by a line of strong to severe storms late Tuesday night which poses the greatest threat for 50+ mph gusts. - One more chance for showers/storms Wednesday before a cooler and less humid airmass arrives for the rest of the workweek. && .AVIATION... High based (6-10 kft), mostly scattered CU field developing with diurnal heating/instability, with potential for scattered strong thunderstorm development. Much higher confidence across Tri-Cities region (MBS) and Flint vicinity as circulation/shortwave trough tracking out of the Midwest lifts through northern Lower Michigan this evening. Still, warm advection arm/instability gradient lifting through southeast Michigan still presents a low chance for southern areas, especially as activity becomes more surface based later today. The 500 MB trough axis will be slow to move through the Central Great Lakes, and with strong low level jet, scattered rain showers/thunderstorms tonight, which will also tend to help lower cloud bases more in the 2-6 kft range, mainly northern taf sites, closest to the departing circulation. Southwest winds today around 10 knots becoming weak westerly or variable tonight. For DTW/D21 Convection... Low chance of thunderstorms this afternoon into tonight, with the bulk of storms expected to be north of the terminal. With timing very difficult to pin down and the low chances of the airport being directly impacted, preference is to leave out of the taf and monitor trends for possible inclusion if confidence increases. Otherwise, cloud ceilings look hard to come by, and any bkn-ovc layers above 5000 feet. Best chance for cloud bases aob 5000 feet looks to be Tuesday morning. DTW THRESHOLD PROBABILITIES... * Low for thunderstorms this afternoon through tonight. * Low for aob 5000 feet Tuesday morning. && .PREV DISCUSSION... Issued at 1118 AM EDT Mon May 20 2024 UPDATE... Convective trends are the update focus for this afternoon and evening in a combination of ongoing activity and new development across southern Lower Mi. Mid to late morning surface analyses show a distinct warm front lying roughly along the I-96/696 corridor feeding into a cluster of hybrid elevated to near surface based convection from the Lansing area into central Lake Michigan. Satellite imagery and surface obs also indicate a gravity wave feature aiding expansion of altocu extending eastward from Lansing. This supports model soundings that suggest an uncapped profile just waiting for imminent surface based convective temps and scattered new development to the east along and north of I-96 as surface based CAPE builds toward about 1500 J/kg early to mid afternoon. Other than the surface warm front, the remaining storm environment is low shear and weakly forced out ahead of the Midwest MCV which is timed to move into Lower Mi later today/this evening. In the meantime, a single cell/pulse to weak multicell convective mode is expected early to mid afternoon presenting a disorganized hail and wind hazard along with locally heavy rainfall. Short term update trends allow an upward nudge in POPs to entry level likely/numerous north of I-96 and west of I-75 for this first round of activity. The upstream MCV then brings another round of storms for the late afternoon and evening. PREV DISCUSSION... Issued at 422 AM EDT Mon May 20 2024 DISCUSSION... Shortwave trough shearing off the southern stream jet and coincident with an MCV over Missouri will continue to progress/decay northeastward this morning. The convectively augmented wave takes aim at northern Lake Michigan while another day of anomalous warmth bears down on Southeast Michigan. In the absence of airmass modification, expect the combination of afternoon dewpoints in the low-mid 60s and high temperatures the mid-upper 80s to result in SBCAPE values of 1750-2250 J/kg, mirroring the previous day's SPC mesoanalysis data. While the low-shear/high-CAPE setup drives the prevailing forecast narrative, some enhancement to shear profiles arrives later in the day north of I-69 with the approach of the aforementioned remnant wave. Although surface-based convective storms are possible across the entire forecast area this afternoon and evening, locations along/north of M-46 are favored for enhanced storms given proximity to improved shear profiles and positioning along the PWAT gradient. This offers the best chance for severe- adjacent cells. Localized outflow boundaries intersecting pockets of higher instability may suffice in the production of hail approaching 1 inch in diameter or gusts to 50 mph. Uncertainty exists regarding the persistence of nocturnal convective activity as elevated instability lingers until approximately midnight. Interfacing of the polar and subtropical jets amplifies a speed max over the central Plains Tuesday. This drives a deepening surface low into southern Minnesota while the southerly flow within its broad cyclonic shield pushes the resident surface boundary northward across the MI/OH border. Dewpoints respond to the ThetaE plume with most locations crossing into the mid-60s, but forecast soundings indicate a slightly capped thermodynamic structure given the warm frontal boundary. Still expect some degree of afternoon convection as shear vectors improve with ample MUCAPE. Main event looks to arrive late Tuesday night into Wednesday morning as the system's cold front races through Lower Michigan. Potential exists for an organized QLCS to accelerate through the area ahead of the front which poses a strong to severe wind threat. Latest SPC SWODY2 includes a combination of Marginal (1/5) to Slight (2/5) Risk for isolated to scattered severe events. The upper level pattern undergoes major adjustments Wednesday as an energetic low drops into the Pacific Northwest triggering down stream ridge amplification. An orphaned upper low parked over Saskatchewan dampens the height rises, but it still unlocks the stalled eastern Plains jet axis. One more dose of CVA triggers a secondary convection response Wednesday before the more potent cold front clears through Wednesday night. Post-frontal conditions should be noticeably drier and cooler for the latter portion of the workweek as temperatures and dewpoints drop by roughly 10F and 15F, respectively. MARINE... Weak winds this morning organize predominantly out of the southeast today as a warm front lifts across the region in response to low pressure tracking in from the Midwest. This system brings an increasing coverage of showers and thunderstorms this evening into tonight, especially across northern/central Lake Huron closer to where the center of the low is forecast to track overnight. Conditions are expected to remain below Small Craft Advisory criteria, though locally higher winds and waves will be possible within any thunderstorms. A stronger low develops over the Plains on Tuesday, lifting into western Lake Superior on Wednesday. Winds increase out of the south to 20 to 30 knots ahead of the associated cold front Wednesday, then veer to the west Wednesday night into Thursday while remaining gusty to around 25 knots. Less humid air settles in for the late week as high pressure builds in. CLIMATE... Here are the record high temperatures for May 20th through May 22nd: May 20th: Detroit 91 (set in 1977) Flint 92 (set in 1934) Saginaw/Tri-Cities 93 (set in 1977) May 21st: Detroit 92 (set in 1977) Flint 93 (set in 1921) Saginaw/Tri-Cities 94 (set in 1977) May 22nd: Detroit 90 (set in 1994) Flint 91 (set in 1934) Saginaw/Tri-Cities 89 (set in 1992) Here are the record high low temperatures for May 20th through May 22nd: May 20th: Detroit 68 (set in 1934) Flint 65 (set in 1939) Saginaw/Tri-Cities 70 (set in 1975) May 21st: Detroit 71 (set in 2013) Flint 67 (set in 1934) Saginaw/Tri-Cities 66 (set in 2021) May 22nd: Detroit 67 (set in 1941) Flint 65 (set in 1977) Saginaw/Tri-Cities 68 (set in 1977) && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && AVIATION.....SF UPDATE.......BT DISCUSSION...KGK MARINE.......TF CLIMATE......KGK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.
Hazardous Weather Outlook National Weather Service Detroit/Pontiac MI 446 AM EDT Mon May 20 2024 MIZ047>049-053>055-060>063-068>070-075-076-082-083-210830- Midland-Bay-Huron-Saginaw-Tuscola-Sanilac-Shiawassee-Genesee-Lapeer- St. Clair-Livingston-Oakland-Macomb-Washtenaw-Wayne-Lenawee-Monroe- 446 AM EDT Mon May 20 2024 This hazardous weather outlook is for portions of southeast Michigan. .DAY ONE...Today and Tonight Showers and thunderstorms develop this afternoon with highest confidence for broader coverage north of I-69. Brief heavy downpours, gusty winds, and small hail are the main concerns today, although an isolated storm could produce gusts to 50 mph or hail near 1 inch in diameter. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Additional sub-severe storms are possible Tuesday afternoon followed by a line of strong to severe storms late Tuesday night which poses the greatest threat for 60 mph gusts. One more chance for storms Wednesday before a cooler and less humid airmass arrives for the remainder of the workweek. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected today and tonight. LCZ460-LEZ444-LHZ361>363-421-422-441>443-462>464-210830- Lake St Clair- Michigan Waters of Lake Erie from Detroit River to North Cape MI- Lake Huron from 5NM east of Mackinac Bridge to Presque Isle Lt beyond 5 NM off shore- Lake Huron from Presque Isle Light to Sturgeon Point MI beyond 5NM off shore- Lake Huron from Sturgeon Point to Alabaster MI beyond 5NM off shore- Outer Saginaw Bay SW of Alabaster to Port Austin MI to Inner Saginaw Bay-Inner Saginaw Bay SW of Point Au Gres to Bay Port MI- Port Austin to Harbor Beach MI-Harbor Beach to Port Sanilac MI- Port Sanilac to Port Huron MI- Lake Huron from Port Austin to Harbor Beach beyond 5NM Off Shore- Lake Huron from Harbor Beach to Port Sanilac beyond 5NM Off Shore- Lake Huron from Port Sanilac to Port Huron beyond 5NM Off Shore- 446 AM EDT Mon May 20 2024 This hazardous weather outlook is for portions of Lake Erie, Lake Huron and Lake St Clair. .DAY ONE...Today and Tonight Showers and thunderstorms develop this afternoon with highest confidence for broader coverage north of I-69. Brief heavy downpours, gusty winds, and small hail are the main concerns today, although an isolated storm could produce gusts to 40 knots or hail near 1 inch in diameter. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Additional sub-severe storms are possible Tuesday afternoon followed by a line of strong to severe storms late Tuesday night which poses the greatest threat for 50 knot gusts. One more chance for storms Wednesday before a cooler and less humid airmass arrives for the remainder of the workweek. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected today and tonight. You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit. KGK
Special Weather Statement
National Weather Service Detroit/Pontiac MI
1206 PM EDT Mon May 20 2024
MIZ053-060-201700-
Shiawassee MI-Saginaw MI-
1206 PM EDT Mon May 20 2024
...STRONG THUNDERSTORMS WILL IMPACT WESTERN SAGINAW AND NORTHERN
SHIAWASSEE COUNTIES THROUGH 100 PM EDT...
At 1205 PM EDT, Doppler radar was tracking a cluster of strong
thunderstorms near Elsie, or 7 miles northeast of St. Johns, moving
northeast at 35 mph.
HAZARD...Winds in excess of 40 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Owosso, Chesaning, St. Charles, Laingsburg, New Lothrop, Corunna,
Merrill, Oakley, Henderson, Marion Springs, Nelson, Bennington, Swan
Creek, Brant, Garfield, Burt, Fenmore, Layton Corners, Juddville, and
Shiawassee National Wildlife Refuge.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4348 8437 4348 8417 4334 8392 4322 8392
4322 8393 4303 8393 4285 8436
TIME...MOT...LOC 1605Z 218DEG 28KT 4304 8443
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
KDKThe Detroit radar (KDTX), 80 km away, was scanning. The volume nearest the first event began at 16:41 UTC.
4 thunderstorm wind, 2 hail. Local standard time, as filed.
Two to four inch diameter tree limbs downed, along with a pine tree uprooted.
Trees reported blown down across the county, with the Vassar area particulary the hardest hit.
Sporadic tree limbs and trees reported down in Sanilac County.
Tree observed down on the road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2024Every state in 2024This day in weather historyWarnings in Michigan, May 2024
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1182996, 1182995, 1182997, 1183003, 1182999, 1183005.