Thunderstorm Wind, Shiawassee
- When
- May 21, 12:35 PM EST
- Where
- Shiawassee County, Vernon
- Measured
- 56 kt (64 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.933, -84.033
A trained spotter estimated a 65 mph thunderstorm wind gust.
Flash Flooding and Hail in Michigan, May 21, 2004
A derecho track along a stalled frontal boundary which was located over northern Indiana and Ohio during the early afternoon hours of the 21st. Washtenaw County was one of the hardest hit, with 28,000 homes losing power.
Where it happened
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 51
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.
What happened
The episode as NWS DTX wrote it up.
A derecho track along a stalled frontal boundary which was located over northern Indiana and Ohio during the early afternoon hours of the 21st. Washtenaw County was one of the hardest hit, with 28,000 homes losing power.
What forecasters said that day
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 21, 10:16 AM EST, 2 hours 19 minutes earlier.
Area forecast discussion, May 21, 10:16 AM EST, 2 hours 19 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1116 AM EDT FRI MAY 21 2004
.UPDATE...
UPDATE TO INCREASE POPS THIS AFTERNOON AND ISSUE FLOOD WATCH FOR
SOUTHERN CWA. FORWARD PROPAGATING MCS NOW MOVING ACROSS LAKE
MICHIGAN INTO WESTERN LOWER...AND MAINTAINING ITS STRENGTH PER
RADAR/IR SATELLITE IMAGERY. REGIONAL MOSAICS SHOW RETURNS DEVELOPING
SOUTHWARD...BECOMING MORE ROOTED IN AN UNSTABLE BOUNDARY LAYER.
FARTHER NORTH THERE IS STILL ENOUGH ELEVATED INSTABILITY TO MAINTAIN
STRONG STORMS...WITH STEEP MID LEVEL LAPSE RATES APPARENT ON 12Z DTX
SOUNDING. WILL INCREASE POPS TO LIKELY/NUMEROUS FOR THIS AFTERNOON.
AT LEAST ACROSS THE SOUTHERN CWA IT LOOKS TO BE A COMPARATIVELY
QUICK SHOT /AROUND AN HOUR/ BUT MOST AREAS SHOULD GET SOME RAIN. IN
ADDITION...GIVEN WIDESPREAD 1-2 INCH RAINFALLS OBSERVED IN THE
GENERAL VICINITY OF I-94 LAST NIGHT...COMBINED WITH THE POTENTIAL
FOR ADDITIONAL HEAVY RAINFALL THIS AFTERNOON...WILL ISSUE A FLOOD
WATCH FOR THE SOUTHERN CWA. ADDITIONAL MCS LOOKS TO TRACK THROUGH
THE STATE YET AGAIN TONIGHT. WILL RUN THE WATCH THROUGH 600 AM
SATURDAY ACROSS THE SOUTH...AND EVALUATE THE HEAVY RAIN POTENTIAL
FARTHER NORTH AGAIN AFTER REVIEWING THE 12Z MODEL DATA.
&&
BRAVENDER
.PREV DISCUSSION...325 AM EDT FRI MAY 21 2004
VERY BUSY MORNING...AS A SEVERE LINE OF THUNDERSTORMS HAS JUST
FINISHED CLEARING THE SOUTHERN THIRD OF THE CWA. WITH CAPES OF 3000
J/KG...PER 00Z DTX SOUNDING...SEVERE WEATHER REALLY NOT A BIG
SURPRISE. COLD FRONT WILL CONTINUE TO SINK SOUTH OF THE MICHIGAN
BORDER THIS MORNING...PROVIDING A SHORT REPRIEVE TO SOUTHEAST
MICHIGAN. LATER TODAY...AND RIGHT THROUGH THE WEEKEND...IT LOOKS TO
BE ACTIVE AS THE FRONTAL BOUNDARY LINGERS ACROSS THE LOWER GREAT
LAKES....AND PIECES OF ENERGY EJECT NORTHEAST FROM THE PLAINS.
PLENTY OF MOISTURE AND INSTABILITY...ALONG WITH GOOD WIND FIELDS TO
SUPPORT CHANCE OF SEVERE WEATHER RIGHT THROUGH THE WEEKEND AS WELL.
WILL FOLLOW THE MAJORITY OF THE MODELS...AND LEAN TOWARD THE
GFS/CANADIAN/UKMET...WHICH IS IN AGREEMENT WITH HPC. MCS OVER THE
MIDWEST THIS MORNING EXPECTED TO HEAD INTO LOWER MICHIGAN BY THIS
EVENING. FRONTAL BOUNDARY LOOKS TO BE CLOSE TO THE MICHIGAN/OHIO
BORDER AT 00Z...BEFORE TRYING TO PUSH NORTH. WILL LEAVE THE CURRENT
MAX TEMPERATURE FORECAST ALONE...AS IT SEEMS REASONABLE.
COULD SEE A LATE DAY HIGH OF 80 DEGREES IN LENAWEE/WASHTENAW
COUNTIES. WITH THE REASONABLE AGREEMENT OF THE SHORT TERM MODELS
TRACKING THE MCS/SHORTWAVE THROUGH CENTRAL LOWER MICHIGAN THIS
EVENING...WILL GO AHEAD AND BUMP POPS UP. POTENTIAL FOR SEVERE
WEATHER...DEPENDING ON HOW MUCH INSTABILITY WE GENERATE TODAY...AS
50 KNOT LOW LEVEL JET WORKS INTO THE AREA. EVEN IF THE CONVECTION
REMAINS ELEVATED...STILL COULD SEE SOME HAIL. GFS INDICATING 850 MB
COMPUTED CAPES OF AROUND 1500 J/KG.
ANY NORTHWARD PROGRESS OF THE FRONTAL BOUNDARY TONIGHT/SATURDAY
MORNING SHOULD BE TEMPORARILY HALTED IN THE WAKE OF THE MCS.
GFS INDICATING FRONTAL BOUNDARY ALONG OR JUST NORTH OF I 69 BY
AFTERNOON. REALLY NOT SEEING MUCH OF A CAP IN PLACE IN THE WARM
SECTOR...AS 700 MB TEMPS ONLY EXPECTED TO CLIMB TO 7 TO 8 C. WILL
BUMP POPS UP SATURDAY THROUGH SUNDAY...AS THE STREAM OF MOISTURE
CONTINUES AND PW VALUES REMAIN ABOVE 1.5 INCHES. WITH THE TIGHT
BAROCLINIC ZONE OVER THE LOWER GREAT LAKES...BIG BUST TEMPERATURES
WITH RESPECT TO TEMPERATURES THROUGH THE WEEKEND...AS MAXES WILL
EASILY RISE INTO THE 80S SOUTH OF THE FRONTAL BOUNDARY. TRYING TO
PIN DOWN THE FRONTAL BOUNDARY WITHIN 30 MILES REMAINS DIFFICULT.
HAVE RAISED MAXES SIGNIFICANTLY ON SUNDAY...AS CONFIDENCE IS
REASONABLY HIGH MOST OF THE CWA WILL BE IN THE WARM SECTOR.
BANKING ON A MONDAY MORNING FROPA...PER 00Z ETAXX...WHICH SHOULD
KEEP US DRY IN THE AFTERNOON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...FLOOD WATCH...THIS AFTERNOON AND
TONIGHT...MIZ068>070-075-076-082-083.
&&
SF
EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT
HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE)Hazardous weather outlook, May 21, 11:19 AM EST, 1 hour 16 minutes before
HAZARDOUS WEATHER OUTLOOK FOR SOUTHEAST MICHIGAN NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1219 PM EDT FRI MAY 21 2004 MIZ047>049-053>055-060>063-221100- BAY-GENESEE-HURON-LAPEER-MIDLAND-SAGINAW-SANILAC-SHIAWASSEE- ST. CLAIR-TUSCOLA- 1219 PM EDT FRI MAY 21 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST MICHIGAN ALONG AND NORTH OF INTERSTATE 69. .DAY ONE...THIS AFTERNOON AND TONIGHT SEVERE THUNDERSTORM WATCH NUMBER 232 IS IN EFFECT UNTIL 5 PM. SCATTERED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...WITH ADDITIONAL THUNDERSTORMS LIKELY TONIGHT. SOME OF THESE THUNDERSTORMS MAY BE SEVERE...WITH HAIL TO ONE INCH IN DIAMETER BEING THE MAIN HAZARD. HOWEVER...DAMAGING WINDS TO 70 MPH AND A POSSIBLE TORNADO CAN NOT BE RULED OUT TONIGHT. THUNDERSTORM MOVEMENT WILL BE TO THE EAST AT 40 MPH. THUNDERSTORMS WILL ALSO PRODUCE LOCALLY HEAVY RAINFALL...WHICH COULD LEAD TO LOCALIZED FLOODING. A FRONTAL BOUNDARY OVER THE NORTHERN OHIO VALLEY WILL RETURN NORTH AS A WARM FRONT LATE THIS AFTERNOON AND TONIGHT. .DAY TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THERE IS A CHANCE OF MORE SEVERE THUNDERSTORMS ON SATURDAY AND SUNDAY...AS A FRONTAL BOUNDARY LINGERS ACROSS THE REGION. A FEW THUNDERSTORMS MAY LINGER INTO MONDAY MORNING...OTHERWISE THE NEXT CHANCE OF THUNDERSTORMS WILL BE LATE TUESDAY. .SPOTTER INFORMATION STATEMENT... DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY. THE SPOTTER NETWORK HAS BEEN ACTIVATED. MIZ068>070-075-076-082-083-221100- LENAWEE-LIVINGSTON-MACOMB-MONROE-OAKLAND-WASHTENAW-WAYNE- 1219 PM EDT FRI MAY 21 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST MICHIGAN ALONG AND SOUTH OF M-59. .DAY ONE...THIS AFTERNOON AND TONIGHT SEVERE THUNDERSTORM WATCH NUMBER 232 IS IN EFFECT UNTIL 5 PM. NUMEROUS THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...WITH SCATTERED THUNDERSTORMS POSSIBLE AGAIN TONIGHT. SOME OF THESE THUNDERSTORMS MAY BE SEVERE...WITH HAIL TO ONE INCH IN DIAMETER AND WIND GUSTS TO 70 MPH BEING THE MAIN HAZARDS. A BRIEF TORNADO CAN NOT BE RULED OUT AS WELL TONIGHT. THUNDERSTORM MOVEMENT WILL BE TO THE EAST AT 40 MPH. A FLOOD WATCH IS IN EFFECT UNTIL 6 AM SATURDAY. THUNDERSTORMS THIS AFTERNOON AND TONIGHT MAY ALSO PRODUCE LOCALLY HEAVY RAINFALL. THIS IS IN ADDITION TO THE 1 TO 2 INCHES OF RAIN THAT FELL LAST NIGHT. THE ADDITIONAL RAINFALL MAY CREATE FLOODING PROBLEMS. FOR ADDITIONAL INFORMATION...PLEASE SEE THE LATEST FLOOD WATCH STATEMENT. A FRONTAL BOUNDARY OVER THE NORTHERN OHIO VALLEY WILL RETURN NORTH AS A WARM FRONT LATE TODAY AND TONIGHT. .DAY TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THERE IS A CHANCE OF MORE SEVERE THUNDERSTORMS ON SATURDAY AND SUNDAY...AS A FRONTAL BOUNDARY LINGERS ACROSS THE REGION. A FEW THUNDERSTORMS MAY LINGER INTO MONDAY MORNING...OTHERWISE THE NEXT CHANCE OF THUNDERSTORMS WILL BE LATE TUESDAY. .SPOTTER INFORMATION STATEMENT... DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY. THE SPOTTER NETWORK HAS BEEN ACTIVATED. BRAVENDER
The radar
The Detroit radar (KDTX), 53 km away, was scanning. The volume nearest the first event began at 17:32 UTC.
Event by event
29 thunderstorm wind, 19 hail, 3 flash flood. Local standard time, as filed.
Hail, Lenawee
- When
- May 21, 12:45 PM EST
- Where
- Lenawee County, Cambridge Jct
- Measured
- 1 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.050, -84.217
Thunderstorm Wind, Livingston
- When
- May 21, 12:45 PM EST
- Where
- Livingston County, 2 mi SE of Gregory
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- EMERGENCY MANAGER
- Coordinates
- 42.433, -84.050
Numerous trees were blown down.
Thunderstorm Wind, Lenawee
- When
- May 21, 12:45 PM EST
- Where
- Lenawee County, Cambridge Jct
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.050, -84.217
A trained spotter estimated a 60 mph thunderstorm wind gust.
Hail, Lenawee
- When
- May 21, 12:50 PM EST
- Where
- Lenawee County, 2 mi E of Addison
- Measured
- 1.75 in hail
- Reported by
- LAW ENFORCEMENT
- Coordinates
- 41.983, -84.317
Thunderstorm Wind, Lenawee
- When
- May 21, 12:50 PM EST
- Where
- Lenawee County, 2 mi E of Addison
- Measured
- 61 kt (70 mph) estimated gust
- Reported by
- LAW ENFORCEMENT
- Coordinates
- 41.983, -84.317
Law enforcement estimated a 70 mph thunderstorm wind gust.
Thunderstorm Wind, Washtenaw
- When
- May 21, 12:55 PM EST
- Where
- Washtenaw County, Chelsea
- Measured
- 56 kt (64 mph) estimated gust
- Reported by
- GENERAL PUBLIC
- Coordinates
- 42.317, -84.017
A person from the general public estimated a 65 mph thunderstorm wind gust.
Thunderstorm Wind, Lenawee
- When
- May 21, 12:59 PM EST
- Where
- Lenawee County, 1 mi NW of Tecumseh
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.017, -83.950
A trained spotter estimated a 60 mph thunderstorm wind gust.
Hail, Lenawee
- When
- May 21, 1:00 PM EST to 1:03 PM EST
- Where
- Lenawee County, Adrian
- Measured
- 0.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 41.900, -84.033
Thunderstorm Wind, Washtenaw
- When
- May 21, 1:00 PM EST
- Where
- Washtenaw County, 3 mi WSW of Ann Arbor
- Measured
- 65 kt (75 mph) estimated gust
- Reported by
- EMERGENCY MANAGER
- Coordinates
- 42.267, -83.783
Ten utility poles were toppled along Wagner Road between Scio Church and Ellsworth Roads in Lodi Township.
Thunderstorm Wind, Livingston
- When
- May 21, 1:00 PM EST
- Where
- Livingston County, Hamburg
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- EMERGENCY MANAGER
- Coordinates
- 42.450, -83.800
The emergency manager reported trees and wires down.
Thunderstorm Wind, Washtenaw
- When
- May 21, 1:01 PM EST
- Where
- Washtenaw County, Saline
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- EMERGENCY MANAGER
- Coordinates
- 42.167, -83.767
The emergency manager reported 8 inch tree limbs down.
Hail, Washtenaw
- When
- May 21, 1:01 PM EST
- Where
- Washtenaw County, Saline
- Measured
- 1 in hail
- Reported by
- EMERGENCY MANAGER
- Coordinates
- 42.167, -83.767
Thunderstorm Wind, Washtenaw
- When
- May 21, 1:05 PM EST
- Where
- Washtenaw County, (Arb)ann Arbor Muni
- Measured
- 53 kt (61 mph) measured gust
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 42.250, -83.833
Hail, Washtenaw
- When
- May 21, 1:05 PM EST
- Where
- Washtenaw County, Ypsilanti
- Measured
- 0.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.233, -83.617
Hail, Lenawee
- When
- May 21, 1:05 PM EST
- Where
- Lenawee County, Adrian
- Measured
- 1 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 41.900, -84.033
Thunderstorm Wind, Washtenaw
- When
- May 21, 1:10 PM EST
- Where
- Washtenaw County, Ann Arbor
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.283, -83.733
A trained spotter estimated a 60 mph thunderstorm wind gust.
Thunderstorm Wind, Washtenaw
- When
- May 21, 1:15 PM EST
- Where
- Washtenaw County, Ann Arbor
- Measured
- 70 kt (81 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.283, -83.733
A trained spotter estimated a 80 mph thunderstorm wind gust.
Thunderstorm Wind, Livingston
- When
- May 21, 1:15 PM EST
- Where
- Livingston County, 3 mi SE of Brighton
- Measured
- 54 kt (62 mph) estimated gust
- Reported by
- EMERGENCY MANAGER
- Coordinates
- 42.500, -83.717
The emergency manager reported numerous trees and wires down.
Thunderstorm Wind, Monroe
- When
- May 21, 1:20 PM EST
- Where
- Monroe County, Milan
- Measured
- 83 kt (96 mph) estimated gust
- Reported by
- GENERAL PUBLIC
- Coordinates
- 42.083, -83.667
A person from the general public estimated a 95 mph thunderstorm wind gust.
Thunderstorm Wind, Washtenaw
- When
- May 21, 1:20 PM EST
- Where
- Washtenaw County, Ypsilanti
- Measured
- 60 kt (69 mph) measured gust
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 42.233, -83.617
Hail, Monroe
- When
- May 21, 1:20 PM EST
- Where
- Monroe County, Milan
- Measured
- 0.75 in hail
- Reported by
- GENERAL PUBLIC
- Coordinates
- 42.083, -83.667
Hail, Washtenaw
- When
- May 21, 1:20 PM EST
- Where
- Washtenaw County, Ypsilanti
- Measured
- 2 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.233, -83.617
Thunderstorm Wind, Washtenaw
- When
- May 21, 1:20 PM EST
- Where
- Washtenaw County, Salem
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.400, -83.567
A trained weather spotter reported small trees blown down.
Hail, Washtenaw
- When
- May 21, 1:20 PM EST
- Where
- Washtenaw County, Saline
- Measured
- 1 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.167, -83.767
Thunderstorm Wind, Washtenaw
- When
- May 21, 1:20 PM EST
- Where
- Washtenaw County, Saline
- Measured
- 56 kt (64 mph) measured gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.167, -83.767
Hail, Monroe
- When
- May 21, 1:20 PM EST
- Where
- Monroe County, 2 mi W of Carleton
- Measured
- 0.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.050, -83.417
Thunderstorm Wind, Oakland
- When
- May 21, 1:25 PM EST
- Where
- Oakland County, Clarkston
- Measured
- 60 kt (69 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.733, -83.400
A trained spotter estimated a 60 mph thunderstorm wind gust. Large tree limbs were also reported down.
Hail, Wayne
- When
- May 21, 1:25 PM EST
- Where
- Wayne County, Dearborn
- Measured
- 0.88 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.317, -83.250
Thunderstorm Wind, Wayne
- When
- May 21, 1:25 PM EST
- Where
- Wayne County, Dearborn
- Measured
- 56 kt (64 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.317, -83.250
A trained spotter estimated a 65 mph thunderstorm wind gust.
Hail, Wayne
- When
- May 21, 1:28 PM EST
- Where
- Wayne County, 3 mi N of Sheldon
- Measured
- 1 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.317, -83.467
Thunderstorm Wind, Wayne
- When
- May 21, 1:28 PM EST
- Where
- Wayne County, 3 mi N of Sheldon
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.317, -83.467
A trained spotter estimated a 60 mph thunderstorm wind gust.
Thunderstorm Wind, Wayne
- When
- May 21, 1:28 PM EST
- Where
- Wayne County, Romulus
- Measured
- 61 kt (70 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.217, -83.383
A trained spotter estimated a 70 mph thunderstorm wind gust.
Flash Flood, Washtenaw
- When
- May 21, 1:29 PM EST to 2:29 PM EST
- Where
- Washtenaw County, Countywide
- Reported by
- LAW ENFORCEMENT
- Coordinates
- 42.253, -83.839 (the zone’s center; the record gives no point)
Several reports of flooded roads, some of which were four feet deep.
Hail, Wayne
- When
- May 21, 1:30 PM EST
- Where
- Wayne County, Westland
- Measured
- 0.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.317, -83.300
Hail, Wayne
- When
- May 21, 1:30 PM EST
- Where
- Wayne County, Romulus
- Measured
- 1.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.217, -83.383
Hail, Washtenaw
- When
- May 21, 1:30 PM EST
- Where
- Washtenaw County, Milan
- Measured
- 0.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.083, -83.667
Thunderstorm Wind, Washtenaw
- When
- May 21, 1:30 PM EST
- Where
- Washtenaw County, Milan
- Measured
- 55 kt (63 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.083, -83.667
Numerous trees were blown down.
Thunderstorm Wind, Oakland
- When
- May 21, 1:30 PM EST
- Where
- Oakland County, 2 mi W of Bloomfield Hills
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.583, -83.267
A trained spotter estimated a 60 mph thunderstorm wind gust.
Hail, Monroe
- When
- May 21, 1:33 PM EST
- Where
- Monroe County, South Rockwood
- Measured
- 0.75 in hail
- Reported by
- GENERAL PUBLIC
- Coordinates
- 42.067, -83.250
Hail, Wayne
- When
- May 21, 1:35 PM EST
- Where
- Wayne County, Redford
- Measured
- 0.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.417, -83.283
Thunderstorm Wind, Wayne
- When
- May 21, 1:35 PM EST
- Where
- Wayne County, Taylor
- Measured
- 56 kt (64 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.200, -83.300
A trained spotter estimated a 65 mph thunderstorm wind gust.
Flash Flood, Wayne
- When
- May 21, 1:36 PM EST to 2:45 PM EST
- Where
- Wayne County, Central Portion
- Reported by
- LAW ENFORCEMENT
- Coordinates
- 42.285, -83.261 (the zone’s center; the record gives no point)
Flooding was reported along I-94 and Telegraph.
Hail, Wayne
- When
- May 21, 1:38 PM EST
- Where
- Wayne County, Dearborn Hgts
- Measured
- 0.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.367, -83.283
Thunderstorm Wind, Oakland
- When
- May 21, 1:40 PM EST
- Where
- Oakland County, 2 mi NW of Rochester Hills
- Measured
- 55 kt (63 mph) measured gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.700, -83.167
Thunderstorm Wind, Oakland
- When
- May 21, 1:50 PM EST
- Where
- Oakland County, Troy
- Measured
- 56 kt (64 mph) measured gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.600, -83.150
A trained spotter measure a 65 mph thunderstorm wind gust. Trees were also reported blown down.
Hail, Wayne
- When
- May 21, 1:50 PM EST
- Where
- Wayne County, Detroit
- Measured
- 0.75 in hail
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.333, -83.067
Flash Flood, Oakland
- When
- May 21, 1:55 PM EST to 2:25 PM EST
- Where
- Oakland County, Waterford
- Reported by
- LAW ENFORCEMENT
- Coordinates
- 42.660, -83.386 (the zone’s center; the record gives no point)
Dixie Highway in Waterford was flooded with a foot of water.
Thunderstorm Wind, Macomb
- When
- May 21, 1:56 PM EST
- Where
- Macomb County, Roseville
- Measured
- 65 kt (75 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.500, -82.900
A trained spotter estimated a 75 mph thunderstorm wind gust. Numerous trees were also reported down.
Thunderstorm Wind, Macomb
- When
- May 21, 2:15 PM EST
- Where
- Macomb County, 5 mi NE of Utica
- Measured
- 56 kt (64 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.700, -82.967
A trained spotter estimated a 65 mph thunderstorm wind gust.
Thunderstorm Wind, St. Clair
- When
- May 21, 2:30 PM EST
- Where
- St. Clair County, Algonac
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- TRAINED SPOTTER
- Coordinates
- 42.617, -82.533
A trained spotter reported trees blown down.
What these are
- Thunderstorm Wind
- Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
- Hail
- Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
- Flash Flood
- Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Damaging Winds in Michigan, May 21, 2004
- Tornadoes and Flash Flooding in Iowa, May 21 to 22, 2004
- Tornado in Iowa, May 21, 2004
- Flooding in Michigan, May 21 to 23, 2004
- Flash Flooding and Hail in Ohio, May 21, 2004
- Flash Flooding and Hail in Ohio, May 21 to 22, 2004
- Tornado and Hail in Ohio, May 21, 2004
- Flash Flooding in Ohio, May 21, 2004
- Flash Flooding and Flooding in Ohio, May 21, 2004
- Flash Flood in Pennsylvania, May 21, 2004
- Flooding in Ohio, May 21 to 24, 2004
- Flood and Damaging Winds in Wisconsin, May 21, 2004
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Every storm in Michigan in 2004Every state in 2004This day in weather historyWarnings in Michigan, May 2004
Sources
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: 5399609, 5399610, 5399611, 5399620, 5399621, 5399622, 5399612, 5399623, 5399624, 5399625, 5399631, 5399626, 5399627, 5399628, 5399629, 5399630, 5399660, 5399661, 5399662, 5399613, 5399614, 5399663, 5399664, 5399665, 5399666, 5399667, 5399668, 5399615, 5399669, 5399670, 5399671, 5399672, 5399673, 5399616, 5399674, 5399675, 5399676, 5399677, 5399678, 5399679, and more.