1 lightning, as filed by the National Weather Service.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 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, 3:03 AM EST, 5 hours 14 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 403 AM EDT THU MAY 20 2004 .DISCUSSION... AN STRONG OMEGA BLOCK PATTERN CONTINUES ACROSS THE PACIFIC...FORCING A DEEP TROUGH OVER THE WEST COAST AND A SUB TROPICAL RIDGE INTO THE SOUTHERN MISSISSIPPI VALLEY. A MID LEVEL SHORT WAVE OVER THE MINNESOTA ARROW HEAD REGION HAS AN ASSOCIATED SURFACE LOW JUST NW OF LAKE SUPERIOR WITH A TRAILING COLD FRONT EXTENDING ACROSS MINNESOTA AND INTO CENTRAL KANSAS. A SURFACE WARM FRONT EXTENDS FROM THE LOW INTO SW LOWER MI THEN BACK INTO NORTHERN OHIO. A LOW LEVEL JET IS TRANSPORTING GULF MOISTURE ALL THE WAY INTO THE WESTERN GREAT LAKES REGION. A MESO SCALE CONVECTIVE SYSTEM (MCS) IS NOW ON GOING ACROSS CENTRAL WISCONSIN AT THE NOSE OF THE LOW LEVEL JET. THE SURFACE COLD FRONT IS STILL EXPECTED TO PASS THROUGH SE MICHIGAN THIS EVENING AS THE SURFACE LOW MOVES EAST. THE FRONT WILL THEN BECOME ORIENTED EAST-WEST...PARALLEL TO THE MEAN FLOW ALOFT...AND REMAIN OVER THE GREAT LAKES REGION THROUGH THE WEEKEND. TIMING AND CHANCES OF CONVECTION ALONG THIS FRONT IS AGAIN THE MAIN FORECAST CHALLENGE THIS PACKAGE. THE CURRENT MCS IS POSITIONED A LITTLE FARTHER NORTH THAN EARLIER MODEL RUNS HAVE INDICATED. IN FACT...THE LATEST TAQ RUC ACTUALLY HAS THE BEST HANDLE ON THE CONVECTION OVER WISCONSIN AND BASICALLY SHOWS SOME REMNANTS OF THIS MCS AFFECTING THE SAGINAW VALLEY THIS MORNING...LEAVING THE DETROIT AREA DRY. WILL LEAN THE FORECAST IN THIS GENERAL DIRECTION AND LOWER POPS THIS MORNING IN DETROIT. WITH THE MCS A LITTLE FARTHER NORTH...AND JUST SOME BROKEN MID WARM AIR ADVECTION CLOUDS UPSTREAM...SHOULD SEE SOME BREAKS IN THE CLOUDS THIS MORNING/EARLY AFTERNOON. THIS WILL ALLOW THE BOUNDARY LAYER TO DEEPEN. WITH THE 925 AND 850MB FRONTS AND MOISTURE ADVECTION ALREADY NORTH OF THE FORECAST AREA...MIXING WILL ACTUALLY ALLOW SFC DEWPOINTS TO RISE WELL INTO THE 60S...SENDING THE WARM FRONT NORTH VERY QUICKLY THIS MORNING. ETA SOUNDINGS SUGGEST SURFACE BASE CAPE WILL BE ABLE TO RISE TO AROUND 2500 J/KG BY 21Z GIVEN A TEMP OF 81 OVER 67 DEWPOINT. MODELS ALSO SHOW A FAIRLY WEAK CAP. THIS INSTABILITY COMBINED WITH DEEP LAYER SHEER ON THE ORDER OF 40 M/S WILL ALLOW FOR THE POTENTIAL OF SEVERE STORMS THIS AFTERNOON/EVENING...WITH DAMAGING WINDS BEING THE PRIMARY CONCERN GIVEN THE UNIDIRECTION WIND FIELDS. SEVERAL MESO SCALE MODELS INDICATE THAT CONVECTIVE OUTFLOW FROM UPSTREAM MCS AND PREFRONTAL TROUGHING MAY TOUCH OFF CONVECTION MUCH EARLIER THAN FROPA. THUS WILL CARRY A MENTION OF THUNDERSTORMS THROUGH THE AFTERNOON AND INTO THE EVENING. THE FRONT WILL SETTLE SOUTH OF THE FORECAST AREA TONIGHT AS HIGH PRESSURE BUILDS INTO THE NORTHERN GREAT LAKES. THIS HIGH WILL FILTER IN MORE STABLE LOW LEVEL AIR...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA. FOCUS FOR MCS DEVELOPMENT ON THE NOSE OF THE LOW LEVEL JET WILL ACTUALLY BE WELL WEST OF THE AREA TONIGHT. WILL ONLY CARRY SCATTERED POPS ACROSS THE SOUTH WITH SOME ELEVATED INSTABILITY ALONG THE 850MB FRONT. SURFACE LOW PRESSURE IS EXPECTED TO DEEPEN ON FRIDAY IN THE HIGH PLAINS...SENDING THE FRONT NORTH ACROSS LOWER MICHIGAN AS A WARM FRONT. THE ETA...CANADIAN AND UKMET SOLUTIONS NOW BRING THIS FRONT MUCH FARTHER NORTH THAN EARLIER MODEL RUNS...MUCH LIKE WHAT THE GFS HAS BEEN SHOWING. SINCE THE GFS HAD A SLIGHTLY BETTER INITIALIZATION OF THE RIDGE OVER THE SOUTHERN US...WILL TREND THE FORECAST TOWARD A MORE NORTHERLY FRONTAL POSITION...KEEPING IN MIND THOUGH THAT CONVECTIVE OUTFLOW MAY STILL SLOW ITS NORTHWARD MOVEMENT MORE THAN CURRENT MODELS INDICATE. IN SHORT...WILL CONTINUE WITH CHANCE POPS ON FRIDAY AS THE WARM FRONT LIFTS NORTH. MODELS INDICATE A TREND TOWARD WARMER MID LEVEL TEMPS BY FRIDAY...WHICH MAY ACTUALLY CAP CONVECTION. THUS WILL CARRY A LOW 30 POP FOR THE TIME BEING. A 50-60 KT LOW LEVEL JET WILL BECOME COUPLED TO THE RIGHT ENTRANCE REGION OF A 160KT UPPER JET OVER QUEBEC. THERE IS OVERALL VERY GOOD AGREEMENT AMONG THE MODEL SOLUTIONS THAT THE STRONGEST CONVERGENCE AND MOISTURE TRANSPORT WILL ACTUALLY OCCUR ACROSS NORTHERN/CENTRAL LOWER MICHIGAN FRIDAY NIGHT/EARLY SATURDAY MORNING. GIVEN THIS TREND...WILL CARRY A HIGH CHANCE POPS ACROSS THE SAGINAW VALLEY AND THUMB...AND LOW CHANCE ACROSS THE FAR SOUTH WHERE A CAPPING INVERSION MAY PREVENT ANY CONVECTION AT ALL. THE FRONTAL BOUNDARY WILL LINGER OVER SOUTHERN LOWER MICHIGAN THROUGH THE WEEKEND. STRONG MID LEVEL WIND FIELDS WILL MAKE SEVERE WEATHER POSSIBLE THROUGHOUT THE WEEKEND AS WELL. THERE IS ALSO SOME CONCERN FOR AN MCS TO BRING MORE HEAVY RAINFALL TO THE REGION SATURDAY NIGHT. WILL BLANKET THE ZONES WITH SCATTERED POPS AT THIS TIME SINCE THESE MESO SCALE FEATURES ARE NEARLY IMPOSSIBLE TO TIME THIS FAR OUT IN THE FORECAST. THERE IS FAIRLY GOOD AGREEMENT AMONG THE MEDIUM RANGE MODEL SOLUTIONS THAT AN UPPER WAVE WILL DROP INTO BRITISH COLUMBIA ON SATURDAY...THEN INTO OREGON BY SUNDAY. THIS WILL SEND SOME SHORT WAVE ENERGY INTO THE WESTERN LAKES REGION ON SUNDAY. THIS IDEA WOULD SEND THE FRONT SOUTH OF THE REGION BY MONDAY AFTERNOON. GIVEN THE AGREEMENT AMONG THE CANADIAN...GFS AND ETAXX...WILL LEAN TOWARD A DRY MONDAY AFTERNOON. NO OTHER UPDATES HAVE BEEN MADE TO THE EXTENDED. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && CONSIDINE EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE)
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 512 AM EDT THU MAY 20 2004 MIZ047>049-053>055-060>062-202100- BAY-GENESEE-HURON-LAPEER-MIDLAND-SAGINAW-SANILAC-SHIAWASSEE-TUSCOLA- 512 AM EDT THU MAY 20 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR MID MICHIGAN AND THE THUMB. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS ARE EXPECTED TODAY AND THIS EVENING. THERE IS A CHANCE THAT SOME OF THESE STORMS WILL BE SEVERE...CAPABLE OF PRODUCING WIND GUSTS TO 70 MPH AND HAIL TO ONE INCH IN DIAMETER. THE CHANCE FOR SEVERE WEATHER WILL BE FROM 1 PM THIS AFTERNOON THROUGH 7 PM THIS EVENING. THUNDERSTORMS WILL MOVE EAST AT 30 MPH. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA THIS MORNING. A THUNDERSTORM COMPLEX OVER CENTRAL WISCONSIN WILL SLOWLY MOVE EAST ACROSS THE REGION THIS MORNING. THESE STORMS WILL GENERALLY WEAKEN AS THEY MOVE EAST. STRONGER THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AHEAD OF A COLD FRONT. THIS COLD FRONT WILL MOVE THROUGH THE REGION THIS EVENING. .DAY TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY SCATTERED THUNDERSTORMS ARE EXPECTED FRIDAY AFTERNOON THROUGH SUNDAY NIGHT. THERE IS A SLIGHT CHANCE OF SEVERE WEATHER FRIDAY...SATURDAY AND SUNDAY. SOME OF THESE STORMS WILL PRODUCE VERY HEAVY RAINFALL. THIS MAY LEAD TO LOCALIZED FLOODING. THE WARM FRONT WILL LIFT NORTH ACROSS THE REGION ON FRIDAY...THEN LINGER OVER SOUTHERN MICHIGAN THROUGH THE REST OF THE WEEKEND. THIS WILL RESULT IN A PROLONGED PERIOD OF SCATTERED THUNDERSTORMS ACROSS THE REGION. THERE IS ALSO A CHANCE OF THUNDERSTORMS ON TUESDAY AS A COLD FRONT MOVES THROUGH THE AREA. .SPOTTER INFORMATION STATEMENT... DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY. SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING. MIZ063-068>070-075-076-082-083-202100- LENAWEE-LIVINGSTON-MACOMB-MONROE-OAKLAND-ST. CLAIR-WASHTENAW-WAYNE- 512 AM EDT THU MAY 20 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST MICHIGAN. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND TONIGHT. SOME OF THESE STORMS MAY BE SEVERE...CAPABLE OF PRODUCING WIND GUSTS TO 70 MPH AND HAIL TO ONE INCH IN DIAMETER. THE CHANCE FOR SEVERE WEATHER WILL BE BETWEEN 2 PM THIS AFTERNOON AND 9 PM THIS EVENING. THUNDERSTORMS WILL MOVE EAST AT 30 MPH. A COLD FRONT WILL MOVE INTO THE REGION THIS EVENING. THUNDERSTORMS ARE EXPECTED TO DEVELOP AHEAD OF THIS COLD FRONT. THE COLD FRONT WILL SLOWLY MOVE SOUTH OF THE AREA OVERNIGHT. SCATTERED THUNDERSTORMS ARE STILL EXPECTED OVERNIGHT. THESE STORMS ARE NOT EXPECTED TO BE SEVERE THOUGH. .DAY TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY SCATTERED THUNDERSTORMS ARE EXPECTED FRIDAY MORNING THROUGH SUNDAY NIGHT. THERE IS A SLIGHT CHANCE OF SEVERE WEATHER FRIDAY...SATURDAY AND SUNDAY. SOME OF THESE STORMS WILL ALSO PRODUCE VERY HEAVY RAINFALL. THIS MAY LEAD TO LOCALIZED FLOODING. THE WARM FRONT WILL LIFT NORTH ACROSS THE REGION ON FRIDAY...THEN LINGER OVER SOUTHERN MICHIGAN THROUGH THE REST OF THE WEEKEND. THIS WILL RESULT IN THE PROLONGED PERIOD OF SCATTERED THUNDERSTORMS ACROSS THE REGION. THERE IS ALSO A CHANCE OF THUNDERSTORMS ON TUESDAY AS A COLD FRONT MOVES THROUGH THE AREA. .SPOTTER INFORMATION STATEMENT... DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY. SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING. CONSIDINE
The Detroit radar (KDTX), 62 km away, was scanning. The volume nearest the first event began at 13:19 UTC.
1 lightning. Local standard time, as filed.
Lightning stuck two houses on M-21 between Meridian and Elm Roads.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2004Every state in 2004This day in weather historyWarnings in Michigan, May 2004
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: 5399740.