On August 21, a cold front moving across Michigan's Upper Peninsula kicked off scattered showers and thunderstorms during the morning and early afternoon. Several of the thunderstorms became severe over eastern Upper Michigan, producing high winds and large hail.
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 MQT wrote it up.
On August 21, a cold front moving across Michigan's Upper Peninsula kicked off scattered showers and thunderstorms during the morning and early afternoon. Several of the thunderstorms became severe over eastern Upper Michigan, producing high winds and large hail.
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 Marquette, MI wrote its last area forecast discussion before the first event at Aug 21, 2:20 AM EST, 5 hours 56 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 320 AM EDT THU AUG 21 2003 MAIN FCST CONCERN IS TSRA/SVR WX POTENTIAL TODAY AS COLD FRONT SWEEPS THRU THE AREA. WV IMAGERY SHOWS A PAIR OF SHORTWAVES MOVING INTO/THRU UPPER MIDWEST/WRN LAKES. FIRST SHORTWAVE IS LIFTING NE THRU UPPER MI/LAKE SUPERIOR ATTM AND HAS TRIGGERED SCATTERED TSRA...MAINLY ACROSS LAKE SUPERIOR AND NWD OVERNIGHT. SECOND SHORTWAVE IS LOOKING FAIRLY STRONG AS IT TRACKS INTO MN. AT 07Z...THE ASSOCIATED COLD FRONT EXTENDED FROM ABOUT KINL TO JUST W OF KMSP. IT IS THIS COLD FRONT THAT WILL BE THE FOCUS FOR POTENTIAL SVR CONVECTION. AS SHOULD BE EXPECTED ONLY 12-24HRS INTO A MODEL RUN...GFS/ETA ARE IN EXCELLENT AGREEMENT TIMING SHORTWAVE/COLD FRONT ACROSS FCST AREA TODAY. TIMING WILL BE CRITICAL FOR SVR TSRA POTENTIAL...AND SIMPLE EXTRAPOLATION OF FRONT SUGGESTS MODELS ARE ON TARGET WITH THIS VITAL FEATURE. SFC COLD FRONT WILL REACH FAR W FCST AREA SHORTLY AFTER 12Z AND SHOULD EXTEND FROM ROUGHLY MUNISING TO MENOMINEE AT 18Z... PLACING ERN FCST AREA UNDER THE GUN FOR POTENTIAL SVR STORMS AS SBCAPE ON ETA FCST SOUNDINGS RISES ABOVE 2K J/KG WITH A REASONABLE T/TD OF LWR 80S/AROUND 70F. WITH PUNCH OF DRIER MIDLEVEL AIR AND COOLING ASSOCIATED WITH SHORTWAVE...WETBULB ZERO HEIGHTS FALL TO A MORE FAVORABLE 10-10.5KFT...INCREASING THREAT FOR LARGE HAIL. IN ADDITION...DELTA THETA-E FROM SFC TO MIDLEVELS INCREASES DRAMATICALLY TO 30-35K...STRONGLY INCREASING THE THREAT FOR DAMAGING WINDS. AND OF COURSE NOT TO MENTION THE STRONGER WIND FIELDS IN GENERAL THAT OVERSPREAD THE AREA ASSOCIATED WITH SHORTWAVE. THUS...BELIEVE ONCE STORMS GET GOING ALONG FRONT AND/OR ONGOING STORMS TAKE ADVANTAGE OF INCREASING DAYTIME INSTABILITY...SOME WILL LIKELY GO SVR WITH BEST POTENTIAL OBVIOUSLY OVER THE E. WILL CARRY MENTION OF LOW END POPS UNTIL FRONT PASSES OVER ABOUT THE W HALF AND WILL LEAVE LIKELY POPS E FOR A TIME THIS AFTN. EXPECT PCPN TO BE OUT OF ERN AREAS BY 22Z. DECENT SHOT OF CAA (850MB TEMPS FALLING ABOUT 9C DURING THE DAY) WILL LEAD TO BREEZY POST FRONTAL CONDITIONS...ESPECIALLY ON THE KEWEENAW UNDER IDEAL WNW FLOW REGIME. ETA SHOWS 35KT IN THE BUILDING BNDRY LAYER AND WOULD SEEM REASONABLE TO HAVE FREQUENT GUSTS 30 TO POSSIBLY 40 MPH ON THE KEWEENAW THIS AFTN. 30-35KT SFC WINDS FROM GFS OVER KEWEENAW AND ERN LAKE ARE ALSO RESPECTABLE...SUPPORTING BREEZY/WINDY CONDITIONS. AND FINALLY...ISALLOBARIC COMPONENT TO WIND (THOUGH NOT ESPECIALLY STRONG) IS ALSO ALIGNED IN DIRECTION OF GRADIENT WIND TO GIVE A BOOST. GOING TEMP FCST LOOKS ON TRACK FROM 70S W TO UPPER 80S E. EXPECT HIGHEST TEMPS IN WRLY DOWNSLOPE AREAS OF MENOMINEE/DELTA COUNTIES. TEMPS COULD SHOOT UP FARTHER E ALONG LAKE MICHIGAN SHORELINE ONCE FRONT PASSES...BUT IT MAY BE TOO LATE IN THE DAY TO GET READINGS WELL INTO THE 80S THERE. COOLER/MUCH DRIER AIRMASS SETTLES OVER THE AREA TONIGHT THRU SAT WITH SFC DWPTS FALLING TO 45-55F. DEEP DRY AIRMASS WILL LIMIT CU DEVELOPMENT TO PROBABLY NOTHING MORE THAN SCT FRI/SAT AFTN INLAND FROM MARINE INFLUENCE. WEAK SHORTWAVE RIDING AROUND RIDGE MAY BRING SOME HIGH CLOUDS ON SAT THOUGH. 850MB TEMPS DROP NEARLY ENOUGH FOR SOME LAKE CLOUD DEVELOPMENT TONIGHT/FRI NIGHT...BUT VERY DRY AIRMASS CERTAINLY ARGUES AGAINST ANY POSSIBILITY GIVEN THAT ITS BORDERLINE FOR BEING COOL ENOUGH. GOING FCST HIGHS FOR FRI/SAT LOOK GOOD BASED ON FCST 850MB TEMPS AND MOS GUIDANCE. HAVE DROPPED MINS ON FRI NIGHT BLO MOS GUIDANCE INTO LWR/MID 40S OVER INTERIOR W HALF AS SFC RIDGE AXIS ARRIVES WITH DEEP DRY AIRMASS IN PLACE. SOME MODEL DISAGREEMENT WITH PATTERN AFTER SAT. ETA IS FLATTER WITH CNTRL CONUS RIDGE...ALLOWING FOR RETURN FLOW AND SHORTWAVE TO BRING SHRA THREAT POSSIBLY AS EARLY AS LATE SAT NIGHT. GFS MUCH MORE PRONOUNCED WITH RIDGE...KEEPING AREA DRY THRU SUN. FOR NOW...WILL LEAVE GOING FCST BEYOND SAT AS IS TO SEE WHAT TRENDS DEVELOP WITH 12Z MODEL RUNS. .MQT...NONE. ROLFSON
MIZ001>007-009>014-084-085-221200- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MARQUETTE MI 645 AM EDT THU AUG 21 2003 ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL UPPER MICHIGAN. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS THIS MORNING WILL BECOME NUMEROUS EARLY THIS AFTERNOON OVER CENTRAL UPPER MICHIGAN...EAST OF A LINE FROM MUNISING TO MENOMINEE. TO THE WEST OF THAT LINE...SCATTERED THUNDERSTORMS WILL END BY MIDDAY AS A COLD FRONT PASSES. SOME OF THE STORMS TODAY MAY BECOME SEVERE...MAINLY EAST OF A LINE FROM MUNISING TO MENOMINEE. THE MAIN HAZARDS FROM ANY SEVERE STORMS WILL BE DAMAGING WIND GUSTS GREATER THAN 60 MPH AND HAIL UP TO ONE INCH IN DIAMETER. ALL THUNDERSTORMS PRODUCE DANGEROUS LIGHTNING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THERE IS A CHANCE OF THUNDERSTORMS ACROSS WEST AND CENTRAL UPPER MICHIGAN MONDAY AND TUESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY. ADDITIONAL WEATHER INFORMATION MAY BE OBTAINED AT THE FOLLOWING URL: HTTP://WWW.CRH.NOAA.GOV/MQT (ALL LOWER CASE) ROLFSON
The Marquette radar (KMQT), 157 km away, was scanning. The volume nearest the first event began at 13:18 UTC.
3 thunderstorm wind, 1 hail. Local standard time, as filed.
Several travel trailers were damaged and numerous trees were blown down in Muskallonge State Park.
Several trees were blown down along highway M-77.
Nickel sized hail was reported.
Two large trees were knocked over along highway M-123.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2003Every state in 2003This day in weather historyWarnings in Michigan, August 2003
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: 5377524, 5377525, 5377526, 5377775.