Severe thunderstorms resulted in flash flooding, damaging winds and large hail in Ontonagon County in the late afternoon of the 25th.
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.
Severe thunderstorms resulted in flash flooding, damaging winds and large hail in Ontonagon County in the late afternoon of the 25th.
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 May 25, 3:50 PM EST, 4 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 450 PM EDT TUE MAY 25 2010 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH OVER THE WRN CONUS. A MID LEVEL LOW WAS LOCATED OVER SRN SASK AND A RIDGE EXTENDED FROM NEW ENGLAND INTO THE ERN GREAT LAKES RESULTING IN SRLY FLOW FROM THE PLAINS THROUGH THE CNTRL PLAINS THROUGH THE UPPER MS VALLEY. AT THE SFC...A COLD FRONT EXTENDED FORM NEAR KINL INTO NW IA. A WEAK SHORTWAVE COMBINED WITH MLCAPE VALUES AOA 3K J/KG TRIGGERED STRONG/SVR TSRA FROM WI INTO FAR WRN UPPER MI. DAMAGING WIND OUTFLOWS WERE AIDED BY STEEP LOW LEVEL LAPSE RATES. ADDITIONAL TSRA WERE ALSO LOCATE OVER ERN IA INTO SW WI BUT HAVE NOT SHOWN NORTHWARD MOVEMENT. && .SHORT TERM...TONIGHT AND WEDNESDAY AS THE SASK MID LEVEL AND SFC LOW LIFTS TO THE NE THE COLD FRONT WILL GRADUALLY MOVE INTO THE CWA. ALTHOUGH THERE SHOULD BE A LULL IN THE TSRA INTO W UPPER AFTER THE MCS MOVES NORTH OF THE AREA AND WEAKENS...SOME ADDITIONAL TSRA MAY DEVELOP IN W UPPER MI AHEAD OF THE ADVANCING FRONT IN PROXIMITY TO BEST MOIST CONV. THE FRONTAL BOUNDARY AIDED BY LAKE BREEZES WILL MOVE INTO CNTRL UPPER MI WED WITH BEST CHANCE OF TRIGGERING CONV OVER INLAND PORTIONS OF CNTRL UPPER MI. HOWEVER...ONLY SCT/ISOLD COVERAGE IS EXPECTED AS BETTER MI LEVEL DYNAMICS LIFT NORTH OF LAKE SUPERIOR AND GREATER INSTABILITY REMAINS TO THE SOUTH. AFTERNOON MLCAPE VALUES IN THE 1K- 2K J/KG RANGE STILL COULD SUPPORT SOME STRONGER TSRA. .LONG TERM /WED NIGHT ONWARD/... QUIET WEATHER IS EXPECTED THROUGHOUT THIS PERIOD WITH TEMPERATURES MODERATING...BUT REMAINING ABOVE NORMAL. WHATEVER CONVECTION DEVELOPS DURING THE DAY ON WEDNESDAY WILL BE PUSHING OUT OF THE EASTERN ZONES WED NIGHT...THEREAFTER...MAINTAINED A DRY FORECAST THROUGHOUT AS LARGE SCALE DRYING DOMINATES THE CWA THROUGH THE WEEK AND RIDGING SLOWLY BUILDS SOUTH FROM CANADA. STILL SOME CONCERN W.R.T DEW POINTS ON THURSDAY AND FRIDAY AS DRYING FINALLY BEGINS WED NIGHT. SAW NO REASON TO LOWER DEW POINTS FURTHER FROM GOING FORECAST AS OVERALL MIXING ISN/T TOO IMPRESSIVE WITH LARGE SCALE SUBSIDENCE STILL OVER THE CWA. ON THURSDAY THE AREA OF BIGGEST CONCERN IS THE CENTRAL AND EASTERN PORTIONS OF THE CWA WHERE TIGHTER SFC PRESSURE GRADIENTS...LOCALLY ENHANCED BY LAKE BREEZES...MAY WARRANT RED FLAG CONDITIONS. CRITICAL FIRE WEATHER CONDITIONS APPEAR MARGINAL ON FRIDAY AS COOL CANADIAN RIDGE BUILDS SOUTH FROM MANITOBA ALLOWING WINDS TO SLIGHTLY WEAKEN. LONG RANGE GUIDANCE SHOWS POTENTIAL FOR A FRONTAL PASSAGE ON SUN NIGHT/MONDAY. GUIDANCE IS JUST NOW STARTING TO SHOW A TREND TOWARDS THIS HAPPENING. WILL LET THE NEXT SHIFT ADD IN POPS DURING THIS PERIOD IF THIS TREND HOLDS UP. && .AVIATION /FOR THE 18Z TAF ISSUANCE/... EXPECT SCT TSRA TO REMAIN MAINLY SW OF KCMX THIS AFTERNOON AND EVENING. OTHERWISE...VFR CONDITIONS SHOULD PREDOMINATE UNTIL LATER TONIGHT WHEN SOME MVFR FOG IS POSSIBLE. SOME SCT OR ISOLD SHRA AND POSSIBLY A TSRA MAY ALSO DEVELOP AS A WEAK FRONT MOVES FROM W CNTRL UPPER MI LATE TONIGHT AND WED MORNING. && .MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/... SATELLITE IMAGERY SUGGEST THAT MOST OF THE DENSE FOG HAD DISSIPATED OVER ERN LAKE SUPERIOR BUT REMAINED OVER THE WRN PORTION OF THE LAKE. SO...THE ADVY WAS EXTENDED THROUGH THIS EVENING OVER THE WEST. HIGH DEWPOINTS WILL KEEP WIDESPREAD FOG ACROSS THE LAKE INTO WEDNESDAY. OTHERWISE...EXPECT WINDS TO GENERALLY REMAIN BLO 20 KT THROUGH MUCH OF THE FCST PD UNDER THE INFLUENCE OF A HIGH PRESSURE RIDGE. A LOW PRESSURE SYSTEM LIFTING FROM THE NRN PLAINS TOWARD HUDSON BAY WILL DRAG A COLD FRONT ACROSS LAKE SUPERIOR ON WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && SYNOPSIS... SHORT TERM... LONG TERM... AVIATION... MARINE...
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MARQUETTE MI 443 PM EDT TUE MAY 25 2010 MIZ001>007-009>014-084-085-261100- KEWEENAW-ONTONAGON-NORTHERN HOUGHTON-BARAGA-MARQUETTE-ALGER-LUCE- GOGEBIC-IRON-DICKINSON-MENOMINEE-DELTA-SOUTHERN SCHOOLCRAFT- SOUTHERN HOUGHTON-NORTHERN SCHOOLCRAFT- 443 PM EDT TUE MAY 25 2010 /343 PM CDT TUE MAY 25 2010/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN UPPER MICHIGAN AND CENTRAL UPPER MICHIGAN. .DAY ONE...TONIGHT SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TONIGHT OVER WESTERN UPPER MICHIGAN. SOME STORMS MAY PRODUCE DAMAGING WINDS AND HAIL THE SIZE OF QUARTERS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THERE IS A CHANCE OF THUNDERSTORMS ACROSS WESTERN AND CENTRAL UPPER MICHIGAN ON WEDNESDAY. .SPOTTER INFORMATION STATEMENT... THE NEED FOR WEATHER SPOTTER REPORTS IS NOT ANTICIPATED AT THIS TIME. LSZ162-240>251-263>267-261100- LAKE SUPERIOR WEST OF A LINE FROM SAXON HARBOR WI TO GRAND PORTAGE MN BEYOND 5NM-SAXON HARBOR WI TO BLACK RIVER MI- BLACK RIVER TO ONTONAGON MI- ONTONAGON TO UPPER ENTRANCE OF PORTAGE CANAL MI- UPPER ENTRANCE OF PORTAGE CANAL TO EAGLE RIVER MI- EAGLE RIVER TO MANITOU ISLAND MI- MANITOU ISLAND TO POINT ISABELLE MI- POINT ISABELLE TO LOWER ENTRANCE OF PORTAGE CANAL MI- LOWER ENTRANCE OF PORTAGE CANAL TO HURON ISLANDS MI INCLUDING KEWEENAW AND HURON BAYS-HURON ISLANDS TO MARQUETTE MI- MARQUETTE TO MUNISING MI-MUNISING TO GRAND MARAIS MI- GRAND MARAIS TO WHITEFISH POINT MI- LAKE SUPERIOR FROM SAXON HARBOR WI TO UPPER ENTRANCE TO PORTAGE CANAL MI 5NM OFF SHORE TO THE US/CANADIAN BORDER INCLUDING ISLE ROYALE NATIONAL PARK- LAKE SUPERIOR FROM UPPER ENTRANCE TO PORTAGE CANAL TO MANITOU ISLAND MI 5NM OFF SHORE TO THE US/CANADIAN BORDER- LAKE SUPERIOR WEST OF LINE FROM MANITOU ISLAND TO MARQUETTE MI BEYOND 5NM FROM SHORE- LAKE SUPERIOR EAST OF A LINE FROM MANITOU ISLAND TO MARQUETTE MI AND WEST OF A LINE FROM GRAND MARAIS MI TO THE US/CANADIAN BORDER BEYOND 5NM FROM SHORE- LAKE SUPERIOR FROM GRAND MARAIS MI TO WHITEFISH POINT MI 5NM OFF SHORE TO THE US/CANADIAN BORDER- 443 PM EDT TUE MAY 25 2010 /343 PM CDT TUE MAY 25 2010/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN LAKE SUPERIOR...CENTRAL LAKE SUPERIOR AND WESTERN LAKE SUPERIOR. .DAY ONE...TONIGHT A DENSE FOG ADVISORY IS IN EFFECT FOR ALL OF LAKE SUPERIOR THROUGH EARLY THIS EVENING. PLAN ON WIDESPREAD FOG THE REST OF TONIGHT... WITH VISIBILITY UNDER ONE QUARTER MILE IN SOME AREAS. THERE IS A CHANCE OF THUNDERSTORMS OVER WESTERN LAKE SUPERIOR TONIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY WIDESPREAD FOG IS POSSIBLE ON WEDNESDAY...WITH PATCHY DENSE FOG. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS OVER WESTERN LAKE SUPERIOR WEDNESDAY MORNING. .SPOTTER INFORMATION STATEMENT... THE NEED FOR WEATHER SPOTTER REPORTS IS NOT ANTICIPATED AT THIS TIME. LMZ221-248-250-261100- GREEN BAY NORTH OF LINE FROM CEDAR RIVER MI TO ROCK ISLAND PASSAGE-SEUL CHOIX POINT TO POINT DETOUR MI- 5NM EAST OF A LINE FROM FAIRPORT MI TO ROCK ISLAND PASSAGE- 443 PM EDT TUE MAY 25 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHERN LAKE LAKE MICHIGAN. .DAY ONE...TONIGHT WIDESPREAD FOG IS EXPECTED. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY WIDESPREAD FOG IS EXPECTED ON WEDNESDAY. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING. .SPOTTER INFORMATION STATEMENT... THE NEED FOR WEATHER SPOTTER REPORTS IS NOT ANTICIPATED AT THIS TIME. PEARSON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MARQUETTE MI 240 PM EDT TUE MAY 25 2010 MIZ002-251915- ONTONAGON- 240 PM EDT TUE MAY 25 2010 ...SIGNIFICANT WEATHER ALERT FOR ONTONAGON COUNTY UNTIL 315 PM EDT... AT 238 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 15 MILES SOUTHWEST OF REDRIDGE TO 7 MILES NORTHEAST OF ONTONAGON TO 9 MILES EAST OF BERGLAND. THESE STORMS WERE MOVING NORTHWEST AT 20 MPH. PEA SIZE HAIL...WINDS UP TO 40 MPH...AND HEAVY DOWNPOURS ARE EXPECTED WITH THESE STORMS. * LOCATIONS IN OR NEAR THE PATH OF THESE STORMS INCLUDE... NORWICH... ONTONAGON... SILVER CITY... STAY TUNED TO NOAA WEATHER RADIO...COMMERCIAL RADIO...OR YOUR LOCAL TELEVISION STATIONS FOR LATER STATEMENTS AND POSSIBLE WARNINGS CONCERNING THIS WEATHER SITUATION. SRF
The Marquette radar (KMQT), 158 km away, was scanning. The volume nearest the first event began at 20:52 UTC.
3 thunderstorm wind, 1 hail, 1 flash flood. Local standard time, as filed.
Thunderstorm winds removed small branches from trees. Pea-sized hail was also reported.
The Ontonagon Sheriff's office reported branches and small trees down in Ontonagon due to thunderstorm winds.
One inch hail and 60 mph winds were reported.
The Ontonagon Sheriff's office reported roads in and near Ontonagon washed out due to heavy rainfall of two to three inches which fell in less than an hour. Flooding on River Street in Ontonagon forced water over the sidewalks and into some area businesses.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2010Every state in 2010This day in weather historyWarnings in Michigan, May 2010
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: 234334, 234335, 234337, 234338, 234342.