Several clusters of severe thunderstorms moved across western Lake Superior from the evening of the 19th into the morning of the 20th.
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.
Several clusters of severe thunderstorms moved across western Lake Superior from the evening of the 19th into the morning of the 20th.
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 Jun 19, 6:27 PM EST, 1 hour 33 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 727 PM EDT TUE JUN 19 2012 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 425 PM EDT TUE JUN 19 2012 STRONG 500MB RIDGE OVER THE OHIO RIVER VALLEY THIS AFTERNOON...ALONG WITH TWO 500MB SHORTWAVES MOVING NORTH EAST FROM THE NORTHERN PLAINS...HAVE CAUSED A TIGHT HEIGHT GRADIENT ACROSS THE UPPER GREAT LAKES. FIRST SHORTWAVE PASSED JUST TO THE NORTH OF LAKE SUPERIOR DURING THE OVERNIGHT HOURS AND THROUGH THE MORNING...CAUSING A PRECIPITATION SHIELD TO TRAVERSE UPPER MI. THE SECOND SHORTWAVE /CURRENTLY OVER MONTANA/ IS ASSOCIATED WITH SURFACE LOW PRESSURE OVER EASTERN SOUTH DAKOTA. STEMMING FROM THIS IS A WARM FRONT...STRETCHING FROM EASTERN SOUTH DAKOTA TO SOUTHERN AND EASTERN UPPER MI...AND INTO FAR EASTERN ONTARIO. JUST AHEAD OF THIS WARM FRONT PRECIPITABLE WATER VALUES ARE 175 PERCENT OF NORMAL WITH STRONG Q-VECTOR CONVERGENCE OVER MUCH OF MN AND FAR WESTERN LAKE SUPERIOR. AS THE WARM FRONT HAS TRAVERSED NORTHWARD FROM WI DURING THE DAY...BEST LIFT AND INSTABILITY HAS LAID ON ITS BOUNDARY. WITH 12Z NAM SHOWING 0-3KM COMPUTED CAPE VALUES OF 1-1.5K J/KG AND MU CAPE VALUES OF 2-4K J/KG ALONG THE WARM FRONT BOUNDARY...ALONG WITH CIN VALUES LESS THAN 100 J/KG AT 15Z THIS MORNING IN MN JUST TO THE NORTH OF THE BOUNDARY...IT DIDN/T TAKE MUCH WARMING TO START INITIATION OF STORMS THIS MORNING. STORMS HAVE BEEN INITIATING ALONG THE 700MB MOISTURE TRANSFER...AROUND THE SAME PLACE THAT THE WARM FRONT LIES. ANYTHING TO THE SOUTH OF THAT THE CIN HAS BEEN TOO GREAT TO OVERCOME. AS WARM FRONT HAS PUSHED NORTHWARD DURING THE DAY...SO HAS THE CONVECTIVE CELLS. DURING THE MORNING HOURS...CELLS WHICH DEVELOPED IN CENTRAL MN AND NORTHERN WI MOVED EASTWARD ALONG THE GRADIENT INTO UPPER MI. AS THE BOUNDARY AND BEST INSTABILITY MOVED NORTH...SO DID THE STORM TRACK. UNFORTUNATELY...MODELS HAVE NOT HAD A GOOD HANDLE ON THE LOCATION OF CONVECTION THROUGH THE MORNING AND EARLY AFTERNOON HOURS...SO WENT OFF OF INSTABILITY PARAMETERS AND CURRENT RADAR/SATELLITE IMAGERY TO UPDATE POPS THROUGHOUT THE DAY. EXPECT STORMS TO CONTINUE ALONG THE WARM FRONT AND INSTABILITY GRADIENT THROUGH THE EVENING...MAINLY AFFECTING THE ARROWHEAD OF MN AND WESTERN LAKE SUPERIOR. DRIER AIR AND SUBSIDENCE BEHIND THE WARM FRONT WILL CONTINUE TO CLEAR OUT CLOUDS FROM THE SOUTH AND CENTRAL...ALLOWING TEMPERATURES TO RAPIDLY INCREASE WHERE EVER CLEARING OCCURS. HOWEVER...WITH GOOD MOISTURE TRANSPORT CONTAINED ACROSS FAR WESTERN LAKE SUPERIOR...EXPECT CONTINUED CLOUDS ACROSS THE WESTERN HALF OF UPPER MI THROUGH THE NIGHT. WITH ABUNDANT MOISTURE AND CLOSE PROXIMITY TO SURFACE LOW...HAVE KEPT LIKELY POPS IN ACROSS THE FAR WESTERN LAKE DURING THE EVENING/OVERNIGHT HOURS AS WELL. BY 12Z WEDNESDAY MORNING...0Z GFS PLACES SURFACE LOW ON THE NORTHERN TIER OF MN...WITH THE WARM FRONT STRETCHING ALONG THE NORTHERN SHORES OF LAKE SUPERIOR. AT THIS POINT...ASSOCIATED COLD FRONT WILL SLOWLY PUSH EASTWARD ACROSS THE WESTERN HALF OF UPPER MI AND LAKE SUPERIOR DURING THE DAY. WITH PRECIPITABLE WATER VALUES AROUND 200 PERCENT OF NORMAL JUST AHEAD OF THE FRONT...EXPECT GOOD PRECIPITATION BAND AS FRONT PROGRESSES. STRONG GRADIENTS JUST AHEAD OF THE COLD FRONT INDICATE A LINE OF STORMS DEVELOPING AND MOVING EASTWARD. BY 15Z WEDNESDAY...MU CAPE WILL INCREASE RAPIDLY TO 1.5-3K J/KG ACROSS THE WESTERN HALF OF UPPER MI...THEN UP TO 3.5K J/KG BY 18Z AS COLD FRONT NEARS CLOSER. DCAPE VALUES WILL ALSO BE BETWEEN 1.4 AND 1.8K J/KG AT THIS TIME...SO COULD EXPECT SOME GUSTY WINDS WITH THIS LINE OF STORMS. SPC DID PUT US IN A SLIGHT RISK DURING THE DAY AS WELL. LOOKING AT 12Z FORECAST SOUNDINGS...FAR WESTERN UPPER MI /IRONWOOD/ WILL SEE NICE CAPE PROFILES DURING THE LATE MORNING/EARLY AFTERNOON HOURS...WITH SOME LOW LEVEL MOISTURE AND STRONG DRYING ALOFT. WITH SURFACE BASED CAPE VALUES BETWEEN 1K-1.5K...COULD SEE SOME INITIATION OF CONVECTIVE CELLS AHEAD OF THE MAIN LINE SO INCLUDED CHANCE POPS WELL AHEAD OF MAIN COLD FRONT/PRECIP BAND. STRONG MOISTURE BUILDS IN AS FRONT NEARS AND MAIN LINE OF PRECIP MOVES THROUGH THE AREA BETWEEN 18 AND 21Z...THEN DRY AIR ALOFT WILL WORK ITS WAY IN. HOWEVER...LINGERING LOW LEVEL MOISTURE AND POTENTIAL FOR STRATIFORM RAIN WILL PERSIST THROUGH 0Z. BEST INSTABILITY AND MAIN LINE OF CONVECTION/PRECIP WILL SHOULD REACH CENTRAL AND EASTERN UPPER MI BETWEEN 21 AND 0Z WEDNESDAY. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 425 PM EDT TUE JUN 19 2012 TEMPERATURES THROUGHOUT EACH PERIOD SHOULD BE NEAR NORMAL WITH HIGH TEMPERATURES IN THE LOW TO MID 70S AND LOWS IN THE LOW TO MID 50S. WEDNESDAY NIGHT...SURFACE LOW JUST TO THE NORTH OF LAKE SUPERIOR WILL CONTINUE LIFTING NORTHEASTWARD TO NEAR JAMES BAY BY EARLY THURSDAY MORNING. MODELS DIFFER WITH THE PLACEMENT OF THIS FEATURE HOWEVER WITH THE EC/GFS KEEPING THE LOW A BIT FARTHER SOUTH ENCOMPASSING A LARGE PORTION OF LAKE SUPERIOR. THE MOVEMENT THROUGH THURSDAY MORNING IS FAIRLY SIMILAR THOUGH. EACH OF THE AFOREMENTIONED MODELS SHOW THE UPPER LEVEL SUPPORT PROVIDED BY THE 500MB LOW STAGGERED JUST TO THE WEST OF THE SURFACE LOW INDICATING THE POTENTIAL FOR LOW INTENSIFICATION. THE UPPER LEVEL TROUGH AT 00Z THURSDAY IS DRAPED FROM NORTH TO SOUTH OVER MUCH OF WESTERN MN INTO EASTERN NE...WHILE THE COLD FRONT STRETCHES FROM WESTERN LAKE SUPERIOR SOUTHWESTWARD INTO SOUTHEASTERN NE. EXPECT SHOWERS AND THUNDERSTORMS THAT DEVELOP WEDNESDAY EVENING TO CONTINUE MOVING EASTWARD ALONG AND JUST AHEAD OF THE COLD FRONT. THE GFS/EC/UKMET SOLUTIONS TEND TO SLOW THE EASTWARD PROGRESSION OF THE FRONT THROUGH THE OVERNIGHT HOURS WITH THE FRONT PROGGED TO BE OVER EASTERN UPPER MI BY 12Z...WHILE THE NAM HAS THE FRONT POSITIONED OVER NORTHEASTERN LOWER MI AROUND THE SAME TIME FRAME. LEANING MORE TOWARD THE SLOWER SOLUTIONS...IT IS FEASIBLE THAT HEAVIER RAIN COULD FALL ACROSS THE UPPER PENINSULA WITH SOLUTIONS RANGING FROM ONE HALF TO ONE INCH. ALONG WITH THE RAINFALL...SOME OF THE STORMS MAY PRODUCE SEVERE WIND GUSTS. THE UPPER PENINSULA WILL BE IN THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET HELPING TO INCREASE UPPER LEVEL DIVERGENCE ALONG THE FRONT. 0-6KM SHEAR ORIENTED ALONG THE FRONT WOULD BE SUPPORTIVE OF AN ORGANIZED LINE OF STORMS MOVING THROUGH THE AREA. 0-1 KM SHEAR VALUES ARE EXPECTED TO BE AROUND 20 TO 30 KNOTS OVERNIGHT DUE TO THE DEVELOPMENT OF A 35 TO 40 KNOT LLJ. THE MAIN LIMITING FACTOR FOR SEVERE THUNDERSTORM DEVELOPMENT WILL LIKELY BE DUE TO TIMING OF THE FRONT...WITH FRONTAL PASSAGE OCCURRING OVERNIGHT...LIMITING THE AMOUNT OF CAPE. THURSDAY THROUGH FRIDAY...THE SURFACE LOW CONTINUES TO SHIFT NORTHEASTWARD MOVING INTO NORTHWESTERN QUEBEC BY 00Z FRIDAY...WHILE DRAGGING THE COLD FRONT INTO THE EASTERN GREAT LAKES. IN ITS WAKE...A SURFACE AND UPPER LEVEL RIDGE WILL BUILD INTO THE REGION FROM THE CENTRAL PLAINS EFFECTIVELY ENDING THE CHANCES FOR PRECIPITATION ACROSS THE AREA. WINDS WILL BE AROUND 20 TO 25 MPH DURING THE DAY THURSDAY BUT FAIRLY LIGHT THROUGH THE REMAINDER OF THE PERIOD AS THE PRESSURE GRADIENT RELAXES ACROSS THE REGION. FRIDAY NIGHT THROUGH SUNDAY...A SURFACE LOW WILL ATTEMPT TO MOVE NORTHWARD INTO WESTERN MN BY SATURDAY MORNING...WHILE AN UPPER LEVEL LOW AND TROUGH MOVES INTO THE REGION FROM THE NORTH. THERE SHOULD BE ENOUGH MOISTURE AROUND ALONG WITH FORCING AS SHOWN BY 1000-500MB RH AND Q-DIV TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA. AT THIS POINT IT APPEARS AS IF THE BEST FORCING AND MOISTURE OVERLAP SATURDAY AFTERNOON THROUGH SATURDAY NIGHT. GUIDANCE WAS INCONSISTENT WITH BRINGING THE MOISTURE IN FOR FRIDAY NIGHT SO ONLY WENT WITH A SLIGHT CHANCE AT THIS POINT. LATER SHIFTS WILL NEED TO MONITOR TO SEE IF GUIDANCE CONVERGES TOWARD A SINGLE SOLUTION. SUNDAY NIGHT THROUGH TUESDAY...AS THE UPPER LEVEL LOW SHIFT TO THE EAST OF THE REGION AND A RIDGE OF HIGH PRESSURE BEGINS TO BUILD IN EXPECT THE SHOWERS AND THUNDERSTORMS TO COME TO AN END. WINDS SHOULD BE FAIRLY LIGHT OUT OF THE NORTH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 726 PM EDT TUE JUN 19 2012 EXPECT SOME SHRA/POSSIBLY A TS AND MVFR CONDITIONS TO IMPACT CMX THIS EVNG IN ADVANCE OF WARM FNT APRCHG FM THE S. ONCE THE WARM FNT SHIFTS TO THE N OF THE SITES TNGT...EXPECT LLWS UNDER STRENGTHENING SSW LLJ AS WELL AS VFR CONDITIONS. WITH THE ONSET OF DAYTIME HEATING ON WED...THE STRONG WINDS ABV THE SFC WL MIX OUT WITH GUSTY SFC WINDS. THE APRCH OF A COLD FNT TOWARD WRN UPR MI LATE IN THE DAY WL LIKELY BRING SOME TS IN THE AFTN AT IWD/CMX. GIVEN THE DEGREE OF FCST INSTABILITY...FELT CONFIDENT ENUF TO INCLUDE MENTION OF TS THIS FAR OUT. BUT TIMING MAY CHANGE A BIT IF THE COLD FNT ENDS UP MOVING FASTER OR SLOWER THAN EXPECTED. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 425 PM EDT TUE JUN 19 2012 A TROUGH OF LOW PRESSURE LIES ACROSS THE DAKOTAS THIS AFTERNOON...AND WILL PUSH ACROSS MN AND WESTERN LAKE SUPERIOR OVERNIGHT...BEFORE MAKING IT TO N CENTRAL ONTARIO WEDNESDAY EVENING. AS IT MOVES NORTHEASTWARD...AN ASSOCIATED COLD FRONT WILL TRAVERSE THE UPPER GREAT LAKES WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. HIGH PRESSURE WILL THEN BUILD ACROSS THE UPPER GREAT LAKES THURSDAY THROUGH FRIDAY...PUTTING AN END TO ANY LINGERING FOG ACROSS E LS. EXPECT THE HIGH TO SLIDE TO THE LOWER GREAT LAKES FRIDAY NIGHT INTO SATURDAY...WITH AN ADDITIONAL HIGH SLIDING INTO THE AREA FROM S CENTRAL CANADA. WINDS SHOULD REMAIN PRIMARILY SOUTHERLY THROUGH WEDNESDAY...BEFORE VEERING TO THE WEST AFTER THE PASSAGE OF THE COLD FRONT WEDNESDAY NIGHT. DO NOT EXPECT ANY MARINE CONCERNS...WITH HIGHEST WIND GUSTS AROUND 20 KNOTS WEDNESDAY MORNING OVER WESTERN LAKE SUPERIOR AND MUCH OF LAKE MI. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && SHORT TERM...JMW LONG TERM...KEC AVIATION...KC MARINE...JMW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MARQUETTE MI 356 PM EDT TUE JUN 19 2012 MIZ001>007-009>014-084-085-202000- KEWEENAW-ONTONAGON-NORTHERN HOUGHTON-BARAGA-MARQUETTE-ALGER-LUCE- GOGEBIC-IRON-DICKINSON-MENOMINEE-DELTA-SOUTHERN SCHOOLCRAFT- SOUTHERN HOUGHTON-NORTHERN SCHOOLCRAFT- 356 PM EDT TUE JUN 19 2012 /256 PM CDT TUE JUN 19 2012/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN UPPER MICHIGAN AND CENTRAL UPPER MICHIGAN. .DAY ONE...TONIGHT ISOLATED THUNDERSTORMS ARE POSSIBLE...MAINLY OVER THE KEWEENAW. SOME STORMS MAY PRODUCE GUSTY WINDS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH TUESDAY THUNDERSTORMS ARE POSSIBLE WEDNESDAY AND WEDNESDAY NIGHT...SOME STORMS COULD PRODUCE SEVERE WIND GUSTS AND SMALL HAIL. THUNDERSTORMS ARE ALSO POSSIBLE FRIDAY NIGHT THROUGH SUNDAY. .SPOTTER INFORMATION STATEMENT... ANY REPORTS OF LARGE HAIL OR DAMAGING WINDS WOULD BE GREATLY APPRECIATED. LSZ162-240>251-263>267-202000- 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- 356 PM EDT TUE JUN 19 2012 /256 PM CDT TUE JUN 19 2012/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN LAKE SUPERIOR...CENTRAL LAKE SUPERIOR AND WESTERN LAKE SUPERIOR. .DAY ONE...TONIGHT ISOLATED THUNDERSTORMS ARE EXPECTED TONIGHT. SOME STORMS MAY CONTAIN GUSTY WINDS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH TUESDAY THUNDERSTORMS ARE POSSIBLE WEDNESDAY AND WEDNESDAY NIGHT...SOME STORMS COULD PRODUCE SEVERE WIND GUSTS TO 35 KNOTS AND SMALL HAIL. THUNDERSTORMS ARE ALSO POSSIBLE FRIDAY NIGHT THROUGH SUNDAY. .SPOTTER INFORMATION STATEMENT... ANY REPORTS OF LARGE HAIL OR WINDS OVER 35 KNOTS WOULD BE GREATLY APPRECIATED. LMZ221-248-250-202000- 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- 356 PM EDT TUE JUN 19 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHERN LAKE MICHIGAN. .DAY ONE...TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH TUESDAY THUNDERSTORMS ARE POSSIBLE WEDNESDAY AND WEDNESDAY NIGHT...SOME STORMS COULD PRODUCE SEVERE WIND GUSTS TO 35 KNOTS AND SMALL HAIL. THUNDERSTORMS ARE ALSO POSSIBLE FRIDAY NIGHT THROUGH SUNDAY. .SPOTTER INFORMATION STATEMENT... ANY REPORTS OF LARGE HAIL OR WINDS OVER 35 KNOTS WOULD BE GREATLY APPRECIATED.
The Marquette radar (KMQT), 165 km away, was scanning. The volume nearest the first event began at 01:01 UTC.
13 marine thunderstorm wind. Local standard time, as filed.
The Cason J. Callaway measured wind gusts to 69 mph over western Lake Superior.
Wind gust measured by Lake Superior buoy 45001.
Lake Superior buoy 45001 measured wind gusts to 76 mph.
The western Lake Superior buoy 45006 measured a wind gust to 47 mph.
Wind gust measured by the Rock of Ages C-MAN station.
Wind gust measured by the Lake Superior buoy 45001.
Wind gust measured by the observing site at the upper entrance of Portage Canal.
Wind gust measured by the observing site at the upper entrance of Portage Canal.
Wind gust measured by the observing site at the upper entrance of Portage Canal.
Wind gust measured by the observing site at the upper entrance of Portage Canal.
Wind gust measured by the observing site at the upper entrance of Portage Canal.
Wind gust measured by the Saxon Harbor marine observing site.
Wind gust measured by the Saxon Harbor marine observing site.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Lake Superior in 2012Every state in 2012This day in weather history
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: 395974, 395991, 395979, 395976, 395982, 396004, 395999, 396001, 396011, 396012, 396013, 396006, 396007.