A weak cold front moving through a warm and unstable air mass triggered isolated severe thunderstorms over portions of south central Upper Michigan on the 14th.
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.
A weak cold front moving through a warm and unstable air mass triggered isolated severe thunderstorms over portions of south central Upper Michigan on the 14th.
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 14, 6:17 AM EST, 5 hours 34 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 717 AM EDT FRI AUG 14 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 326 AM EDT FRI AUG 14 2015 SHOWERS AND THUNDERSTORMS NEARING FROM NW LAKE SUPERIOR DIMINISHED INITIALLY AROUND 05Z...BUT HAVE SINCE BECOME PULSE THUNDERSTORMS. ALTHOUGH MUCH OF THE BETTER DYNAMICS ARE OVER E MN AND N WI...A FAVORABLE ENVIRONMENT STILL EXISTS IN OUR NW FLOW IN THE VICINITY OF THE COLD FRONT. DAYTIME HEATING AND THE SE PASSAGE OF THE COLD FRONT WILL EQUAL AFTERNOON CONVECTION OVER MAINLY S CENTRAL AND E UPPER MI NEAR LAKE MI...AS IT SLOWS DOWN OVERHEAD. ISOLATED STRONG STORM WILL REMAIN POSSIBLE...AND WITH DCAPE VALUES NEARING 1K J/KG STRONG WINDS WILL BE POSSIBLE. TS ARE EXPECTED TO SLIDE TO THE SE OF THE CWA BY 01Z...WITH DRY WEATHER THEN OVERNIGHT TONIGHT. COLD FRONT WILL BE A BIT OF A MISNOMER TODAY...AS THE COOLING FACTOR WILL BE LIMITED. ESPECIALLY WHEN WE CONSIDER NORMAL HIGH TEMPERATURES FOR THIS TIME OF YEAR IN THE MID TO UPPER 70S ACROSS MUCH OF UPPER MI. THE RECORD HIGH 95 FOR NWS MQT SET BACK IN 1965 LOOKS VERY SAFE TODAY...BUT 80-85 IS PRETTY WARM FOR THIS TIME OF YEAR /75F IS THE NORMAL HIGH/. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 453 AM EDT FRI AUG 14 2015 SAT AND SAT NIGHT...EXPECT DRY WEATHER UNDER RISING HEIGHTS WITH MID/UPPER RIDGE BUILDING NE FROM THE NORTHERN PLAINS INTO THE UPPER LAKES. WARM/HUMID CONDITIONS WILL PREVAIL WITH HIGH TEMPS WELL INTO THE 80S PERHAPS EVEN LOWER 90S GIVEN MIXING THROUGH 850 MB TEMPS AROUND 20C. SUN...850 MB THETA-E ADVECTION WILL SUPPORT AT LEAST A SLIGHT CHANCE OF SHRA/TSRA MAINLY OVER THE FAR WEST AND THROUGH LAKE SUPERIOR IN THE MORNING. LOOK FOR ANOTHER WARM DAY WITH TEMPS INTO THE UPPER 80S TO AROUND 90 AS 850 MB TEMPS REMAIN NEAR 20C. WITH GUSTY SOUTHWEST WINDS TO 25 MPH AT TIMES BY AFTERNOON...THE HIGHEST READINGS ARE EXPECTED NEAR LAKE SUPERIOR WHERE DOWNSLOPE FLOW WILL PREVAIL. SUN NIGHT INTO MON...SHORTWAVE TROF MOVING ACROSS THE NRN ROCKIES SAT WILL LIFT ENE INTO NRN ONTARIO SUN. THE GFS AND GEM REMAIN FASTER WITH THE FRONT COMPARED TO THE ECMWF WHICH ONLY BRINGS THE FRONT TO CNTRL UPPER MI BY 12Z/MON. SINCE THE BEST HEIGHT FALLS AND STRONGER DEEP LAYER QVECTOR CONV REMAIN WELL TO THE N OVER NRN ONTARIO ONLY CHANCE POPS WITH SCT SHRA/TSRA ARE EXPECTED. HOWEVER...AS THE 250-300 MB JET MOVES INTO NRN ONTARIO UPPER LEVEL DIV WITH THE RIGHT ENTRANCE MAY BRING AN INCREASE IN COVERAGE LATE SUN NIGHT INTO MONDAY. WITH 0-6KM SHEAR OF 30-40 KNOTS THERE MAY ALSO BE A RISK FOR ISOLD HAIL OR DAMAGING WINDS AS MUCAPE VALUES TO AROUND 2K J/KG ARE EXPECTED. MUCH COOLER AND DRIER AIR WILL EVENTUALLY MOVE INTO THE AREA BEHIND THE FRONT WITH HIGHS FROM AROUND 70 NORTH TO THE MID 70S SOUTH. MON NIGHT INTO TUE...LOOK FOR DRY WEATHER MON NIGHT INTO TUE AS SFC HIGH PRES MOVES ACROSS AND DOMINATES THE UPPER LAKES. WITH SFC HIGH PRES OVER THE AREA AND PRECIPITABLE WATER UNDER 0.5 INCHES...EXPECT MIN TEMPS MON NIGHT TO FALL INTO THE MID 40S IN THE INTERIOR. SHRA/TSRA CHANCES WILL INCREASE AGAIN BY TUE NIGHT INTO WED AS A TROUGH DEVELOPS OVER THE PLAINS AND SLIDES TOWARD THE UPPER MS VALLEY DRAWING A WARM FRONT AND MOISTURE TOWARD THE REGION. CONFIDENCE IN THE DETAILS IS LOW AS THE ECMWF BRINGS THE VIGOROUS CNTRL ROCKIES SHRTWV AND ASSOCIATED SFC LOW INTO THE WRN LAKES WHILE THE GFS AND GEM DEVELOP A CUTOFF LOW WITH WEAKER SHORTWAVES SLIDING FROM THE NRN PLAINS INTO THE NRN LAKES. HOWEVER...EITHER SCENARIO WOULD BRING THE POTENTIAL FOR SOME HEAVY RAIN INTO THE REGION AS PWAT VALUE CLIMB TO NEAR 2.0 INCHES. TEMPS SHOULD AGAIN CLIMB TO AROUND SEASONAL AVERAGES WITH HIGHS IN THE 70S BUT MAY BE HELD LOWER IF MORE PERSISTENT PCPN DEVELOPS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 716 AM EDT FRI AUG 14 2015 LIMITED SHOWER ACTIVITY AGAIN TO START THE TAF PERIOD IS LEADING TO UNCERTANTY ON LATE MONRING/AFTERNOON COVERAGE AS THE COLD FRONT SINKS ACROSS THE AREA. IWD AND CMX WILL BE BEHIND THE FRONT...WITH VFR CEILINGS AND VIS EXPECTED THROUGH THE PERIOD. SAW SHOULD BE ON THE N EDGE OF POP UP SHOWERS AND THUNDERSTORMS AROUND 16-20Z. FOG MAY DEVELOP OVERNIGHT...WITH THE LIGHT WINDS AND CLEAR SKY AT SAW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 326 AM EDT FRI AUG 14 2015 FOG WILL REMAIN POSSIBLE THROUGH TONIGHT OVER E AND NE LAKE SUPERIOR. A TROUGH WILL CROSS LAKE SUPERIOR THIS MORNING. IN ITS WAKE...A HIGH WILL BUILD INTO THE UPPER GREAT LAKES THIS AFTERNOON. THIS HIGH WILL DRIFT INTO THE MID ATLANTIC STATES OVER THE WEEKEND. DURING THIS TIME...A LOW WILL THEN MOVE FROM S SASKATCHEWAN ACROSS NW ONTARIO... AND TO JAMES BAY LATE ON SUNDAY WHILE DEEPENING. THIS LOW WILL CONTINUE INTO QUEBEC ON MONDAY AND DRAG A COLD FRONT ACROSS THE UPPER LAKES SUNDAY NIGHT. EXPECT A PERIOD OF STRONGER SW WINDS...WITH GUSTS NEARING 30KTS OVER THE HIGHER PLATFORMS SUNDAY. A HIGH OVER MANITOBA MONDAY MORNING WILL FOLLOW INTO THE UPPER GREAT LAKES ON TUESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && SHORT TERM...KF LONG TERM...JLB AVIATION...KF MARINE...KF
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MARQUETTE MI 549 AM EDT FRI AUG 14 2015 MIZ001>007-009>014-084-085-151200- KEWEENAW-ONTONAGON-NORTHERN HOUGHTON-BARAGA-MARQUETTE-ALGER-LUCE- GOGEBIC-IRON-DICKINSON-MENOMINEE-DELTA-SOUTHERN SCHOOLCRAFT- SOUTHERN HOUGHTON-NORTHERN SCHOOLCRAFT- 549 AM EDT FRI AUG 14 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN UPPER MICHIGAN AND CENTRAL UPPER MICHIGAN. .DAY ONE...TODAY AND TONIGHT ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE INTO EARLY THIS EVENING MAINLY OVER EAST AND SOUTH CENTRAL UPPER MICHIGAN. SMALL HAIL AND GUSTY WINDS TO 40 MPH ARE POSSIBLE WITH ANY STRONGER STORMS THAT DEVELOP. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THUNDERSTORMS ARE POSSIBLE AGAIN ACROSS FAR WESTERN UPPER MICHIGAN SUNDAY AFTERNOON INTO SUNDAY EVENING...AND OVER CENTRAL UPPER MICHIGAN SUNDAY NIGHT INTO MONDAY. THE CHANCE OF THUNDERSTORMS RETURNS AGAIN TUESDAY NIGHT INTO THURSDAY. .SPOTTER INFORMATION STATEMENT... THE NEED FOR WEATHER SPOTTER REPORTS IS NOT ANTICIPATED AT THIS TIME. LSZ162-240>251-263>267-151200- 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- 549 AM EDT FRI AUG 14 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN LAKE SUPERIOR...CENTRAL LAKE SUPERIOR AND WESTERN LAKE SUPERIOR. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS ARE POSSIBLE OVER FAR EASTERN LAKE SUPERIOR THIS MORNING. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THUNDERSTORMS ARE POSSIBLE OVER THE EAST HALF OF THE LAKE SUNDAY NIGHT INTO MONDAY MORNING. THE CHANCE OF THUNDERSTORMS RETURNS TUESDAY NIGHT INTO THURSDAY. .SPOTTER INFORMATION STATEMENT... THE NEED FOR WEATHER SPOTTER REPORTS IS NOT ANTICIPATED AT THIS TIME. LMZ221-248-250-151200- 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- 549 AM EDT FRI AUG 14 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHERN LAKE MICHIGAN. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS ARE POSSIBLE FROM LATE THIS MORNING INTO THIS EVENING. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY THUNDERSTORMS ARE POSSIBLE AGAIN SUNDAY NIGHT INTO MONDAY AND THEN WEDNESDAY INTO THURSDAY. .SPOTTER INFORMATION STATEMENT... THE NEED FOR WEATHER SPOTTER REPORTS IS NOT ANTICIPATED AT THIS TIME. JLB
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MARQUETTE MI
1201 PM EDT FRI AUG 14 2015
MIZ006-141700-
ALGER MI-
1201 PM EDT FRI AUG 14 2015
...STRONG THUNDERSTORMS MOVING OFF THE LAKE TOWARD GRAND
ISLAND...MUNISING...AND PICTURED ROCKS...
AT 1157 AM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
NEAR GRAND ISLAND...MOVING SOUTHEAST AT 15 MPH. ADDITIONAL STRONG
STORMS WERE NORTH OF GRAND ISLAND...MOVING SOUTHEAST TOWARD PICTURED
ROCKS.
HALF INCH HAIL...WINDS IN EXCESS OF 30 MPH AND HEAVY RAIN WILL BE
POSSIBLE WITH THESE STORMS.
LOCATIONS IMPACTED INCLUDE...
MUNISING...GRAND ISLAND...CHAPEL LAKE...MINERS CASTLE...CHRISTMAS...
GRAND PORTAL POINT AND WETMORE.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
FREQUENT LIGHTNING ARE OCCURRING WITH THESE STORMS. LIGHTNING CAN
STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE SHELTER INSIDE
A BUILDING OR VEHICLE.
&&
LAT...LON 4655 8643 4633 8663 4645 8682 4648 8675
4651 8674 4647 8674 4644 8668 4653 8671
4656 8669 4654 8663 4648 8663 4649 8661
4647 8661 4646 8667 4641 8664 4656 8647
TIME...MOT...LOC 1557Z 305DEG 14KT 4653 8675
JLASPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MARQUETTE MI
1229 PM EDT FRI AUG 14 2015
MIZ006-141700-
ALGER MI-
1229 PM EDT FRI AUG 14 2015
...SPECIAL WEATHER STATEMENT...
AT 1228 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
NEAR TRENARY...OR 20 MILES SOUTHWEST OF MUNISING...MOVING SOUTHEAST
AT 20 MPH.
HALF INCH HAIL AND WINDS IN EXCESS OF 30 MPH WILL BE POSSIBLE WITH
THIS STORM.
THIS STRONG THUNDERSTORM WILL BE NEAR...
TRENARY AROUND 1240 PM EDT.
OTHER LOCATIONS IMPACTED BY THIS STORM INCLUDE DIFFIN...TRAUNIK AND
KIVA.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.
&&
LAT...LON 4616 8666 4616 8710 4617 8712 4626 8711
4635 8699 4617 8664
TIME...MOT...LOC 1628Z 315DEG 16KT 4623 8701
07SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MARQUETTE MI 1238 PM EDT FRI AUG 14 2015 MIZ006-013-141715- DELTA MI-ALGER MI- 1238 PM EDT FRI AUG 14 2015 ...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL DELTA AND SOUTHWESTERN ALGER COUNTIES UNTIL 115 PM EDT... AT 1237 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM OVER TRENARY...OR 21 MILES SOUTHWEST OF MUNISING...MOVING SOUTHEAST AT 10 MPH. DIME SIZE HAIL AND WINDS IN EXCESS OF 30 MPH WILL BE POSSIBLE WITH THIS STORM. THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF NORTH CENTRAL DELTA AND SOUTHWESTERN ALGER COUNTIES...INCLUDING THE FOLLOWING LOCATIONS...ROUND LAKE. PRECAUTIONARY/PREPAREDNESS ACTIONS... TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS. FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE SHELTER INSIDE A BUILDING OR VEHICLE. && LAT...LON 4614 8711 4628 8693 4616 8665 4596 8691 TIME...MOT...LOC 1637Z 312DEG 7KT 4617 8695 07
The Marquette radar (KMQT), 63 km away, was scanning. The volume nearest the first event began at 16:51 UTC.
3 hail. Local standard time, as filed.
Golf ball sized hail observed south of Trenary near Highway US-41. Report was relayed via social media.
Nickel sized hail reported via a video on social media.
There were multiple reports of dime to quarter sized hail via social media.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2015Every state in 2015This day in weather historyWarnings in Michigan, August 2015
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: 598523, 598524, 598525.