A cold front moving through a moist and unstable air mass generated isolated severe thunderstorms over portions of Dickinson County during the afternoon of the 14th.
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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 cold front moving through a moist and unstable air mass generated isolated severe thunderstorms over portions of Dickinson County during the afternoon of 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, 1:14 PM CST, 1 hour 11 minutes earlier.
Area Forecast Discussion National Weather Service Marquette MI 314 PM EDT Tue Aug 14 2018 .SHORT TERM...(This evening through Wednesday) Issued at 238 PM EDT TUE AUG 14 2018 Upper air pattern consists of a 500 mb closed low along the NY/PA border and another over northern KS with a ridge over the upper Great Lakes and a shortwave passing across Ontario and this drags into the northern Rockies. The ridge gets flattened as the shortwave moves across Ontario this afternoon and then troughing remains over the upper Great Lakes through Wed. Weak cold front fizzles out over the area this forecast period and will have some slight chance to low chance pops across the central and south through Wed afternoon before lake breezes help to push the weak front out of the area by Wed evening. Overall, did not make too many changes to the going forecast. .LONG TERM...(Wednesday night through Tuesday) Issued at 314 PM EDT TUE AUG 14 2018 High pressure will provide a quiet and generally seasonable stretch of weather late in the work week. Shortwave moving through the lower lakes should keep some cloud cover across the southern half of the forecast area through Wednesday night. If skies clear sooner...conditions will be set for locally dense fog late Wednesday night/early Thursday. Surface ridge axis will slide just east of the area for the weekend with light return southwesterly flow returning to the area. This should help boost temperatures back to well above normal for the weekend. A diurnally driven shra or tsra cannot be ruled out either afternoon, but most locations will remain dry. Upper trough moving across central Canada will push a cold front through the Upper Lakes on Monday with the next best chance of rain for the area. Once again the main upper dynamics will pass well north of the area and the current timing of the front is not ideal for maximum diurnal heating ahead of it. Thus, expect precipitation to only be scattered. Temperatures behind the front will briefly return to normal for early next week. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1259 PM EDT TUE AUG 14 2018 VFR conditions will continue through the forecast period at CMX. Will go briefly MVFR at IWD due to fog late tonight and at SAW with lower clouds Wed morning. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 238 PM EDT TUE AUG 14 2018 The wind will remain below 20 knots through this forecast period. The strongest winds will be late tonight into Wed morning. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && SHORT TERM...07 LONG TERM...MZ AVIATION...07 MARINE...07
Hazardous Weather Outlook National Weather Service Marquette MI 330 PM EDT Tue Aug 14 2018 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- 330 PM EDT Tue Aug 14 2018 /230 PM CDT Tue Aug 14 2018/ This Hazardous Weather Outlook is for portions of western Upper Michigan and central Upper Michigan. .DAY ONE...Tonight There is a chance of thunderstorms through tonight, especially over southern Upper Michigan. Patchy fog is expected tonight. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Thunderstorms are possible Sunday and Monday. .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- 330 PM EDT Tue Aug 14 2018 /230 PM CDT Tue Aug 14 2018/ This Hazardous Weather Outlook is for portions of Eastern Lake Superior...Central Lake Superior and Western Lake Superior. .DAY ONE...Tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Wednesday through Monday There is a chance of thunderstorms on Lake Superior late Sunday into Monday. .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- 330 PM EDT Tue Aug 14 2018 This Hazardous Weather Outlook is for portions of Northern Lake Michigan. .DAY ONE...Tonight There is a chance of thunderstorms through tonight. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Thunderstorms are possible late Sunday into Monday. .SPOTTER INFORMATION STATEMENT... The need for weather spotter reports is not anticipated at this time. MZ
The Marquette radar (KMQT), 90 km away, was scanning. The volume nearest the first event began at 20:23 UTC.
2 thunderstorm wind. Local standard time, as filed.
A spotter reported two to three inch diameter branches broken off of trees near Iron Mountain. Small hail was also reported.
A spotter reported small trees and small branches down along Highway M-95 from just north of Channing through Silver Lake.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Michigan in 2018Every state in 2018This day in weather historyWarnings in Michigan, August 2018
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: 779894, 779895.