Thunderstorms developed during the afternoon of the 29th along a warm front lifting north across the region. Severe thunderstorms across Piscataquis county produced damaging winds and large hail.
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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 CAR wrote it up.
Thunderstorms developed during the afternoon of the 29th along a warm front lifting north across the region. Severe thunderstorms across Piscataquis county produced damaging 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 Caribou, ME wrote its last area forecast discussion before the first event at Aug 29, 3:45 PM EST, 0 minutes earlier.
Area Forecast Discussion National Weather Service Caribou ME 445 PM EDT Wed Aug 29 2018 .SYNOPSIS... Low pressure from Quebec will cross the northern Maine this evening. A trailing cold front will move southward towards the coast late tonight into Thursday morning. Cooler and drier air will move into the area later Thursday and Friday as Canadian high pressure builds southward. && .NEAR TERM /THROUGH THURSDAY/... SPC has issued a Severe Thunderstorm Watch for Northern Somerset, Piscataquis and Penobscot County until 11 PM. Radar showed activity apchg the western ME border running into the region where the latest RAP showed MUCAPE of 1500+ joules w/0-6km bulk shear of 50 kts. Meso analysis continues to point to the best area of Severe potential to be across the Piscataquis and Mount Katahdin region into the Penobscot region. This is not without saying that portions of north Maine such as Clayton Lake into Shin Pond. The RAP and the latest LAP soundings showed potential for cells to have Supercell structure w/good rotation. Some storms could deviate to the right showing potential for tornadic potential. Sfc warm front was lifting nne as dewpoints were climbing. Heat index values reached 90-95 across portions of interior Downeast thanks to more heating and dewpoints around 70. As clouds move in later, readings will drop off. One other note to make is that PWs are nearing 2" and w/cells possibly aligning w/wsw flow aloft leading to training w/heavy rain. This will need to be assessed. Cold front is slated to push across the region later in the evening as sfc low rides across northern ME. There appears to be a decent amount of rain w/0.25 to 0.50 inches. across portions of western and northern areas. Cooler and drier air to follow behind the front overnight into early Thursday morning. The downeast region will be the last to see this drier and cooler air. Thursday will definitely have a much different feel to the day w/breezy conditions and much cooler temps. Might see some stratocumulus development through the day but any shower activity will be in the morning. Daytime temps will run into the upper 60s to lower 70s north and west w/central and Downeast areas in the 70s. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... High pressure builds through the period. On Friday night, lows will dip to the upper 30s to lower 40s in the Allagash with a steep radiation inversion, but remain in the mid to upper 50s for Bangor and the coast as winds are expected to prevent as steep of an inversion. With the high to the north, H925 to H850 moisture moving eastward is always a concern. At this time, will add some clouds along the coast Friday morning, but clear it out by afternoon. Highs will be mostly in the lower 70s. On Friday night, all areas should radiate well with widespread lows in the 40s. The high continues to strengthen in the Canadian Maritimes into Saturday. H850 temps look slightly warmer on Saturday...supporting surface highs creeping back to the low to mid 70s. Overall H850 moisture looks more widespread on Saturday and will go with partly sunny for most of the area. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Forecast for the latter half of the weekend and into next week remains similar to previous shift's thoughts. High pressure remains parked off the coast of North Carolina with anticyclonic flow aloft guiding shortwave disturbances around it. These will intermittently train across Maine. Lingering showers Saturday night cross central ME and Downeast. Another shortwave boundary approaches Sunday, crossing Monday/Monday night with GFS and ECMWF most aggressive, while the GEM is weaker in precipitation coverage. Kept PoPs slight to low chance. High pressure slides north of the region Wednesday, with continued slight chances of showers. && .AVIATION /17Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: VFR w/periods of MVFR/IFR in showers and tstms mainly n of KBGR and KBHB this evening. As the front drops s, MVFR for KBGR and KBHB later tonight into Thursday morning. VFR for all terminals on Thursday after 12z. SHORT TERM: VFR into Sunday w/a brief period of MVFR by Sunday morning mainly for KBGR and KBHB. && .MARINE... NEAR TERM: No headlines w/winds 5 to 10 kts tonight picking up to 10-15 kts and veering to the nnw as the front drops across the waters Thursday morning. Seas will stay around 2-3 ft. SHORT TERM: No headlines expected for this term. Winds will drop off by Friday to 5 to 10 kt as high pres moves in and look like they will hold that way into Sunday. Seas will remain 2-3 ft. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && Near Term...Hewitt Short Term...MCW Long Term...Cornwell Aviation...Hewitt/MCW Marine...Hewitt/MCW
Hazardous Weather Outlook...UPDATED National Weather Service Caribou ME 357 PM EDT Wed Aug 29 2018 MEZ003>005-010-011-015-031-302000- Northern Somerset-Northern Piscataquis-Northern Penobscot- Central Piscataquis-Central Penobscot-Southern Penobscot- Southern Piscataquis- 357 PM EDT Wed Aug 29 2018 ...SEVERE THUNDERSTORM WATCH 360 IN EFFECT UNTIL 11 PM EDT THIS EVENING... This Hazardous Weather Outlook is for East Central Maine, Interior DownEast Maine, North Central Maine and West Central Maine. .DAY ONE...This Afternoon and Tonight. Please listen to NOAA Weather Radio or go to weather.gov on the Internet for more information about the following hazards. Severe Thunderstorm Watch. Severe thunderstorms expected with the main threat being damaging wind gusts in excess of 58 mph and very heavy rainfall. Some of the more intense cells could show rotation with the potential for hail up to one inch in diameter. The areas with the highest threat for Severe thunderstorms will be from the Allagash Waterway and Mount Katahdin region down through the Piscataquis and Penobscot region. Remember, any thunderstorm is capable of producing dangerous cloud to ground lightning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. MEZ001-002-006-016-017-029-030-032-302000- Northwest Aroostook-Northeast Aroostook-Southeast Aroostook- Interior Hancock-Central Washington-Coastal Hancock- Coastal Washington-Northern Washington- 357 PM EDT Wed Aug 29 2018 This Hazardous Weather Outlook is for Coastal DownEast Maine, Eastern Maine, Far Northern Maine, Interior DownEast Maine and Northern Maine. .DAY ONE...This Afternoon and Tonight. Scattered thunderstorms are expected into this evening. A few storms may reach Severe limits with the main threat being damaging wind gusts in excess of 58 mph and very heavy rainfall. Some of the more intense cells could show rotation with the potential for hail up to one inch in diameter. The areas with the highest threat for Severe thunderstorms will be from the Allagash Waterway and Mount Katahdin region down through the Piscataquis and Penobscot region. Remember, any thunderstorm is capable of producing dangerous cloud to ground lightning. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures. ANZ050>052-302000- Coastal Waters from Eastport, ME to Schoodic Point, ME out 25 NM- Coastal Waters from Schoodic Point, ME to Stonington, ME out 25 NM- Intra Coastal Waters from Schoodic Point, ME to Stonington, ME- 357 PM EDT Wed Aug 29 2018 This Hazardous Weather Outlook is for Atlantic Coastal Waters. .DAY ONE...This Afternoon and Tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures.
The Caribou radar (KCBW), 120 km away, was scanning. The volume nearest the first event began at 20:45 UTC.
1 thunderstorm wind, 1 hail. Local standard time, as filed.
Trees were toppled at the Umbazooksus Campground by wind gusts estimated at 60 mph. The time is estimated.
Hail ranged in size up to 1.75 inch in diameter.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maine in 2018Every state in 2018This day in weather historyWarnings in Maine, 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: 782266, 782270.