An occluding low pressure system to the northwest in Quebec, bringing a strong cold front through Maine on the evening of May 10th. There was a period of clearing ahead of the frontal system, allowing instability to increase and storms to develop.
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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.
An occluding low pressure system to the northwest in Quebec, bringing a strong cold front through Maine on the evening of May 10th. There was a period of clearing ahead of the frontal system, allowing instability to increase and storms to develop. Thunderstorms moved into Aroostook county by early evening. Favorable instability helped an organized line of storms to develop, which bring elevated wind gusts and heavy rainfall. Low-level mesovortex within the line produced a microburst in the Caribou area, causing significant damage to a locally confined region. Multiple trees were reported down in woman's backyard, along with structural damage to outdoor structures.
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 May 10, 1:07 PM EST, 3 hours 53 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Caribou ME 207 PM EDT Sun May 10 2026 .WHAT HAS CHANGED... Extended SCA for the coastal ocean waters through 22z Monday. Expanded area with frost forecasted into zones 15-17 for Monday night and Tuesday night. && .KEY MESSAGES... 1) Showers this afternoon and early this evening, most numerous this afternoon. Thunderstorms are possible, mainly across the north, as well. Any storms could produce gusty winds and small hail. 2) Scattered showers Monday afternoon, mainly over Northern Maine. 3) Areas of frost possible across interior Downeast Maine and the Bangor region Monday and Tuesday night, which could impact sensitive plants. 4) Another soaking rainfall possible for central and southern areas Wednesday night – Thursday night which could further improve drought conditions. && .DISCUSSION... KEY MESSAGE 1... Showers this afternoon and early this evening, most numerous this afternoon. Thunderstorms are possible, mainly across the north, as well. Any storms could produce gusty winds and small hail. KEY MESSAGE 1 DESCRIPTION... A combination of the passage of multiple northern stream shortwaves and the approach of a surface to 850 mb cold front will trigger showers across the region into the early evening hours. Across the North, there should be sufficient low level CAPE of around 250-500 J/kg, along with mid-level lapse rates around 7.5-8C/km, to support some isolated to scattered thunderstorms as well. Any storms could produce wind gusts up to 35-45 mph and small hail. The risk for any thunderstorms should die out fairly quickly as the sunsets. Showers will tapper off from NW to SE from late this afternoon into early this evening. Rainfall from these showers/thunderstorms should not have any significant hydrologic impact. KEY MESSAGE 2... Scattered showers Monday afternoon, mainly over Northern Maine. KEY MESSAGE 2 DESCRIPTION... The main axis of the mean northern stream trough approaches Monday, with the North in the left front quadrant of a 120+ kt 300 mb jet. So even though values of CAPE should only be at most 200 J/kg, low level lapse rates should run around 8.5-9C/km. This should be enough instability to support small hail in any stronger showers, but not quite enough mixing to support any thunder. However, because we are right on the margins for having thunder or not, will not completely rule it out at this time. Once again, no significant hydrologic issues are expected. KEY MESSAGE 3... Areas of frost possible across interior Downeast Maine and the Bangor region Monday and Tuesday night, which could impact sensitive plants. KEY MESSAGE 3 DESCRIPTION... The frost/freeze program begins on 5/11 for zones 15-17 (Bangor Region, Northern Hancock and Central Washington) and zones 29-30 (coastal Downeast Maine). So, while frost may occur further north, the climatological growing season has not begun yet there, so impacts there will not be discussed. A combination of mainly clear to clear sky conditions and light winds should allow for lows to fall into the upper 30s Monday night across zones 15-17. This should allow for areas of frost to occur, especially outside of developed city/town centers. At this time, there is still some uncertainty on exactly how much cloud cover there will be on Monday night, so no frost headlines will be issued at this time. On Tuesday night, mostly clear skies and calm winds should allow temperatures to drop rapidly as a result of strong radiational cooling. Currently expecting temperatures to dip into the low to mid 30s across the interior Downeast and Bangor regions which should result in some areas of frost that could damage tender plants. A harder frost is possible in typically cool spots that radiate energy well such as valleys KEY MESSAGE 4... Another soaking rainfall possible for central and southern areas Wednesday night – Thursday night which could further improve drought conditions. KEY MESSAGE 4 DESCRIPTION... Low pressure over the Great Lakes Wednesday will approach the area from the west. As it reaches coastal New England, a secondary low pressure system may develop just offshore. Rain begins Wednesday evening and eventually clears out early Friday although a few showers could linger. Expect the highest totals in the Bangor and Downeast regions where ensemble models show the probability of at least 0.5” of rain to be around 50%. This event should further contribute to drought relief by recharging soil moisture and helping groundwater deficits. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... MVFR throughout to get started. A thunderstorm is possible late this afternoon/early this evening at KFVE/KCAR/KPQI - so have continued the PROB30 group there. The winds could be a bit stronger than previously forecast, so have bumped gusts to 30KT in the PROB30. Outside if convection, ceilings should gradually lift this afternoon, becoming VFR throughout by early- mid evening, except at KBHB, where LIFR to VLIFR conditions develop early this evening. MVFR conditions should return to KBGR around midnight. Both KBHB and KBGR should become VFR early Monday morning. High confidence in all terminals VFR from 12z Monday on. Winds become light and variable throughout by early this evening and remain so into Monday morning. Winds become WNW-NW at under 10KT or less at all terminals by mid Monday morning. Late Monday afternoon/Monday night: VFR, with a very low chance of MVFR at northern terminals Monday afternoon in any showers. Tuesday - Tuesday night...VFR. NW winds 5-15kt, with gusts to 20kt possible during the afternoon. Winds shift W and relax overnight becoming light and variable. Wednesday - Wednesday night...VFR during the day. MVFR overnight as showers begin to move in, south to north. W/SW winds 5-15kt. Shift S/SE overnight. Thursday-Thursday night...MVFR with rain showers. IFR possible southern terminals. S/SE winds 10 to 15 kts today becoming E/NE around 5 kts overnight Friday...MVFR/VFR with rain showers. NW wind 5 to 10 kts. && .MARINE... Persistent S swells should keep seas at SCA levels on the coastal ocean waters through at least Monday, so have extended the SCA there through 22z Monday. There is some uncertainty as to how fast the swells dissipate, so did not feel comfortable pushing the SCA into Monday night on the coastal ocean waters at this time. The intra-coastal waters should remain below SCA levels through Monday night. On the outer waters, winds should be 20 kt or less and seas in the 4-6 ft range, mainly due to southerly swells, through Monday night. Below SCA conditions Tuesday through Wednesday. SCA conditions on the coastal waters possible Wednesday night – early Thursday night and on the intracoastal waters Thursday. Seas not expected to get above 5 ft on the coastal and intracoastal waters and 6 ft on the outer waters Tuesday-Friday. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ050-051. && DISCUSSION...PM/SM AVIATION...PM/SM
Special Weather Statement National Weather Service Caribou ME 1254 PM EDT Sun May 10 2026 MEZ001-003-004-101900- Northwest Aroostook-Northern Somerset-Northern Piscataquis- Including the cities of Allagash, Clayton Lake, Madawaska, Fort Kent, Frenchville, Baker Lake, Billy-Jack Depot, Baxter St Park, Churchill Dam, Mount Katahdin, Ripogenus, Telos Lake, Caucomgomoc Lake, and Chamberlain Lake 1254 PM EDT Sun May 10 2026 ...Strong Thunderstorms possible into the North Woods into mid afternoon... Strong thunderstorms are possible across portions of the North Woods through 3 pm. Thunderstorms may contain small hail and wind gusts up to 35 mph. Strong thunderstorms can become severe, producing large hail, damaging winds, deadly lightning, and very heavy rainfall. Continue to monitor the National Weather Service or your local media outlet for updates on this developing weather situation.
Special Weather Statement
National Weather Service Caribou ME
322 PM EDT Sun May 10 2026
MEZ001-002-102000-
Northeast Aroostook ME-Northwest Aroostook ME-
322 PM EDT Sun May 10 2026
...STRONG THUNDERSTORMS WILL IMPACT NORTHEASTERN AROOSTOOK COUNTY
THROUGH 400 PM EDT...
At 321 PM EDT, a trained weather spotter reported strong
thunderstorms along a line extending from 12 miles north of
Madawaska to New Canada to near Fish River Lake. Movement was
northeast at 50 mph.
HAZARD...Wind gusts up to 40 mph.
SOURCE...Trained weather spotters.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Fort Kent, Madawaska, Van Buren, Eagle Lake, Portage, Ashland,
Frenchville, Portage Lake, New Canada, Lille, Cross Lake, Madawaska
Lake, Fish River Lake, Nashville Plantation, New Sweden, Wallagrass,
Grand Isle, Perham, Stockholm, and Winterville.
This includes the following highways...
US Highway 1 between Grand Isle and Frenchville.
State Highway 11 between Portage and Wallagrass.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4736 6823 4734 6821 4733 6816 4731 6815
4724 6802 4670 6838 4672 6888 4708 6863
4730 6851 4730 6847 4728 6846 4728 6843
4729 6841 4729 6838 4732 6839 4735 6837
TIME...MOT...LOC 1921Z 212DEG 45KT 4747 6824 4715 6847 4680 6873
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
ASBSpecial Weather Statement
National Weather Service Caribou ME
352 PM EDT Sun May 10 2026
MEZ001-102015-
Northwest Aroostook ME-
352 PM EDT Sun May 10 2026
...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN AROOSTOOK COUNTY
THROUGH 415 PM EDT...
At 352 PM EDT, Doppler radar was tracking a strong thunderstorm over
Madawaska, moving northeast at 25 mph.
HAZARD...Wind gusts up to 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Madawaska, Frenchville, Grand Isle, and Saint Agatha.
This includes US Highway 1 between Grand Isle and Frenchville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4736 6823 4734 6821 4733 6816 4731 6815
4728 6810 4721 6818 4725 6845 4728 6843
4729 6837 4732 6839 4734 6838 4735 6837
4736 6835
TIME...MOT...LOC 1952Z 219DEG 22KT 4730 6831
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
ASBSpecial Weather Statement
National Weather Service Caribou ME
551 PM EDT Sun May 10 2026
MEZ002-102230-
Northeast Aroostook ME-
551 PM EDT Sun May 10 2026
...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL AROOSTOOK COUNTY
THROUGH 630 PM EDT...
At 550 PM EDT, Doppler radar was tracking a strong thunderstorm near
Ashland, or 12 miles south of Portage, moving northeast at 45 mph.
HAZARD...Wind gusts up to 40 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Presque Isle, Caribou, Fort Fairfield, Mapleton, Washburn, Ashland,
Easton, Woodland, Masardis, Oxbow, Scopan, Nashville Plantation, New
Sweden, Westfield, Chapman, Connor, Castle Hill, Perham, Wade, and
Westmanland.
This includes the following highways...
US Highway 1 between Presque Isle and Caribou.
State Highway 11 between Masardis and Ashland.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4704 6804 4665 6784 4638 6844 4638 6850
4665 6859
TIME...MOT...LOC 2150Z 223DEG 37KT 4659 6841
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH
ASBThe Caribou radar (KCBW), 90 km away, was scanning. The volume nearest the first event began at 22:01 UTC.
1 thunderstorm wind. Local standard time, as filed.
Woman reported significant damage to her house after line of thunderstorms moved through the area. Resulted in multiple downed healthy trees in her backyard. Damage to her backyard deck and garage were also reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maine in 2026Every state in 2026This day in weather historyWarnings in Maine, May 2026
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: 1341794.