A line of thunderstorms formed just ahead of a cold front that moved toward the Midcoast of Maine during the afternoon hours on the 14th. The line of storms stayed sub-severe except for one isolated storm that was strong enough to knock down a few trees.
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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 GYX wrote it up.
A line of thunderstorms formed just ahead of a cold front that moved toward the Midcoast of Maine during the afternoon hours on the 14th. The line of storms stayed sub-severe except for one isolated storm that was strong enough to knock down a few trees.
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 Gray, ME wrote its last area forecast discussion before the first event at Aug 14, 10:45 AM EST, 3 hours 25 minutes earlier.
Area Forecast Discussion National Weather Service Gray ME 1145 AM EDT Sat Aug 14 2021 .SYNOPSIS... A cold front crosses today bringing chances for showers and storms along with much cooler and drier air tonight into Sunday. High pressure builds in Sunday lasting into midweek for fair weather along with comfortable humidity levels and temperatures in the 70s to 80s. Humidity increases Wednesday and Thursday along with increasing chances for afternoon showers and possibly thunderstorms. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... 11:45 Update.. Bumped up temperatures and dew points along the coast for the next few hours, which have jumped up quickly so far this morning. Southern coastal areas are flirting with heat advisory criteria, but with dew points ticking down slightly over the next couple of hours with afternoon mixing these areas should fall below this criteria shortly. Otherwise mainly tweaked POPs and timing to better match current observations and trends, but largely the forecast and afternoon thunderstorm evolution remains on track. 700 AM Update... Little change was made, but I did go ahead and refresh the forecast nearly top to bottom (T/Td/PoP/Wx/Sky/QPF) according to latest convective and modeled convective trends. At this hour... a poorly organized line of storms containing downpours is tracking across the Rangeley lakes region. Looking upstream, a decaying complex will clip the northern zones later this morning. Scattered activity along the cold front is expected to blossom with surface heating as it tracks into our area. Previously... We start the day in the warm sector of a frontal complex draped across the Northeast, extending from low pressure centered over eastern Quebec down through Appalachia. The front crosses New England from west to east through today with showers and storms, exiting Downeast this evening. A refreshing westerly to northwesterly breeze works in behind the front with crashing dew points and clearing skies. Ahead of the wave, we remain very much entrenched in the warm and humid airmass... so temperatures over eastern and southern zones will still warm into the 80s, perhaps touching 90 degrees one more time. Meanwhile further west... between clouds, precipitation, and the cold FROPA itself... highs will only be in the 70s. Overall there's little change in thinking with this FROPA in terms of thunderstorm activity. While the warm and humid airmass certainly aids in destabilization... favorable mid-level lapse rates outpace better shear associated with the incoming trough, so there will be a bit of a cap to overcome in any scenario. This could happen with sufficient surface heating in the warm sector, however the cold front should be tracking through our eastern zones during the afternoon, just before peak heating. Storms that fire early will have more favorable lapse rates, but will lack a mechanism for organization. With these factors in mind, convective threat is centered on the overlap of maximum SFC/ML based destabilization and frontal position, which for this FROPA will be centered over central and eastern Maine... poking back through the Capitol Region and toward the Midcoast. With PWATs increasing to around 2" along the surface front, localized downpours can be expected and when combined with a few hundred J/kg DCAPE in the mature mixed layer, localized strong to damaging winds can't be ruled out. && .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/... High pressure centered near the Ottawa Valley in Canada builds behind the departing cold front tonight with skies clearing and a northwest breeze going calm in some of our sheltered valley sites. Lows tonight will hinge primarily on how much of the incoming cooler/drier airmass we can manage to mix down before mixing is lost. For this forecast have lows ranging from around 50 toward the international border to the low-60s over the coastal plain and urban centers. Sunday will be a fantastic day weather-wise with mostly sunny skies, a light northwesterly breeze, and comfortable temperatures. With h850 temperatures back down to around +10C, highs will be in the 70s with weak downsloping and sunshine allowing temperatures closer to 80 over portions of the coastal plain. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Fair weather with pleasant temperatures and humidity will continue for the first part of the work week followed by increasing humidity and unsettled conditions for the middle to latter half of the week. Broad surface high pressure will be overhead Monday and slowly shifts offshore Tuesday into Wednesday. This will bring fair weather Monday into Tuesday with temperatures and dewpoints slowly increasing through midweek. Increasing humidity will allow for increasingly instability and chances for afternoon showers and possibly thunderstorms Wednesday with better chances Thursday as a mid level wave will be tracking near New England. Chances for showers continue Friday as humid air remains in place and mid level waves will be in the vicinity of the Northeast. High pressure will crest over the area Sunday night into Monday allowing for temperatures to drop in the 40s north and 50s south by early Monday morning. Temperatures will warm into the 70s to near 80F Monday and with mostly fair skies and dewpoints mainly in the 50s it will be a nice mid-August day. High pressure slowly shifts eastward Tuesday providing fair weather with temperatures climbing a few degrees above Monday's values. Broad southwest flow will advect moisture in the region Wednesday allowing for more clouds and an increasingly muggy airmass with dewpoints into the upper 60s. With the increasing moisture will come chances for afternoon showers and possibly a thunderstorm Wednesday, although forcing for ascent looks limited. Chances for showers and thunderstorms look better on Thursday as mid level wave will be passing over New England. Global models do generate a fair amount of CAPE Thursday, although there is no signal for a front, limiting shear, and thus severe potential. The lack of front means that the muggy airmass looks to be with us through the end of the week, but no signal for oppressive heat like the past couple days is present in the extended period. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... Short Term...A cold front crosses the region today with TEMPO MVFR/local IFR in SHRA/TSRA possible... particularly for northern terminals including KHIE and KAUG. Ahead of the wave a marine fog bank may impact RKD for a short time later this morning. VFR prevails behind the front with significant clearing and a northwest breeze tonight and tomorrow. Long Term...Valley fog may impact KHIE and KLEB Sunday night with VFR for all during the day Monday. Fog coverage may increase Monday night potentially impacting all terminals before a return to VFR during the day Tuesday. Increasing clouds Tuesday night will limit fog potential mainly VFR expected into Wednesday. && .MARINE... Short Term...Southwesterly winds increase today ahead of an approaching cold front. The front crosses late this afternoon and exits Downeast by the end of the evening with showers and a few gusty thunderstorms possible... mainly near the Midcoast. Winds turn to the northwest tonight, then west through tomorrow. Waves and seas are both expected to remain below SCA thresholds, except for possibly in thunderstorms. Long Term...Winds and seas will remain SCA thresholds into midweek as high pressure passes over the waters. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && SYNOPSIS...Casey NEAR TERM...Clair SHORT TERM...Casey LONG TERM...Schroeter AVIATION...Clair/Schroeter MARINE...Clair/Schroeter
Hazardous Weather Outlook National Weather Service Gray ME 257 PM EDT Sat Aug 14 2021 MEZ018-022>028-NHZ010-012>014-151900- Interior York-Interior Waldo-Coastal York-Coastal Cumberland- Sagadahoc-Lincoln-Knox-Coastal Waldo-Strafford-Eastern Hillsborough- Interior Rockingham-Coastal Rockingham- 257 PM EDT Sat Aug 14 2021 This Hazardous Weather Outlook is for south central Maine, southwest Maine, central New Hampshire and southern New Hampshire. .DAY ONE...This afternoon and tonight. A few thunderstorms may be strong to severe for the remainder of the afternoon. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MEZ007>009-012>014-019>021-033-NHZ001>009-011-015-151900- Northern Oxford-Northern Franklin-Central Somerset-Southern Oxford- Southern Franklin-Southern Somerset-Central Interior Cumberland- Androscoggin-Kennebec-Interior Cumberland Highlands-Northern Coos- Southern Coos-Northern Grafton-Northern Carroll-Southern Grafton- Southern Carroll-Sullivan-Merrimack-Belknap-Cheshire- Western And Central Hillsborough- 257 PM EDT Sat Aug 14 2021 This Hazardous Weather Outlook is for Maine, south central Maine, southwest Maine, west central Maine, western Maine, New Hampshire, central New Hampshire, northern New Hampshire and southern New Hampshire. .DAY ONE...This afternoon and tonight. No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Sunday through Friday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. ANZ150>154-151900- Coastal Waters from Stonington, ME to Port Clyde, ME out 25 NM- Penobscot Bay- Coastal Waters from Port Clyde, ME to Cape Elizabeth, ME out 25 NM- Casco Bay- Coastal Waters from Cape Elizabeth, ME to Merrimack River, MA out 25 NM- 257 PM EDT Sat Aug 14 2021 This Hazardous Weather Outlook is for Atlantic coastal waters. .DAY ONE...This afternoon and tonight. A couple storms may be strong over the coastal waters with gusty winds. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Hazardous weather is not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
Special Weather Statement
National Weather Service Gray ME
1245 PM EDT Sat Aug 14 2021
MEZ012-013-020-141715-
Southern Oxford ME-Androscoggin ME-Southern Franklin ME-
1245 PM EDT Sat Aug 14 2021
...A strong thunderstorm will impact portions of east central Oxford
and north central Androscoggin Counties through 115 PM EDT...
At 1244 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles southeast of Bethel, moving east at 30 mph.
HAZARD...Winds in excess of 40 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Turner, Jay, Dixfield, Canton, Waterford, Leeds, Livermore,
Buckfield, Hartford, Greenwood, West Paris, Woodstock, Sumner, Paris,
Peru, Norway and Albany.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4420 7067 4437 7076 4455 7027 4430 7013
TIME...MOT...LOC 1644Z 248DEG 27KT 4432 7062
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
JCSpecial Weather Statement
National Weather Service Gray ME
111 PM EDT Sat Aug 14 2021
MEZ014-021-141745-
Southern Somerset-Kennebec-
111 PM EDT Sat Aug 14 2021
...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN KENNEBEC AND SOUTH
CENTRAL SOMERSET COUNTIES...
At 111 PM EDT, a strong thunderstorm was located near Belgrade, or 10
miles west of Oakland, moving east at 30 mph.
Winds in excess of 40 mph and pea size hail are possible with this
storm.
Locations impacted include...
Waterville, Fairfield, Oakland, Belgrade, Fayette, Rome, Winslow,
Mount Vernon, Vienna, Vassalboro, Smithfield and Sidney.
This includes Interstate 95 between mile markers 121 and 131.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
LAT...LON 4447 6956 4443 7001 4450 7004 4451 7003
4452 7005 4454 7006 4467 6967
TIME...MOT...LOC 1711Z 249DEG 24KT 4451 6993
TubbsSpecial Weather Statement
National Weather Service Gray ME
146 PM EDT Sat Aug 14 2021
MEZ014-021-022-141830-
Interior Waldo-Southern Somerset-Kennebec-
146 PM EDT Sat Aug 14 2021
...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN KENNEBEC AND
NORTHWESTERN WALDO COUNTIES...
At 146 PM EDT, a strong thunderstorm was located over Fairfield,
moving east at 30 mph.
Winds in excess of 40 mph and penny size hail are possible with this
storm.
Locations impacted include...
Waterville, Fairfield, Thorndike, China, Clinton, Unity, Knox,
Benton, Albion, Burnham, Brooks, Detroit, Freedom, Jackson, Troy,
Winslow and Vassalboro.
This includes Interstate 95 between mile markers 129 and 140.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
LAT...LON 4455 6912 4447 6963 4460 6968 4474 6927
4472 6926 4473 6920 4464 6918 4466 6909
TIME...MOT...LOC 1746Z 254DEG 27KT 4457 6957
TubbsSpecial Weather Statement National Weather Service Gray ME 206 PM EDT Sat Aug 14 2021 MEZ021-025-026-141830- Kennebec-Lincoln-Sagadahoc- 206 PM EDT Sat Aug 14 2021 ...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL KENNEBEC... NORTHWESTERN LINCOLN AND NORTHERN SAGADAHOC COUNTIES... At 205 PM EDT, a strong thunderstorm was located near Gardiner, moving east at 25 mph. Winds in excess of 40 mph and pea size hail are possible with this storm. Locations impacted include... Gardiner, Jefferson, Dresden, Alna, Whitefield, Richmond, Nobleboro, Pittston, Somerville and Newcastle. Torrential rainfall is also occurring with this storm, and may cause localized flooding. Do not drive your vehicle through flooded roadways. LAT...LON 4408 6979 4419 6980 4426 6948 4409 6944 TIME...MOT...LOC 1805Z 258DEG 22KT 4415 6970 Tubbs
Special Weather Statement National Weather Service Gray ME 236 PM EDT Sat Aug 14 2021 MEZ021-025>027-141900- Kennebec-Lincoln-Knox-Sagadahoc- 236 PM EDT Sat Aug 14 2021 ...A STRONG THUNDERSTORM WILL AFFECT SOUTHERN KENNEBEC...NORTHWESTERN KNOX...CENTRAL LINCOLN AND NORTHEASTERN SAGADAHOC COUNTIES... At 234 PM EDT, a strong thunderstorm was located 7 miles north of Damariscotta and another storm was located near Richmond, moving east at 25 mph. Winds in excess of 40 mph and pea size hail are possible with this storm. Locations impacted include... Bath, Rockland, Damariscotta, Wiscasset, Bremen, Thomaston, Rockport, Woolwich, Bowdoinham, Jefferson, Dresden, Hope, Appleton, Alna, Nobleboro, Whitefield, Newcastle, Washington, Union and Waldoboro. This includes Interstate 295 between mile markers 41 and 44. If outdoors, consider seeking shelter inside a building. Torrential rainfall is also occurring with this storm, and may cause localized flooding. Do not drive your vehicle through flooded roadways. LAT...LON 4397 6984 4410 6990 4433 6926 4412 6911 TIME...MOT...LOC 1834Z 249DEG 20KT 4415 6953 Tubbs
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAY ME
309 PM EDT SAT AUG 14 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0259 PM TSTM WND GST ROCKLAND 44.10N 69.11W
08/14/2021 M51 MPH KNOX ME PUBLIC
MEASURED BY A PERSONAL WEATHER STATION AT
259 PM.
&&
TUBBSThe Portland,ME radar (KGYX), 86 km away, was scanning. The volume nearest the first event began at 19:12 UTC.
1 thunderstorm wind. Local standard time, as filed.
Severe thunderstorm outflow winds downed a few trees in Cushing, one of which blocked traffic on River Road. A nearby observation recorded a wind gust of 51 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maine in 2021Every state in 2021This day in weather historyWarnings in Maine, August 2021
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: 982552.