On the afternoon of June 28th, a warm front was draped across Southern Maine. A very moist air mass was in place as thunderstorms begin to develop along this frontal boundary.
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The episode as NWS GYX wrote it up.
On the afternoon of June 28th, a warm front was draped across Southern Maine. A very moist air mass was in place as thunderstorms begin to develop along this frontal boundary. Widely scattered severe thunderstorms occurred in southern Maine along this boundary with the damaging storms concentrated across York and Oxford Counties.
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 Jun 28, 2:09 PM EST, 31 minutes earlier.
Area Forecast Discussion National Weather Service Gray ME 309 PM EDT Sun Jun 28 2020 .SYNOPSIS... Daily chances for showers and storms exist through the middle of the coming week as upper level low pressure settles overhead. Showers and thunderstorms are likely through this evening, with an isolated severe thunderstorm possible. Unsettled conditions continue through midweek with beneficial rainfall for many areas. && .NEAR TERM /THROUGH TONIGHT/... Little change to the forecast thru this evening. The best...albeit marginal...shear remains S of the forecast area...but sufficient instability across the entire area for thunder ahead of the approaching trof. The strongest storms are expected from generally the Lake Region of NH Swd...and far SWrn ME. I will maintain small hail and gusty winds...as confidence is just not there for damaging wind in a widespread enough area at this point. Tonight guidance is coalescing around weak low pressure spinning up the Gulf of ME and getting captured by upper trof. This stalling will focus showers across the forecast area. With weakening instability I do not expect much thunder...but cannot rule it out thru late this evening. Hi-res guidance is showing QPF amounts well in excess of 1 to 2 inches in some cases...but my gut feeling is this will be more isolated than currently depicted. This should amount is many locations seeing a welcome rainfall overnight though. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... With upper low and moist...onshore flow continuing Mon I expect another uptick in afternoon convective coverage. Showers and thunderstorms should be fairly common again. Will have to watch for a more concentrated area of rainfall...as some mesoscale guidance is hinting at this with the moisture feed off the Gulf of ME. At this point the rain will be welcome. Clouds and rain should hold temps below normal for much of the area. && .LONG TERM /TUESDAY THROUGH SUNDAY/... The ensemble and deterministic model solutions are in good agreement on the long wave pattern through the upcoming holiday weekend. We begin the period with an upper low over New England. The upper low will meander across the region through Wednesday before weakening. In its wake...the models maintain northwest flow and some degree of troughing across the northeast with an upstream ridge stretching from southern Canada and the Great Lakes southwestward into the four corners region and northern Mexico. This pattern will keep the bulk of the excessive heat and humidity bottled up to our south and west...with the exception of Thursday as the westerly flow ahead of a backdoor cold front allows temperatures to soar into the 80s and lower 90s along with building humidity levels. In the dailies...the meandering upper low will produce widespread clouds and areas of convection. The clouds and precipitation will produce below normal temperatures both days. Slow cell movement with the weak upper flow could result is some localized flooding concerns both Tuesday and Wednesday. As mentioned above...Thursday will be a hot and humid day ahead of the backdoor cold front with the prospect for scattered convection along and ahead of the boundary. A ridge of high pressure with cooler and drier air follows for Friday into Saturday. The return flow of warmer and more humid air around the exiting ridge could spark scattered afternoon convection on Sunday. A late day shower or storm will be possible late Monday near the international border as a frontal boundary sinks slow southward across Quebec. This boundary will act as a focus for more scattered convection on Tuesday as it settles across the forecast area. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Short Term...Scattered convection thru evening may lead to local IFR or lower conditions at any terminal...though will be more likely away from the Midcoast where early fog/stratus kept instability low. I do expect onshore flow tonight to lead to more fog/stratus moving into the coast. Fog will be most likely at AUG/RKD...but low CIGs may work all the way down the coast this time...affecting PWM and PSM. With upper low moving into the Gulf of ME tonight SHRA should persist for much of the overnight. Again Mon afternoon SHRA/TSRA should pop up with daytime heating...with local IFR conditions under the heaviest cells. Long Term... Tue - Thu...Sct MVFR in afternoon and evening SHRA/TSRA. Lcl IFR in early morning fog and stratus. && .MARINE... Short Term...Winds and seas are expected to remain below SCA thresholds thru the period. Main concern will be regarding convection thru this evening and fog tonight. Some thunderstorms may be capable of 34 kt gusts thru the late evening. Then fog begins to redevelop along the coast. Again expect this to mainly be a problem for waters N of Cape Elizabeth where flow remains more onshore. Long Term... Fri...SCA's are possible outside the bays. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && NEAR TERM...Legro SHORT TERM...Legro LONG TERM...Schwibs
Hazardous Weather Outlook National Weather Service Gray ME 230 PM EDT Sun Jun 28 2020 MEZ007>009-012-013-018>020-023-024-033-NHZ001>015-291830- Northern Oxford-Northern Franklin-Central Somerset-Southern Oxford- Southern Franklin-Interior York-Central Interior Cumberland- Androscoggin-Coastal York-Coastal Cumberland- Interior Cumberland Highlands-Northern Coos-Southern Coos- Northern Grafton-Northern Carroll-Southern Grafton-Southern Carroll- Sullivan-Merrimack-Belknap-Strafford-Cheshire-Eastern Hillsborough- Interior Rockingham-Coastal Rockingham- Western And Central Hillsborough- 230 PM EDT Sun Jun 28 2020 This Hazardous Weather Outlook is for 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. Showers and thunderstorms are likely through this evening. A few of the thunderstorms could be strong to severe, with hail, gusty winds, and torrential downpours with localized flooding the main threats. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Showers and thunderstorms continue Monday through Wednesday. There is a low probability of localized flash flooding during this time as storms will be slow-moving. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MEZ014-021-022-025>028-291830- Southern Somerset-Kennebec-Interior Waldo-Sagadahoc-Lincoln-Knox- Coastal Waldo- 230 PM EDT Sun Jun 28 2020 This Hazardous Weather Outlook is for south central Maine. .DAY ONE...This Afternoon and Tonight. Showers and thunderstorms are possible this evening. A few of the thunderstorms could be strong, but the most likely threat from any storm will be torrential rainfall and localized flooding. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Showers and thunderstorms continue Monday through Wednesday. There is a low probability of localized flash flooding during this time as storms will be slow-moving. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. ANZ150>154-291830- 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- 230 PM EDT Sun Jun 28 2020 This Hazardous Weather Outlook is for Atlantic coastal waters. .DAY ONE...This Afternoon and Tonight. A few strong thunderstorms are possible on the waters through this evening and could produce wind gusts in excess of 34 knots. .DAYS TWO THROUGH SEVEN...Monday through Saturday. No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. ES
Special Weather Statement
National Weather Service Gray ME
128 PM EDT Sun Jun 28 2020
NHZ007-281830-
Sullivan-
128 PM EDT Sun Jun 28 2020
...A STRONG THUNDERSTORM WILL AFFECT WEST CENTRAL SULLIVAN COUNTY...
At 128 PM EDT, a strong thunderstorm was located over Weathersfield,
or near Claremont, moving east at 15 mph.
Winds in excess of 40 mph and half inch hail are possible with this
storm.
Locations impacted include...
Claremont, Charlestown, Newport, Cornish, Croydon and Unity.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
LAT...LON 4339 7240 4346 7239 4348 7216 4331 7217
4332 7240 4334 7241 4336 7239 4336 7241
4338 7242
TIME...MOT...LOC 1728Z 263DEG 11KT 4338 7245
MECSpecial Weather Statement
National Weather Service Gray ME
301 PM EDT Sun Jun 28 2020
MEZ012-033-281930-
Southern Oxford-Interior Cumberland Highlands-
301 PM EDT Sun Jun 28 2020
...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL OXFORD AND
NORTHWESTERN CUMBERLAND COUNTIES...
At 300 PM EDT, a strong thunderstorm was located near Bridgton,
moving east at 10 mph.
Winds in excess of 40 mph and pea size hail are possible with this
storm.
Locations impacted include...
Bridgton, Fryeburg, Naples, Harrison, Brownfield, Denmark, Sweden and
Sebago.
Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.
LAT...LON 4412 7089 4412 7061 4395 7064 4394 7065
4398 7093
TIME...MOT...LOC 1900Z 269DEG 9KT 4404 7081
WatsonThe Portland,ME radar (KGYX), 41 km away, was scanning. The volume nearest the first event began at 19:41 UTC.
3 thunderstorm wind, 3 hail. Local standard time, as filed.
Several trees downed by thunderstorm wind gusts across southern Denmark.
Quarter size hail reported via the public in Hiram.
Quarter size hail reported just west of Newfield.
Severe thunderstorm winds gusts caused several downed trees on wires in Shapleigh.
Severe thunderstorm wind gusts downed multiple trees in Shapleigh along Goose Pond Rd.
Quarter size hail reported by the public in Alfred.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maine in 2020Every state in 2020This day in weather historyWarnings in Maine, June 2020
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: 906263, 906267, 906266, 906264, 906268, 906270.