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337
FXUS61 KGYX 180326
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1126 PM EDT Mon Jun 17 2024

.SYNOPSIS...
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A warm front continues to lift through the area overnight,
which will be followed by a stretch of very hot and humid
conditions through the week. Record high temperatures and
potentially dangerous heat index values are possible. A weak
cold front will slowly cross through the region on Thursday and
Friday with an increasing chance for scattered showers and
cooler temperatures this weekend.
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&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...

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11:25pm Update... No notable changes with this update. Increased
clouds slightly more for tonight as some continue to stream in,
but otherwise nothing else of note as the forecast remains on
track.

7:55pm Update... No significant changes with this update, mostly
just tweaking temps based on trends so far this evening and from
the latest high res guidance. Did add a bit more cloud cover for
tonight as clouds continue to roll around the ridge this
evening, which may be enough to help keep temps up by an extra
degree or two overnight. Otherwise no notable changes as the
forecast remains on track.

Previous...

A warm front that was forecast to lift through the area today
has slowed resulting in more cloud cover across the region this
afternoon. This front will continue east this evening with cloud
cover thinning SW to NE this evening. Heights will build over
the region tonight with return flow around high pressure
offshore will set up a warm air advection regime over the
Northeast. Lows tonight will generally be in the 60s with patchy
fog.
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&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
Tuesday will mark the start of a hot a humid stretch of weather
as high pressure remains anchored southeast of New England.
Temperatures will climb into the upper 80s to low 90s by mid
day with highs in portions of southern NH and interior western
ME climbing into the mid 90s. Dewpoints will also be on the rise
climbing into the upper 60s to low 70s. Winds will turn onshore
helping to keep coastal areas cooler as temperatures drop
during the afternoon. Across the interior and south of the
mountains the combination of heat and humidity will bring heat
index values into the upper 90s and the Heat Advisory has been
expanded across interior central Maine.

The building heat and humidity will also lead to building
instability this afternoon. CAMs have been highlighting an area
of convergence along the sea breeze boundary leading to
isolated showers and thunderstorms tomorrow afternoon near the
foothills with additional isolated storms possible over the
mountains. Any showers and thunderstorm activity should diminish
with the loss of heating Tuesday evening.

The increasingly humid airmass will limit cooling Tuesday night
as lows only drop into the upper 60s to around 70 degrees.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
There remains little in the way of changes to the operational and
ensemble solutions regarding the heat wave which continues into the
long range portion of the forecast. A large ridge of high pressure
will remain seated over the Northeast on Wednesday. This dome will
allow H8 temperatures to climb to +20C by Wednesday afternoon under
partly to mostly sunny skies. Air temperatures will climb into the
mid and upper 90s over most areas with sea breezes expected along
the coast. However a westerly flow aloft, albeit light, will keep
the sea breeze from penetrating very far inland.

Surface dew points are still expected to climb into the 65 to 70
degree range. This will allow apparent temperatures to climb to over
100 degrees at times away from the coast. It will be mainly rain-
free however an isolated shower or thunderstorm will be possible
over northern areas late as precipitation rotates around the
periphery of the ridge. Nighttime lows will be on the warm side as
well, mainly in the lower 70s. This will aggravate heat stress.

The peak of the heat will arrive on Thursday as a strong upper level
ridge remains centered near Long Island New York. After a warm night
with patchy fog, temperatures will soar once again under a light
westerly flow aloft. Widespread mid to upper 90s can be expected
with a few communities, mainly in southern New Hampshire exceeding
100 degrees. Relatively high dew point values will allow for
apparent temperatures to climb into the 100 to 105 degree range,
very near to the Excessive Heat Thresholds. Scattered showers and
thunderstorms will once again rotate around the periphery of the
ridge and mainly be centered over northern areas.

A weak front will then be draped over the region on Friday. It
will be about 10 degrees cooler than on Thursday, mainly due to
the increased cloud cover and the scattered showers and storms
across the forecast area. Slightly lower dew points can be
expected which will be an ongoing trend into the weekend. A
nearly stationary front will allow for scattered showers and
thunderstorms throughout the weekend.

&&

.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
Short Term...Increasing moisture will bring some potential for
restrictions in fog tonight with the highest probabilities
along the CT Valley and central Maine. Otherwise, VFR likely
prevails tonight through Tuesday. Isolated TSRA will be
possible Tuesday afternoon mainly along the foothills with KAUG
being the TAF site with the highest likelihood of seeing brief
restrictions. Patchy fog will again be possible Tuesday night.

Long Term...Mainly VFR conditions through Wednesday followed by more
showers and thunderstorms with a cold frontal passage by late
Thursday into Friday. Areas of IFR conditions are possible as well
during the night time period with patchy valley fog and associated
with more scattered showers and thunderstorms throughout the weekend.

&&

.MARINE...
Short Term...A warm front lifting through the waters while high
pressure becomes centered southeast of the waters will bring S
to SE winds with gusts around 20 kts through this evening. Winds
relax tonight with winds and seas remaining below SCA
thresholds Tuesday through Tuesday night.

Long Term...Winds and seas will primarily be out of the south during
the extended portion of the forecast and below SCA thresholds.
Highest wind gusts likely will be during the afternoon hours as the
sea breeze attempts to form. The winds will briefly become westerly
on Friday.

&&

.CLIMATE...
Record breaking high temperatures and warm overnight low
temperatures are likely Tuesday through Friday of next week.

Here are the records...

RECORD HIGHS FOR JUNE 19: Concord-98, 1995 Augusta-98, 1995 Portland-
94, 1995

RECORD HIGHS FOR JUNE 20: Concord-98, 1993 Augusta-95, 1953 Portland-
93, 2020

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Heat Advisory from noon to 8 PM EDT Tuesday for MEZ012>014-
     018>021-033.
     Excessive Heat Watch from Wednesday afternoon through Thursday
     evening for MEZ012-018>020-033.
NH...Heat Advisory from noon to 8 PM EDT Tuesday for NHZ004>013-015.
     Excessive Heat Watch from Wednesday afternoon through Thursday
     evening for NHZ006-008>010-012-013-015.
MARINE...None.

&&

$$


NEAR TERM...Clair
SHORT TERM...Schroeter
LONG TERM...Cannon