672
FXUS61 KGYX 130630
AFDGYX
Area Forecast Discussion
National Weather Service Gray ME
230 AM EDT Wed Aug 13 2025
.SYNOPSIS...
Hot weather continues through today before a cold front
cools things off a bit for Thursday. There will likely be
scattered thunderstorms both this afternoon and Thursday, some
of which may be strong. However widespread rains are unlikely
and most locations will see little aid to growing deficits. The
weekend looks to be dry at this time with a warming trend this
weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Much like the last couple of days...full sunshine and recent dry
weather will allow temps to quickly start rising this morning.
Another day of widespread 90s is anticipated. Model guidance
does mix out the low level moisture fairly quickly as well.
Dewpoints may be flirting with the 50s by peak heating...and
this should limit the coverage of the heat index values around
95 degrees. However the apparent temps will be close enough to
95 that I will not change the current Heat Advisory.
Aside from the heat we will also have to watch the prefrontal
trof as it moves into the forecast area this afternoon.
Convection is expected to develop in the Green Mtns and spill
over into NH by this afternoon. As previously mentioned
dewpoints mixing out will lead to large inverted V sounding
profiles...supportive of enhanced downdrafts. With mid level dry
air set to birth those downdrafts thru evaporational
cooling...all signs point towards gusty thunderstorm potential.
Collaboration with SPC has led to a marginal risk for severe
storms across southern NH...where CAMs are most focused with
storms across our forecast area. Shear is pretty meager so the
threat will be rather disorganized and isolated in
nature...unless merging cold pools can lead to a small area of
concentrated wind. I have added gusty winds to any thunderstorms
across the marginal risk area and adjacent zones. With the loss
of daytime heating convection should begin to steadily weaken
and it is unlikely that much survives to the coast.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
Tonight will be more mild than recent nights...as moisture is
advecting in ahead of the cold front. That means that marine fog
will also be possible...with guidance suggesting generally north
of Port Clyde and Penobscot Bay being the most likely location
for lower visibility.
Models are definitely in agreement now that cold front will not
cross the area until Thu. As a result we should get a very warm
day with higher moisture than today. In the end apparent temps
will feel like the upper 80s to lower 90s...and not a whole lot
different than today. CAMs also develop showers and storms along
the front as it nears the coast in the afternoon. Much like
today there is a good pocket of dry air in the mid levels to
support evaporational cooling and downburst development. There
are steep low level lapse rates to sustain that downdraft to the
surface. And there is fairly weak shear to limit the
organization of the storms. So it may be another day of isolated
strong to severe storms before the boundary clears the coast and
we lose daytime heating.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Early morning long term update...No significant change to the
going long term forecast with the inclusion of latest ensemble
and NBM forecasts. Still looking at mainly dry weather with a
warming trend over the weekend in advance of a cold front that
will likely move through sometime on Sunday with the potential
for showers and thunderstorms. High pressure still looks to move
in for early next week with cooler weather but little in the way
of appreciable rainfall.
Previously...
Dry and warmer weather is expected to continue through the
extended weekend, through troughing will allow for more cooler
temperatures to arrive for early next week. An upper-level low
over Canada may bring a weak cold front southward, with some
very light rainfall accumulations possible Sunday.
Next week`s forecast remains very dry, but troughing should
bring some cooler weather into the forecast. Highs look to be in
the upper 70s and lower 80s.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Primarily VFR conditions expected thru Thu. Valley
fog may develop in the CT River prior to sunrise...but otherwise
will lift quickly. SHRA/TSRA develop during the afternoon and
move into western NH. The best chances will be from LEB to CON
and MHT...likely weakening before reaching PSM. Coastal fog is
possible around RKD tonight before cold front arrives. SHRA/TSRA
may be more widespread along the coast Thu before moving east of
the area late in the afternoon.
Long Term...
Mostly VFR expected on Friday and Saturday. Restrictions may
lower again on Sunday due to scattered showers and
thunderstorms. VFR is expected to remain through early next
week other than river valley fog.
&&
.MARINE...
Short Term...Winds and seas expected to remain below SCA
thresholds. The expectation is that showers and thunderstorms
weaken before reaching the waters tonight. This may allow
patches of marine fog to form...especially north of Port Clyde.
Cold front crosses the waters by Thu afternoon...this time with
showers and thunderstorms expected over the coastal waters.
Long Term...
Northerly winds pick up briefly on Friday morning. Winds
slacken and become light and variable by the end of the day on
Friday and stay light through daybreak Saturday. Saturday
afternoon, winds pickup from the south. Winds shift to
southwesterlies by Sunday morning. Seas will remain at 2-4ft
through the entire forecast period.
&&
.CLIMATE...
Daily record highs and year(s) for Portland, Augusta, and
Concord.
Portland Augusta Concord
Aug 13 99F (1947) 94F (2004) 99F (1944)
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Heat Advisory until 8 PM EDT Wednesday for MEZ012>014-018>022-
033.
Air Quality Alert until 11 PM EDT this evening for MEZ023>025.
NH...Heat Advisory until 8 PM EDT Wednesday for NHZ010-012-013.
Air Quality Alert until 10 PM EDT this evening for NHZ013-014.
MARINE...None.
&&
$$
NEAR TERM...Legro
SHORT TERM...Legro
LONG TERM...Ekster/Palmer