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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KGYX 221454
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1054 AM EDT Sun May 22 2022

.SYNOPSIS...
Another hot a humid day is expected today away from the coast
before a cold front starts to drop south into the the area. This
cold front will bring the threat for severe thunderstorms this
afternoon and evening with the main threats being large hail,
damaging winds, and torrential downpours. High pressure builds
in behind the front Monday bringing fair weather through
Wednesday with temperatures closer to normal and much lower
humidity levels. A frontal system will approach towards the end
of the work week for unsettled conditions possible Thursday and
Friday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
10:50AM Update... Mainly minor tweaks to temps based on trends
and high res data so far this morning. Also refreshed POPs with
some high res guidance. The severe threat remains on track for
today. Some stronger storms have already developed along an
outflow boundary left from storms last night in Caribou`s
forecast area, so we`re already getting signs that conditions
are conducive for strong to severe storms this afternoon.

Update...Minor changes to reflect latest observational trends.

Previous discussion...Convection continues this morning...along
the periphery of the EML...riding the CAPE gradient. These
storms will mainly affect the Boundary Range thru this morning.
Not a lot of CAM guidance handling this particular well...but a
gradual weakening is anticipated as it moves northeast.
Elsewhere the fog and stratus remain locked in place thru
morning.

Much like yesterday we will have to scatter out the fog before
temps can start to really take off. So once again western ME
and adjacent NH will be slow going thru mid to late morning.
Based on those trends from yesterday high temps across much of
NH are still hot but only low to mid 90s now. I will keep the
heat advisory in place despite the fact that heat index values
will just touch 95 and likely not get much hotter than that.
Dewpoints under this EML are fairly run of the mill humid...and
not pushing 70 that would really make heat indices
uncomfortable.

As the cold front approaches this afternoon those temps in the
90s and dewpoints in the mid to upper 60s will support moderate
CAPE...even as mid level lapse rates start to decrease. It looks
like two potential triggers for convection this afternoon. This
first will be differential heating in the higher terrain. CAM
guidance to varying degrees tries to initiate storms off the
White and Longfellow Mtns. There will be enough shear to
organize storms but messy hodographs suggest clustering is most
likely. In addition theta-e differences around 20 to 25K
supports the development of cold pools. So at least any early
convection should favor damaging winds as the primary hazard.
Any discrete updraft may be able to tap the departing EML for
some large hail before upscale cell mergers.As the afternoon
wears on and the cold front approaches a more broken line of
convection should result. This will still favor wind damage as
the primary concern...but the approaching upper trof and
attendant southwesterly LLJ may elongate low level hodographs
just enough to bring an all hazards threat for a narrow time
window. It is still most likely that any tornado threat is going
come from a brief QLCS-type mesocyclone. That threat is most
apparent for northern and western zones...matching HREF and CSU
machine learning forecasts well...along with the SPC slight
risk. This is where I have severe wording in the forecast...with
gusty winds/small hail south and east of there.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Convection will tend to follow a more climatologically favored
weakening with the loss of diurnal heating as the EML will have
departed to the east by tonight.

Winds gradually turn offshore and that should bring an end to
the fog threat. Just how long it takes the winds to shift will
determine how long fog sticks around the coast...if at all.

Much drier air will filter into the region overnight...so while
air temps may not be much different for most of the area it will
feel more comfortable. Similar story is expected Mon
afternoon...with highs topping out in the 60s and 70s.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
High pressure will continue to build in from the west Monday
night, cresting over the area Tuesday before shifting to our
east Wednesday. This will bring a stretch of mostly dry weather
with temperatures near normal away from the coast. Onshore winds
will keep coastal areas slightly below normal Tuesday and
Wednesday. An upper trough will slide into the Ohio Valley
Wednesday night into Thursday with an area of low pressure
developing over the Great Lakes. The attendant warm front will
lift towards New England Thursday bringing increasing chances
for showers. Low pressure will then track northeastward into
Quebec with a cold front crossing New England sometime between
Friday and Saturday morning.

High pressure will bring mostly clear skies and light winds
Monday night allowing lows to drop into the 30s north and 40s
south. As high pressure slides across northern Maine Tuesday,
winds will turn onshore knocking temperatures down near the
coast during the afternoon. Highs will generally be in the 60s
with low 70s along the CT Valley. High pressure continues to
slide east Wednesday with southeast winds turning more
southerly. This will allow the interior to warm into the low 70s
while coastal areas will be restricted to the 60s with more in
the way of clouds than Tuesday.

Conditions may turn unsettled Thursday as a warm front
approaches New England. Over the past 24 hours there has been a
trend for less in the way of showers on Thursday from the warm
front, although there continues to be a fair amount of spread
amongst ensembles with some members bringing widespread showers
during the day Thursday. Going into Friday a cold front will
approach from the west. There continues to be some timing
differences amongst ensembles in the frontal passage with the
FROPA occuring sometime between Friday and Saturday morning.
Widespread showers will be likely with the FROPA and continue
to stick close to the NBM which brings the highest PoPs Friday
afternoon. Cyclonic flow aloft may bring continue chances for
showers Saturday, primarily in the mountains, with an overall
drying trend through the weekend.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
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Short Term...Some fog and low stratus linger around RKD today.
The marine stratus may try and work back into coastal zones as
TSRA approach from the west...but overall not expecting it to be
as widespread as tonight. SHRA/TSRA along the cold front may be
strong to severe...with large hail and damaging winds possible.
Inland TAF sites are most at risk for stronger
convection...including HIE...LEB...MHT...CON...and AUG. VFR
conditions return behind the front.

Long Term...Mainly VFR Monday night through Wednesday. A warm
front approaches Thursday with thickening and lowering cigs
bringing potential for MVFR conditions.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
Short Term... A cold front will sweep away fog and stratus this
evening...but bring a chance of showers and thunderstorms. Some
of the storm may bring gusty winds to the coastal waters before
they move east. Winds and seas are expected to remain below SCA
thresholds.

Long Term...Winds and seas will remain below SCA thresholds
Monday night through Wednesday. Increasing southerly flow
Thursday into the Friday may bring marginal SCA winds and seas
building to 5 ft.
-- End Changed Discussion --

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
ME...None.
NH...Heat Advisory until 8 PM EDT this evening for NHZ008-011>013-
     015.
MARINE...None.
-- End Changed Discussion --

&&

$$
SYNOPSIS...
NEAR TERM...Clair
SHORT TERM...Legro
LONG TERM...Schroeter
AVIATION...
MARINE...