371
FXUS61 KGYX 240253
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1053 PM EDT Sun Jun 23 2024

.SYNOPSIS...
A strong cold front will push offshore tonight. Showers will
develop Monday with an upper level low overhead. High pressure
then settles in for Tuesday before another cold front moves in
for Wednesday night. Best chances for rain and thunderstorms
will be late Wednesdays, but this should clear out Thursday as
high pressure returns for the end of the week. Temperatures and
humidity will swing with the passing of each frontal boundary.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
1030pm Update...Rounds of showers and a rumble of thunder or two
will continue tonight, but severe threat has passed. Item to be
aware of going into Monday will be what areas received decent
rainfall amounts throughout the day today. 24 hr MRMS
estimates bring a wide area of 1-2" across coastal to interior
ME and through the Lakes region. Gauge observations mainly
weight on the lower end, but isolated areas did pick up around
2" of rainfall. Fog will likely not be terribly widespread
tonight. HREF probs are low across the interior, with best
chances along the Midcoast and into the Kennebec Valley.

850pm Update...Main thunderstorms are concentrated along a
broken line approaching the coast and through the southern half
of NH. 00z GYX RAOB displayed a stout sfc inversion, but even
this broke as a line of storms came through the interior with
gusty winds. While a general downtrend in activity, both
intensity and coverage, is expected...elevated instability will
keep the chance of thunder through the first half of the night
with deeper cells. Will have another update shortly to close out
the Tornado Watch for the event, but expect prominent impacts of
hail/wind/tornado to be dwindling.


750 PM Update: Quick update to extend the watch through 10pm in
collaboration with SPC across southern NH/SW ME given ongoing
convective activity and MLCAPE still around 1000 J/kg in this
area. Will continue to monitor current convective activity
trends to determine when the cancel the watch.

Previous discussion below...

Likely to see a couple rounds of convection this afternoon into
early evening, with the first one approaching the CT vly attm.
There are a few damage reports to our W, and we continue to
break out from the marine lyr from W to E as well, so theres
still some time, but 18Z ALY sounding showing a bit of weak
capping layer. So, too early to say anything about reducing the
threat, and certainly some strong winds are possible into early
evening as well as heavy rain.

I think by 02-03Z should see the convection begin to move out of
the CWA or weaken, with showers coming to an end between then
and daybreak. Probably the early to mid evening will be the best
potential for heavy rain as there might be some training of
storms. It unlikely we see much, if any of the drier air mix
down to the sfc, and this will make for a mild and humid night,
with the potential for fog, Lows will mostly be in the 60s,
warmest in SW ME and srn NH where itll mostly be in the upper
60s.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
500 MB low will cross the CWA on Monday, and this will keep the
mtns cloudy, with some showers and thunderstorms developing
there, and perhaps moving SE toward srn NH and the coast by mid
to late afternoon. Highs range from 70-75 in the mtns to around
in srn NH and along the ME coast, as flow shifts more to the W.
It will start off humid, but should see Tds drop down into the
low 60s across much of the area by afternoon.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
The upper level trough will lift out of the region to be replaced
by brief ridging. This will produce warm conditions and bring a
reprieve in the shower activity. Return flow Tuesday night will
usher in warmer and more humid conditions for Wednesdays, with
highs in the mid to upper 80s for much of the area. A cold front
sinking south out of the Great Lakes on Wednesday will support
scattered to numerous showers and thunderstorms into Wednesday
night. The forcing with the system Wednesday night is
concerning, but for now the instability ahead of it could
will be a limiting factor. Will have to watch for heavy rain
producers as well as some concern about strong winds, but these
will be conditional and timing dependent so confidence is low
at this time. The front will bring a brief cool down for the
latter part of the work week. The airmass starts to modify with
surface high moving in Friday. Dew points in the 50s will mean
very tolerable humidity levels for late June. Another frontal
system approaches from the Great Lakes over the weekend,
bringing another opportunity for showers.

&&

.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Short Term...A trend toward VFR tonight, but MVFR ceilings will
still exist in patches. I think, given the higher Tds, and the
light flow overnight, will see some fog, and IFR cigs at most
spots. A more definitive VFR trend is expected to return Monday
morning.


Long Term...Predominantly VFR conditions are then expected
Tuesday and early Wednesday, followed by another increased risk
of TSRA by Wednesday afternoon into Thursday.

&&

.MARINE...
Short Term...SCA for tonight, as S-SW flow ahead of a cold front
persists. Winds expected to diminish by Monday morning.

Long Term...
- Increased thunderstorm risk Wednesday Night

 - Brief elevated winds and seas mid-week

A potent cold front will move through the waters Wednesday Night or
early Thursday and will feature an increased risk of thunderstorms.
Ahead of the front, elevated winds and seas will linger, with SCA
conditions possible. Southerly flow then quickly returns by
Wednesday and Thursday, with subsiding seas for late week.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 8 PM EDT Monday for ANZ150>152-154.

&&

$$


NEAR TERM...Arnott/Cornwell
SHORT TERM...Cempa
LONG TERM...Jamison