Area Forecast Discussion
Issued by NWS Portland, ME

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096
FXUS61 KGYX 230225
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1025 PM EDT Wed May 22 2024

.SYNOPSIS...
Very warm conditions continue through Thursday with a cold
front bringing scattered thunderstorms Thursday afternoon. Drier
air arrives Friday with mostly dry weather into Saturday. A
frontal system brings chances for showers late Saturday into
Sunday. A more organized system approaches for early next week
bring better chances for widespread showers late Monday into
Tuesday.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
1020 PM Update...No changes to the forecast at this time. A
mostly clear and warm evening continues. A few showers and
perhaps a rumble of thunder may affect western zones later on
tonight.

715 PM Update...Little change to the going forecast this
evening. MOstly clear skies are likely to continue into the
weekend along with light winds and warm temperatures. Showers
and thunderstorms over Upstate NY should gradually weaken over
the next few hours with loss of daytime heating. Will still
watch for some widely sct activity getting into the CT River
zones late this evening or overnight.

Previously...

Mid level ridge axis is cresting over northern New England this
afternoon making for very warm conditions across the area with
temperatures in upper 80s to low 90s. Latest satellite shows CU
have blossomed over the higher terrain of Maine and New
Hampshire with some attempt of CU developing along the sea
breeze boundary from interior York County through interior Waldo
County. CAMs suggest that an isolated shower or thunderstorm
cannot be ruled out along this boundary through sunset with the
best chances toward central Maine.

Tonight will be mild and humid with temperatures and dewpoints
generally staying in the low 60s. There may be enough SW flow
ahead of an approaching cold front to limit fog potential with
the best chances for fog near the Mid Coast. The approaching
front is currently triggering convection over PA and western NY
with some CAM solutions suggesting this remnant convection will
spill into northern and western zones tonight. There is a fair
amount of spread in guidance as to how widespread this shower
and thunderstorm activity will be and have generally carried
chance PoPs across northern zones and much of NH with this
activity weakening as it moves east into Maine. There will be
limited instability overnight night limiting the potential for
any strong thunderstorms.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
The cold front will be entering NW zones Thursday morning and
will push into the coastal Plain in the afternoon. The 12Z HREF
mean brings MU CAPE into the 1000-1500 J/kg range ahead of the
front with deep layer shear of 35-40 kts. Some individual HREF
members bring MU CAPE greater than 2000 J/kg along the coastal
plain early tomorrow afternoon. This convective parameter space
will favor strong to severe storms while the prior to peak
heating passage of the front should limit overall coverage of
storms. SPC maintains a Marginal Risk for severe storms south of
the mountains to the coast where the best instability will be.
The 12Z CAM suite suggest storms could fire by mid day along the
foothills and strengthen as these storms track to the coast
between 2 PM to 5 PM. Instability drops off after 5 PM with
convection waning into sunset. The hazards from strong to severe
storms will be strong damaging winds and hail.

Drier air works into the region Thursday night behind the
front. Lows will range from the low 50s north to near 60 degrees
across the south.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Friday isn`t looking quite as dry as it did this time yesterday
with models trending a bit farther south 500mb trough swinging
across southern Quebec. This will send another weak frontal
boundary through during the day, and although moisture is rather
limited, there could be a few showers out of this, primarily
across northern areas (20-30% chances). Outside of showers, it
will still be rather warm with temperatures away from the
immediate coast again reaching the 80s for much of the area.
Somewhat breezy conditions to around 25 mph at times per BUFKIT
forecast soundings should offer some relief.

Once this wave and front pass, we get a ridge briefly build in
Friday night and Saturday, keeping things mostly dry along with
the continued warmth. Temps again Saturday look to reach the mid
70s to lower 80s for most of the area.

Late in the day and into Saturday night, a weak wave aloft and
broad area of low pressure will bring another opportunity for
showers through Sunday morning, but amounts look light with
ensemble means from the GFS and ECMWF both indicating amounts in
the 0.10-0.25" range. Depending if this low remains close
enough nearby on Sunday, a few showers may again develop during
the afternoon.

Models are showing good continuity for early next week with a
low pressure system setting up over or just north of the Great
Lakes region. While they have shied away from the coastal low
scenario for the most part, a cold front looks to be sent toward
New England, bringing the next potential for widespread
rainfall across the area in the Monday-Tuesday timeframe. There
are also signals for heavy rainfall out of this system as
ensembles from the ECMWF/GFS are already showing decent
probabilities for PWATs in excess of 1.50", but we`ll watch
trends over the coming days. Another wave could follow quickly
behind the front, so there is uncertainty if next Wednesday will
be dry or not.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Short Term...Mainly VFR tonight across the area except for some
potential for fog at KAUG and KRKD, although confidence is low.
A cold front brings scattered TS to the area tomorrow with the
best chance for TS along and south of a line from KCON to KAUG.
Timing of TS is around 18Z to 22Z Thursday afternoon. Drier air
arrives Thursday night for mainly VFR.

Long Term...Mainly VFR Friday, but a few showers are possible
as another weak frontal boundary crosses, mainly north of the
TAF sites. Going into the weekend, with southerly flow
continuing, marine fog/stratus may impact the coastal sites, but
this is of low confidence. Additional showers also look to
arrive late Saturday and into Sunday with a higher potential for
more widespread rainfall and flight restrictions early next
week.

&&

.MARINE...
Short Term...Winds will predominantly be out of the S to SW
tonight through Thursday while winds and seas remain below SCA
thresholds. A cold front pushes into the waters Thursday
afternoon with a few strong to severe storms possibly tracking
off land into the waters. Winds shift westerly Thursday night
behind the front.

Long Term...W/SW flow starts out Friday but will gradually
become more southerly by the afternoon. Winds will then switch
to northerly late in the day into Friday night as another
frontal boundary crosses but remaining below SCA levels. High
pressure becomes centered southeast of the waters over the
weekend leading to a prevailing southerly flow with fog possible
at times. A weak low pressure may bring some showers late
Saturday and into Sunday. Going into early next week, a more
potent low pressure north of the Great Lakes will send a cold
front toward New England with increasing south to southeast
winds potentially surpassing SCA levels late Monday into
Tuesday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$


NEAR TERM...Ekster/Schroeter
SHORT TERM...Schroeter
LONG TERM...Combs