Area Forecast Discussion
Issued by NWS Portland, ME

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294
FXUS61 KGYX 241947
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
347 PM EDT Fri May 24 2024

.SYNOPSIS...
A much cooler night can be expected overnight with dry weather
into Saturday. A frontal system brings chances for showers late
Saturday into Sunday. A more organized system approaches for
early next week bringing better chances for widespread showers
Monday night into Tuesday. An upper level trough crosses the
region Wednesday through Friday with more scattered showers.

&&

.NEAR TERM /THROUGH TONIGHT/...

Breezy conditions will persist into early this evening with
winds shifting to the northwest as a cold front continues
pushing through the region. Expect the higher of the gusts to
occur over the next couple of hours when the stronger winds
aloft are overhead and mixing is the deepest. Gusts could be as
high as 30-35 mph, but after that generally around 25 mph or so
into this evening.

After sunset, winds will continue to diminish into this evening
but could still be somewhat breezy at times as forecast
soundings show shallow mixing persisting. Diurnal cumulus will
dissipate, and the drier air brought in by the northwest winds
will keep skies mostly clear overnight. Eventually, the gradient
should weaken enough to decouple over many areas for a good
period of radiational cooling, and I have blended in some
cooler MOS guidance, especially across northern areas. This puts
lows in the 40s for most of the area except lower 50s over
portions of southern NH/SW ME. The other exception will be
northern valleys, which could see temps drop into the 30s for a
brief period just prior to sunrise since dewpoints are forecast
to fall into the mid-upper 30s. With the potential for these
cooler temps, I have added patchy frost for some of the
northern valleys.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Light offshore flow starts the day on Saturday but will start
to become more W/SW by the afternoon with high pressure becoming
centered south of the Gulf of Maine. This light flow will allow
the seabreeze to move inland in contrast to today, which keeps
forecast temps cooler along the coast but still well into the
60s. Inland areas are forecast to reach the low-mid 70s with
upper 70s still possible across southern NH, which is slightly
above MOS guidance due to the dry airmass. The drier air will
provide plenty of sunshine, but the upper levels start to
moisten later in the day, so we should start seeing more cirrus
during the afternoon.

Going into Saturday evening, hi-res guidance is in pretty good
agreement showing an area of convection steadily weakening
around sunset as it approaches the CT Valley. It may survive
long enough to bring a few light rain showers in NH, but it
looks like the better chance for showers holds off for the
overnight hours as clouds continue to lower and thicken ahead
of a weak area of low pressure. Rainfall amounts are expected to
be light at around a tenth of an inch.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
A very weak system will be crossing the region on Sunday. This
will bring a chance for showers which will be light and brief if
they occur at all. It will be coolest along the coast with
onshore winds and temperatures in the 60s. 70s will dominate
most inland areas with the exception of lower 80s across
southern New Hampshire.

12Z models and ensemble solutions continue to indicate a more
robust system will approach the region on Monday. This may
bring a chance for a shower in the morning as low pressure
intensifies and enters into Canada bringing a warm front towards
New England. An area of more widespread precipitation will
enter the region from the west during the rest of the day
Monday. Models however remain in disagreement as to the timing
of this rainfall. In any case, the highest pops will arrive
Monday night as a band of increased moisture arrives ahead of an
approaching cold front. Sufficient instability may allow for an
embedded thunderstorm as well. Some of the precipitation may be
locally heavy, especially across upslope regions of the
mountains. PWs will be running as high as 1.5 inches as deep
moisture rides up the coastline.

On Tuesday, drier air will works it way into the region on
westerly winds aloft. Some sunshine will allow for temperatures
to climb to warmer conditions than Monday with temperatures
topping out in the 70s with lower 80s in southern New Hampshire.

For the period Wednesday through Friday, a slow moving, upper
level trough will approach and then cross the region. This will
bring scattered showers to the region, especially after daytime
heating during the afternoon hours. Temperatures will be
seasonable for this time of the year.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Short Term...Mainly VFR through Saturday night. A secondary
front crosses by this afternoon/evening, shifting winds to the
north into tonight while remaining somewhat breezy into this
evening. Light westerly flow on Saturday will becoming more
S/SW at the coastal sites in the afternoon with the seabreeze.
Ceilings lower Saturday night ahead of a low pressure that may
also bring light rain showers, but there`s uncertainty if there
will be any flight restrictions through 12Z Sunday.

Long Term...A few light and widely scattered showers will
continue on Sunday with a higher potential for more widespread
rainfall and flight restrictions arriving from west to east
Monday and continuing through Monday night. An upper level
trough will bring a few more scattered showers during the
midweek period with pockets of IFR conditions at times.

&&

.MARINE...
Short Term...A few gusts to around 25 kt are possible over the
eastern waters and Penobscot through this afternoon, but due to
the short duration, have not issued an SCA. A cold front
crosses the waters early this evening with winds shifting
northwesterly and then northerly through tonight. High pressure
becomes centered south of the waters and will switch winds back
to more westerly Saturday morning and then out of the south to
southwest the rest of Saturday and most of Saturday night. An
approaching weak low pressure could turn winds out of the NE
toward daybreak Sunday.

Long Term...A light southerly flow will become southeast on
Sunday and continue through Monday. The gradient flow and winds
will increase out of the southeast for late Monday night into Tuesday
with SCA conditions. A southerly flow will continue on
Tuesday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Beach Hazards Statement until 8 PM EDT this evening for
     MEZ023>028.
NH...Beach Hazards Statement until 8 PM EDT this evening for NHZ014.
MARINE...None.

&&

$$
NEAR/SHORT TERM...Combs
LONG TERM...Cannon