401
FXUS61 KGYX 211430 AAA
AFDGYX

Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1030 AM EDT Sat Sep 21 2024

.SYNOPSIS...
Low pressure south of Cape Cod lingers into tomorrow before
slowly drifting southward tomorrow and into early next week.
The low continues to bring cooler conditions, a few showers and
light rain near the coast, along with high surf and minor
coastal flooding impacts along the coastline. High pressure
builds southward across New England by early next week, bringing
seasonable temperatures and dry conditions.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Convergence on the eastern side of an inverted trof continues to
produce some showers and light rain across southern parts of the
forecast area this morning. Little change in forcing is forecast
thru this evening based on latest hi-res guidance. I have
increased PoP thru around midnight...with the largest increases
thru sunset...as I think this precip is going to linger. A
welcomed rainfall for areas that have been abnormally dry of
late.

Previous...

Low pressure south of Cape Cod continues to bring cool air on
northeasterly flow and some periods of light rain. A weak
inverted trough helped to bring a little more rainfall to the
southern Maine coast overnight, and continues to serve as a
focus for some steadier light rain this morning. This likely
drifts inland while weakening today, bringing some intermittent
periods of light rain in parts of southern and central New
Hampshire. Amounts look to remain light, mainly less than a
tenth of an inch. Parts of the New Hampshire Seacoast could see
up to a quarter inch, but this looks to remain limited in
coverage.

Farther north and west, mainly dry conditions are expected,
with little more than a light sprinkle expected. Across the
drier northern and western areas, temps warm to near 70 degrees
with more filtered sunshine. 60s are expected elsewhere where
clouds and any rainfall continue.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
The chance for rain gradually diminished tonight as the low
begins to drift southward, and the trough continues to weaken.
Patchy fog is possible again across northern and western areas
with more clear skies. Temps looks to remain fairly uniform
across the area, with upper 40s across the north, to low 50s
along the coast.

By tomorrow the low will be far enough away from New England
that its influence begins to wane. High pressure builds
southward and takes more control of the weather pattern. Skies
gradually clear through the day, bringing slightly warmer temps
with the increasing sunshine. Seas will remain elevated as the
low lingers across the western Atlantic, keeping the threat of
rip currents ongoing.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Overview: Uncertain weather pattern evolving in the extended
after the breakdown of a block. After upper low lifts out of the
Gulf of ME...the blocky nature of the pattern will remain.
Guidance attempts to set up another rex block but the location
remains low confidence.

Impacts: Pretty wide range of potential impacts...from
continued dry weather and increasing fire weather risk...to a
more changeable pattern with rain chances.

Forecast Details: The higher confidence portion of the forecast
this weekend will feature at least brief ridging as upper low
departs the local waters and drifts east. Northeast flow should
keep temps on the near normal side versus the mild weather of
late. We will also have to keep an eye on lingering moisture and
potential fog/stratus near the coast before westerly winds can
sweep it away.

Beyond Mon a trof will approach from the west and that is where
forecasts diverge. Some guidance favors the base of the trof
cutting off and pinwheeling around for several days. Other
guidance favors a more progressive trof. Some of this may be
tied to potential tropical cyclone development in the Gulf of
Mexico later in the period...and ridge building ahead of it.
Examining clusters in DESI...guidance is roughly split 50/50
between the two ideas...though the location of the cutoff will
determine local sensible weather. As a result I will not stray
too far from the multi-model consensus blend.

In general temps will gradually moderate thru the week. Rain
shower chances will develop by midweek and may linger into the
weekend.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Any IFR conditions at LEB with valley fog improves
to VFR by mid morning today. Light rain across southern and
coastal terminals becomes more intermittent through the day.
Terminals with IFR to MVFR ceilings this morning slowly improve
to VFR conditions by late today. Fog is possible at LEB and HIE
tonight with IFR conditions, then VFR returning tomorrow
morning. Some MVFR ceilings are possible at PSM and MHT this
evening, but otherwise VFR conditions prevail tonight and
tomorrow.

Long Term...Generally VFR conditions expected to start the
period...though there is a low probability of some IFR or lower
conditions near the coast in marine fog/stratus. Local MVFR or
lower conditions possibly develop by midweek in SHRA as a trof
approaches from the west. Valley fog would be most likely Sun
night/Mon morning as surface ridge noses into the region from
the northeast.

&&

.MARINE...
Short Term...SCA conditions continue across the outer waters
and Casco Bay with seas lingering above 5 feet through at least
tomorrow. A gale center south of Cape Cod weakens as it drifts
southward through tomorrow. High pressure begins to build
southward into the waters by late tomorrow.

Long Term...Behind the departing low pressure northeast winds
may gust near 25 kt outside of the bays on Sun. That will
support continued wave heights above 5 ft. Those will gradually
diminish thru the week...but may remain at or above 5 ft thru at
least Thu.

&&

.TIDES/COASTAL FLOODING...
We remain near the peak of our astronomical tide cycle this
weekend with the highest tides occuring during the afternoon
hours. Meanwhile, a gale center remains south of Cape Cod
through tomorrow. This will lead to multiple cycles of minor
coastal flooding due to storm surge values around a foot, mainly
from Portland and points south.

Beach surveys and Emergency Managers continue to indicate
compromised dune systems along the coastline from our storms
this past winter. Therefore, building nearshore waves may lead
to splash-over as well.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...High Surf Advisory until 7 PM EDT this evening for MEZ023-024.
     Coastal Flood Advisory until 4 PM EDT this afternoon for
     MEZ023-024.
NH...High Surf Advisory until 7 PM EDT this evening for NHZ014.
     Coastal Flood Advisory until 4 PM EDT this afternoon for
     NHZ014.
MARINE...Small Craft Advisory until 8 PM EDT Sunday for ANZ150-152>154.

&&

$$

NEAR TERM...Legro