541
FXUS61 KGYX 200756
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
356 AM EDT Fri Sep 20 2024

.SYNOPSIS...
Low pressure south of Cape Cod meanders through tomorrow
before slowly drifting southward by early next week. The low
continues to bring cooler conditions, a few showers, and impacts
along the coastline. High pressure builds in across New England
by late this weekend and early next week, bringing seasonable
temperatures and dry conditions.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Low pressure centered south of Cape Cod continues to bring
cooler and cloudier conditions for much of the forecast area.
Western areas remain the exception, with more sunshine and highs
still warming into the mid 70s there today. Elsewhere, highs
mainly top out in the upper 60s to low 70s with increasingly
thicker cloud cover toward the coastline. A few scattered
showers are also possible today near the coast and into southern
New Hampshire, but most of the rainfall continues to remain
offshore. A stiff onshore breeze will also be felt along the
coast today, with the breezy conditions diminishing away from
the coast.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
The onshore flow continues overnight, bringing some moisture
and patchy fog at times. Tonight looks like the best chance to
see some showers that may be enough to wet the grass along the
coast, but even this chance remains low. The HRRR is the most
robust with bringing in rainfall along the coastal plain
tonight, but appears to be the outlier, and has so far not
performed very well with this system. The rest of the guidance
remains nearly dry, with the Seacoast of NH standing the best
chance for a little bit of rainfall up to a tenth of an inch.

Tomorrow looks similar to today overall, but just a bit cooler
with highs in the 60s in most areas. Sunshine gradually
increases through the afternoon across northern areas as the
system begins to drift southward. Another day with minor coastal
flooding concerns and potentially dangerous surf is expected
tomorrow.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Overview: Low pressure will begin to drift southeast over the
weekend. This will slowly decrease shower chances in southern NH
and ME. Impacts continue along the coast in the way of coastal
flooding during high tide, dangerous rip currents and beach
erosion caused by high surf. High pressure to the northeast will
keep deeper moisture at bay, bringing a dry stretch through
early next week. The next chance for area-wide rainfall appears
to be around midweek as low pressure spins into the eastern
Great Lakes.

Details: With the center of low pressure set to remain outside
the Gulf of Maine into the weekend, there will be a challenge on
spread of showers and QPF. Currently forecast the best chance
for showers to remain along the southern coast and inland across
far western ME and central/southern NH Saturday daytime.
NAM/Canadian regional both depict a small, weak inverted
troughing feature developing across southern NH that could
prolong or increase rainfall amounts. Global guidance is not
picking up on this as this moment, but will keep PoPs lingering
in the area albeit slight chance to chance. Also opted to lower
daytime highs Sat in southern NH given more cloud cover. Extent
of cloud cover is a bit more uncertain for the other two thirds
of the CWA, but model soundings depict substantial mid level
drying that should only keep some cu around beneath broken to
overcast cirrus.

Highlight for the weekend will be continuing surge and swell
from the offshore low. See the below section on Coastal Flooding
for more details there.

Temperatures will remain in the 60s through to midweek. High
pressure to the northeast will back cool, dry air into Maine.
Preliminary lows fall into the 40s as well, with lower values
possible should some of these nights be clear with calm winds.
The next weather system to bring a chance of rain to the area
arrives towards midweek. This will be another slow moving low
pressure system, and there is still uncertainty on timing and
how potent its source of moisture will be. The system attempts
to occlude in the eastern Great Lakes, and this plus the
downstream block tends to modify its translation east. So, the
forecast includes a period of shower chances later this upcoming
week due to this uncertain passage.


&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
Short Term...Any LIFR due to fog at LEB and HIE improves by mid
morning. Elsewhere, IFR conditions gradually improve to MVFR by
late morning and linger most of the day. A period of VFR is
possible late this afternoon, and then ceilings likely lower
across most terminals again tonight. HIE and LEB likely see
nighttime valley fog again tonight. A few showers are possible
along the coast and southern New Hampshire tomorrow morning, and
then ceilings gradually improve to VFR by late in the day.

Long Term...MVFR ceilings improve towards VFR during the day
Saturday along with the chance for SHRA at southern terminals.
MVFR may work back in Sunday across a more broad area, but could
remain scattered under higher cirrus. General trend should be
towards VFR late weekend into early next week as high pressure
pushes in from the northeast.

&&

.MARINE...
Short Term...SCA conditions continue through tomorrow as a gale
center lingers south of Cape Cod. The system gradually begins
to drift southward by late tomorrow, but seas remain elevated
even as winds begin to gradually decrease.

Long Term...Waves remain 6 to 10 ft over the open waters
through the weekend. Waves will be lesser in the bays and
harbors, but swell will still be elevated. The source low
pressure system will be slowly drifting southeast, and do expect
these waves to be on the downtrend as a result, but waves to
6ft may continue into mid week.

&&

.TIDES/COASTAL FLOODING...
We are at the peak of our astronomical tide cycle through the
weekend with the highest tides occuring during the afternoon
hours. Meanwhile, a gale center will remain south of Cape Cod
over the next few days. This will lead to multiple cycles of
minor coastal flooding due to storm surge values approaching 1.5
feet, mainly from Portland and points south, however the
MidCoast may have some minor coastal flood issues or splash-
over as well this afternoon and tomorrow.

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 additional splash-over or coastal flooding as well.


&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...High Surf Advisory from 8 AM this morning to 7 PM EDT this
     evening for MEZ023-024.
     Coastal Flood Advisory from noon today to 3 PM EDT this
     afternoon for MEZ023>028.
NH...High Surf Advisory from 8 AM this morning to 7 PM EDT this
     evening for NHZ014.
     Coastal Flood Advisory from noon today to 3 PM EDT this
     afternoon for NHZ014.
MARINE...Small Craft Advisory until 8 PM EDT Saturday for ANZ150>154.

&&

$$


NEAR TERM...Clair
SHORT TERM...Clair
LONG TERM...Cornwell