519
FXUS61 KGYX 212309
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
709 PM EDT Sat Sep 21 2024

.SYNOPSIS...
Low pressure south of Cape Cod lingers into Sunday before
slowly drifting southward 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 AM SUNDAY MORNING/...
700 PM Update... Issued a coastal flood advisory for coastal
Cumberland, York, and Rockingham counties for Sunday afternoon`s
high tide cycle. Otherwise, some light rain continues across
portions of NH and extreme western ME, which as noted previously
is poorly represented in model guidance. This light rain will
likely persist for a few more hours as it slowly drifts eastward
while becoming more isolated in nature as a subtle vort max
sinks southeastward. Other than making some minor adjustments
to temperatures, winds, and sky cover the inherited forecast
remains on track.

Inverted trof continues to produce steady light rain over much
of southern NH. I have increased PoP again and keep it more or
less thru daybreak...especially for the Seacoast. I had to go a
little off script from model guidance...which does not have a
very good handle on precip at the moment. I do not see much
changing regarding forcing at least into the evening...so I
suspect rain will continue to fall. While amounts are not going
to reach levels seen down on Cape Cod...an additional half inch
is possible in the most persistent rain bands. Cloud cover will
keep temps on the mild side tonight...but clearing on the edges
of the clouds may result in some radiation and valley fog
formation. I have added it to the CT River Valley based on
persistence from last night.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Clouds will continue to gradually clear Sun...though northeast
winds will ensure that temps remain near normal to below normal.
Clearing and surface ridging will allow temps to radiate better
than the last couple of nights...with lots of 40s and some upper
30s possible. Valley fog is likely...especially in the CT River
Valley.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
The 500 MB pattern through next week across NOAM continues to
become more blocky, especially over the E half of the continent
and the N Atlantic. The cooler ridge that move in for early next
week will be replaced by an approaching trough to our W, and
which models close off /to differing degrees/ over the E CONUS
Thu-Fri. So, the period from Wed-Fri looks unsettled, although
unlikely to rain the whole period, still need to have models in
batter agreement on the timing, and strength of the systems.
Still, it should warm up in the mid levels mid-late week, but
given the way things are setting up, it looks like onshore or NE
flow may dominate, keeping temps cooler, but still fairly close
to normal. Interestingly enough, it is around the time of the
equinox, and there is almost no below freezing air at 850 mb S
of the arctic circle, and no sign of a major cold air intrusion
any time soon according tho the models.

Monday and Tuesday should be partly to mostly sunny with highs
mostly in the mid to upper 60s, and overnight lows mid 40s to
low 50s. By Wed, as the 500 trough deepens equatorward out of
ON/QC will begin to see the threat of some showers, but for now
the best chance looks more Wed night. Highs on Wed may end up a
few degrees cooler than Mon or Tue but still in the 60s. That
upper level closed low then drift Se across New England and
deepens Thu, which continue the threat for rain, and then may or
may not produce a coastal low near S New England which moves
offshore. Moisture in the column is fairly high by Friday, and
the 12Z Euro brings a bullseye of heavy rain into New England,
which does raise a red flag, as sometimes the models are onto
something, but it is more of general signal to watch for heavy
rain, that something to be taken too literally. Despite the
rain, the warmer and more humid air will allow for highs mid 60s
to around 70 at the end of the week.

&&

.AVIATION /23Z SATURDAY THROUGH THURSDAY/...
Short Term...Areas of MVFR CIGs will continue across southern NH
northeast into the Casco Bay region. Gradually those CIGs will
scatter out and lift this evening and overnight. On the fringes
of cloud cover some valley fog may form tonight...and I have
added IFR VSBY to LEB. VFR conditions expected Sun...with a
better potential for valley fog Sun night.


Long Term...Mainly VFR expected Mon-Wed, although flight
restrictions become possible by Wed night into Thu, as there is
some potential for rain and low cigs.

&&

.MARINE...
Short Term...Persistent northeast winds continue thru the
period. Gusts will be marginal SCA at times...but seas will
remain at or above 5 ft outside of the bays into Mon. Even the
eastern portions of Casco Bay will see the higher seas...so SCA
remains for those waters.

Long Term...While winds are likely to remain
below SCA criteria the pulses of low pressure S of the waters
over the next several days will keep the swell up near 5-6 feet
through the middle of next week.

&&

.TIDES/COASTAL FLOODING...
Tides continue at their astronomical peak for the month...with
the highest tides occurring during the afternoon hours. With an
ocean storm still spinning south of Cape Cod...storm surge will
continue to run between one half and one foot on northeast
winds. Another round of minor coastal flooding...splash-
over...and erosion is likely from Portland south Sun afternoon.

Beach surveys and Emergency Managers continue to indicate
compromised dune systems along the coastline from our storms
this past winter...which will limit natural protection.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...High Surf Advisory until 8 PM EDT Sunday for MEZ023-024.
     Coastal Flood Advisory from 2 PM to 5 PM EDT Sunday for MEZ023-
     024.
NH...High Surf Advisory until 8 PM EDT Sunday for NHZ014.
     Coastal Flood Advisory from 2 PM to 5 PM EDT Sunday for NHZ014.
MARINE...Small Craft Advisory until 8 PM EDT Sunday for ANZ150-152>154.

&&

$$

NEAR TERM...Tubbs
SHORT TERM...Legro
LONG TERM...Cempa