424
FXUS61 KGYX 181409
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1009 AM EDT Wed Sep 18 2024

.SYNOPSIS...
High pressure lingers for one more day, but does begin to break
down tonight. Moisture over the southeastern states builds
north behind this this high with a slight chance for showers
over southern New Hampshire by Thursday. There may be a better
chance for showers Thursday night into Friday as low pressure
develops south of New England. High pressure builds in from the
north this weekend with more seasonable temperatures and dry
weather expected.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

1000AM Update...
Satellite imagery currently shows some lingering patchy fog in the
Connecticut River Valley, some isolated high-altitude clouds over
the region, with a bank of fog over the Gulf of Maine that is moving
into the coast of Maine. Will be keeping an eye on how this fog bank
evolves through the day as a sea breeze could help fog creep
into the Midcoast and Penobscot Bay this afternoon. Made some
slight modifications to the temperatures today, refreshing the
forecast with more recent guidance and observations.



Previously...
The ridging from the sfc through 500 MB hangs
around one more day, but it is being broken by 500 MB closed low
to our SW, and by weak waves moving through the jet well to our
N. So other than morning fog weve become so used to, and some
cirrus, it should be another warm and mainly sunny day, although
maybe more of a filtered sunshine in the south. While maxes
wont be as warm as Tuesday, they will still be quite warm by
mid September standards, and range form the mid to upper 70s on
the coast and into the low to mid 80s inland.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
By tonight, there will be very little flow up through 700 MB.
A mid-level col settles overhead, with no real sfc gradient.
This should allow the sea breeze to get going this afternoon,
and persist through this evening. With the passage of the sea
breeze, some marine fog and stratus is expected on the coast
later this evening. Higher dewpoints and some cirrus in the N
half of the CWA fog is expected. Low temps will generally be in
the 50s, low 50s N, to upper 50s in S NH and SW ME.

Thursday is a more tricky forecast, at least for temps. Given
that weak sfc low will track from roughly W-E S of New England
should see an onshore E-NE flow develop. Although it will be
weak. This combined with more clouds on the coast and in S NH E
of the CT vly will lead to the coolest temps in these areas.
There is also a slight chance of showers in srn NH as well,
with highs closer to 70 and probably some 60s on the immediate
coast. Most inland areas should make into the the mid to upper
70s, while the CT vly could see some reading near 80, given the
downslope and 850 MB temps temps still around 13-14C. I think
much of the CWA will see a partly sunny day, but S NH and the
coast will be mostly cloudy.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
12Z operational models and ensemble solutions continue to
indicate a disorganized area of low pressure will be centered
off the Northeast coast at the beginning of the extended period.
Moisture attempts to advect towards the Maine and New Hampshire
coastline with the best chances for precipitation Thursday into
Thursday night. Whether or not these showers will reach
southern portions of the forecast area will be highly dependent
on the amount of dry air in place over northern New England in
which the system would need to displace. For the time being,
will only have low probabilities for precipitation as our very
dry period continues across the region.

An upper level trough may bring a sprinkle or an isolated shower
to the interior of Friday. However, yet again any precipitation
would be very light. Otherwise, high pressure over eastern
Canada will keep us dry over the weekend and into early next
week.

Above normal temperatures on Thursday will be replaced by
seasonable readings for the remainder of the extended forecast.

Coastal Flooding...The onshore winds forecast for the coast late
in the week will coincide with very high astronomical tides.
This may lead to minor coastal flooding near the times of high
tide.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Yet another morning with valley fog and maybe some
brief sunrise fog at KCON/KAUG/KRKD, but VFR should return and
persist through sunset. Coastal terminals will likely see some
coastal stratus move in later this evening, with some fog
possible, while valley fog should return to KHIE/KLEB. Probably
the coastal stratus will linger through much of the day at the
coastal terminals, but should improve somewhat later in the
morning. The rest of the terminals should see improvement to VFR
by mid morning, which should last through the day.

Long Term...VFR likely prevails during the day time Friday
through Sunday. Night time valley fog will bring the potential
for IFR/LIFR most nights at KLEB and KHIE. Onshore flow and
increasing clouds from a system passing south of New England
will also bring the potential for cigs around MVFR thresholds
Thursday night and possibly into Friday.

&&

.MARINE...
Short Term...Winds/seas stay below SCA criteria through Thu, but
will see seas start to come up during the day on Thu, as low
pressure moves offshore from the mid Atlantic coast.

Long Term...Winds and seas remain below SCA thresholds Thursday.
a northeast flow will develop Thursday as low pressure
approaches and stays south of New England. Low pressure passing
south of the Gulf of Maine will bring seas building to 5 ft by
Friday with continued NE flow with gusts around 25 kts. Seas
remain elevated around 5 feet into the weekend with NE winds
subsiding from their peak on Friday.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...Cempa/Palmer
SHORT TERM...Cempa/Palmer
LONG TERM...Cannon
AVIATION...
MARINE...