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000
FXUS61 KGYX 180318
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1118 PM EDT Wed Apr 17 2024

.SYNOPSIS...
Clouds will be on the increase tonight into Thursday as a weak
disturbance brings a chance for light showers across New
Hampshire and far western Maine Thursday into Thursday
night. Temperatures will trend cooler as an onshore component to
surface flow builds, culminating in the passage of a frontal
system with light rain late Friday into  Saturday. Quiet, mild,
and dry weather, this time with more westerly flow, returns
late Saturday through early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
1115 PM Update... Minor changes to reflect latest observational
trends. Other than a stray sprinkle or light shower overnight
across southwestern NH, it will continue to be a dry night with
partly to mostly cloudy skies depending on location. Lows will
range from the upper 20s across northwestern ME and northern NH
to the lower 40s in southern NH.

Previously...
645 PM Update... High altitude clouds continue to slowly
advance over the region in association with a trough of low
pressure and sfc warm front that is located well to our south
and west. Other than loading in the latest sfc observations and
tweaking temperature/dewpoint/sky cover cover trends, the
inherited forecast remains unchanged.

Previously....
Another quiet night is in store, but clouds will
continue to increase from southwest to northwest through the
course of the night. Most of this will be across NH and to some
extent SW ME, and this should help keep temps milder across the
areas. Farther to the east and north, I have blended in some
cooler MOS to account for less clouds and light winds. Enough
moisture may also allow for a few light showers overnight across
SW NH as a shortwave trough approaches, but I think the better
potential will hold off closer to daybreak Thurs.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
The approaching shortwave trough will shift the upper ridge
ever so slightly to the east Thursday into Thursday night. This
shortwave will bring an increase in moisture across the region,
particularly over NH and far western ME (near the NH border),
and these areas will see more cloud cover along with some
showers, again especially over into NH. The farther east one
goes, there will be drier air and influence/subsidence from the
ridge, which should allow for some sun along with dry
conditions. Highs in the cloudiest areas are forecast to be limited
to the upper 40s to lower 50s, but farther north and east temps are
still forecast to reach the mid 50s.

Showers could stick around over these areas into the early part
of Thursday night, but once the wave passes, shortwave ridging
will build in, returning dry conditions the rest of the night.
For those that see rain showers, amounts are expected to be
light, ranging from a few hundredths to a tenth of an inch.
Worth mentioning, the GFS is more amplified with the shortwave,
which is the outlier solution, but should this occur, rain
amounts could be slightly higher.

An abundance of cloud cover and light southerly flow will keep
temperatures a little more mild than previous nights, ranging
from the mid 30s to lower 40s. Will also have to watch for fog
overnight as well with light onshore flow returning.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
An upper level ridge of high pressure off the Eastern Seaboard
is replaced by a broad upper level trough over the weekend.
While it will bring some unsettled weather, it is expected to be
largely unimpactful with light precipitation amounts. If
anything, this change in synoptic setup results in a change of
gradient flow more favorable for westerly flow... and less
favorable for onshore flow, which should make for a pleasant
stretch of Spring weather.

Starting Friday... surface high pressure will be centered near
the Bay of Fundy while a frontal system approaches from the
Great Lakes. Although starting the day dry, onshore flow off the
Gulf of Maine will keep conditions cooler and more humid. The
bigger question Friday morning will be what the status of the
marine layer will be... if it will be supportive of marine
stratus, and if so how widespread the stratus will be. Model
guidance has been less than impressed with stratus potential,
but does hint at this possibility over central and western New
Hampshire, which is where deeper moisture supports more cloud
cover anyway. Cloud coverage will have a lot of bearing on the
high temperature forecast as well, with highs in the 50s,
although closer to 50 (or the 40s) where clouds and marine air
combine... and closer to 60 where more sunshine and/or mixing
can take place. A cold front brings light rain showers,
generally less than a quarter inch total across the region later
in the day Friday through Friday night with some question as to
how quickly the front will move out. Would expect the overnight
to be fairly humid with potential for low clouds and fog too,
given more onshore flow residency.

Saturday will see the cold front exit with stronger mixing, drier
air, and breezier winds up to around 25-30 mph out of the west. This
will allow warmer temperatures as well despite a little bit of a dip
in t850, with highs generally in the 50s across the north but into
the low/mid-60s south of the mountains. There is a chance the front
hangs up a bit near our area, which would prolong clouds and lead to
a little cooler temperatures.

A cooler airmass briefly settles across the international border
Sunday into Monday under a broad upper level trough with clearing
skies. Predominantly westerly flow continues in the meantime, which
will keep the maritime influence at bay for the most part and allow
for a warming (and drying) trend. Highs are forecast to be in the
50s and low-60s, with light flow and interior surface heating likely
allowing seabreezes to develop. By Tuesday, high pressure is more
likely to be located to our south... setting up a more southerly
flow, with further warming over the interior especially west but
allowing more maritime influence along the coast and into
interior southern Maine.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Short Term...Mainly VFR through Thursday night. A weak
disturbance will bring some showers to the region early Thursday
into Thursday night, mainly across NH and maybe toward PWM.
Potential for MVFR ceilings will also be increasing for the NH
terminals during this time, perhaps IFR Thursday night.

Long Term...Restrictions in lowered CIGs possible Fri,
especially early in the day when IFR/LIFR is possible at NH
terminals. Confidence is low with these restrictions. MVFR to
IFR is more likely to develop Fri night into Sat with -SHRA and
lowered CIGs. VFR and W winds return late Sat or Sun, lasting
through the start of the coming week.

&&

.MARINE...
Short Term...SCA conditions are not expected through Thursday
night. Light S/SW flow will become NE/ENE tonight with high
pressure becoming centered north of the waters. The high moves
slightly to the east on Thurs/Thurs night veering winds more
E/ESE during the day Thursday with more light and variable
speeds/direction Thurs night.

Long Term...SE flow increases Fri/Fri night, with an unlikely
chance of touching 25 kts while seas similarly increase to 2-4
ft. A cold front crosses Sat with winds turning W to SW AOB 20
kts thru Sun and into Mon with daily sea breezes possible. S to
SE flow develops by midweek.

&&

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

&&

$$

NEAR TERM...Tubbs