498
FXUS61 KGYX 080351
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1151 PM EDT Tue May 7 2024

.SYNOPSIS...
High pressure shifts out of the area tonight as low pressure
approaches from the west. Widespread showers overspread the
region on Wednesday with some thunder possible across southern
and western NH Wednesday afternoon or evening. Another system
follows for the end of the week, bringing more showers into the
forecast. The unsettled, showery pattern may continue through
the weekend.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...

11:50pm Update... Just minor tweaks to temps and cloud cover
for tonight. Temps have dropped into the upper 40s and 50s in
most spots, and will only slowly fall further overnight as
clouds continue to increase. High tide looks to be cresting just
below flood stage in Portland, and a hair above in Hampton, but
both sites are within an inch of minor flooding. The tide will
be going out soon, and the rest of the night looks quiet until
showers begin to arrive tomorrow morning in the daylight hours.

8:30pm Update... Just a quick update to add the coastal flood
statement. Tides are running about 0.5 to 0.7ft above the
astronomical tides, and should be right near minor flood stage
during tonight`s high tide.

7:15pm Update... Mostly just tweaked temps for this evening
based on trends and latest guidance. Warm temps have held on
into the early evening hours, but should fall quickly over the
next few hours before clouds spread in from the west overnight.
Still watching the high tide in a few hours as well, which may
require a statement if the water anomaly doesn`t slacken off
over the next hour or so as the sea breeze dissipates.

Previous...

The sfc high over the area continues to get pushed gets slowly
tonight, as weak sfc wave moves in from the W. Sfc flow
generally becomes stagnant tonight, with zonal flow at 500 MB,
and mostly weak flow at mid levels. It should stay fairly clear
through the evening but cirrus starts to move in around the
middle of the night, with lower clouds and showers possible in
NH toward daybreak. Should see some decent cooling early, but
the warm afternoon will counteract this a bit with a warmer
starting point. So, mins drop into the 40s in many spots, with
some colder upper 30s in ME mtns, and maybe bottoming out
around 50 in the more populated areas of S NH.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
Showers move in early in the morning across the CWA, with the N
and E holding off until closer to midday. As the weak sfc low
approaches from the W, will pick up a light to moderate onshore
flow which will limit initial warming in the morning, and kind
of stall temps where there are by noon, or allow them to cool
some closer to the coast. This should bring maxes into the 55-60
range across most of the area, but temps will drop closer to 50
during the afternoon near the coast. Also, once the onshore, E
flow picks up could see some downsloping, which may allow spots
in the CT valley to get into the low 60s. Some thunder is
possible too, especially around midday as the marine layer will
not be well established and there will more instability being
generated from lowers levels. Best chance for T will be over the
srn third of NH. The best chance for rain to become steadier at
times will be Wed be from around midday Wed to around sunset.

Showers linger into Wed evening but should see some drying after
midnight, as we move to the back side of the low, and some
drying behind it. Should also more fog late Wed night, and still
a lot of clouds, as low level flow becomes weak again. Lows will
be mainly in the 40s again.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The pattern of unsettled weather will continue to finish up this
workweek and the upcoming weekend with chances for rain each day,
especially Thursday and Friday, and possibly light snow
accumulations in the highest elevations. This is due to longwave
troughing setting up basically over the eastern CONUS with embedded
waves bringing these opportunities for precip.

Starting Thursday...some drying aloft may provide a lull in precip,
but with abundant moisture in the low levels, skies look to remain
mostly cloudy with drizzle possible as well, especially in the
morning. The better chances for rain arrive later in the day into
Thursday night as shortwave energy moves overhead and low pressure
moves offshore of the DELMARVA region. The better moisture will be
closer to the low with a steady drop off with northward extend so
the higher amounts and chances will be generally across southern NH
and SW Maine. I have gone slightly cooler with high temps for
Thursday as we`ll have a light NE flow in addition to the expected
cloud cover and increasing rain chances.

This cloudy, cooler, and showery weather will likely persist into
Friday, and we`ll be holding onto the NE flow, so I have again kept
temperature cooler than the NBM, which puts highs in the upper
40s to low 50s. Light snow accumulations are possible in the
highest elevations for Thursday and Friday.

The weekend doesn`t look like a washout, but additional shortwaves
will bring more chances for rain with some breaks in between. The
global models are struggling with the timing and placement in these
waves, so I have not deviated too much from the NBM chances PoPs
through the weekend.

There are hints of a brief drier period around Monday in the
operational GFS/ECMWF with a shortwave ridge building in. However,
the majority of the individual ensemble members continue to
advertise additional QPF in this time frame, and given the pattern,
it seems like a good idea to keep a chance of rain showers in the
forecast.

&&

.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
Short Term...VFR should hold through tonight, with MVFR cigs
arriving at the coast around 12Z or so, as the marine layer
moves in, and overspreading much of the rest of the CWA during
the morning. As is often the case, KHIE, may stay VFR well into
the afternoon as downswing develops. By Wed evening, it seems
like everything should drop to IFR, with some LIFR possible in
fog at the coast.

Long Term...The weather pattern will remain active to finish up this
week and going into the weekend. Multiple waves of low pressure will
bring opportunities for rain each day with increasing potential for
MVFR to IFR flight restrictions, especially Thursday and Friday.
Between rounds of rain, some improvement is possible, but there
will continue to be the threat for fog and low ceilings.

&&

.MARINE...
Short Term...Winds/seas pick up a little out of the east and NE
on Wed, but for a brief time, and are expected to stay below SCA
criteria through Wed night.

Long Term...SCA conditions are not expected on Thursday but will be
possible Thursday night into the Friday timeframe with low
pressure expected to pass near but just east of the waters.
However, timing of the low pressure is uncertain right now.
Depending on when this low passes, a period of improvement will
probably occur, but another low pressure center may move across
the waters in the Sunday to early next week time frame.

&&

.TIDES/COASTAL FLOODING...
High astronomical tides combined a small of storm surge may
push water levels to minor flood stage along the coast with
this evening`s high tide, as well as the Wednesday night and
Thursday night high tide.

&&

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

&&

$$


NEAR TERM...Clair
SHORT TERM...Cempa
LONG TERM...Combs