Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 171425
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1025 AM EDT Wed Apr 17 2024

.SYNOPSIS...
High pressure nearby will ensure a quiet period of spring
weather in New England for today. Temperatures will trend
cooler as an onshore component to surface flow builds,
culminating in the passage of a frontal system with light rain
late in the week. Quiet, mild, and dry weather, this time with
more westerly flow, returns by the start of next week.

&&

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

1025 AM Update...Forecast remains in good shape at this hour
with only the usual edits to near term temps/dewpoints to
align with observations.

645 AM Update...Very little change to the going forecast. Just
some slight adjustments to temperatures for the next couple of
hours.

Previously...

High pressure will be nearly directly overhead today providing
for a fair weather day with lighter winds and and near normal
temperatures. The center of the high slides to our southeast a
bit this afternoon. This combined with weakening opposing
westerly flow will allow a seabreeze to form this afternoon
which will cool the coast down.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
The next short wave trough will approach from the west tonight
and Thursday. The high pressure system nearby will attempt to
fight off clouds and any precipitation. However, at the very
least, we expect an increase in high clouds tonight, especially
across NH. There remains some model differences in how effective
the dry air mass in place will ward off light rain showers. Some
guidance allows for light rain across western NH as early as
tonight while others remain too dry to precipitate, even through
much of Thursday. Will compromise here and add some chance PoPs
to southwestern NH tonight and then spreading these lower PoPs to
much of the rest of the state on Thursday while keeping Maine
dry. Any rain that falls in NH late tonight and Thursday is
bound to be light.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Overview: A few chances at light precipitation Thursday night
and again Friday night into Saturday morning, then a period of
dry weather. Temperatures run a couple degrees within normal,
and will be at mercy of cloud cover for the first half of the
weekend.

Details: Some mid range models, namely in the NAM camp have
come a bit higher in PoPs and QPF for Thursday evening and
overnight. This continues to be mainly across NH, as dry air
remains in the low and upper levels in much of southern ME.
Globals tend to be lighter and thinner in coverage, and
continue to follow this trend through midnight. Think this could
easily dwindle to be a few isolated showers with sprinkles in
between, offering little additional wetting potential.

Some breaks in clouds will be possible Friday afternoon, but
otherwise moisture remains in low levels for daytime heating to
develop cu out of. Multiple cloud levels may temper daytime
highs a bit, but main talking point is incoming cold front with
additional rain chances overnight into Saturday.

High pressure will be shifting east out of the Gulf of Maine
Friday afternoon and evening as front rushes east into New
England. Combo of retreating high and S flow in warm sector will
encourage onshore winds with humid low levels, so overnight
lows will be mild. While moisture profile looks better, they
still lack deeper moisture for higher QPF amounts. Bulk of
precip should fall overnight, with just some wrap up showers
come Sat morning. Clouds should decrease into afternoon across
interior and coastal locations, but moisture around 700mb keeps
some mid deck clouds around. Deep mixing will aid with surface
drying and breeze into the evening.

Drier conditions arrive Sunday thru Tuesday as high pressure
moves into the eastern CONUS. Will see warming trend starting to
take effect early next week, with temps pushing a few degrees
above normal. Afternoons likely become breezy as mixing level
deepens and picks up on passing mid level jet and low level NW
flow.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
Short Term...VFR expected through tonight. The seabreeze will
result in a wind shift at coastal sites in the 16Z to 19Z
timeframe, and it may progress far enough to inland to reach MHT
and CON by 22Z to 23Z Wednesday which would turn winds easterly.
Some light rain is possible across western NH late tonight and
Thursday but conditions should remain VFR.

Long Term...VFR, with MVFR ceilings beginning to spread into NH
Thursday night and Friday morning. Ceilings continuing to
deteriorate late Friday with MVFR moving into ME terminals and
IFR spreading north into the evening. -SHRA likely accompanies
these ceilings, with occasional lower vis. Some uncertainty how
quickly ceilings improve come Saturday morning, but should be
west to east progression. Chances of MVFR/IFR become much lower
after noon local time.

&&

.MARINE...
Short Term...Conditions expected to remain below SCA levels
through Thursday. NW winds will go onshore this afternoon as a
seabreeze develops.

Long Term...Seas/winds remain below SCA, but conditions do
approach these levels Friday night into Sat morning as a cold
front passes over the waters. Waves build 3 to 4 ft, with some
gusts to 25 kt possible during this passage.

&&

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

&&

$$


NEAR TERM...Combs/Ekster
SHORT TERM...Ekster
LONG TERM...Cornwell


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