Area Forecast Discussion Issued by NWS Portland, ME
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000
FXUS61 KGYX 181939
AFDGYX
Area Forecast Discussion
National Weather Service Gray ME
339 PM EDT Mon Mar 18 2024
.SYNOPSIS...
Cyclonic flow this week promotes breezy west-northwest flow,
temperatures trending cooler toward seasonal averages, and light
snow and rain showers driven by instability. Showers will be
mostly confined to the mountains, however, a quick-hitting
clipper will likely bring more widespread showers all the way
to the coast Wednesday into Thursday. Cool high pressure returns
late in the week, with a low potential for another system this
weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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Visible satellite imagery this afternoon shows a plethora of
diurnally driven and upslope clouds across the region with
Northeast radar mosaic showing some weak returns, mainly over
the mountains. Current temperatures range from the 30s across
the north to the middle 40s in southern NH and southwestern ME.
It will continue to be a partly cloudy afternoon with a few
scattered flurries and sprinkles.
After some initial clearing this evening, clouds will be on the
increase again overnight as a shortwave trough and associated
cold front drop south over New England. Scattered snow showers
will remain possible through the night but they will be mainly
confined to the far north and mountains. Low temperatures will
range from around 20 across the north to the lower 30s in
southern NH and coastal southwestern ME. Locally colder readings
will be possible wherever winds decouple and skies remain more
clear.-- End Changed Discussion --
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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The upper level pattern will become more zonal in nature on
Tuesday as sfc high pressure builds to our south and west.
Similar to today, daytime heating will allow for the development
of a cumulus field during the afternoon but moisture depth does
not look very deep as afternoon mixing helps to dry out the
lower and mid-levels. As a result, despite these clouds, any
scattered flurries will be limited in scope and confined to the
higher terrain... especially early in the day. Highs will range
from the 30s across the north to the middle 40s south. It will
remain a little breezy with west-northwest gusts up to around 25
mph, which will make it feel a little cooler.
Tuesday night will feature increasing clouds ahead of a weak
system that will be approaching from the west. There will also
be an increasing chance for scattered snow showers after
midnight, especially over western NH. Lows will range from the
upper teens to upper 20s from north to south.-- End Changed Discussion --
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
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An Alberta Clipper will cross the region to start out the long
term portion of the forecast. This will bring snow showers or a
period of steady snow to northern portions of the forecast area
Wednesday with temperature profiles supporting rain showers over
southern sections. This system will likely lead to redevelopment
along the Maine coastline Wednesday night. Cold air advection
will develop on the back side of this system. This will change
any leftover liquid precipitation back over to snow during the
night. Some icy locations may develop with morning lows in the
20s in the north and near 30 degrees in the south by morning.
The low pressure system will continue to undergo intensification
on Thursday as the surface low exits through the Canadian
Maritimes. Winds will become aligned through an increasing
layer in a full cold air advection mode. Bufkit profiles suggest
wind gusts up to 40 kt will be possible during the day with
higher gusts over the mountains and hilltops. It will be chilly
with highs only in the 20s north to the 30s south.
It will also be very dry with low surface dew points during this
period. Have forecast on the lower spectrum of guidance in terms
of the dry air advecting over the region in addition to the
influence of downslope drying.
Windy and cold conditions will continue Thursday night. Have
increased pops for the mountains where upslope snow showers will
be continuing.
High pressure will build into New England from Canada on Friday
with cold and dry air remaining over the region. This sets the
stage with rain and snow possible over the weekend. Models
continue to struggle with the timing and placement of an area of
low pressure ejecting out of the southeastern United States. In
any case, additional precipitation would be tacked on to our
wettest start to the month of March in Portland.-- End Changed Discussion --
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
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Short Term...VFR conditions expected with WNW winds prevailing.
Gusts up to around 25 kts will remain possible through 00Z
Tuesday and again from 14Z-00Z Wednesday. The exception will be
at KHIE where MVFR ceilings are likely tonight through early
Tuesday. No LLWS is expected.
Long Term...Lowering ceilings and precipitation in the form of
rain and snow showers will enter the region on Wednesday.
Conditions will lower to IFR in most areas, especially northern
areas which may have a period of steady snow along with areas of
LIFR conditions. These conditions continue Wednesday night as
low pressure develops near the Maine coastline.
VFR conditions expected outside the mountains on Thursday and
Thursday night. A tight west to northwest gradient will lead to
very gusty winds in a cold air advection pattern with wind gusts
up to 40 kts possible. Windy conditions will continue Thursday
night with some upslope snow showers remaining across the
upslope facing higher terrain.
VFR conditions expected all areas on Friday as high pressure
settles over the region with diminishing winds.-- End Changed Discussion --
&&
.MARINE...
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Short Term...WNW wind gusts up to around 30 kts will remain
possible through early this evening across the outer eastern
waters with seas of 3-5 ft. Winds weaken some tonight through
Tuesday with gusts generally between 15-20 kts, although a few
gusts up to around 25 kts will remain possible. Across the bays,
wind gusts up to around 20 kts can be expected with seas of 1-3
ft.
Long Term...Low pressure approaches the waters on Wednesday,
with the low then strengthening in the Gulf of Maine late
Wednesday night and Thursday. Westerly gales are possible behind
this low Thursday afternoon and night as the low moves into the
Canadian Maritimes. High pressure then builds across the waters
late in the week behind the low. Low pressure develops south of
the waters off the Carolina coast next weekend.-- End Changed Discussion --
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
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ME...None.
NH...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for
ANZ150- 152.-- End Changed Discussion --
&&
$$
NEAR/SHORT TERM...Tubbs
LONG TERM...Cannon