Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 260223
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
923 PM EST Sun Feb 25 2018

.SYNOPSIS...
Low pressure will track northeast this evening bringing an end
to the precipitation across the region. High pressure will build
east from the Ohio Valley tonight through Tuesday. A weak cold
front will cross the area late Wednesday or Wednesday night. A
complex low pressure system will affect the area Thursday night
and Friday.

&&

.NEAR TERM /TONIGHT/...
930PM UPDATE...
All of the remaining measurable precipitation has fully exited
the forecast area, however there have been some pockets of
drizzle remaining. High low level moisture remains in place east
of the mountains in the wake of the departing low and is supported
by a lingering inverted trough. Some moisture also remains
trapped in western valleys. This will lead to fog and steady
temperatures overnight. Drier air moves in from the west during
the early morning hours which may bring the fog to an end
shortly before daybreak for some, and just after along the
coastal plain.

6PM UPDATE...
Will update the forecast primarily to drop the Winter Weather
Advisory as snow is ending. Will also adjust temperature
forecast over the next few hours based on latest observations.

ORIGINAL DISCUSSION...
Precipitation is starting to come to an end from west to east
as low pressure continues to track northeast along the coast.
Winter Weather advisories will be cancelled with this update
package for New Hampshire and southwestern Maine while the
eastern portion remains for a few more hours. Radar cc shows the
warm air aloft has shifted back to the south leaving a straight
rain/snow scenario for the next few hours.

As precipitation ends and skies begin to clear low level moisture
will linger allowing fog to form. Expect some patchy dense fog
overnight.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
Fog will rapidly lift after sunrise Monday morning as west flow
develops behind the departing system. This will lead to a few
upslope showers in the mountains. A high froude number for the
afternoon means a few of the showers may propagate over the
mountains and into the foothills but the overall low coverage of
shower activity means no significant accumulation is expected.

As high pressure builds in to start the week temperatures will
climb into the 40s across the region under light winds. Monday
night will be clear and colder as high pressure remains in
place.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
The ridge of high pressure over the area Tuesday will move offshore
Tuesday night.  Tuesday`s high temperatures will be mainly in the
40s across the region.  As the ridge moves offshore Tuesday night, a
cold front will drop slowly southeast from Canada and cross the
region late Wednesday and Wednesday night.  The frontal passage
could be accompanied by a brief sprinkle or flurry in the
mountains, otherwise, the front should pass through the
remainder areas without any precipitation. Before the front
passes, temperatures across northern areas will reach near 40
with southern New Hampshire reaching the low to mid 50s.

On Thursday, low pressure moving southeast from the Ohio River
Valley will bring the threat of precipitation to New Hampshire
and southwestern Maine by late in the day as warmer air streams
northward ahead of the system. Models have been flip-flopping on
the track of this system. Latest GFS tracks the system much
farther south with only limited impacts on just southern New
Hampshire and southwestern Maine. In contrast, the latest
European model has now shifted the storm farther north with
more significant impacts, especially across southern section. In
either case, the storm could produce strong northeast winds and
building seas on Friday. Given the inconsistencies among models
and the inconsistencies between runs of the same model, there
is considerable uncertainty in the eventual track of the storm
and any impacts.

The low is forecast to move well out to sea Saturday. A ridge
of high pressure will then build into the area for Sunday and
Monday.

&&

.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
Short Term...Snow will come to an end from west to east with
ceilings returning to VFR in its wake. The increase in clouds
will be short lived as many location drop to IFR in fog
overnight. Fog will burn off after sunrise as VFR returns to
start the week.

Long Term...VFR conditions expected Tuesday into Thursday.
Depending on storm track, IFR conditions are possible late
Thursday through Friday, especially across southern New
Hampshire and southwestern Maine.

&&

.MARINE...
Short Term...SCA remains in effect through tonight as onshore flow
continues to gust around 30kts. Winds and seas will subside later
tonight as the low exits the area.

Long Term...Winds and seas are expected to be below SCA criteria
Tuesday into Thursday. Increasing winds and seas are expected
during the day Thursday. An intensifying storm off the mid-
Atlantic coast Friday could produce gale force winds across the
waters.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 7 AM EST Monday for ANZ150-152-154.

&&

$$

NEAR TERM UPDATE...Kimble
SHORT TERM...Curtis
LONG TERM...Jensenius


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