Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 230212
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
912 PM EST Wed Nov 22 2017

.SYNOPSIS...
Low pressure will depart the region this evening. Thanksgiving
will be mostly sunny as high pressure moves into the area.
Another weak cold front crosses the region late Saturday
bringing rain showers with snow in the north. More high pressure
builds in for the start of next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
910 PM Update...Have made some minor forecast adjustments this
evening. Have increased wind gusts a bit for the next few hours
as strong CAA continues to aid in low level mixing. The back
edge of the rainfall (with some flakes mixing in) is located
over the Midcoast zones now and should be offshore in about 2
hours. Otherwise, increased cloud cover across NH for the next
few hours as well as bkn strato-cu advects overhead.

530 PM Update...Have updated the forecast mainly for
PoPs...based on latest trends in radar imagery. The back edge of
the precipitation shield is currently near the ME/NH border and
should last exit the region on the Mid coast of ME between 8 and
9 pm. Otherwise, temperatures will continue to cool and winds
will be gusty at times. Clearing downwind of the mountains
should begin in a few hours.

Previously...

Precip should be winding down from SW-NE late this afternoon and
early evening as sfc low offshore heads east and takes
deformation zone with it. Some reports from Coos county of rain
already changing to snow there, and snow the change to snow will
likely shift SW into parts of nrn Grafton before precip ends,
although little accum is expected with the tail end of this
system, and any more measurable accums will likely occur in
upslope areas this evening.

Shortly after the rain ends should see NW winds pick up, with
some gusts to around 20 mph possible this evening as well. CAA
should begin right behind the wind shift, and temps will begin
to drop. The CAA will be steady, but not overly strong, so temps
in most spots should fall slow enough to the wind and mixing to
dry out the roads before temps fall below freezing. Could be
some issues in the mountains, where temps are closer to
freezing now. Lows will drop to around 20 in the mountains, and
the mid to upper 20s in the southern zones. Skies will clear
quickly this evening. The winds will stay gusty through the
midnight hours, but should diminish during the pre-dawn.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
sfc high builds to our south on Thanksgiving beneath weakly
anticyclonic zonal flow at 500 MB. should see light winds and
plenty of sun. However, cold air aloft will limited highs to
around 30 in the north to the upper 30 to around 40 in the
south.

Thursday night will see a weak wave pass just the N of the CWA,
and this will spill some clouds across the CWA, and maybe some
SHSN in the far north. Lows will mainly be in the 20s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
The weekend begins with fairly zonal flow establishing itself
across North America with a weak system passing through on
Saturday. A few weak disturbances will cause some upslope
flurries and clouds but conditions will be generally mild
through the start of next week. Another trough digs in for the
middle of next week.

Friday will be fairly mild with weak ridging. High temperatures
will be in the 40s south to mid 30s north as we remain in the
warm sector of a cyclone passing through southern Quebec. Some
clouds and showers as possible along the international border as
the system passes to our north.

Saturday the low over Quebec deepens as it passes towards Happy
Valley (Labrador), this will bring a weak cold front across our
region for Saturday afternoon. With temperatures mostly rising
above freezing by the time the front pulls through mid afternoon
expect mostly rain showers but a bit of sleet or snow mixing in
at elevation is a good bet.

After the front we move into a period of general cyclonic flow
aloft without any major storms through the start of next week.
This will bring continued upslope snow shower to the
international border region.

Another storm system may impact the region by the middle of
next week but the variability in the deterministic guidance is
still so large it`s not reasonable to pin down any details at
this point.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Short Term...Any flight restrictions will improve to VFR at
most terminals by, if not before, 00Z, with VFR persisting
through Thursday into Thursday night. Could see a few N-NW wind
gusts to around 20 kt this evening.

Long Term...VFR conditions will continue through much of the
extended. The main exception to this will be along the
international border where upslope snow showers will persist
through much of the time period resulting in brief periods of
MVFR ceilings possible.

&&

.MARINE...
Short Term...SCA will remain in effect outside of the Casco bay
through Thu, as winds will pick up early this evening from the
NW, and begin to diminish during the day Thu. Seas will likely
stay abv SCA levels into Thu afternoon.

Long Term... Conditions will be fairly mild through much of the
next week with winds and waves remaining below small craft
through most of the time. A weak cold front moving through on
Saturday may result in a few 25kt gusts.

&&

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

&&

$$

NEAR TERM UPDATE...MLE


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