Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 250223
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
923 PM EST Fri Nov 24 2017

.SYNOPSIS...
A warm front will lift northeast through southern Canada through
tonight. A cold front will approach from the west and cross the
region Saturday afternoon and evening. A shallow ridge of high
pressure will build in from the west on Sunday. A secondary cold
front will drop south through the region Sunday night. High
pressure will build in from the west Monday and will crest over
the region Monday night. High pressure will shift east on
Tuesday as a cold front approaches from the west. The front will
cross the region Tuesday night and early Wednesday and will be
followed by high pressure Wednesday afternoon.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
925 PM Update...Just a few minor adjustments to the going
forecast, mainly for temperatures. Some mixing is beginning to
take place resulting in rising temperatures while other areas
are still coming down due to radiation. Have tried to adjust for
that as good as possible. Otherwise, mostly clear skies will
persist with dry weather overnight.

625 PM Update...Have lowered min temps for tonight in most
places as clear and calm conditions are present over a good
portion of the forecast area. The biggest change was across NH
where mins are already close to being met in many areas. There
is a chance that temps will rise in some areas later tonight as
the low level jet gets going, but not before going down into the
20s.

535 PM Update...Little change to the going forecast. Increased
clouds a bit across northernmost zones in the western ME
mountains as a short wave trough crosses the region. A few snow
showers possible on the Canadian border through 00z or so.
Otherwise, mostly clear elsewhere.

Previously...

WAA ongoing from the intl border northward, and see some some
SHRASN skim the far nrn boundaries of the CWA this afternoon,
but the trend will be for all this to lift poleward tonight,
with a continue clearing trend through the evening. For the most
part should stay mainly clear through most of the night, with
some cirrus moving in from the west late. Temps are a bit of a
challenge due to strong low level jet developing above the
strong BL inversion. How much this prevents decoupling in the
sheltered is the question. For the most part, the bulk of our
temp falls will occur this evening, before low level jet
arrives, with temps staying close to steady late tonight. Look
for mins in the mid-upper 20s N, to the mid 30s in the south.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Saturday will see approach of a sfc cold front from the west as
500 mb trough deepens near the Great Lakes. This looks to
develop weak anticyclonic flow at 500 mb, which should help keep
precip out of the CWA for most of the day. Could see a few
showers work in N of the Whites and along the intl border in ME
during the afternoon, but for the most part any showers should
hold off across the rest of the CWA until after sunset. Even in
the N, these will mainly be SHRA, with any snow limited to the
higher terrain. Highs will be mild in the SW flow, ranging from
the mid 40s to the low 50s. Mid-high clouds should overspread
most of the CWA in the mid-late afternoon.

Sat night will see the front move through the CWA. There`s not
forcing out ahead of the front initially, will cap with chc
pops, which are highest in the N. South of the mtns any showers
will likely be rain overnight. SHRA will begin to change over to
SHSN, especially after midnight, as the front moves through and
flow shifts NW, we move into the upslope phase there. Also,
could see some showers develop along the mid-coast and Penobscot
valley as nrn stream wave begins to phase with sfc coastal low
and srn stream wave to our S and E, and precip starts to develop
in mid level deformation zone as that low deepens to our east.
Temps will fall off slowly Sat evening, and then drop more
quickly one the front moves through late with lows once again on
the mild side, generally in the upper 20s N, to mid 30s S.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
The deterministic models remain in decent agreement on the long
wave pattern through early next week. We begin the period with
an upper trough quickly going negative tilt in response to
shortwave energy arriving from the Great Lakes. An offshore cold
front and rapidly deepening surface low over the maritimes will
have little or no impact on our sensible weather...as model trends
has been ever further offshore. We`ll see some gusty northwest
winds on Sunday behind the offshore system...and a few clouds
and snow showers mainly over our eastern Maine zones and in
upslope across the higher terrain. Otherwise...a quiet and
seasonable day to round out the weekend. Another shortwave
impulse will cross the region Sunday night and early Monday with
clouds... and a few snow showers across the higher terrain. The
associated surface cold front will introduce even cooler air
into the area for the start of the new work week. The upper
trough will lift out by Monday night with rising heights and
resultant ridging downstream of an upper trough over the western
CONUS providing the forecast area with milder weather Tuesday
and Wednesday. Passing shortwave energy to our north with an
associated surface low will drive a trailing cold front with
rain/snow showers through the region Wednesday. Ridging and dry
air follows briefly for Thursday.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Short Term...VFR expected through Sat evening. Low level jet
moving across the areas will likely remain above the BL, and
should produce some wind shear with light sfc winds and 30-40
kts at 2K feet after midnight tonight into Sat morning.

Could see some tempo MVFR flight restrictions in showers Sat
night.  Best chc would be at KHIE and KRKD.

Long Term...

Sun - Mon AM...NW sfc wind gusting to 25 kt.
               Sct MVFR in MTN -shra/-shsn.

Wed...Sct MVFR in Mtn -shra/-shsn.

&&

.MARINE...
Short Term...SCA will remain in place tonight and Sat as SW
winds increase this evening, and peak out with 30 kt gusts late
tonight into Mon morning. Winds diminish Sat afternoon.

Long Term...

Sun - Tue...Small craft conditions are possible outside the bays.

Wed...Small craft conditions are possible with gusts approaching
 Gale outside the bays.

&&

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

&&

$$

NEAR TERM...Ekster
SHORT TERM...Cempa
LONG TERM...Schwibs



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