Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 220811
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
411 AM EDT Tue Aug 22 2017

.SYNOPSIS...
High pressure moves off to the east today. A strong cold front
will move across the region tonight and early Wednesday. High
pressure and drier air follows the front Wednesday night through
Friday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Some patchy early morning Valley fog along the Ct River
otherwise a mostly sunny start to the day. Considerable
moisture advection with very high PW`s and increasing shear
will result in rapid destabilization of the atmosphere during
the afternoon. This will result in strong to possibly severe
thunderstorms to develop first across NH and then spread east
into Maine by mid to late afternoon. Temps will be very warm
with highs in the mid to upper 80s. Pooling dewpoints reaching
near 70 will make it feel very muggy.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
The cold front and upper trof press east tonight allowing the
strong thunderstorms to continue in advance through most of the
evening before slowly weakening later at night and becoming
more widely scattered. The cold front moves off the coast
Wednesday morning allowing for cooler, drier air, and clearing
in its wake during Wed as high pressure builds in from the
west.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The system that will bring rain to us today and Wednesday will
be its way out on Thursday. The parent surface circulation will
be well north in Quebec while the cold front which sweeps
through Wednesday morning will be well offshore. Aloft a deep
trough will continue to spin bringing occasional clouds and
isolated showers to the mountains...mainly in the heat of the
day each afternoon. However, for the most part large sprawling
high pressure which has been dominating the central states will
move into and strengthen over New England. This along with drier
air will suppress any further activity despite the persistent
troughing aloft. The exception to this may be a back door cold
front which could spark off a few showers on Sunday.

Temperatures will generally be close to normal values /mid 60s
north to mid 70s south/ for highs. Overnight lows should drop
into the 40s and 50s most nights under partial to complete
clearing and light winds.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
Short term...Patchy early morning fog in the CT River Valley
otherwise VFR this morning. Conditions lowering to MVFR and
locally IFR in developing afternoon and evening thunderstorms.
Some of the storms will be strong with gusty winds and possible
hail. The thunderstorms will weaken later in the evening but
scattered showers with MVFR conditions will continue until the
passage of the cold front by Wednesday morning. Conditions will
improve to VFR behind the FROPA Wednesday.

Long Term...Some patchy fog is possible early Thursday
morning...especially where it has rained. Also some mountain
valleys may radiate to the dew point each morning Friday and
Saturday.

&&

.MARINE...
Short Term...Winds and seas will increase later today and
tonight as the south to southwest flow increases ahead of the
approaching cold front. SCA conditions will develop this
afternoon and continue through tonight and into Wednesday.
The cold front will cross the waters Wednesday allowing a
gradually wind shift to the west helping knock down the seas by
later in the day.

Long Term...Winds and seas will remain calm for the remainder of
the week.

&&

.TIDES/COASTAL FLOODING...
We`re in the period of high astronomical tides for the month of
August. The high tides of potential concern (referencing
Portland Harbor where flood stage is 12.0 ft MLLW) are:

1231 AM Wednesday. 11.1 ft MLLW

The Tuesday night high tide (1231 AM Wednesday) could see some
splashover as onshore flow and seas increase ahead of an
approaching cold front.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory from 8 PM this evening to 8 AM EDT
     Wednesday for ANZ151-153.
     Small Craft Advisory from 3 PM this afternoon to 8 AM EDT
     Wednesday for ANZ150-152-154.

&&

$$

NEAR TERM...Marine
SHORT TERM...Marine
LONG TERM...Hanes



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