Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 302232
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
632 PM EDT SAT JUL 30 2016

.SYNOPSIS...
High pressure will gradually shift east tonight through Sunday as
a weak area of low pressure moves into southern New England. Low
pressure will slowly move off the New England coast Monday and
will continue to slowly drift east on Tuesday as high pressure
builds in from the west. High pressure will crest over the region
Wednesday and will shift offshore on Wednesday night. High
pressure will hold off the coast on Thursday. A cold front will
approach from the west on Friday and will cross the region Friday
night.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
625 PM...This updates fine tuned pops a bit...based on latest
mesoscale models...20Z HRRR/18Z NAM4K/19Z meso model blend...all
of which keep the threat of showers or isolated thunder from a
KLEB-KSFM line southward through at least daybreak, and probably
closer to 13-15Z. This is not a significant change to the forecast
and does agree with 12/18Z larger scale models that best dynamic
forcing stays mainly west of CWA, but weak WAA will slowly
pushinto SRN NH overnight. In this area, could see a few sprinkles
this evening, but best chance for precip will be after midnight.
Also, made some adjustments T/Td/Sky based on current obs and
tweaked mins slightly.

Previously...It will be a quiet start to the night...as clouds
increase from the W. This should keep it a few degrees warmer than
last night...especially for Srn zones where high clouds will be
the thickest. Farther N I think there will be enough clearing for
more temps in the 50s...and patchy fog in the favored low lying
areas.

A s/wv trof approaches late tonight...and though WAA increase
across the whole area...the strongest vorticity advection looks to
pass W of the forecast area. This means showers will increase
towards dawn...and be most likely for SWrn parts of NH.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Showers Sun will continue to slowly lift N and E as WAA continues
during the day. I will keep likely PoP confined to Srn NH and the
CT River Valley...where confidence is the highest. Farther N and
E...with precip tied to WAA and not vorticity advection I feel the
coverage will be more scattered to isolated. Forecast soundings do
show a small amount of CAPE...especially in Srn zones...so a
rumble of thunder is not out of the question. With all available
guidance right now...including hi-res ensembles...the best chance
for rnfl amounts approaching a half inch will from the Lakes
Region of NH and S to the MA border.

Upper trof continues to move overhead Sun night...so showers will
likely persist into the overnight. Without daytime heating the
coverage will probably be less widespread than earlier in the
day...but I think at least some PoP is warranted overnight. with
abundant clouds the overnight lows will be more mild and likely
remain in the 60s across the entire forecast area.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Broad area of weak low pressure will keep clouds and the chance of
showers in the forecast for both Monday and Tuesday. Moist onshore
flow will produce low clouds and area of drizzle...especially in
coastal areas.  Low pressure will continue to drift east on
Tuesday. Should see the chance of showers decreasing during the day
as best lift heads east into the maritimes. Expect clearing by late
in the day as high pressure builds in from the west. Should see
highs on both days in the lower to mid 70s.

Sunshine will return on Wednesday as high pressure crests over the
region. Highs will range from the mid 70s to lower 80s.

High pressure will shift offshore Wednesday night and will hold
off the coast on Thursday. Return flow will bring warmer and more
humid air back into the region. Expect highs on Thursday in the
lower to mid 80s. Fair weather will continue Thursday night with
lows ranging through the 60s.

A cold front will approach from the west on Friday. After a mostly
sunny morning clouds will be on the increase during the afternoon.
Showers and thunderstorms will likely arrive in northwest zones
during the late afternoon and early evening and this activity will
cross the region Friday night as the front continues east. High on
Friday will range through the 80s to near 90.

Cooler and less humid air will return for the weekend on gusty
northwest winds.

&&

.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
Short Term...There is some uncertainty with fog development
tonight...as cirrus moves in overhead. A thicker cloud layer may
prevent cooling enough to preclude fog...but for now I feel it is
likely enough at HIE to include in the TAF there. Otherwise VFR
conditions expected overnight. SHRA move into Srn zones early in
the morning...and MHT...PSM...LEB could see local MVFR in heavier
SHRA. CON is less certain until the afternoon hours. SHRA are most
likely for NH terminals...while it will be significantly more
scattered to isolated across Wrn ME.

Long Term...mvfr/ifr ceilings Monday and into Tuesday. Becoming
VFR Tuesday night and remaining VFR through Thursday.

&&

.MARINE...
Short Term...Winds and seas are expected to remain below SCA
thresholds thru the weekend.

Long Term...SCA"s may be needed Friday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$
SYNOPSIS...
NEAR TERM...Cempa/Legro
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...



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