Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 200229
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1029 PM EDT Thu Oct 19 2017

.SYNOPSIS...
A cold front will cross the region tonight and will be followed
by high pressure on Friday. High pressure will hold over the
region on Saturday and will drift east saturday night and
Sunday. A cold front will slowly approach from the west Sunday
night and Monday and will stall to the west of the region Monday
night and Tuesday. The front will slowly drift east Tuesday
night and Wednesday.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
1025 PM...Just some tweaks to T/Td overnight, bit otherwise
forecast in good shape. Mins will ultimately depend on how
quickly front moves through and if there any chance for
decoupling behind the front through sunrise. Latest forecast mins
are a bit lower than current obs would suggest given some light
mixing to account for the late decoupling.

730 PM...Just a quick update, mainly to show higher sky cover,
with lots of cirrus, but very little of it is opaque, so more
partly cloudy than mostly cloudy thru the evening. Once the
front goes thru should clear out again after midnight. Also
made a few adjustments to T/Td/wind based on currents obs, but
overall forecast remains on track.


Weak moisture starved cold front will swing through the region
overnight with little more than passing clouds through the
evening hours. Lows overnight will generally range through the
40s.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
High pressure will gradually build in from the west on Friday.
Will see a slightly cooler day but temperatures will remain
above normal. Should see a mix of clouds and sun in the north
and mostly sunny skies south. Highs will range from the mid 50s
to lower 60s north and mid 60s to near 70 south.

High pressure will continue to build in from the west Friday
night. Expect partly cloudy skies overnight with lows from the
mid 30s north to the mid 40s south.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
This weekend an anomalous ridge will build along the East Coast
Nwd thru Hudson Bay. Ensemble progs suggest the middle of the
ridge will be around 3 standard deviations above normal for this
time of year. What that means for sensible wx is continued much
above normal temps and dry. Model guidance continues to push low
teens H8 temps and mid teens H9 temps around the periphery of
the surface high and into New England. Mixing should stay fairly
shallow and remain around H9...but those temps still translate
to widespread 70s and pushing 75+ in the warm spots. The multi-
model consensus blend seems a little cool...especially into
early next week...so I have increased temps a few degrees by
mixing down H9 temps and blending in some MOS guidance.

With deep...meridional flow developing early next week across
the central CONUS...flow parallel to the front will tend to keep
things slow moving. 19.12z model guidance did slow the arrival
of precip compared to yesterday. So I have decreased PoP a
little from the multi-model consensus Tue...with likely PoP
reserved for Tue night/Wed. Late in the period deterministic and
ensemble guidance is also trending towards a blocky pattern in
the North Atlantic. This may keep the baroclinic zone just
offshore and allow a focus for when the upper low ejects out of
the Southeast. Consensus has trended towards a two part rainfall
event...with the lead wave arriving midweek...and the upper low
arriving late in the week.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Short Term...Mainly VFR tonight into Fri night. Would not be
surprised to see a little bit of vly fog very late tonight,
more around sunrise, as some late decoupling may occur. As
terminals go, best chc would be at KLEB, but not included in
the TAF attm.

Long Term...Widespread VFR conditions will continue under high
pressure. High will be more centered overhead over the
weekend...so valley fog and LIFR conditions will be possible at
HIE and LEB. Return flow develops Mon into Tue...and that may
keep things mixed enough to prevent fog in the valleys.
Increasing moisture may lead to coastal stratus however.

&&

.MARINE...
Short Term...Continuing SCA`s for the bays and outer waters.

Long Term...As trof digs into the central CONUS early next
week...developing Sly flow may build seas above 5 ft outside the
bays. As Sly LLJ increases midweek...SCA are likely with seas
approaching 10 ft. In general wind gusts should remain below 25
kts on the coastal waters until midweek.

&&

.FIRE WEATHER...
Relative humidities will drop into the upper 20s to mid 30s in
southeast New Hampshire and southwest Maine tomorrow afternoon
along with winds of 10 to 20 mph. This would come in just under
meteorological RFW conditions, and will elevate the threat of
wildfires.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ151-153.
     Small Craft Advisory until 6 PM EDT Friday for ANZ150-152-154.

&&

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


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