Area Forecast Discussion
Issued by NWS Portland, ME-- Highlight Changed Discussion --
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FXUS61 KGYX 300032 AAC
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
732 PM EST Tue Nov 29 2016
Low pressure developing over the Gulf of Maine will bring rain and
a wintry mix of precipitation to the region this evening before
moving off to our east after midnight. A very brief lull in the
precipitation is expected Wednesday morning before another low
pressure system spreads rain back into the region Wednesday
afternoon...with a changeover to snow possible over far
northwestern Maine Wednesday night. Somewhat drier air will arrive
on Thursday and Friday with temperatures cooling as we move into
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --729PM Update: PoPs/Precip type generally looking good. Adjusted
temperatures down inland and up along the immediate coast based on
evening observations. Have also matched current wind trends...with
upward adjustments over the marine waters /see 47 kt peak wind at
IOSN3/. Back edge of heavier precipitation marching east...and may
be able to clear some of the advisory area before the night is
543PM Update: Have made a few adjustments to continue to trim
winter weather advisory based on latest mesonet observations and
correlation coefficient values from the GYX 88D showing a
deepening llevel warm layer and surface temperatures slowly
edging above freezing. Have extended advisory for a few more hours
for Oxford/Franklin/Somerset counties based on multiple reports of
temperatures around 30F as webcams have shown some /albeit not
much/ snow...and a transition to freezing rain here.
Temperatures/precip timing continue to be on track with little
Previous Discussion below:
Winter weather advisories have been dropped for all but the
northernmost counties in western Maine. Cold air wedge remains
entrenched over the capital area and the foothills as well and is
taking its time to erode as warmer air arrives from the SW. Areas
still in the advisory will continue to see a mix of snow and
freezing rain...gradually changing over to rain as the night wears
on. Elsewhere expect rain, heavy at times, and dense fog.
Precipitation chances ramp up this evening to near 100% as a
coastal low pressure system closes off near Portsmouth and tracks
along the New England coast towards the Canadian maritimes.
Franklin and Somerset Counties may see temperatures at all levels
staying cold enough for snow through tonight, allowing for
accumulations 3 to 6 inches.
Overnight lows will be tricky and depend on how far the warm air
can mix down and impinge northward. In general lows will be within
a few degrees of 3 pm temperatures...or in the lower 30s to lower
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.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
After a break in the precipitation for most areas overnight and
into early tomorrow morning, another short wave and associated
warm front begin to move in from the west. Precipitation will be
rain for almost all areas but there could be a few cold mountain
valleys that may see snow mixing in and light accumulations.
Temperatures will be in the 40s across the region with mid 30s
towards Jackman. It will be another foggy and dreary day and
night. By the end of these 2 events much of northern New England
will receive between 1 and 2 inches of rain.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Both ensemble and deterministic solutions are now in decent
agreement on the longwave pattern through early next week.
Temperatures through at least Sunday will average above normal as
mean jet stream position keeps the really cold air bottled up to
our north and west. We begin the period with an upper low centered
over the Great Lakes. The associated surface low will be over
western Quebec with an occluded front extending southeast into the
region with a triple-point low over the Maine coastal waters. This
frontal system and coastal low will race northeast in response to
associated shortwave impulse exiting into New Brunswick. The upper
low will gradually open up as it slides into New Brunswick by
Friday with a broad lingering trough across the Great Lakes and
New England through Saturday. by Sunday...rising heights as ridge
approaches New England. In the dailies...occluding frontal system
pushes into northern New England with models agreeing on
developing triple point low over the Maine coastal waters. This
surface development will draw colder air into the higher terrain
which will help precipitation end as snow there on Thursday.
Behind this departing disturbance...a broad trough with a series
of embedded shortwaves that will traverse the forecast area
through Saturday. This will result in considerable clouds for the
higher terrain with upslope snow showers. Elsewhere...varying
amounts of clouds with passing shortwave impulses as well as a low
pop for rain/snow showers with p-type boundary layer temperature
dependent. By Sunday...model blend offers ridging and a brief
respite through Monday before the next disturbance approaches the
region late Tuesday. It should be noted that over the past 12
hours the extended model solutions...both ensemble and deterministic...
have come into much better agreement regarding early next week...lending
increasing confidence in sensible weather details for that period.
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
Short Term /through Wednesday Night/...
Summary: Low pressure strengthening over the Gulf of Maine will
continue the rainy conditions through the first half of tonight
before gradual improvement arrives after midnight. After a brief
respite Wednesday morning...rain will arrive from another low
pressure system Wednesday afternoon...renewing the poor flying
conditions that will continue through Wednesday night.
Restrictions: Widespread LIFR/IFR conditions in rain...low
clouds...and fog overnight will improve to MVFR/VFR Wednesday
morning before deteriorating back to IFR/LIFR late Wednesday and
Wednesday night in rain and fog.
Winds: Light northerly winds inland and southeasterly winds 10g18kts
at the coast will become light northwesterly everywhere by early
Wednesday before shifting northeasterly 5-10kts Wednesday afternoon
and evening...before shifting northwesterly towards daybreak
LLWS: Southerly winds 30-40kts at 2kft will continue at most sites
for the next 2-3 hours before diminishing.
Thu...Widespread IFR in RA and mtn ra/SN...improving to mvfr in
mtn shsn and VFR elsewhere.
Fri - SAT...Areas of MVFR in mtn shsn.
Short Term...Southeast winds ahead of the developing low tracking
near the coastline will strengthen and likely gust to gale force
over the outer waters this evening into tonight. Winds should
diminish a bit after the low moves by, but waves may stay up a few
Thu - Fri AM...Small Craft conditions are possible.
ME...Winter Weather Advisory until 11 PM EST this evening for
Winter Weather Advisory until 1 AM EST Wednesday for MEZ008-
MARINE...Small Craft Advisory until 4 AM EST Wednesday for ANZ151-153.
Gale Warning until 1 AM EST Wednesday for ANZ150-152-154.