Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 190538
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1238 AM EST Thu Jan 19 2017

.SYNOPSIS...
Low pressure will pass through the region tonight with some
additional light snow. High pressure will build in for the
remainder of the week, with above normal temperatures expected
into Monday. A storm system may affect the region beginning Sunday
night and continuing into early next week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1am update... band of light snow associated will move through to
the coast overnight. Some additional accumulations is possible.


1015 PM Update...
Additional light snow is falling in association with a short wave
moving through Quebec and into northern Maine. The atmosphere
remains saturated below 700 mb so orographic lift will be
squeezing out an additional inch or so overnight. Have removed
drizzle from the forecast as profiles are also becoming too cold
for it with the approach of the short wave.


630 PM Update...
Minor ocean effect snow is still falling from Portland to the New
Hampshire seacoast. Additional showers have developed over the
foothills ahead of a short wave disturbance. Not expecting
anything but minor accumulations so have cancelled the winter
weather advisory. Patchy freezing drizzle also a possibility for
southern NH and SW Maine and will be issuing a Special Weather
Statement to cover this hazard as amounts will be extremely light.
Temperatures were adjusted slightly as well as weather grids...
overall forecast is on track.


Previous discussion...
Overall, the coverage and intensity of snowfall has lessened
across the forecast area, and has ended in many places. Therefore,
a large portion of the winter weather advisory was cancelled.
However, we have left the the advisory going for coastal portions
of York, Cumberland, and Rockingham Counties as an ocean enhanced
band continues to occasionally produce moderate snowfall and some
accumulations. Therefore, a slippery afternoon commute is likely,
especially on untreated roadways. That advisory will expire at 6
PM unless it is determined it needs to be extended.

Patchy light freezing drizzle is possible at times this evening as
well, mainly across southern zones that are below freezing. We are
not seeing this threat as widespread at this time, and especially
since roads have been treated for the earlier snowfall. Therefore,
will cover this threat with a special weather statement instead of
an additional advisory.

Later tonight, another short wave trough will approach from the
northwest. The moisture availability and forcing for ascent will
be sufficient for a another period of light snow across mainly the
northern 2/3rds of the CWA...with an additional 1 to 2 inches
possible mainly between midnight and 6 am.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
The short wave trough moves off the the east Thursday morning
allowing for a return to fair weather and warmer than normal
temperatures. High pressure then builds in Thursday night.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A ridge will move overhead Friday. A weak shortwave will shear out
south of the forecast area Friday night and early Saturday. This
will likely result in some clouds especially in the southwest
portion of the forecast area but no precipitation is expected as
this feature will be weakening. Ridging aloft will move in for
Sunday but high pressure will build in from the northeast Monday
and this high will set the stage for what may be a messy storm
Tuesday into Wednesday. There may be enough cold air in the
interior to have precipitation start ans snow and then transition
to a mixed bag. The change to rain should be fairly quick along
the coast and in southern New Hampshire but interior portions of
western Maine and New Hampshire might be a different story.
Forecast confidence is low at this time. There could be copious
amounts of precipitation with this so precipitation type will be
important as we may have to watch for the possibility of some
urban type flooding or even the chance of river ice movement.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Short Term...IFR/MVFR cigs/vsbys continue this evening, mainly on
the coastal plain. A brief period of improvement is expected
before another round of light snow after midnight brings them down
again for a few hours before 12z Thursday. VFR conditions return
Thursday and Thursday night.

Long Term...Expect VFR conditions Friday through early Monday.
Conditions begin to deteriorate late Monday to IFR.

&&

.MARINE...
Short Term...SCA conditions likely into Thursday morning, with
them possibly continuing into Thursday night on the outer waters.

Long Term...SCA for seas possible early Friday. then quite on the
waters through Sunday. Winds and seas build with an increasing
east to southeast flow. Gales might be needed for Tuesday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 4 AM EST early this morning for
     ANZ153.
     Small Craft Advisory until 3 PM EST this afternoon for ANZ150-
     152-154.

&&

$$
SYNOPSIS...
NEAR TERM...Curtis
SHORT TERM...Ekster
LONG TERM...Hawley
AVIATION...
MARINE...


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