Area Forecast Discussion
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FXUS61 KGYX 040328 AAB
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1028 PM EST Sat Dec 3 2016
A ridge of high pressure will slowly build into the region tonight
and Sunday, before moving offshore Sunday night. A weak weather
disturbance will bring some light snow to the region on Monday,
especially southern and western sections of the forecast area.
High pressure will settle in for Tuesday. Low pressure may affect
the region with mixed precipitation Thursday and Friday with a
cold blast following for the weekend.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
1025 PM Update...
Upslope showers still reaching the ground especially in northern
NH and the western Maine mountains. Light snow is also reaching
the Notches but does not appear to be making it very far
downstream. This pattern will persist overnight with a 20-30kt
LLJ form the NW. Cold air arrives throughout the night with 850mb
temperatures dropping to near -10 degrees C. Areas north of the
terrain will see lows in the teens and lower 20s with widespread
20s downstream. Have adjusted PoPs, clouds, winds, and QPF/snow
amount for the next several hours.
535 PM Update...
No major changes to the forecast. Some dwindling snow showers in
the region tonight with clearing skies across the coastal plain.
Upslope showers continue overnight on northward facing slopes.
A short wave trough embedded in the general cyclonic flow aloft
will pass to the southeast of our CWA by early this evening. Any
widely scattered rain and snow showers on the coastal plain
should shut off by early evening as a result. However, upslope
snow showers in the Whites will continue into the overnight hours
with another 1 to 3 inches expected in NW-facing terrain. Wind
gusts around 30 MPH very early on will diminish this evening.
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
High pressure will build in on Sunday. Winds will be a little
gusty through early-mid afternoon but nowhere near gusty as
Saturday`s values. We`ll also see quite a bit more sun on Sunday
as subsidence and drying in the column increases.
High pressure settles over the region Sunday evening. This will
allow for temperatures to plummet...allowing for lows in the teens
in many areas. Clouds will begin to increase around midnight
across southwestern zones a short wave trough approaches from the
west. The clouds should spread northeastward and reach the coastal
plain by dawn. Deeper layer moisture and ascent should arrive
across southwestern NH between 5 and 7 am. This should allow for
light snow to begin falling there during that timeframe...mainly
across Cheshire County, but could possibly reach the MHT/ASH
corridor by the morning commute as well.
.LONG TERM /MONDAY THROUGH SATURDAY/...
Both ensemble and deterministic solutions are now in decent agreement
on the longwave pattern through next weekend. We begin the period
with a shortwave impulse over the eastern Great Lakes on Monday.
It`ll weaken as it slides across New england along with an associated
warm front. Some light overrunning wintry precipitation will be
possible with this weak system. Ridging and fair weather will quickly
follow this system for Monday night and Tuesday...in response to deepening
upper trough over western CONUS. By Wednesday...the upper trough begins
to slide east and in response our downstream ridge will exit the
coast. At the surface...a surface low near Hudson Bay with an occluded
front extending southeast to a a coastal low situated off the DELMARVA.
There`ll be an initial shot of light overrunning precipitation on
Wednesday...but only limited QPF given weakening shortwave and light
precipitation trying to press northeast into offshore high and initially
dry airmass. For Wednesday night and Thursday...the upper trough to
our west goes negative tilt with faster GFS/CMC solutions preferred.
The occluded front will pivot northeast across the region with
cold air injection causing the coastal low to rapidly deepen as it
crosses the Gulf of Maine late Thursday. Forecast thermal profiles
suggest snow for the mountains and foothills...with rain along the
coastal plain. In between...a messy wintry mix is likely. Still
plenty of uncertainty regarding track and exact timing of coastal
low deepening making QPF amounts and type challenging at this
juncture. Blustery with the coldest weather of the season behind
the system for Friday and the upcoming weekend with clouds and
accumulating snows across the higher terrain.
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Short Term /through Sunday/...VFR conditions are expected tonight
except for MVFR conditions in the mountains. VFR conditions
everywhere on Sunday and much of Sunday night. Southwestern NH may
start to see MVFR conditions in light snow developing between 10z
and 12z Monday.
Mon...Areas of MVFR in -sn/-ra.
Wed...Areas of MVFR in -sn/-ra.
Wed night - Thu...IFR and lcl LIFR in ra/sn and fog. Sfc wnd
gusts to 30 kt are psb.
Short Term /through Sunday Night/...SCA conditions continue
tonight across the waters before subsiding late tonight and
especially on Sunday.
Thu...Gales force winds are possible...with gusts approaching
storm outside the bays.
MARINE...Small Craft Advisory until 8 AM EST Sunday for ANZ150>152-154.