Area Forecast Discussion
Issued by NWS Portland, ME
FXUS61 KGYX 041428
Area Forecast Discussion
National Weather Service Gray ME
928 AM EST Sun Dec 4 2016
A ridge of high pressure will slowly build into the region today,
before moving offshore tonight. 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 with a cold blast following for
Friday and over the weekend.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
930 AM Update...Just a few minor adjustments to the going forecast
this morning to take into account latest trends in sky cover,
temperatures, and winds. Skies continues to clear out on the
coastal plain this morning, and further clearing is expected today
as subsidence increases. It will still take much of the day for
the mountain zones to clear out though, as upslope conditions
still favorable for clouds much of the day.
645 am update: Cyclonic northwest flow continues to spread a
solid layer of stratocumulus clouds across the entire forecast
area so updated sky grids to reflect the stubborn cloud cover
through mid morning. By late morning enough subsidence moves into
region with approaching ridge axis to dissipate this shallow layer
of cloud cover.
High pressure builds across the region today with skies becoming
mostly sunny over southern and central sections while some clouds
linger in the mountains through the afternoon. Temperatures will
be colder today as cold air advection continues. Highs will range
from the upper 20s in the mountains to upper 30s along the coast.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
The ridge axis of high pressure crests over the region but by
later at night mid/high clouds will begin spilling through the
upper ridge axis. During the evening with clear skies/calm winds
radiational cooling is expected so temps will drop quickly and
lows to fall into the teens to mid 20s. The clouds that move in
late may be enough to keep temps from falling further.
On Monday a fast moving upper short wave with limited moisture
will move through the region bringing snow showers across the area
with some very light accumulations possible...especially over
the hills of western and southwest NH where 1-2 inches is
possible. Less than an inch accumulation expected further east
into Maine as most of the moisture dries up as it moves across the
mountains. High should be mostly in the upper 20s to lower 30s as
per the blended model guidance.
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
High pressure will settle over New England Monday night. With
light winds and a snowpack over northern areas, radiational
cooling will allow for a chilly night. The cold air will be in
place as a weak system passes south of the region late Tuesday
night into Wednesday. As this system exits east of the New Jersey
coastline a weak trough will cross the region from the west. This
will bring a mixture of light rain and snow to the region.
Very cold air will move east from the Great Lakes on Thursday. As
it does so, cyclogenesis may result along the boundary, bringing
low pressure through the Gulf of Maine. 00Z model suite is not
totally on board with this solution, however many areas may have a
shot of snow during the day as the system intensifies.
Behind this area of developing low pressure, cold air will pour
into the region on strong westerly winds late in the work week and
over the weekend.
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
Short Term...VFR through tonight except MVFR cigs at KHIE through
mid morning. Conditions becoming MVFR in snow showers Monday.
Areas of MVFR conditions in periods of light rain and snow on
Monday and again Wednesday. The precipitation may be heavier by
Thursday with areas of IFR conditions.
645 am update: have dropped the SCA for the outer waters as winds
have finally dropped below criteria. Winds will continue to slowly
diminish throughout the day.
Wind gusts continue to exceed 25 kts but will
diminish over the next few hours. Will let the SCA over the outer
waters expire at 8am. High pressure crests over the waters later
today and tonight with near calm winds. Light winds will continue
Long Term... Gale force winds are possible behind a departing
system on Thursday as winds shift out of the west. Gusty winds
will continue right into the weekend.
NEAR TERM UPDATE...Ekster