Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
950 PM EST Thursday Jan 29 2015
Synopsis... another storm system will bring a period of moderate
to heavy snowfall to the area late tonight through early Saturday.
High pressure follows over the weekend...with another system
moving south of New England on Monday. High pressure will follow
midweek. Low pressure will pass by to our south on Thursday.
Near term /tonight/...
950 PM update...updated the forecast to slow the eastward
progression of light snow this evening...basically delaying it
a few hours due to the presence of low level dry air. Otherwise...
not sigificant changes.
725 PM update...no major changes to the going forecast. Have updated
temperatures and probability of precipitation based on latest trends in observational data.
Look for clouds to overspread the County Warning Area this
evening...with snow breaking out from west-east after midnight as clipper
system tracks eastward out of the Great Lakes and into New England. Parts
of New Hampshire could see up Tennessee inch or so by the morning commute...but bulk
of snowfall will hold off until later in the morning. Mins tonight
will drop off somewhat this evening...more so in the east...where
skies will be clear a little longer...but SW above the boundary layer
and a weak onshore flow should start set temperatures on the rise after
midnight...especially in coastal areas.
Short term /6 PM Friday and Friday night/... 500mb trough
associated with the clipper moves into the eastern Continental U.S. And phases
with southern stream wave while getting reinforcing shot of energy from
upstream. This will tilt the trough negative and close it off the 500
mb low allowing surface low to intensify and middle level system to close
off. This will generate some deformation and banding Friday afternoon
and evening across ME...which will likely spill over into eastern New Hampshire. The
12z model suite...overall showed more quantitative precipitation forecast...and have thus snow
amts have increased as well...and expanded the warning into eastern
New Hampshire. Heaviest snow would be found north and east of Portland from Friday
after through Friday evening where 8-12" will be common with locally
higher amts. The banding could produce snowfall rates of 1-2"
hour. Through the storms winds will generally be light...but northwest flow
behind the system will pick up late Friday night and could produce
some blowing and drifting.
Long term /Saturday through Thursday/...
low pressure continues rapid cyclogenesis on Saturday along the
easternmost portions of the Gulf of Maine as it exits into the
Canadian Maritimes. Snow will wind down over eastern sections.
Clearing...breezy and cold conditions to follow.
12z model suite is then in better agreement depicting a
reinforcing shot of cold air associated with an Arctic front
crossing through the region during the midday and early afternoon
hours. Models are also converging on a solution that a wave of low
pressure will move along this front which will be situated over
the middle Atlantic region. This is further south than previous runs.
High pressure to quickly follow this progressive and positively
tilted system. The next frontal system will cross our region
Aviation /18z Thursday through Tuesday/...
short term...VFR this evening deteriorates to IFR or lower at times
in snow and low ceilings...persisting into Friday night. Some improvement
may be possible late Friday night in kleb/khie/khie...but will have
to wait until Sat most everywhere else.
Long term...conditions will improve to VFR across all airports
Saturday and remain VFR through the weekend.
short term...water will be quiet through the day Friday...but northwest
flow will start to increase Friday evening...with gales expected after
Long term...gales will likely continue into Saturday.
ME...Winter Storm Warning from 1 am Friday to 6 am EST Saturday for
Winter Storm Warning from 3 am Friday to 10 am EST Saturday
New Hampshire...Winter Storm Warning from 1 am Friday to 6 am EST Saturday for
Winter Weather Advisory from 11 PM this evening to 6 am EST
Saturday for nhz003-005-007-008-011-012-015.
Marine...gale watch from late Friday night through late Saturday night
Near term update...mle