Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Caribou ME
342 am EST Thursday Dec 18 2014
low pressure will exit across the Maritimes today. High pressure
will build across the region later Friday into Sunday.
Near term /through tonight/...
no changes made to snow totals from the last update at this time. Latest radar
reference imagery does show a band of good light to MDT snfl pivoting NE
to SW from Easton to just east of Patten ME. Models indicate this
banding to continue to nearly 12z and then begin to move east into New Brunswick
prov. Light steady snfl over the rest of the region will then taper
to scattered-numerous snow showers this after...with up to an inch or two of
additional snfl after 18z today...mainly over northern/northestern portions of the
region. Snow showers will slowly wind down from SW to NE across the
region late this afternoon through tonight with little additional accumulation...
lingering longest over the far north. Wntr weather hdlns may be able to be
dropped sooner than the 20z expiration tm later today over the SW
portions of the hdln area.
Otherwise...brisk northwest winds will continue today into this evening as the
pressure gradient on the west side of the departing surface low tightens.
Hi temperatures today will be closer to average...but lows tonight will be held
above average due to cloud cover and a MDT northwest breeze bringing little in the
way of additional low level cold advcn.
Short term /Friday through Sunday/...
on Friday...surface and upper ridges will slowly build. A north to
northwest flow will produce widespread stratocumulus fields...but
some clearing will move into the Allagash later in the day and
spread southward during Friday night. Meanwhile...clouds will fill
in again from the northeast corner of the state later in the night
as an easterly low level flow develops. This tricky cloud cover
forecast and slowly diminishing winds equates to a difficult low
temperature forecast. Readings below zero are possible with clear
skies and light winds all night...but it does not appear probable
that these criteria will be met except in the Allagash where the
forecast will call for readings just above zero. Towards
Bangor...expect low to middle teens as winds are expected to stay up
most of the night. On Saturday...the subsidence inversion is
expected to trap a shallow layer of moisture and create a cloudy
and chilly day with highs around 20f in The Crown of Maine and
upper 20s to near 30f for Bangor and down east. The subsidence
inversion is expected to continue through the weekend with cloudy
conditions and a few flurries in a very shallow unstable layer..
as a result...have gone on the higher side of guidance for lows on
Saturday night. Highs on Sunday will be similar to those on
Long term /Sunday night through Wednesday/...
the forecast becomes more complicated for early next week as a
weak southern stream low pressure system moves up the Atlantic
coast. Nwp offers a wide range of solutions ranging from a
complete miss to most of the area being affected on Tuesday. Have
gone with steadily increasing chance probability of precipitation Monday into Monday
night...and slowly decreasing them Tuesday. The highest chances
will be down east...due both to the proximity of the low and the
fact that a persistent easterly flow will likely produce light
rain and drizzle regardless of the low's track. Critical
thicknesses will be rising during this period with the most likely
p-type being rain for the down east region. After this system
exits...a broad synoptic-scale southeast flow is expected to bring
significant warming Wednesday with light rain and drizzle
transitioning to steady rain late in the day. The system has the
potential to bring an inch of rain Christmas evening...but is likely
to move through quickly enough to lessen Hydro concerns.
Aviation /08z Thursday through Monday/...
near term: IFR/LIFR clg and visibilities all sites this morning in snow will
improve to MVFR over downeast sites this afternoon and then to northern taf
sites by tonight...while downeast sites improve to VFR tonight.
Short term: MVFR ceilings will be the predominant condition Friday
into Monday. Intermittent periods of IFR conditions will be
possible at locations such as fve and in flurries.
near term: Small Craft Advisory winds and/or seas will continue today through tonight...especially
over outer mzs050-051. We merged latest buoy observation to ww3 forecast WV heights
this afternoon...then stayed close to ww3 WV heights through tonight.
Short term: an Small Craft Advisory is likely Friday morning...but tranquil
conditions are anticipated until Wednesday when a gale is a strong
ME...Winter Weather Advisory until 3 PM EST this afternoon for
Winter Storm Warning until 3 PM EST this afternoon for mez006-
Marine...Small Craft Advisory until 4 am EST Friday for anz050>052.