Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
307 am EST Sat Dec 27 2014
high pressure will build south of New England today. A cold front
will approach from the west tonight and will cross the region on
Sunday. A little light rain is expected from this feature...and
perhaps a little light freezing rain tonight across portions of
the interior. Cold high pressure returns again Sunday night
Near term /today/...
high pressure ridging will crest over New England today while a
cold front approaches from the west. Low clouds trapped beneath a
subsidence inversion across the interior and portions of the
coastal plain will hold firm through the early morning hours
before retreating back into the mountains by midday. Maximum temperatures
will once again be above normal...with highs in the 40s at most
locations outside of the mountains.
Short term /tonight and Sunday/...
low pressure tracking northeastward across Ontario and Quebec
tonight will drag a cold front across New England late tonight and
Sunday morning. Moisture and forcing for ascent should be
sufficient for measurable light precipitation tonight most
areas...except perhaps southernmost zones. Much of this light
precipitation should be in the form of rain. However...some
marginally sub-freezing surface air may become trapped in the
mountains and foothills. This may allow for some light freezing
rain for a few hours. Have followed a blend of mesoscale model
guidance for overnight temperatures. This blend indeed yields a
little light freezing rain...especially across southern Oxford and
Franklin counties. Have not issued an advisory at this time due to
relatively small area of sub-freezing temperatures and potential
that model guidance is too low.
Nearing should take place from northwest to southeast on Sunday...with high
temperatures once again rising to well above normal levels.
Long term /Sunday night through Friday/...
cold air begins pouring into the area Sunday night on a north to
northwest flow. The decent pressure gradient will keep winds up
overnight so actual low temperatures will not be that cold. But
highs on Monday will be 10 to 15 degrees colder than Sunday...
ranging from the upper 20s in the north to the upper 30s near the
coast. Monday should be the last time Portland sees the freezing
mark until sometime next year.
Large high pressure has its center well to the west in the Western
Plains... though its influence extends across the continent to the
East Coast. Expect cold and dry conditions through the week. Axis
of high pressure moves through New England Tuesday night...
possibly providing an opportunity for some better radiational
cooling conditions by bringing lighter wind speeds. Temperatures
Wednesday morning will likely fall into the single digits even to
the coast... and below zero in northern areas.
Large upper trough over Canada has its axis cross eastern Canada
and New England on Thursday. This could provide a few snow showers
mainly in northern areas. But chances of significant accumulation
are pretty low considering how dry the air mass is and the lack of
a moisture stream into the system. The dry and cold weather likely
extends through at least Friday. Models then move another
trough... this time with moisture with it... through the
northeastern United States this weekend... bringing snow and/or
rain to the area.
Aviation /08z Saturday through Wednesday/...
short term...VFR ceilings this morning /MVFR in the mountains/ should
give way to VFR conditions all locations today. A cold front will
approach from the west tonight. This may allow for a little light
rain as well as MVFR conditions. VFR is expected Sunday morning
Long term...expect VFR conditions to be the rule trough the week
as dry high pressure remains over the region.
short term...Small Craft Advisory for most zones after midnight tonight through
Sunday as winds and seas build in advance of a cold front.
Long term...with broad high pressure over the center of the
continent... expect a general northwest flow over the Gulf of
Maine through Wednesday. A trough moving through southern Canada
may increase the pressure gradient enough on Thursday to produce
25 to 35 knots gusts out of the west. This would generate higher seas
in the eastern waters.