Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Caribou ME
246 PM EST Friday Feb 27 2015
a large area of high pressure centered across the Midwest will
build south of the region this weekend. Low pressure will pass
south of the area Monday morning and intensify as it moves into
the Canadian Maritimes Monday afternoon. High pressure will build
toward the area Monday night and Tuesday from the west. Another
low will likely cross the region Wednesday.
Near term /through Saturday/...
a sprawling area of high pressure centered in the Midwest this
afternoon covers a lot of real estate from the northern High
Plains to the eastern Great Lakes. The center of the high will
move slowly east and will be centered over the Poconos down into
the Tidewater of Virginia by 00z Sunday. Aloft...a quasi-zonal
flow pattern will persist through Saturday with a couple of minor
shortwaves to pass to our south.
The air mass will slowly moderate through Sat and the 925 mb temperature
which was -22c at 12z this morning at Caribou is expected to rise
to around -14z by Sat afternoon. For tonight...it will be clear
and the atmosphere will quickly decouple in the valleys as a
radiation inversion forms. Expect lows tonight to be similar to
last night...perhaps a few degrees warmer on the hill tops. That
said...a number of the colder northwest valleys will be 20 below or
colder again tonight. Most areas across northern Maine will have
lows in the 10 to 20 below range...and from 10 below to zero for
much of the down east region. No changes were made to the forecast
lows. Saturday will be another sunny day and with a moderation of
the air mass as the inversions break expect temperatures to moderate
significantly. Based on the temperatures this afternoon getting
warmer than forecast did raise the high temperatures a few degrees
Short term /Saturday night through Monday/...
at the start of the period the models are in good agreement on
the major systems. A high pressure ridge will be built across the
Atlantic coast thats and New England. A low over Hudson Bay with
its associated Arctic frontal system...a second low pressure
system centered in The Four Corners regions with its associated
front extending east into southern Illinois. Sun morning the high builds east
into the North Atlantic...the warm front associated with the low
over Four Corners extend east into PA. The Arctic front extends
south into the northern plains. By sun evening... these two low pressure
system merge over the central Great Lakes region...the GFS/NAM shows
a new new low over Lake Ontario. The European model (ecmwf) shows a broad area of
lower pressure in the same area. The Gem shows the low over northern Kentucky.
The new low will rapidly deepen and move east. The GFS moves it to
VT/NH...the European model (ecmwf) into SW Gulf of Maine. The Gem/NAM into the southeast
Gulf of Maine. By the end of the period...the low will be east of
the area...drawing Arctic air once again into the area as a
Canadian high begins to build in.
Loaded a blend of the GFS/NAM/Gem/ECMWF for T/TD/wnd/pop. Loaded
nawave 4 for seas in the coastal waters. Added 15 percent to winds
for gusts over land...35 percent for gusts over coastal waters.
Long term /Monday night through Friday/...
At the start of the extended a low exiting the area over the
Canadian Maritimes combined with an advancing Canadian high
produce gusty winds and very cold area over the area Monday night. The
high will crest over the area Tuesday afternoon...as another frontal
system moves into the central US. By early Wednesday morning the front will
move into western Maine. Early Wednesday afternoon the front will move
through Maine into New Brunswick...the associated low will move to
eastern Quebec. By Thursday morning the low will move east into the
Maritimes...a secondary trough will move through northern Maine. A
ridge of higher pressure will build into western Maine. A trough will
move through northern Maine early morning Friday...otherwise the ridge
will dominate the weather into early Saturday. A new low will move
southeast out of northwest Canada on Thursday evening...to Lake Superior Friday
afternoon. The GFS shows its associated warm front will move into
western Maine early Sat morning and by the end of the period the low will
be over southwestern Quebec...with the warm front extended through central
Maine. The European model (ecmwf) is similar but about 6 hours behind.
Aviation /20z Friday through Wednesday/...
near term: VFR for the next 24 hours.
Short term: clear to pc through Sun afternoon...increasing clouds
Sunday afternoon from the SW to NE. VFR conditions all sites
through early sun evening...MVFR bhb and bgr sun evening as a low moves
across northern New England into the Gulf of Maine. IFR conditions
after midnight bhb...bgr...VFR other sites as the low moves
through the coastal Maine region. Conditions returning to VFR Monday
afternoon all sites.
near term: the wind and seas will remain below Small Craft
Advisory levels for the next 24 hours. A freezing spray advisory
has been issued for tonight through middle-morning Sat.
Short term: winds and seas below Small Craft Advisory sun and early Monday. Winds and
seas will build as a low track across coastal regions Sunday
afternoon and evngs at this time winds appear to be in the upper
end of Small Craft Advisory lower end gale force. Seas building to around 7 feet.
Climate...this February will end as the all-time coldest month
on record at Bangor...and the coldest February at Caribou. More
information on the cold February is available on the news
headlines on the top of our web Page at weather.Gov/car
Marine...freezing spray advisory from 8 PM this evening to 9 am EST
Saturday for anz050>052.