Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Gray ME
938 PM EST Sat Dec 27 2014

Synopsis...
a cold front will move into northern New Hampshire and northwest
Maine late tonight and will move off shore on Sunday. A little
light rain can be expected...and perhaps a little light freezing
rain tonight across the northern forecast area. Cold high pressure
returns again Sunday night and will be over the area through at
least midweek.

&&

Near term /until 6 am Sunday morning/...
940 PM update: no changes needed at this time.

645 PM update: minor tweaks to temperatures otherwise no changes needed at this time.

Previous disc:
low pressure will pass our area from the north tonight and drag a
cold front across the region late tonight and tomorrow. Looks like
only light measurable precipitation with this front across the north and
mountains...while the chance for any measurable precipitation will
decrease farther south. Figuring precipitation type across the north late
tonight is challenging as a few spots may hold on to the cold air
as mesoscale models are indicating. This could bring a very light
coating of ice with freezing for a few hours before the
temperature climbs above freezing everywhere by early Sunday
morning. Still not confident that this will actually occur and if
it does it may be in only a few isolated locations where cold air
is trapped...so have decided not to issue freezing rain advisories
for these northern zones due to the uncertainty.

&&

Short term /6 am Sunday morning through Sunday night/...
front will move offshore by about noon tomorrow and clearing
should take place from northwest to southeast. Flow will shift back to the northwest
and this will keep clouds lingering in the mountains with upslope
flow...however decreasing clouds and high temperatures well above
normal levels can be expected once again south and east of the
mountains.

&&

Long term /Monday through Saturday/...
a much cooler extended is on tap...versus the weather we have been
having for much of Dec. Cold...Canadian high pressure will build southward
into the Continental U.S....and though the center will remain well to our
west...a branching axis will drop through New England late Monday into Tuesday.
Current forecast is for the coldest morning temperatures since the first
week of Dec.

Much of the rest of the week is relatively quiet. No large scale
changes are noted in the latest suite of ensemble guidance. 27/12z
gefs...CMC ensembles...and European model (ecmwf) eps all continue to feature
higher than normal heights into Alaska through the extended. This should
keep Canada plenty cold...and keep it nearby northern New England. Temperature
forecast remains near to below normal through the extended. Low
heights across eastern Canada and the southwestern Continental U.S....plus the southeastern Continental U.S.
Ridging will keep fast flow aloft...and fast moving shortwave troughs
crossing the area. Expect that the mountains will see some shsn
activity from these features...with a possibly stronger signal for
shsn Thursday with reinforcing cold fnt.

Main shortwave trough looks to eject from the southwestern Continental U.S. Late in the
week...arriving across the northeast sometime this weekend. European model (ecmwf)
has delayed this ejection some 18 to 24 hours than the GFS.
Knowing the European model (ecmwf) bias for holding energy too long in the
southwest...a blend towards the quicker GFS and CMC seems
appropriate. However with lots of energy in the southwest...fast
flow...and little blocking ahead of the system model guidance will
likely continue to waffle on strength...track...and timing for the
next several days. The signal is strong for precipitation around this time
though...so high chance to low likely pop is maintained in the
forecast.

&&

Aviation /03z Sunday through Thursday/...
short term...a cold front will push through the region tonight.
This may allow for a little light rain as well as MVFR conditions.
VFR is expected late Sunday morning Onward.

Long term...VFR conditions expected to prevail through the extended.
Lone exception will be in the northern mountains...where scattered MVFR or lower
is possible in lingering upslope shsn.

&&

Marine...
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...general offshore flow pattern will persist through
midweek. Winds and seas look to reach Small Craft Advisory thresholds Thursday with
passage of a cold fnt across the waters.

&&

Gyx watches/warnings/advisories...
ME...none.
New Hampshire...none.
Marine...Small Craft Advisory from 3 am to 5 PM EST Sunday for
anz150>152-154.

&&

$$

National Weather Service Glossary of Abbreviations