Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
330 am EST Thursday Dec 5 2013
a frontal boundary will move into New England on today...
spreading some light precipitation into the region. The front will
push offshore tonight. A wave of low pressure will track
northeast along the front on Friday and may spread rain or snow
into southern areas. High pressure pushes the front further south
on Saturday with colder air moving in. High pressure shifts east
on Sunday with low pressure tracking up the East Coast on Monday.
Near term /through today/...
models have backed off on the timing of any precipitation in
association with the approaching front early this morning with
each consecutive run. However...a weak area of low pressure off
the New Jersey coastaline is beginning to generate some low level
precipitation in the form of light drizzle and light rain. With
temperatures in the lower to middle 20s across the region...expect
some of this may freeze on contact if it arrives early enough
prior to our expected daytime warmup today. Will continue to
monitor this very closely as latest hrrr run brings light mixed
precipitation into far southern areas shortly after 12z.
Short term /tonight through 6 PM Friday/...
frontal passage finally occurs tonight...changing the precipitation from a
stratiform to a showery type of weather. Temperatures in the
mountains will be cooling off...so there may be some light
accumulations in any persistent snow showers over the high
terrain. Used a blend of mav/met MOS which brings temperatures in
the mountains to below freezing by Friday morning.
Models are in disagreement by late in the day on Friday as to
whether a wave of low pressure will ride up the front and south of
New England or not. Currently...the NAM is most agressive with the
northern proximity of precipitation...which leads US to the long
range portion of the forecast.
Long term /Friday night through Wednesday/...
Friday night a weak wave of low pressure will move east along a stalled
front located S of new engl. Southern areas of ME/New Hampshire will be on the northern
fringe of the precipitation shield so some light precipitation is expected. The precipitation
should produce possibly a few inches of snow over southern areas as any
mixed precipitation gradually changes to snow as cold air advection occurs Friday night. By Sat
morning skies clear as high pressure builds across the region. High pressure
becomes centered over the region sun allowing another nice day.
Sun night the surface/upper ridge axis over new engl moves eastward allowing a
moist southwesterly flow to develop as a broad warm air advection pattern develops and
moves eastward into the region by Monday morning. Models in general
agreement that conds will be cold enough for snow and some accums
expected at the onset Monday morning before changing over to a mix and
then rain from S-north during the day. By Monday night system rapidly
exits and clearing expected as a strong cold front moves through
the region late in the systems wake. Tuesday and Wednesday much colder
temperatures expected with below normal temperatures expected.
Accepted timing and probability of precipitation of superblend guidance for days 4-7.
Aviation /08z Thursday through Monday/...
short term...conditions gradually deteriorate this morning with low
clouds and possibly fog/drizzle move in. This could lead to an
extended period of IFR or LIFR conditions through tonight...before
slowly improving to MVFR conditions on Friday.
Friday night IFR conds in snow or mixed precipitation over southern areas while northern
and central areas maily VFR. On Sat conds become VFR across all
areas and continue through Sunday. The next system approaches Sun
night and Monday lowering conds to IFR/LIFR across all areas.
short term...southerly flow today will gradually build 3 to 5 foot
waves with time. Will issues Small Craft Advisory for seas...which will carry on
into Friday. This is for the outer waters only.
no flags Friday night and Sat. Northwest winds may approach Small Craft Advisory conds sun.
On Monday an increasing east flow will produce Small Craft Advisory conds.
Marine...Small Craft Advisory for hazardous seas from 4 PM this
afternoon to 4 PM EST Friday for anz150-152-154.