Scientific Forecaster Discussion
fxus61 kgyx 221410
Area forecast discussion
National Weather Service Gray ME
910 am EST Fri Nov 22 2019
a warm front will continue to lift through the area this
morning, however warmer weather will be short lived. After
temperatures climb into the 40s and even 50s for some locations
a strong cold front will cross the region this evening.
Temperatures will tumble back down into the teens and 20s with
plenty of snow showers in the mountains. Also expect some gusty
winds overnight, at times reaching 35 mph. After a quieter day
Saturday, low pressure may affect the region on Sunday. This may
bring a mix, snow, and rain before high pressure moves in early
Near term /until 6 PM this evening/...
915 am update...
light showers continue to decrease this morning, corresponding
with temperatures rising above freezing, so expired the west-southwest for
patchy freezing rain on time this morning. Only minor estf
tweaks to temperatures according to observed trends so far, and
tightened up pops a bit with new hires model guidance
available. Precipitation coverage has steadily increased along
and behind the cold front to the west over New York as a trough
aloft swings east into the lower Great Lakes region.
Update...the bulk of the warm air advection rain is moving east of the area at
this hour. Scattered showers remain behind the initial wave of
forcing...so I will continue the winter wx advisory for the time
Surface warm front continues to slowly lift north...with temps
climbing well into the 30s and 40s at
rkd...psm...ash...mht...afn...and up the CT River Valley to leb.
This will be the trend thru the morning. However a narrow area
of clear skies behind the initial warm air advection Wing has allowed temps to
briefly dip back down towards freezing just inland from the
coast. This is allowing some of the puddles leftover from early
morning rain to refreeze. I have issued a Special Weather Statement for black ice to
cover this area where refreezing is most likely.
Previous discussion...this morning we continue to see some
light warm air advection precip lift across the forecast area. By 7 am I expect
much of this to be east of the area...as forcing is best in that
area and we see some drying overhead. Until then temps continue
to be near freezing...so some of this will fall as freezing
rain. The winter wx advisories continue thru morning...as well
as an Special Weather Statement to the S of that where temps are more marginal but
some slick spots are still possible. See no reason why these
products cannot expire on time or be cancelled with the next
update. In fact the surface warm front is beginning to edge into
the area now with afn jumping to 39 degrees at the hour of this
That surface warm front will continue to lift north ahead of
approaching cold front. I expect that temps should surge just
ahead of the front...and many locations will make a run well
into the 40s and even low 50s. However the favored cold air
damming zone from 1p1 thru izg and into the ME foothills will
likely not benefit from any surge...but rather begin falling
quickly after a brief mix out along the front.
Along the front I have pretty low confidence in coverage of
precip...at least until it reaches the far ern zones and over
the water. Otherwise I have low chance or slight chance pop for
some stray showers. Upslope snow showers will be the most likely
form of precip...but those will wait until Post-frontal passage.
Could see a couple inches of snow at the higher elevations of
nrn New Hampshire and wrn ME in this activity.
Will also see strong cold air advection and increasing mixing depths behind the
front. This will tap wly winds around 40 kt at the top of the
mixed layer. Taking about 80 percent of that for gusts gives
pretty widespread 30 to 35 kt gusts...so gusty but solidly sub-
Short term /6 PM this evening through 6 PM Saturday/...
for a few hours in the evening I expect we will still see some
wind gusts around 35 to as high as 40 mph at times. These gusts
will gradually diminish thru the night as the cold air advection and pressure
gradient weakens. Given the mixed boundary layer overnight I
went close to straight mixed down temps and raw 2 M guidance for
low temps. This brings the area down into the 20s with teens in
the far nrn zones. Will also see lingering upslope snow showers
in the mtns. Could see an additional couple of inches in the
highest terrain before upslope precip shuts off.
High pressure briefly moves in Sat and we will see clearing but
cool conditions...with afternoon readings in the 30s.
Long term /Saturday night through Thursday/...
the ensemble and deterministic model solutions are in decent
agreement on the long wave pattern through early next week. With
the mean upper trough position to our west...cold air will be
limited and temperatures should average near normal or slightly
above normal for the period. We begin the period with shortwave
ridging Saturday night ahead of a vigorous shortwave impulse over
the Mississippi Valley. A clear start to the night should allow
temperatures to drop well below freezing...especially away from
the immediate coast. By Sunday morning...clouds will have
overspread much of the forecast area with light precipitation
arriving over southern and coastal sections by early afternoon as
the impulse GOES negative tilt and the coastal low tracks into
southeast New England. The surface low tracks more east then north
across the Gulf of Maine Sunday afternoon before exiting into the
Canadian Maritimes Sunday night. With this track...much of the
available model suite keeps southern and coastal sections on the
western periphery of the precipitation shield with areas near the
international border seeing little if any quantitative precipitation forecast. Given thermal
profiles best chance for frozen is reserved for mountains and
foothills with predominantly rain along the coast. In between...we're
more likely to see a light wintry mix. Behind this system for
Sunday night we're likely to see some upslope snow showers across
the higher terrain before a ridge of high pressure arrives for
Monday. Low pressure passing to our west Monday night and Tuesday
will spread some warm air advection clouds into the area. A second
and more significant low will track from the Mississippi Valley
through the lower Great Lakes Tuesday night and Wednesday before
exiting into the Maritimes by Thanksgiving day.
Aviation /14z Friday through Tuesday/...
short term...despite warm front lifting thru the area this
morning conditions remain widespread VFR. Local MVFR conditions
are occurring in areas of rain showers or freezing rain. These will move thru the
area over the next couple of hours leaving VFR behind them. A
strong cold front will cross the area this afternoon...but with
little in the way of precip. I am not confident enough to but
any rain showers/shsn in the tafs at this time. Main impact will be
gusty wly winds...with surface gusts to 25 or 30 kt. Gusts
gradually diminish overnight. Widespread VFR conditions Sat.
Sun...areas of MVFR in -ra/-sn.
short term...gale warnings continue for strong wly wind gusts
behind cold front late this afternoon into early evening. Gale
force gusts diminish in the bays overnight and on the outer
waters by Sat morning. Small Craft Advisory conditions continue into Sat
afternoon before diminishing under high pressure.
Sun PM - Mon...sca's likely...with gales psb outside the bays.
Marine...Gale Warning from 5 PM this afternoon to 5 am EST Saturday for