Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
1035 PM EST Sat Jan 24 2015
low pressure will move through the Gulf of Maine tonight with high
pressure building in for Sunday. Another more dynamic coastal
storm may affect New England Monday night through Wednesday.
Thereafter...cold and dry weather will move on in.
Near term /overnight/...
finally able to drop winter headlines as the last of the snow
exits the midcoast. Some light snow showers may begin to move into
northwest portions of the area the rest of the night.
snow is rapidly ending this evening. Have dropped the rest of New
Hampshire and most of western Maine from the warnings and
advisories. Still a little more accumulation along the midcoast
before it ends there as well.
finally seeing the end of the snow moving more quickly across the
area. Have dropped the warnings and advisories for Hillsborough,
Cheshire, Merrimack, and Belknap counties. Should be able to drop
the rest of New Hampshire within an hour or so and start chipping
away at the Maine headlines after that. Have further refined final
snowfall totals based on latest reports and additional
accumulations expected over the next few hours. No other changes
were needed at this point.
back edge of the snow has been slow to push east. Final band has
actually expanded as it moved into central New Hampshire. First
report out of this band was about half an inch in 45 minutes... so
some additional accumulation is expected before this finally moves
through. Further east... more moisture continues to stream
northward into the midcoast where snow will continue the longest
and may require an extension of the warnings/advisories. Have
updated hourly precipitation chances to reflect a little slower
ending to the snow. Total snow amounts have been tweaked a little
bit as well... but at this late stage of the game there will not
likely be any more significant changes to these forecast numbers.
heavy snow bands continue to rotate into the midcoast of Maine.
Have expanded the Winter Weather Advisory to include southern
Somerset County where the heavier bands have just begun arriving.
Latest reports are of only an inch or two so far but snow will
continue for a few more hours. Continue to watch the back edge of
snow forming into a more intense line as it very slowly moves east
across New Hampshire and northwest Maine. This will be the final
bit of snow before things wind down. Should be able to start
dropping some advisories and warnings once this moves through. In
between this band and the coastal bands there may exist pockets of
freezing drizzle but this is not expected to cause a significant
at 3pm the low pressure center was located just southeast of
Nantucket and moving northeast. Western New Hampshire and the
Connecticut River valley will see clearing through the evening.
Closer to the coast.. bands of snow will continue to rotate in as
the low pulls into the Gulf of Maine. Strengthening of the low and
an approaching short wave will combine to give the potential for a
brief period of 1"/hour snow rates over the next few hours. Dual
pol radar continues to indicate the melting zone well off shore...
keeping the ptype all snow... however as the back edge of the
precipitation moves out portions of the interior will see a few
hours of freezing drizzle from the low cloud deck before clearing
Short term /6 am Sunday morning through Sunday night/...
the low will move rapidly northeastward through the Gulf of Maine
overnight with colder air moving in for Sunday. Skies will be
mostly clear except in the northern mountains where upslope snow
showers will develop.
Long term /Monday through Saturday/...
both branches of the jet stream remain very active this coming
Monday through Friday. Over the eastern Continental U.S. A deep trough is
carved out as blocking sets up downstream over the Pacific. This
keeps the upper level trough in essentially the same space through
Wednesday morning as short waves ripple through the trough and
move up the Atlantic coast.
Cold high pressure passes to the north on Monday. The colder air
will have infiltrated the coastal plain with temperatures not any
higher than the lower 20s. Tuesday will be another cold
day...although cloud cover will help increase temperatures a bit.
An upper low cuts off Tuesday as the trough becomes negatively
tilted. At the same time a surface low deepens rapidly off the
middle Atlantic coast... however the NAM and GFS keep the center just
outside the benchmark while the European model (ecmwf) steers it inside. The Euro
also favors the primary surface low to linger south of Long Island
through Tuesday night while some other models are more progressive
developing a secondary low center just outside the Gulf of Maine.
The differences would translate could into higher snowfall totals.
An upstream kicker pushes the system ahead on Wednesday and it
moves quickly north-northeast into the Canadian Maritimes.
Based on better model agreement... have increased probability of precipitation to likely or
better... especially along the coast. Again coastal zones as well
as downeast will see the higher snowfall amounts which should
reach double digits given dynamic low pressure and the influence
of the upper level jet.
We will see a gradual warm up Wednesday through Friday as ridging
aloft builds in.
Aviation /04z Sunday through Thursday/...
short term... LIFR ceilings will continue for the next several
hours for pwm...rkd...and psm as the snow continues. Mht and con
will see an improvement to MVFR in the next few hours... with the
coastal sites returning to MVFR by 09z. VFR will return for
Long term...prevailing VFR Monday with MVFR and lower conditions
likely developing Monday night through Tuesday in heavy snow.
Strong winds especially for coastal terminals on Wednesday with
short term... low will move northeast across the waters tonight
with cold air advection moving in behind it. Winds will increase
to gale force on the outer waters in the wake of the departing
Long term...light freezing spray is possible Sunday night into
Monday night...and perhaps right through Tuesday night. Small Craft Advisory for
the bays and gales or even storm force winds over the outer
waters possible late Monday night through Tuesday night as coastal
low tracks just to the S and east.
Marine...Small Craft Advisory until 7 PM EST Sunday for anz153.
Gale Warning until 7 PM EST Sunday for anz150>152-154.