Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
307 am EST Wednesday Dec 11 2013
a cold front will drop south through the region today through
tonight. A weak ridge of high pressure will build in from the west
on Thursday. Low pressure moving east through southern Quebec
Thursday night will swing a trailing cold front through the region
on Friday. High pressure will build in from the northwest Friday
night and Saturday. Low pressure over the Ohio Valley Saturday
night will redevelop off the middle Atlantic coast and will move
northeast off the New England coast on Sunday. Low pressure will
continue northeast into the Maritimes Sunday night. High pressure
will build in from the west on Monday then shift offshore on
Near term /through today/...
another shot of Arctic air on the way for the northeast today as a
cold front drops south from Canada. Will see increasing clouds
this morning in northern zones and some of this cloudiness will
settle into southern zones late this afternoon and this evening.
Will likely see snow showers and some squalls in the mountains
today and there's a chance some of these will drift into southern
zones later this afternoon and this evening. Front will be rather
moisture starved but an inch or so of accumulation will be
possible in the north. High temperatures will only reach the lower to middle
20s north and middle 20s to lower 30s south.
Short term /tonight through 6 PM Thursday/...
cold front will push south of the region overnight with clouds and
any lingering flurries clearing out after midnight as high
pressure builds in from the west. Will see overnight lows once
again well below normal with northern zones bottoming out at zero
to 5 below. Temperatures in central and southern areas will range
through the single numbers to lower teens.
Thursday looking fair as high pressure crests over the region.
Will see some clouds spilling in from the west in the afternoon
as a weak system crossing southern Canada approaches from the
west. Despite sunshine and light winds temperatures will be hard
pressed to make it out of the single numbers and lower teens in
the north. Highs in the south will range from the middle teens to
Long term /Thursday night through Tuesday/...
weak ridge of cold high pressure over the region exits quickly to the east
Thursday night as a weak trough of low pressure moves through Friday associated
with a strong upper level jet. This system may squeeze out a few -shsn
..especially across the mountains late Thursday night through midday
Friday. High pressure noses in from the Great Lakes and southern
Canada Friday night and Saturday bringing fair skies but continuing
the cold weather. Even with below normal temperatures Thursday night through Saturday
the core of the Arctic air mass stays to our north.
Models continue to show a short wave lifting NE along the East Coast
Saturday night and Sunday with low pressure also track NE from the middle
Atlantic coast...tracking inside 40n 70w latitude/Lon benchmark for heavy
snow event for our forecast area per the GFS while the European model (ecmwf) is now a
little further out to sea...going right over 40n 70w...then moving
more to the east-northeast than NE. Some warm air tries to intrude into extreme
southeast New Hampshire and the SW coast of Maine where some mix is possible...but
with high pressure locked in to the north providing cold air funneling
southward into the forecast area on north NE surface winds expect that any mixed
prcp would be sleet or maybe some freezing rain...but not rain.
Current trends suggest a significant snow event is possible for the
forecast area...developing Saturday night then ending Sunday afternoon or
evening. Still plenty of time for track, intensity and timing to
change as models are known to do.
The low intensifies as it moves over the Maritimes with a strong northwest
flow ushering in very cold Canadian air for Sunday night and Monday.
High pressure builds with very cold but dry weather on Monday. A strong upper
level system moving into the Great Lakes region on Tuesday pushes a
surface low and associated warm fnt/cold fnt toward the East Coast which
will spread clouds and prcp into the region. Still way too early to
determine the timing and strength of this system or have high
confidence on prcp type.
Used a blend of models and MOS guidance along with HPC quantitative precipitation forecast for
periods 4 and 5...then used a super blend of various models and MOS
guidance ... with bias corrected guidance and the previous
forecast for days 4 through 8.
Aviation /07z Wednesday through Sunday/...
short term...VFR today with areas of MVFR ceilings and visibility
possible in the mountains in any snow showers. VFR tonight and
Long term /Thursday night through Sunday/...weak trough of low pressure
may produce MVFR ceiling/visibility Friday in -shsn... more so over the
mountains. Coastal low may provide a heavy snow event late
Saturday night and Sunday with IFR/LIFR conditions.
short term...upgrading sca's to gales for the outer waters through
midnight tonight. Continuing sca's for the bays.
Long term /Thursday night through Sunday/...conditions below Small Craft Advisory
levels Thursday night under weak high pressure. Weak trough of low
pressure moves through Friday but a westerly flow sets up with strong
westerly flow aloft that mixes down and may produce Small Craft Advisory level
winds. High pressure builds back in Friday night and Saturday. The wave
height guidance appears too high for late Thursday night through
Saturday with weak pressure pattern...mostly offshore flow and no big
storms anywhere over the Atlantic to generate swells for our
coastal waters. Seas will come up some on gusty west winds Friday but
offshore flow will offset that to keep seas mostly below the 5 feet
Small Craft Advisory threshold. A coastal low may bring strong gales late Saturday
night and Sunday. For now showing gale force gusts over the outer
waters. Seas should build significantly in response to the
strengthening low pressure system per wna4 guidance.
Marine...Small Craft Advisory until 1 am EST Thursday for anz151-153.
Gale Warning until 1 am EST Thursday for anz150-152-154.