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Area forecast discussion...updated 
National Weather Service Gray ME
1026 PM EST sun Jan 25 2015

low pressure will begin to develop off the middle Atlantic coast on
Monday then rapidly develop as it moves northeastward to just
south of Nantucket Massachusetts on Tuesday. The low will linger
around through Wednesday bringing a significant snowfall to our
region. There is also the potential for another storm late week or
early in the weekend but confidence is low at this time.


Near term /until 6 am Monday morning/...
update...minor changes to reflect current observational trends in
temperatures and dew points.

Original discussion...
a cold front crossed the region today bringing gusty
northwesterly winds and cold air advection in its wake. Winds will
begin to decrease overnight as the strong pressure gradient moves
out. Temperatures will fall to around 10 below in the north
however winds should decrease keeping wind chills above advisory

Cold high pressure will very briefly move through the region on
Monday before we see increasing clouds ahead of the approaching
storm system. Temperatures will remain cold with highs only
reaching the 20s.


Short term /6 am Monday morning through 6 PM Monday/...
a significant winter storm will already be affecting northern New
England Monday night as warm air advection spreads snow northward.
Potent surface low pressure deepens to 983 mb by Tuesday morning
with a closed upper low and negatively tilted trough overhead. The
storm remains nearly stationary over the next 12 hours as the trough
battles with downstream blocking. This stalling is key to the
amount of quantitative precipitation forecast and ultimately snow that will fall over northern New
England. The character of the snow will be fluffy as the
atmospheric column remains relatively dry. Went with a 15:1 ratio
although could have gone higher.

The mesoscale banding is highlighted by petersson frontogenesis...
which shows the best banding slicing through central
Massachusetts before curving NE through southern New Hampshire near
Chichester... and then east-northeast towards Fryeburg and Waterville Maine.
This will be consistent with the coastal/warm front as it tries to
work its way inland. Its in this band where the highest snowfall
totals will fall... likely around two feet. The highest amounts
may be found in southern New Hampshire and SW Maine where the frontogenetical
forcing coincides with left exit region of the upper level jet.

Gefs and NAM anomalies for 925 and 850 mb u and even v wind
components of more than 5 Standard deviations below normal show
this storm will pack very strong winds... likely causing wind
damage as these winds mix easily to the surface in precipitation
loading. For this reason felt confident going with blizzard
warnings for the coast and those counties along the coast.
Elsewhere... widespread snowfall totals of 10-20" warrants winter
weather warnings. Over the waters we have issued gales and storm
force warnings. Shadowing on the westward slopes of the whites
should give somewhat lower totals to adjoining counties.. and for
this reason have gone with only an advisory for northern Coos. The
storm begins to move out Wednesday morning with showers tapering


Long term /Monday night through Sunday/...
Thursday will see rapid clearing as the noreaster tracks out of
the area. The highly progressive pattern will continue with
another wave diving southward through the Great Lakes on Thursday.
This system may bring snow to New England for Friday into
Saturday. There is still low confidence as to track and strength
of this system... and have leaned on a weaker northerly track for
this update. The storm will move out of the region on Saturday
with clearing for the weekend.


Aviation /04z Monday through Friday/...
short term...gusty winds will continue through tonight before
decrease. VFR conditions through Monday.

Long term...high confidence in a period of IFR and lower
conditions beginning Monday night through coastal low
pressure spreads snow across the area. Heavy snow and widespread
IFR or lower conditions wind down Tuesday evening...but snow
lingers into Wednesday morning with scattered IFR conditions
possible. Coastal terminals may see NE gusts near 35 kts during
the day Tuesday.


short term... winds will continue to decrease below gale force for
this evening. Light freezing spray is possible... especially in
the bays overnight as temperature drop to the single digits all
the way to the coast.

Long term...strong low pressure south of New England will bring a
period of storm force wind gusts to the outer waters Tuesday into
Tuesday night. A Gale Warning has also been issued for the bays
during this time.


Tides/coastal flooding...
tides are relatively low in the astronomical cycle however
prolonged northeasterly flow will result in a storm surge of up to
2 feet. This will combine with waves of 15 to 20 feet off shore
and may produce flooding and splashover at high tide. At Portland
high tide is 10.0 feet at 420am Tuesday... 9.1ft at 453pm Tuesday
and 9.8ft at 523am Wednesday.


Gyx watches/warnings/advisories...
ME...Winter Storm Warning from 10 PM Monday to 4 am EST Wednesday
for mez007>009-012>014.
Blizzard Warning from 10 PM Monday to 4 am EST Wednesday for
Coastal Flood Watch from late Monday night through late
Tuesday night for mez023>028.
New Hampshire...Winter Storm Warning from 10 PM Monday to 4 am EST Wednesday
for nhz002>009-011-012-015.
Blizzard Warning from 10 PM Monday to 4 am EST Wednesday for
Winter Weather Advisory from 10 PM Monday to 4 am EST
Wednesday for nhz001.
Coastal Flood Watch from late Monday night through late
Tuesday night for nhz014.
Marine...Gale Warning from 1 am Tuesday to 7 am EST Wednesday for
Storm Warning from 1 am Tuesday to 7 am EST Wednesday for



Near term...legro

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