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Area forecast discussion 
National Weather Service Taunton Massachusetts
1250 PM EST sun Jan 25 2015

Synopsis...
chilly and blustery conditions expected through Monday. A major
and potentially historic winter storm will affect the region
Monday night into Tuesday night...travel may become impossible and
life threatening. Drier weather follows Wednesday into early
Thursday...but will have to watch for another chance of snow by
the end of the work week.

&&

Near term /through Monday/...
1 PM update...blustery conditions continue across much of southern
New England with westerly winds gusting up to 30 miles per hour at times.
Temperatures in the 30s combined with these winds are resulting in
wind chills in the teens and 20s.

Tonight...high pressure in Quebec will build southward into southern
New England allowing winds to calm and clear skies continue. This
will allow for decent radiational cooling. However...increasing
clouds from the south in advance of low pressure moving off the
coast may put a stop to radiational cooling early. Therefore...not
dropping temperatures as low as they could be if skies remained
clear. Forecasting lows in the single digits to teens for most
locations.

Monday...high pressure moves northeastward into the Maritimes as low
pressure moves offshore the Delaware-Maryland-Virginia peninsula before approaching
southern New England Monday night. Mostly dry/quiet weather
expected for much of Monday but definitely a deteriorating trend.
Increasing clouds through the day with mostly cloudy to overcast
skies through the day. The GFS is the quickest moving snow over
southern New England around midday. However...the NAM/European model (ecmwf) are the
preferred solutions for the noreaster/blizzard. These solutions
keep the area dry through much of the day with snow moving in from
the south late Monday afternoon. Because of this...only expect a
few inches of snow at most prior to 00z Tuesday /7 PM Monday/.
Temperatures are expected to be in the 20s to middle 30s across southeast
Massachusetts.

&&

Short term /Monday night through Wednesday/...
* major to potentially historic winter storm Monday night into Tuesday night
* blizzard watch eastern Massachusetts/Rhode Island
* 1 to 2 feet of snow for many areas - locally higher amts possible
* damaging winds possible coast especially cape/islands - gusts 60 to 70 miles per hour
* significant coastal flooding possible along the eastern Massachusetts coast

Details...

This is pretty much a text book case for a major winter
storm/blizzard in southern New England. Potent shortwave dives
southeast closes off south of Long Island as low pressure bombs out
and tracks up the New England coast. The highly amplified pattern
will allow for a slow moving/long duration storm. In
addition...high pressure across eastern Canada will supply plenty of
cold air for the storm to work with so ptype will probably only be a
concern for the far southeast New England coast.

We are now quite confident that this will be a major winter storm
and it has the potential to become historic for some locations.
Will break down the various hazards in the next view paragraphs.

1) heavy snow/blizzard conditions/wind and ptype

The middle level low/S are closing off just south of southern New
England Monday night and Tuesday. That will probably put US near
ground zero for the heaviest snow. The models are in very good
agreement in showing 1 to 2 feet of snow for much of the region. Of
course there may be areas that exceed 2 feet where localized banding
sets up...but its too early to worry about that. Very strong
pressure gradient with 1035 mb high over eastern Canada and bombing
surface low will likely result in strong to damaging northeast wind
gusts of 45 to 60 miles per hour across eastern MA/RI. Gusts between 60 to 70
miles per hour expected across the cape/islands!

Will issue a blizzard watch for much of eastern Massachusetts/Rhode Island for 1 to 2
feet of snow and 40 to 60 miles per hour wind gusts. This looks to be a
serious winter storm and travel will likely become extremely
difficult to impossible with near zero visibility. Considerable
blowing and drifting snow also expected.

Across central and western Massachusetts/northern CT have issued a Winter Storm
Watch for 12 to 24 inches of snow. Its possible we may have to
upgrade some of that region to a blizzard watch/warning...but was
uncertain how much wind would mix down across that region and its
still a late 4th and 5th period event. We are also leaning towards
the western envelope of solutions at this time led the consistent
European model (ecmwf). If the storm trends east a bit...we may be overdone with our
snow accumulations across our western zones so something for later
shifts to watch.

The cape and islands present the most challenging forecast.
Depending on exact track of the storm...portions of the region may
mix with or change to rain for a time. If colder solutions verify
there will be blizzard conditions...but if it ends up warmer could
be a fair amount of rain. Therefore...will hoist a winter storm
and high wind watch. In fact...we like going with the high wind
watch here for the potential of 60 to 70 miles per hour winds. This may
combine with any wet snow to cause downed trees and power outages.

2) timing:

The worst of the storm looks to occur Monday night into Tuesday
afternoon. At least snow showers will likely linger Tuesday night
as the system becomes vertically stacked and very slow to depart the
region. Dry weather should finally work into the region sometime
Wednesday morning.

3) narrow swath of damaging wet snow

Will have to watch for a narrow swath of heavy wet snow along the
southeast New England coast. This could be problematic in terms of
downed trees and power outages...especially given the strong winds.
It may be a small area just northwest of the rain/snow line...but
may have a significant impact.



&&

Long term /Wednesday night through Sunday/...

Wednesday night through Saturday...

While the focus of the forecast remains the blizzard...we will
update this portion of the forecast as time permits. At this
point...we may be dealing with another winter storm later Thursday or
Friday.

&&

Aviation /18z Sunday through Friday/...
forecaster confidence levels...

Low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.

Through 00z...high confidence. VFR. Scattered-bkn040 possible through
the day. West winds gust to 30 kts.

Tonight...high confidence. VFR.

Monday...high confidence in trends. Moderate confidence in timing.
Start off VFR with deteriorating conditions throughout the day.
IFR conditions and snow will not occur until late in the
day...likely after 21z. However...they could occur as early as
18z.

Kbos taf...high confidence in taf.

Kbdl taf...high confidence in taf.

Outlook /Monday night through Thursday/...

Monday night and Tuesday...moderate to high confidence. Heavy snow
and strong winds along the coast will result in IFR to LIFR
conditions. Blowing and drifting snow is also expected. Northeast
wind gusts of 45 to 60 knots expected along the coast.

Wednesday...moderate confidence. Conditions to improve to VFR from
west to east...but timing in question. North-northwest wind gusts up to 25-30
knots possible early along the coast.

Thursday...low confidence. Timing of low pressure and next chance of
snow later Thursday or perhaps Friday.

&&

Marine...
forecaster confidence levels...

Low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.

Short term /through Monday/...high confidence.

Winds and seas remain elevated today as a cold front crosses the
waters. Therefore...small craft advisories remain in place through
this evening for all waters...and into the overnight for the ocean
waters. Conditions improve briefly early Monday ahead of an
approaching storm for Monday night into Tuesday.

Outlook /Monday night through Thursday/...

***life threatening storm for mariners with seas building to over 25
feet and winds gusts to 60 knots Monday night into tuesday***

Monday night through Tuesday night...moderate to high confidence.
Rapidly intensifying low pressure moving across the waters will
combine with high pressure across eastern New England. This will
result in northeast wind gusts increasing to 50 to 60 knots and
building seas to over 25 feet across our eastern waters. Storm
watches posted and low probability that we may need hurricane force
wind warnings! This is dangerous and life threatening storm and
mariners should return to port by Monday afternoon.

Wednesday...moderate confidence. Should see at least leftover north-northwest
wind gusts up to small craft criteria during Wednesday...then should
diminish Wednesday night.

Thursday...low confidence. Winds should remain below small craft
criteria. Seas may linger at around 5 feet.

&&

Tides/coastal flooding...
a significant coastal flood event is possible along the eastern Massachusetts
coast during the early Tuesday morning and late Tuesday afternoon
high tide cycle. Northeast wind gusts between 45 and 60 knots will
seas building to over 25 feet across our eastern outer waters.
Astronomical high tide is 10.5 feet in Boston on Tuesday at 430 am.
The potential for a 3+ foot storm surge may result in moderate to
isolated pockets of major coastal flooding. Another high tide will
have to watch closely occurs late Tuesday afternoon/early evening
since seas will be built up. In addition...significant beach
erosion is possible.

A coastal Flood Watch has been issued for eastern Massachusetts including Cape
Cod and Nantucket.

&&

Box watches/warnings/advisories...
CT...Winter Storm Watch from Monday evening through late Tuesday
night for ctz002>004.
Massachusetts...blizzard watch from Monday evening through late Tuesday night
for maz005>007-013>021.
Coastal Flood Watch from late Monday night through Tuesday
evening for maz007-015-016-019-022-024.
Winter Storm Watch from Monday evening through late Tuesday
night for maz002>004-008>012-022>024-026.
High wind watch from Monday evening through late Tuesday night
for maz022>024.
Rhode Island...blizzard watch from Monday evening through late Tuesday night
for riz001>008.
Marine...storm watch from Monday evening through Tuesday evening for
anz230>237-250-251-254>256.
Small Craft Advisory until 7 PM EST this evening for
anz230>234-236-251.
Small Craft Advisory until 1 am EST Monday for anz235-237.
Small Craft Advisory until 7 am EST Monday for anz250-254>256.

&&

$$
Synopsis...Frank/rlg
near term...rlg
short term...Frank
long term...Frank
aviation...Frank/rlg
marine...Frank/doody
tides/coastal flooding...

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