[Weather] [2019.12.15 PM] Boston EM Briefing: Winter Weather Potential Mon Night thru Tue; Arctic blast Wed night/Thu

[BOX Operations - NOAA Service Account]

Good evening,

Winds will be gradually diminishing tonight.  Wind Advisories will expire
between 7 PM and 9 PM this evening and Gale Warnings will be lowered before
daybreak.  Attention will then turn to the next winter weather event, which
will be arriving Monday night and continuing on Tuesday.

*Accumulating Snow to Wintry Mix: Monday Night and Tuesday*

We now have high confidence in a period of wintry weather for Monday night
and Tuesday.
We are expecting snow to develop across the entire region, except for a mix
of rain, sleet and snow along the immediate south coast Monday evening
between 8 PM and 11 PM.  The snow is forecast to change to sleet and
freezing rain over interior sections mainly south of the Mass Pike
overnight. A band of moderate to heavy snow could develop from Springfield
to Worcester, northward to the NH border, mainly between 4 AM and 10 AM
Tuesday morning. Thus, the Tuesday morning commute does look like it will
be adversely impacted by a mix of wintry weather, ranging from snow to
ice.  The Boston area southward to the Cape/Islands, as well as most of RI,
will likely be all rain by early Tuesday morning.

Current snowfall and ice accumulation maps are attached.  We are
forecasting 1 to 3 inches of snow/sleet south of the Mass Pike with 3 to 5
inches of mainly snow north of the Pike, with 6 inches possible near the NH
border.  Freezing rain of up to one-tenth inch is expected in RI, northern
CT, and interior MA south of the Mass Pike, but a few spots of 0.10 to 0.25
inches of ice are possible, especially in  northern CT and northern RI.

*Confidence:* Remains moderate to high on wintry weather impacting the
Tuesday morning commute. Changeovers for precipitation type and timing
remain uncertain which may alter the overall snow and/or ice accumulations.
There is the potential for steadier bands of snow that may produce snow
rates at or an inch per hour or a bit higher into early Tuesday morning,
especially north of the Mass Pike.


*Arctic Blast Wednesday night and Thursday*

A major Arctic cold front will blast through the region Wednesday evening,
accompanied by brief wind gusts that could reach Wind Advisory criteria (40
to 50 mph), possible snow squalls, and then frigid temperatures.  Lows will
range from 0 far northwest MA to the teens in southeast MA and southern RI.
Wind Chill Advisories may be needed for western and central MA, where wind
chills of -10 to -20 degrees are forecast.   Gales are quite likely over
the coastal waters.
Highs on Thursday will only reach 15 to 25 degrees, with wind chill indices
still hovering from -5 to 10 above during the day.

-- Glenn Field
   Warning Coordination Meteorologist
   NWS - Boston/Norton, MA

If you have any questions or would like more information, don't hesitate to
contact us via this email address, on NWSChat <https://nwschat.weather.gov/>,
or at the following:

National Weather Service Boston/Norton, MA
46 Commerce Way
Norton, MA 02766
508.622.3280
Website <http://www.weather.gov/boston> | Facebook
<http://www.facebook.com/NWSBoston> | Twitter
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