[Weather] [2019.12.28 PM] NWS Boston EM Briefing for Wintery Weather and possible Ice Event Sunday night through Tuesday morning

Sat Dec 28 19:43:56 UTC 2019

Hi everyone,

We continue to follow the potential storm that will be impacting our region
Sunday night through Tuesday morning.  This will be a complicated storm
with a mix of precipitation types across Southern New England.

*Changes with the New Forecast:*

1)  The Winter Storm Watch will be expanded east to include Western Essex,
Northwest and Western Middlesex in MA, and Northwest Providence and Western
Kent Counties in RI.  The starting time will be moved an hour earlier, to 6
PM.

2)  A Gale Watch will be issued for the coastal waters, starting 7 AM
Monday.  The ending time will range from 2 AM Tuesday to 10 AM Tuesday.

3)  We anticipate a Wind Advisory will eventually be needed for Cape Cod
and the Islands for Monday, due to east-northeast wind gusts of 40 to 50
mph.

*Main Weather Concerns:  *

1) *Possible ice storm* in the *higher terrain of western MA (eastern
slopes of the Berkshires) and central MA (Worcester County hills)
developing Sunday night* and continuing through Monday night.  Freezing
rain is expected to begin in those areas Sunday evening and continue into
Monday evening, with temperatures around 30 degrees.  Cannot rule out some
freezing rain in northern CT as well.  There is uncertainty at this time as
to amounts, but current projections are for between 0.25 and 0.50 inches of
ice accretion in the slopes of the Berkshires and Worcester hills. There is
some potential for greater than 0.50 inches.

2)* Lower amounts of sleet and freezing rain develop Sunday night and
continue during the morning commute on Monday. * Sleet and freezing rain
continue late Monday in Northern Massachusetts.  Mainly rain is expected
along the coast during the storm, as well as south of the Mass Pike after
Monday morning.

3)  A* brief period of snow* is possible at the start of the storm,
especially in northern  Massachusetts near the New Hampshire border.  Any
snow is expected to be short-lived and turning over to sleet and rain
Sunday night into Monday.

4)  *Strong east to northeast winds* are expected over the coastal waters
and along the South Coast Monday and Monday night.  Expect sustained winds
of 25 to 30 kt/30 to 35 mph, and gusts of 35 to 40 kt/40 to 50 mph.

*Confidence...and what could still change:*

We have high confidence that this storm system will occur and produce a
wintry mix, but still low to moderate confidence on amounts and
distribution of precipitation types.  A colder scenario than currently
forecast would mean less freezing rain and possibly significantly more
sleet and/or snow in northeastern MA.  The potential exists for higher
freezing rain totals in the high terrain of western and central MA, which,
if true, could lead to power outages and downed trees/wires.

Stay tuned for the latest information.

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
<http://www.twitter.com/NWSBoston>
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