[Weather] [2019.12.16 PM] NWS Boston EM Briefing: Winter Weather Tue and Arctic Blast Wed night/Thu

[BOX Operations - NOAA Service Account]

Good afternoon,

*Changed*: Increased snowfall amount by 0.5 to 1 inch south of the MA
turnpike. Moved the freezing rain coverage northwards to include parts of
Worcester and Middlesex county.

We are still expecting a winter storm to impact the region on Tuesday. Not
a major snow/ice event but timing is problematic. Precipitation will start
off as snow around 3 to 4am on Tuesday across Northern CT and RI, spreading
northward through mid morning. Snow is expected to mix with or change over
to sleet/freezing rain and then rain south of the MA turnpike. Wintry mix
changes back to light snow from northwest to southeast Tuesday afternoon
before taping off late Tuesday night.

After that, there is a potential for snow squalls on Wednesday
afternoon/early evening with the passage of an Arctic front, possibly
impacting the evening commute but confidence is low on the extent and
intensity. Lastly, the combination of NW gales and the arctic air mass
could result in light freezing spray near shore Wednesday night into early
Thursday morning.

*Accumulating snow and light to moderate ice accretion:*
*Locations*: All locations.
*Timin*g: Tomorrow early morning into late evening.
*Amounts*: 1 to 3 inches of snow/sleet with a few hundredths of an inch of
freezing rain south of the MA turnpike. Up to two tenths of an inch of
freezing rain is possible across northern CT and RI. 3 to 5 inches of
snow/sleet north of the MA turnpike with up to 6 inches possible in far
Western Franklin and Hampshire county.
*Impact*: Snow accumulations of up to 1 inch per hour resulting in poor
visibility and icy roads making for hazardous morning commute.
*Confidence*: Moderate to high. It remains to be seen when the exact timing
of the changeover to sleet/freezing rain will occur. Highest confidence for
higher ice accretion in Northern CT.

*Potential snow squalls:*
*Locations*: All locations.
*Timing*: Wednesday afternoon into early evening.
*Amounts*: A quick coating to half an inch in less than 30 minutes.
*Impact*: Temporarily reduced visibility could catch drivers off guard,
especially for early evening commute. Also, roads could become snow-covered
quickly, resulting in slippery travel.
*Confidence*: Low to moderate. It remains to be seen if snow squalls could
hold together into Eastern MA and RI and their intensity.

*Dangerous wind chills:*
*Locations*: All locations.
*Timing*: Wednesday night into Thursday morning.
*Amounts*: Wind chill values -5 to -20°F in the interior and +5 to -10°F in
Eastern MA and RI.
*Impact*: Coldest air of the season. Frigid wind chills for school bus
stop.
*Confidence*: High.

*Potential risk of freezing spray:*
*Locations*: Immediate coastal waters off Eastern MA and RI.
*Timing*: Wednesday night into early Thursday morning.
*Amounts*: Light freezing spray possible.
*Impact*: Glaze of ice possible on boats and ships traversing the waters.
*Confidence*: Low.

Please see the attached graphics for the hazards, snow onset timing,
snowfall total, ice total and minimum apparent temperature for Thursday
morning.

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:

Meteorologist: Rodney Chai and Frank Nocera

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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