[Weather] [2019.12.08 4 PM] NWS Boston EM Briefing: Rain and Accumulating Snow Hazards Thru Wednesday

[BOX Operations - NOAA Service Account]

Good afternoon,

We wanted to bring to your attention a couple of periods through Wednesday
that we are watching for possible weather-related impacts.

*Late Monday into Monday Night: Rain (Heavy at Times)*

A period of heavy rain is forecast for later Monday into Monday night. Rain
amounts between about an inch to up to 2 inches, wettest mainly south of
Interstate 90. As temperatures will be unseasonably mild into the 50s on
Monday and upper 40s to near 50 on Monday night, existing snowpack across
northern CT into MA will be melting.

The combination of rain and snowmelt should result in within-bank rises on
area rivers and streams. Minor urban and poor drainage nuisance flooding is
possible especially where storm drains are clogged. Areas of standing water
from rain and/or snowmelt for the Monday evening commute could result in
hydroplaning.

*Confidence:* High. Heaviest rains are expected south of where snowpack is
greatest, and it would take even heavier rainfall further to the north to
produce a greater flood threat.

*Tuesday Night into Wednesday*: *Accumulating Snow*

Rain will change over to a period of accumulating snows overnight into the
first part of Wednesday. Snow is expected to end by Wednesday afternoon.

The potential exists for plowable snowfall across interior MA (to I-95) and
northern parts of CT and RI Tuesday night into the first part of Wednesday.
As temperatures fall, wet pavement from rains Monday into early Tuesday may
freeze and become slick before or during the period of accumulating snow.
This may result in difficult travel into the Wednesday morning commute.

*Confidence: *Moderate to high on impact potential, though moderate on snow
accumulations & changeover time. The axis of heaviest snowfall remains in
question, which could alter snowfall totals (up or down) on the
northwestern or southeastern end. The potential for snowfall rates at or
over 1"/hr is uncertain. Changeover timing is approximate and will depend
on how quickly colder air advances southeast.


Following graphics are rainfall accumulations through Tuesday morning, a
first look at snow accumulations and an approximate rain-to-snow changeover
onset time for Tuesday Night and Wednesday.

**Note:* Please consider the snow accumulation and onset time graphics as
*preliminary* and are subject to further adjustments.

Meteorologists: Andrew Loconto and Frank Nocera


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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