[Weather] [2020.01.17 PM] NWS Boston EM Briefing: Winter Storm Warnings & Advisories Posted

[BOX Operations - NOAA Service Account]

Good afternoon everyone,

Here is the latest forecast update regarding the snow event Saturday
afternoon & evening ...

*What has changed ...*

   - *Winter Storm Warnings* for 4-7" of snow have been posted for western
   & northern portions of MA and Litchfield county of northwest CT
   - *Winter Weather Advisories* for 2-4" of snow have been posted for the
   remainder of MA/RI and CT except no headlines for south coastal MA and RI
   including Cape Cod and the Islands where 1-3" of snow is expected before
   changing over to rain before ending.

*Timing ... *

   - Snow overspreads the area Saturday between 3 pm to 6 pm from west to
   east
   - Precipitation begins to taper off between 10 pm and 1 am from west to
   east

*Duration ... *

   - This is a fast moving system so precipitation will be limited to
   roughly a 3-6 hour window
   - Here is an approximate timeline of the steadiest snow/precip -
   * Boston:* 6pm to midnight,* Worcester to Springfield *5 pm to 11 pm,
   *Providence *6 pm to 10 pm,* Hartford* 4 pm to 10 pm

*Impacts ...*

   - Not a block buster snow event but it will snow moderately for a 3-6
   hour window (times above) with snowfall rates up to an inch per hour
   possible during this time.
   - This will result in roads becoming snow covered late Saturday
   afternoon and evening along with poor visibility.  Travel will become
   difficult during this time.

*Snow Totals ... *

   - Most of MA, RI & CT will receive 2-4 inches of snow before snow
   briefly changes over to rain and/or a wintry mix before ending around
   midnight or shortly thereafter
   - Western & northern Massachusetts along with northwest CT will likely
   receive the highest totals of 4 to 8 inches while the south coast of MA and
   RI likely only receive 1-3 inches before changing to rain before ending.
   This includes Cape Cod and the Islands.

*Forecast Confidence ... *

   - Still some uncertainty on the exact timing of the changeover from snow
   to rain or a brief wintry mix.  Therefore three snowfall maps are included
   to express this uncertainty, StormTotalSnow (most likely snowfall),
   SnowAmt10PrcntilISC (low end amount) and SnowAmt90PrcntilISC (high end
   amount).  Given the very cold airmass over the region late today and
   continuing overnight with morning lows Saturday in the single digits and
   teens, this may delay the changeover and result in an hour or two of
   additional snowfall.  Therefore our most likely snowfall map is very close
   to the high end snow map.

Given the event is still about 24 hours away the exact timing may change by
an hour or two with later forecasts along with snow amounts increasing or
decreasing by an inch or two.  Thus stay tuned to later forecasts and
discussions.  The next email briefing will be issued around 4 am to 5 am
Saturday.

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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