Storm Coordination Message #3 – Wednesday Night 12/16/20-Thursday Afternoon 12/17/20 Major Winter Storm Potential

Hello to all…

..Potential remains for a significant major winter storm across much of Southern New England depending on the track, speed and intensity of the system as it approaches our region. The major winter storm will have the potential to bring heavy snow, the potential for whiteout and near blizzard conditions, strong wind gusts at the coast of up to 50 MPH and the potential for minor to low-end moderate coastal flooding at the time of high tide Thursday..
..A Winter Storm Warning is now in effect from 7 PM Wednesday Night through 1 PM Thursday for Northern Connecticut, Providence and Kent Counties of Rhode Island and Franklin, Hampshire, Hampden, Worcester, Norfolk, Middlesex and Suffolk Counties of Massachusetts for 8-12″ of snow with isolated higher amounts up to 15″ and wind gusts up to 40 MPH inland and 45-50 MPH at the coast. The winds and heavy snowfall may create a period of whiteout and near blizzard conditions..
..A Winter Storm Watch remains in effect from Wednesday Evening through Thursday Afternoon for South-Central Rhode Island and Southeast Massachusetts for 6-12″ of snow and wind gusts to 50 MPH. The possibility of a closer storm track and a possible mix or change to sleet and rain may reduce amounts further and hence why a Winter Storm Watch remains in effect right now due to uncertainty. If the current forecast holds and the storm track doesn’t come closer, the snow could be heavy and wet and along with the winds could result in isolated pockets of tree and wire damage and isolated power outages..
..A Coastal Flood Advisory is now in effect from 10 AM to 4 PM Thursday for East Coastal Massachusetts, Cape Cod, Marthas Vineyard and Nantucket for minor shore road flooding of coastal roads and the time of the Thursday high tide cycle..
..Additional Warnings and/or Advisories may be required in future updates pending future model runs and the track, speed and intensity of the storm as it approaches our region..
..SKYWARN Self-Activation with Amateur Radio Call-Up Nets likely late Wednesday Night through Thursday Afternoon..

A potentially significant and major winter storm is now expected across the central and southern parts of Southern New England but it could spread into all of Southern New England depending on the track, speed and intensity of the winter storm. The headlines depict the current thinking with a conversion of Winter Storm Watches to Warnings across northern and central parts of Southern New England and the potential for some mixing or changeover to sleet and rain for parts or all of southeast New England due to a closer storm track keeping Winter Storm Watches in effect there due to uncertainty. Key factors include:

1.) The cutoff of heavy snow is now expected to be north of the NWS Norton coverage area and hence the Winter Storm Warnings and those warning pushed northward up to the New Hampshire border. This aspect will still be watched carefully.
2.) The southern parts of the area from Southern Rhode Island through Southeast Massachusetts, Cape Cod and Marthas Vineyard could have a mix or changeover to sleet and rain if the storm tracks close enough and brings warm air into this area. The question then becomes how much snow occurs in a front-end thump of heavy precipitation before the mix or changeover. In addition, this could mean a wetter snow for this area and the tree and power line damage potential will need monitoring between the wet snow and strong wind gusts to 50 MPH.
3.) Areas of 12″-15″ of snow could occur somewhere in the Winter Storm Warning area. Specific areas where this could occur aren’t clear but Northern Connecticut is one potential area for right now. This will be monitored for other areas within the Winter Storm Warning area. The strong winds and heavy snowfall rates could cause whiteout and near blizzard conditions.
4.) The low pressure system will not be particularly strong but the pressure gradient of winds between low pressure to the south and high pressure to the north coupled with high astronomical tides will result in minor to possibly low-end moderate coastal flooding depending on the strength of the winds at the time of high tide. A coastal flood advisory is now in effect for East Coastal Massachusetts, Cape Cod and Marthas Vineyard to cover this potential.
5.) Wind gusts of 40-50 MPH are expected along Southeast coastal New England. This could result in isolated tree and power line damage and isolated power outages. If the system were to be stronger than currently modeled, the potential for stronger wind gusts would increase.

SKYWARN Self-Activation with Amateur Radio Call-Up Nets likely late Wednesday Night through Thursday Afternoon. Another coordination message will be posted by 11 AM Wednesday Morning. Below is the NWS Boston/Norton Area Forecast Discussion, Winter Storm Warning/Watch Statement, Coastal Flood Advisory Statement, Enhanced Hazardous Weather Outlook and Snowfall Maps:

NWS Boston/Norton Area Forecast Discussion:
https://kamala.cod.edu/ma/latest.fxus61.KBOX.html

NWS Boston/Norton Winter Storm Warning/Watch Statement:
https://kamala.cod.edu/ma/latest.wwus41.KBOX.html

NWS Boston/Norton Coastal Flood Advisory Statement:
https://kamala.cod.edu/ma/latest.whus41.KBOX.html

NWS Boston/Norton Enhanced Hazardous Weather Outlook:
https://www.weather.gov/box/ehwo

NWS Boston/Norton Snowfall Maps:
https://www.weather.gov/box/winter

Respectfully Submitted,

Robert Macedo (KD1CY)
ARES SKYWARN Coordinator
Eastern Massachusetts ARES Section Emergency Coordinator
Home Phone #: (508) 994-1875 (After 6 PM)
Home/Data #: (508) 997-4503 (After 6 PM)
Work Phone #: 508-346-2929 (8 AM-5 PM)
Email Address: rmacedo@rcn.com
http://ares.ema.arrl.org
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