Severe Weather Coordination Message #1 – Wednesday 7/22/20 and Thursday 7/23/20 Severe Weather Potential

Hello to all…

..Isolated to Scattered Strong to Severe thunderstorms are possible to likely across Western and Central Massachusetts, Connecticut and Northwest Rhode Island. Strong to damaging winds, hail, frequent lightning and heavy downpours leading to urban and poor drainage flooding are the main threats. Threat timeframe is between 12-9 PM Wednesday..
..The Storm Prediction Center (SPC) has placed Western and Central Massachusetts, Most of Connecticut, and the Northwest corner of Rhode Island in a Slight Risk for severe weather and extreme Southeast Connecticut, Rhode Island and Eastern Massachusetts except for Essex County, Eastern Plymouth Counties of Massachusetts and Cape Cod and the Islands in a marginal risk for severe weather for Wednesday Afternoon and Evening..
..It is also noted that there is a marginal risk for severe weather for much of Southern New England Thursday. Details on the severe weather potential for Thursday will be posted in future coordination messages..
..SKYWARN Self-Activation will monitor the severe weather potential for Wednesday Afternoon and evening. SKYWARN Self-Activation will also monitor the severe weather potential for Thursday Afternoon and Evening as needed..

After a brief break in the humidity on Tuesday, a warm front will bring the humidity back into the region during Wednesday Afternoon and evening and allowing for the potential of isolated to scattered strong to severe thunderstorms. The headlines depict the current thinking. Key factors on the severe weather potential for Wednesday are as follows:

1.) The position of the warm front and how far north it makes it through Southern New England. Recent model trends have shift it further northeast so that the warm front will be through at least Western and Central Massachusetts, Connecticut and Northwest Rhode Island and has resulted in an upgrade in severe weather risk to slight risk in the last Day-2 Convective Outlook.
2.) There could be some showers and a few non-severe thunderstorms Wednesday Morning swinging through the area. Clearing to allow for heating and destabilization after this precipitation moves through is another key factor in the severe weather potential. High resolution models are currently showing some level of clearing to allow severe weather development for Wednesday afternoon and evening.

It is noted that there is also a marginal risk for severe weather for much of Southern New England for Thursday. The severe weather potential for Thursday is associated with a cold front and there maybe wider coverage across the region for severe weather on Thursday. Details on the severe weather potential for Thursday will be posted in future coordination messages.

SKYWARN Self-Activation will monitor the severe weather potential for Wednesday Afternoon and evening. SKYWARN Self-Activation will also monitor the severe weather potential for Thursday Afternoon and Evening as needed. Another coordination message will be posted by 1130 AM Wednesday Morning. Below is the NWS Boston/Norton Area Forecast Discussion, Enhanced Hazardous Weather Outlook and SPC Day-2 and Day-3 Convective Outlooks:

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

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

SPC Day-2 Convective Outlook:
https://www.spc.noaa.gov/products/outlook/archive/2020/day2otlk_20200721_1730.html

SPC Day-3 Convective Outlook:
https://www.spc.noaa.gov/products/outlook/archive/2020/day3otlk_20200721_0730.html

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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