Severe Weather Coordination Message #2 – Thursday 7/30/20 Severe Weather Potential

Hello to all…

..Isolated to Scattered Strong to Severe Thunderstorms are possible across much of Southern New England for Thursday Afternoon and Evening. Strong to damaging winds, hail, frequent lightning and heavy downpours with urban to poor drainage flooding are the main threats. The Storm Prediction Center (SPC) has expanded the marginal risk for severe weather for Thursday Afternoon and Evening to all of Southern New England except for Nantucket Island. Threat timeframe is roughly between 12-9 PM Thursday..
..SKYWARN Self-Activation will monitor the severe weather potential for Thursday Afternoon and Evening..

Last night featured a couple unexpected isolated severe thunderstorms. These storms produced up to 3/4″ hail in Holyoke and Belchertown with unknown size hail reported in Palmer. The Local Storm Reports from last night’s severe weather are listed below:

NWS Boston/Norton Local Storm Reports:
https://kamala.cod.edu/offs/KBOX/2007301255.nwus51.html
https://kamala.cod.edu/offs/KBOX/2007301251.nwus51.html

For today, a cold front will make its way into Southern New England on Thursday. A change from yesterday is that the marginal risk area has been expanded to northern and western parts of Southern New England through areas of Connecticut, Rhode Island and Southeast Massachusetts are favored for the severe weather potential today. Key factors on the severe weather potential are as follows:

1.) Cloud cover was a concern based on prior model runs but satellite imagery shows good clearing allowing for strong heating and destabilization. Some high cloud cover in Connecticut and Rhode Island due not appear to be reducing the potential for strong instability and destabilization. Wind shear profiles are sufficient for severe weather potential.
2.) Amount of moisture in the mid-levels of the atmosphere as if it dries out too quickly, this would not allow updrafts to reach strong to severe levels. This appears to be the main player in determining the extent of any severe weather potential.

SKYWARN Self-Activation will monitor the severe weather potential for Thursday Afternoon and Evening.This is the last coordination message as we shift into operations mode. Below is the NWS Boston/Norton Area Forecast Discussion, Enhanced Hazardous Weather Outlook and SPC Day-1 Convective Outlook:

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

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

SPC Day-1 Convective Outlook:
https://www.spc.noaa.gov/products/outlook/day1otlk.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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