Severe Weather Coordination Message #3 – Tuesday 8/25/20 Severe Weather Potential

Hello to all…

..Scattered to Numerous Strong to Severe Thunderstorms likely Tuesday presuming sufficient moisture and instability in the atmosphere associated with a strong cold front that will bring an end to the heat and humidity of the last few days. Strong to damaging winds, hail, frequent lightning and heavy downpours leading to urban and poor drainage flooding are the main threats. The Storm Prediction Center (SPC) has continued a Slight Risk for Severe Weather across all of Southern New England. Timeframe is 12-8 PM Tuesday..
..SKYWARN Self-Activation will be active for the severe weather potential for Tuesday Afternoon and Evening..

While less in coverage and intensity than this weekend, a few strong to severe thunderstorms developed over Southern New England this afternoon. The NWS Boston/Norton Local Storm Report on today’s severe weather event is listed below and photos of the last 3 days of severe weather will be posted today:

NWS Boston/Norton Local Storm Report – Monday 8/24/20 Severe Weather Event:
https://kamala.cod.edu/offs/KBOX/2008250201.nwus51.html

Not much change to the headlines regarding Tuesday’s severe weather potential. SPC had considered an enhanced risk upgrade for Southern New England but is holding off at this time as it remains unclear how much strong to severe thunderstorm coverage there will be. This could still happen as we get into this afternoon. While the greatest potential maybe across Connecticut, Rhode Island and Southeast Massachusetts, the slight risk area covers all of New England and all areas should monitor.

Tuesday, a strong cold front will swing through New England and with it bring a more widespread potential for strong to severe thunderstorms across all of New England. The headlines depict the current thinking and the caveats to the potential for more widespread severe weather for Tuesday. Key factors include:

1.) Timing of the cold front to allow for sufficient heating and destabilization.
2.) Amount of mid-level dry air in the atmosphere and moisture convergence as there needs to be sufficient moisture in the atmosphere for severe thunderstorm development and to sustain updrafts.
3.) Wind shear profiles will be the strongest of the last few days and will need to be monitored if sufficient heating, destabilization and moisture are available for more widespread pockets of wind damage from strong to severe thunderstorms.
4.) There is some cloud cover and a dying area of showers that will slow heating slightly but satellite imagery indicates rapid clearing behind it. Provided moisture remains in place and heating returns as expected, this should allow for scattered to numerous strong to severe thunderstorms in the region.

SKYWARN Self-Activation will be active for the severe weather potential for Tuesday. This will be the last coordination message as we shift into operations mode. Below is the NWS Boston/Norton Area Forecast Discussion, Special Weather Statement on Severe Weather Potential, 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 Special Weather Statement – Severe Weather Potential:
https://kamala.cod.edu/ma/latest.wwus81.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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