Severe Weather Coordination Message #1 – Tuesday 6/29/21 and Wednesday 6/30/21 Heat Wave & Severe Weather Potential

Hello to all…

..Intense heat and humidity with a second heat wave ongoing for much of Southern New England away from Cape Cod and the Islands through at least Wednesday of this week. A few isolated strong to possibly severe thunderstorms are possible today in parts of Western and Central Massachusetts, Northern Connecticut and Northern Rhode Island this Tuesday Afternoon and Evening though the best coverage of strong to severe thunderstorms are likely to be north and west of our area for Tuesday..
..For Wednesday, a more significant potential for isolated to scattered strong to severe thunderstorms is expected with an approaching cold front and the Storm Prediction Center (SPC) has placed the area from Boston to Providence north and west in a slight risk for severe weather with the rest of Southern New England in a marginal risk for severe weather. Strong to damaging winds, hail, frequent lightning and heavy downpours are the main threats..
..A Heat Advisory is now in effect through 7 PM Wednesday Evening for all of the NWS Boston/Norton coverage area except for Cape Cod and the Islands for heat indices between 97-103 degrees. Anyone exerting themselves outside should take frequent breaks, drink plenty of liquids and seek air conditioned areas wherever possible to avoid heat related illnesses..
..SKYWARN Self-Activation will monitor any strong to severe thunderstorm potential that develops on Tuesday Afternoon and Evening and especially Wednesday Afternoon and evening..

Intense heat and humidity continues across much of Southern New England today and will continue through at least Wednesday. Heat Advisories are posted for much of Southern New England away from Cape Cod and the Islands. Links to the apparent maximum temperatures factoring in humidity and dewpoints can be seen here:

NWS Boston/Norton Apparent Maximum Temperatures:
https://wx1box.org/wp-content/uploads/2021/06/Heat-Indices-Tuesday.png
https://wx1box.org/wp-content/uploads/2021/06/Heat-Indices-Wednesday.png

Severe weather potential will be on the increase particularly on Wednesday but there is some potential for an isolated strong to severe thunderstorm or two this Tuesday Afternoon and Evening as there will be some marginal triggers to the unstable atmosphere that could allow for a few isolated strong to severe thunderstorms with the greatest risk in Western Massachusetts, Northern Connecticut and Northwest Rhode Island. The greater potential is noted to be north and west of our coverage area but some models do produce a few pop-up thunderstorms and the potential for an isolated strong to severe thunderstorm or two.

On Wednesday, a cold front will be approaching the region and with the intense heat and humidity in place and increasing winds aloft, it will set the stage for a greater risk of strong to severe thunderstorm development along with a greater coverage of strong to severe thunderstorms across Southern New England. Key items for Wednesday will be how quickly the cold front gets into or close enough to the region to provide a trigger for thunderstorm development and the overlap of the stronger winds aloft with high instability over the region from intense heating and humidity through the day.

SKYWARN Self-Activation will monitor any strong to severe thunderstorm potential that develops on Tuesday Afternoon and Evening and especially Wednesday Afternoon and evening. Another coordination message will be posted by 11 PM Tuesday Evening on Wednesday’s severe weather potential. Below is the NWS Boston/Norton Heat Advisory Statement, Area Forecast Discussion, Enhanced Hazardous Weather Outlook and SPC Day-2 Convective Outlook:

NWS Boston/Norton Heat Advisory Statement:
https://kamala.cod.edu/ma/latest.wwus71.KBOX.html

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-2 Convective Outlook:
https://www.spc.noaa.gov/products/outlook/archive/2021/day2otlk_20210629_0600.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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