Severe Weather Coordination Message #2 – Thursday 7/21/22 Heat & Severe Weather Potential

Hello to all…

..Intense heat and humidity expected through Thursday with a cold front which will bring less humid air that will be a trigger for isolated to scattered strong to severe thunderstorms with damaging winds, hail, frequent lightning and heavy rainfall with urban and poor drainage flooding as the main threats. The Storm Prediction Center has placed much of Southern New England in a slight risk for severe weather north and west of a Lawrence Mass to Willimantic CT line with a marginal risk for severe weather in the rest of Southern New England. The threat timeframe is between 12-8 PM Thursday Afternoon and Evening..
..A Heat Advisory is in effect through 800 PM Thursday Evening for much of Southern New England including Northern Connecticut, Rhode Island except for extreme south coastal areas and much of Western, Central and Eastern Massachusetts for heat indices up to 100-102 degrees expected. Use caution if outdoors doing strenuous activities and drink plenty of non-alcoholic and non-caffeinated drinks during this period..
..SKYWARN Self-Activation will monitor the severe weather potential for Thursday Afternoon and Evening..

We continue to be in a stretch of oppressive heat and humidity over the region that will last through Thursday. During Thursday Afternoon and evening, a cold front or more like a dewpoint front separating higher dewpoint air from lower dewpoint air will move across the region and set the stage for isolated to scattered strong to severe thunderstorm development across much of interior Southern New England with Northern Connecticut, Western, Central and Northeast Massachusetts the favored areas in Southern New England. The headlines depict the current thinking which has little change except to pull the Slight risk area slightly north and west leaving much of Eastern Massachusetts and Rhode Island in a marginal risk for severe weather. Key factors remain:

1.) The amount of forcing and the location of the cold front as it moves through the area at time of peak heating. This will determine the coverage and areal extent of severe thunderstorms in Southern New England. Some models favor just Northern New England with the most widespread activity with less activity in Southern New England while other models keep the coverage more widespread across both Northern and Southern New England away from south coastal areas. At this time, activity is likely to be more isolated to scattered in Southern New England but will bear close watching for more widespread activity given the instability and shear in place.
2.) As stated in item 1, instability, wind shear profiles and other factors are all quite favorable for severe thunderstorm development so if the forcing arrives at the time of peak heating, that will make severe thunderstorms more widespread but if it remains over Northern New England then activity will be isolated or scattered and right now the isolated to scattered case looks reasonable at this time. In either case, not every city or town will receive a strong or severe thunderstorm but the amount of forcing and how quickly it shifts east will determine the coverage over the region.

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

NWS Boston/Norton Heat Advisory Statement:

NWS Boston/Norton Area Forecast Discussion:

NWS Boston/Norton Enhanced Hazardous Weather Outlook:

SPC Day-1 Convective Outlook:

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: