Severe Weather & Flash Flood Coordination Message #1 – Overnight Thursday Night 9/23/21-Friday Evening 9/24/21 Severe Weather & Flash Flood Potential

Hello to all…

..Isolated to Scattered Strong to Severe Thunderstorms are possible across much of Southern New England anytime after 4 AM Friday through 12 PM in Western New England with this potential moving eastward into Eastern New England after 12 PM..
..Strong to damaging winds, frequent lightning, heavy rainfall leading to urban and poor drainage flooding to flash flooding are the main threats with an isolated tornado as a secondary threat. The Storm Prediction Center (SPC) has placed much of Southern New England in a marginal risk for severe weather..
..A Flash Flood Watch is in effect Midnight tonight through Friday Morning for Franklin, Hampshire and Hampden Counties of Massachusetts and Hartford County of Connecticut for 1-3 inches of rainfall with isolated higher amounts causing flooding of urban and poor drainage areas and possibly some small rivers and streams..
..SKYWARN Self-Activation will monitor the severe weather and flash flood potential overnight into early Friday Evening..

A slow moving cold front will push its way through Southern New England overnight through Friday Evening. Warm and humid conditions are out ahead of this cold front. This will set the stage possible localized flash flooding and severe weather potential. The headlines depict the current thinking. Key factors include:

1.) Ability of forcing along the cold front and sufficient wind shear values to compensate for limited instability to allow for heavy rainfall and isolated to scattered strong to severe thunderstorm development.
2.) If more instability is generated than expected, that would potentially increase the severe weather potential in the region.

SKYWARN Self-Activation will monitor the severe weather and flash flood potential overnight into early Friday Evening. This is likely to be the only coordination message on this severe weather potential as we shift into operations mode. Below is the NWS Boston/Norton Flash Flood Watch statement, Area Forecast Discussion, Enhanced Hazardous Weather Outlook and SPC Day-2 Convective Outlook:

NWS Boston/Norton Flash Flood Watch Statement:

NWS Boston/Norton Area Forecast Discussion:

NWS Boston/Norton Enhanced Hazardous Weather Outlook:

SPC Day-2 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:
Like us on Facebook –
Follow us on Twitter –