Severe Weather Coordination Message #1 – Monday Late Afternoon & Evening 6/21/21 Severe Weather Potential

Hello to all…

..Isolated to Scattered Strong to Severe Thunderstorms are possible late Monday Afternoon and Evening across Western Massachusetts along and west of the CT River Valley and Northwest Connecticut. Timeframe is between 5-10 PM Monday with strong to damaging winds, hail, frequent lightning and heavy rainfall with urban and poor drainage flooding as the main threats..
..The Storm Prediction Center (SPC) has placed Western Massachusetts and Northwest Connecticut along and west of the Connecticut River Valley in a marginal risk for severe weather for Monday..
..SKYWARN Self-Activation will monitor the severe weather potential for Monday late Afternoon and Evening..

A pre-frontral trough will move through New York and Northern New England and then spread into Southern New England during Monday in the late afternoon and evening and bring the potential for isolated to scattered strong to severe thunderstorms over portions of Western New England. The headlines depict the current thinking. Key factors include:

1.) Timing of the pre-frontal trough as earlier timing into Western New England would increase the severe weather potential there but later timing would reduce the potential.
2.) Wind shear profiles are favorable which may compensate for lower instability if current timing in the late afternoon/early evening holds.

SKYWARN Self-Activation will monitor the severe weather potential for Monday late Afternoon and Evening. Another coordination message will be posted by 10 AM Monday Morning. Below is the NWS Boston/Norton Area Forecast Discussion, Enhanced Hazardous Weather Outlook and SPC Day-2 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-2 Convective Outlook:
https://www.spc.noaa.gov/products/outlook/archive/2021/day2otlk_20210620_1730.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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