Severe Weather Coordination Message #1 – Saturday 7/17/21 Severe Weather & Flash Flood Potential

Hello to all…

..Another round of isolated to scattered strong to severe thunderstorms likely today centered over Western and Central Massachusetts, Connecticut possibly extending into interior Rhode Island later this Saturday Afternoon and Evening any time between 2-9 PM EDT Saturday. Strong to damaging winds, hail, frequent lightning, heavy rainfall leading to urban and poor drainage to flash flooding are all possible. The Storm Prediction Center (SPC) has placed this area in a marginal risk for severe weather for Saturday Afternoon and Evening..
..A Flash Flood Watch is also in effect for Northern Connecticut, Franklin, Hampshire, Hampden, and Worcester Counties of Massachusetts from 2 PM Saturday Afternoon through late Saturday Night. Heavy downpours in thunderstorms will result in 1-2″ of rainfall with locally higher amounts. This rainfall combined with the wet weather pattern of the last several weeks may result in urban and poor drainage flooding as well as river and stream flooding in these areas..
..SKYWARN Self-Activation will monitor severe weather and flood potential in the region for Saturday Afternoon and Evening..

A round of isolated to scattered strong to severe thunderstorms affected portions of Southern New England Friday Afternoon into Evening. Any storm damage photos, pictures and videos, particularly from Northeast Massachusetts in the Topsfield/Boxford area and Northeast Connecticut particularly in the Thompson/Woodstock area which were the hardest hit areas can be sent as a reply to this email, via our Facebook/Twitter feeds or to the email address and the NWS Boston/Norton Local Storm Report can be seen here:

NWS Boston Local Storm Report – Friday 7/16/21 Severe Weather Event:

Yet another round of isolated to scattered strong to severe thunderstorms are likely today across Western and Central Massachusetts, Connecticut and interior Rhode Island for Saturday Afternoon and Evening between 2-9 PM EDT. The headlines depict the current thinking. Key factors include:

1.) Any leftover cloud cover affecting heating. At this time satellite imagery shows considerable breaks in the clouds but any showers and thunderstorms that form ahead of time of peak heating could affect the intensity of thunderstorms once we get near peak heating time.
2.) Wind shear is stronger than prior days but instability levels and timing will be key in the coverage of strong to severe thunderstorms in the region. With the stronger wind shear, we’ll be monitoring for the potential of any supercells before the storms evolve into lines and then potentially train over the same areas and the situation becomes one with higher flood potential.
3.) Recent heavy rainfall has reduced flash flood guidance so less rainfall may cause flooding to occur more quickly particularly in flood prone urban and poor drainage areas.

SKYWARN Self-Activation will monitor severe weather and flood potential in the region. This will be the only coordination message as we shift into operations mode. Below is the NWS Boston/Norton Area Forecast Discussion, Flash Flood Watch Statement, Enhanced Hazardous Weather Outlook and SPC Day-1 Convective Outlook:

NWS Boston/Norton Area Forecast Discussion:

NWS Boston/Norton Flash Flood Watch Statement:

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:
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