Storm Coordination Message #1 – Wednesday Night 8/4/21-Thursday Morning 8/5/21 Heavy Rainfall & Flood Potential

Hello to all…

..Storm system will move through the region Wednesday Night into Thursday Morning bringing heavy rainfall and a few thunderstorms to Eastern New England..
..A Flash Flood Watch is now in effect for Wednesday Night through Thursday Morning for all of Rhode Island and Eastern Massachusetts except for Cape Cod and the Islands for 1-3″ of rainfall with isolated amounts up to 4″ possible. This rainfall combined with a wet month of July will result in a renewed risk for flooding of urban and poor drainage areas as well as small rivers and streams. Uncertainty remains on the axis of heavy rainfall in Southern New England and could shift west or east in future updates..
..SKYWARN Self-Activation will monitor for rainfall and flooding reports across Eastern New England Tonight into Thursday Morning..

Another round of heavy rainfall is expected across portions of Eastern New England tonight into Thursday Morning. The headlines depict the current thinking. Key factors include:

1.) High resolution models are in different locations with the heaviest rainfall ranging as far west as Eastern Connecticut, Rhode Island and Central and Northeast Massachusetts to areas further southeast even including Cape Cod and the Islands. The current Flash Flood Watch area represents the highest confidence area for potential flooding concerns and this could shift west or east as we get closer to the storm event and models come into a further consensus on location.
2.) If a further west shift to the heavy rainfall occurs, areas of Southeast Massachusetts could see an isolated severe thunderstorm threat develop along with some strong general wind gusts and this will be monitored in future updates.
3.) With the wet month of July, if this rainfall falls in the current Flash Flood Watch area or areas further west, the flood potential for urban and poor drainage areas and small rivers and streams will be fairly high. If the axis shifts further east into Cape Cod and the Islands, the rainfall will be beneficial as this area has actually experienced below normal rainfall whereas areas northwest of the Cape Cod Canal have had above normal rainfall. This will be monitored as we get closer to the storm event.

SKYWARN Self-Activation will monitor for rainfall and flooding reports across Eastern New England tonight into Thursday Morning. Another coordination message will be posted by 1000 PM Wednesday Evening. Below is the NWS Boston/Norton Flash Flood Watch Statement, Area Forecast Discussion and Enhanced Hazardous Weather Outlook:

NWS Boston/Norton Flash Flood Watch Statement:
https://kamala.cod.edu/ma/latest.wgus61.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

NWS Boston/Norton Rainfall Map:
https://wx1box.org/wp-content/uploads/2021/08/StormTotalQPF_SFC1.png

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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