Remnants of Ida Coordination Message #1 – late Wednesday 9/1/21-Thursday Afternoon 9/2/21 – Flash Flood & Severe Weather Potential

Hello to all…

..The remnants of Ida will bring the potential threat of widespread heavy rainfall and flash flooding as the primary concern but also the secondary concern of strong to damaging winds across the region with the threat for an isolated weak tornado or isolated pockets of enhanced wind damage in severe thunderstorms in Southeast Coastal New England..
..A Flash Flood Watch is now in effect for the entire NWS Boston/Norton coverage area for widespread rainfall of 2-6″ with isolated amounts higher amounts in parts of the flash flood watch area. This rainfall forecasted if it occurs in a short period of time will result in widespread pockets of urban and poor drainage flooding with small river and stream flooding likely. It is noted that the Weather Prediction Center (WPC) has placed much of Southern New England in a moderate to high risk of excessive rainfall..
..The Storm Prediction Center (SPC) has placed Southeast Coastal Massachusetts and Rhode Island in a marginal risk for severe weather with strong to damaging winds and an isolated weak tornado as the main threats..
..SKYWARN Self-Activation with Amateur Radio Call-Up Nets Likely overnight Wednesday Night into Thursday Afternoon for the main threats of flash flooding and measured rainfall reports but the secondary threat of strong to damaging winds and isolated severe thunderstorms with an isolated weak tornado..

The remnants of Ida will impact the weather across Southern New England significantly late Wednesday Night through Thursday Afternoon. The headlines depict the current thinking and potential. Key factors include:

1.) The axis of heaviest rain could shift further north and west or shift a little south and east in future updates but a widespread heavy rainfall is expected regionwide. Flash Flooding is the primary concern from this storm event.
2.) Some weather models are depicting strong to damaging wind gusts with the remnants Ida as it taps into non-tropical energy. The key will be weather these strong winds materialize and whether they can reach the surface. This will bear monitoring as a secondary concern as the wet ground, additional rainfall coupled with strong wind gusts could lead to higher impacts in terms of wind damage if those wind gusts were to materialize.
3.) There is the potential for thunderstorms to enhance the wind gusts in Southeast coastal New England along with the potential for isolated weak tornadoes. This is also a secondary concern that bears watching.

SKYWARN Self-Activation with Amateur Radio Call-Up Nets Likely overnight Wednesday Night into Thursday Afternoon for the main threats of flash flooding and measured rainfall reports but the secondary threat of strong to damaging winds and isolated severe thunderstorms with an isolated weak tornado. The next coordination message will be posted by 10 AM Wednesday Morning. Below is the NWS Boston/Norton Flash Flood Watch Statement, Area Forecast Discussion, Enhanced Hazardous Weather Outlook, Rainfall Forecast Map, WPC Excessive Rainfall 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 Flood Watch Statement:
https://kamala.cod.edu/ma/latest.wgus61.KBOX.html

NWS Boston/Norton Enhanced Hazardous Weather Outlook:
https://www.weather.gov/box/ehwo

NWS Boston/Norton Rainfall Map:
http://wx1box.org/wp-content/uploads/2021/08/StormTotalQPF_SFC4.png

WPC Excessive Rainfall Outlook:
https://www.wpc.ncep.noaa.gov/qpf/ero.php?opt=curr&day=2

SPC Day-2 Convective Outlook:
https://www.spc.noaa.gov/products/outlook/archive/2021/day2otlk_20210831_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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