Flood & Severe Weather Coordination Message #2 – Sunday 7/16/23 Significant Flooding & Severe Weather Potential

Hello to all…

..Relentless heavy rainfall for portions of Southern New England will become much more widespread on Sunday with a significant flash flood threat to urban, poor drainage areas, rivers and streams from thunderstorms with frequent lightning and heavy downpours and a secondary threat for isolated to scattered strong to severe thunderstorms with strong to damaging winds, hail and even a isolated weak tornado as a secondary threat..
..A Flood Watch is in effect from 2 AM Sunday through late Sunday Night for all of Southern New England except for Plymouth County Massachusetts, Cape Cod and the Islands for excessive runoff from heavy rainfall may cause flooding of small creeks, streams, urban and poor drainage areas, highways, and low lying spots along with 1-2″ per hour rainfall rates..
..The Weather Prediction Center (WPC) has placed much of Southern New England in a Moderate Risk for Excessive Rainfall and the remaining eastern parts of the region in a slight risk of excessive rainfall for Sunday..
..The Storm Prediction Center (SPC) has expanded the marginal risk for severe weather for Sunday to all of Southern New England..
..SKYWARN Activation with Amateur Radio Operations at NWS Boston/Norton will commence no later than 9 AM for this potentially significant flood event and the secondary threat for severe weather. ARES/RACES groups should closely monitor the progress of Sunday’s weather and seek advice on any activation for this situation. Pictures and videos of flooding and storm damage can be sent as a reply to this message, via our WX1BOX Facebook and Twitter feeds or via the email address pics@nsradio.org with credit being given to the spotter unless otherwise indicated..

A relentless pattern for heavy rainfall, thunderstorms, flooding as the primary threat with isolated to scattered strong to severe thunderstorms as a secondary threat continues particularly for Sunday. Sunday needs to be monitored for significant flooding impacts for the region. The headlines depict the current thinking. Key factors include:

1.) There will be a widespread 1-3″ rainfall but there will be enhanced areas of 3-5″+ rainfall. If this heavier rainfall falls over metro/urbanized areas and/or areas hardest hit by heavy rainfall over the last 2 weeks, it will have the potential to cause a high impact in parts of our coverage area.
2.) The severe weather potential is a secondary threat but any sunshine that increases instability coupled with sufficient wind shear profiles would increase the severe weather potential and NWS Boston/Norton in coordination with SPC has expanded the marginal risk for severe weather to all of Southern New England.
3.) Rain Gauge and flood reports, pictures and videos will be key to closely monitor the impacts of flooding and always are helpful for any severe thunderstorm wind damage.

SKYWARN Activation with Amateur Radio Operations at NWS Boston/Norton will commence no later than 9 AM for this potentially significant flood event and the secondary threat for severe weather. ARES/RACES groups should closely monitor the progress of Sunday’s weather and seek advice on any activation for this situation. Pictures and videos of flooding and storm damage can be sent as a reply to this message, via our WX1BOX Facebook and Twitter feeds or via the email address pics@nsradio.org with credit being given to the spotter unless otherwise indicated. Another coordination message will be posted by 10 AM Sunday depending on what level of activity operations are at during the early morning hours tomorrow. Below is the NWS Boston/Norton Flood Watch Statement & Map, Area Forecast Discussion, Enhanced Hazardous Weather Outlook, WPC Day-2 Excessive Rainfall Outlook & Discussion and SPC Day-2 Convective Outlook:

NWS Boston/Norton Flood Watch Statement & Map:
https://forecast.weather.gov/product.php?site=NWS&issuedby=BOX&product=FFA&format=CI&version=1&glossary=1&highlight=off
https://wx1box.org/wp-content/uploads/2023/07/Flood-Watch.png

NWS Boston/Norton Area Forecast Discussion:
https://forecast.weather.gov/product.php?site=NWS&issuedby=BOX&product=AFD&format=CI&version=1&glossary=1&highlight=off

NWS Boston/Norton Enhanced Hazardous Weather Outlook:
https://www.weather.gov/erh/ghwo?wfo=box

WPC Day-2 Excessive Rainfall Outlook & Discussion:
https://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpferd
https://www.wpc.ncep.noaa.gov/qpf/excessive_rainfall_outlook_ero.php

SPC Day-2 Convective Outlook:
https://www.spc.noaa.gov/products/outlook/archive/2023/day2otlk_20230715_1730.html

Respectfully Submitted,

Robert Macedo (KD1CY)
ARES SKYWARN Coordinator
Eastern Massachusetts ARES Section Emergency Coordinator
Home Phone #: (508) 994-1875
Home/Data #: (508) 997-4503
Email Address: rmacedo@rcn.com
https://ares.ema.arrl.org
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