Severe Weather Coordination Message #1 – Sunday-Tuesday AM 7/9/23-7/11/23 Flood & Severe Weather Potential
Hello to all…
..Thunderstorms and heavy convective showers will bring a renewed threat of flooding and flash flooding particularly to Western and Central Massachusetts and Northern Connecticut though all areas of Southern New England should monitor this potential. There is also a secondary threat for isolated to scattered strong to severe thunderstorms with strong to damaging winds, hail and frequent lightning for Sunday Afternoon, Sunday Evening and on Monday..
..A Flood Watch is now in effect through Tuesday Morning for Northern Connecticut, Western and Central Massachusetts to include Berkshire, Hampshire, Hampden, Franklin, Worcester and Northern Middlesex Counties of Massachusetts for rainfall of 2-4″ with isolated locations or an axis of rainfall that could be 5″ or more in areas that get thunderstorms and heavy rainfall that train over the same areas. This additional rainfall coupled with the rainfall of the last week could cause urban and poor drainage flooding as well as small river and stream flooding in this region..
..The Weather Prediction Center (WPC) has placed much of the Flood Watch area and portions just east of the Flood Watch in a Slight to Moderate risk of excessive rainfall for Sunday through early Tuesday Morning..
..The Storm Prediction Center (SPC) has areas of extreme Western Massachusetts and Western Connecticut in a marginal risk for severe weather Sunday and Western and Central Massachusetts, Connecticut, and Rhode Island in a marginal risk for severe weather for Monday..
..SKYWARN Self-Activation will monitor the flooding and severe weather potential Sunday through early Tuesday Morning. Picture of storm damage or flooding can be sent to our WX1BOX Facebook/Twitter social media feeds, as a reply to this message or to the email address pics@nsradio.org with credit given to the spotter on the photos unless otherwise indicated..
An active weather pattern has resumed across the area. On Saturday, localized flash flooding occurred in parts of Western Massachusetts and in Suffield, CT. Reports from this event can be seen below:
https://wx1box.org/wp-content/uploads/2023/07/reports_7_8_23.pdf
The headlines depict the current thinking on the primary risk for flooding and flash flooding in the region with a secondary risk for isolated to scattered strong to severe thunderstorms later Sunday Afternoon through early Tuesday Morning. Key factors include:
1.) There will be an axis of very heavy rainfall potentially of 5″ or more within the more general area of 2-4″ rainfall in the Flood Watch area. Where that sets up will be fine-tuned in future updates. If this affects metro areas and areas that have had the heavy rainfall over the past week, that will create greater impacts for parts of the region for higher impact flooding of urban and poor drainage areas as well as smaller streams and rivers.
2.) For areas outside of the Flood Watch, this rainfall and axis of heavy rainfall could affect portions of Eastern Massachusetts and Rhode Island depending on the low pressure system track and these areas should monitor, particularly those that were hit hard from early last week’s flash flooding and thunderstorms with heavy rainfall and in metro areas more prone to urban and poor drainage flooding.
3.) The severe weather potential is a secondary threat but one that will also bear close watching. Instability will likely be less due to heavy rainfall and ongoing thunderstorms but wind shear profiles will be stronger and could compensate for less instability.
SKYWARN Self-Activation will monitor the flooding and severe weather potential Sunday through early Tuesday Morning. Picture of storm damage or flooding can be sent to our WX1BOX Facebook/Twitter social media feeds, as a reply to this message or to the email address pics@nsradio.org with credit given to the spotter on the photos unless otherwise indicated. Another coordination message will be posted by 11 PM Sunday Evening if time allows pending any ongoing flood and severe weather operations for later Sunday Afternoon and Evening. Below is the NWS Boston Norton Flood Watch Statement & Map, Rainfall Map, Area Forecast Discussion, Enhanced Hazardous Weather Outlook, WPC Day-1 & Day-2 Excessive Rainfall Outlooks and SPC Day-1 and Day-2 Convective Outlooks:
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/ffa.png
NWS Boston/Norton Rainfall Map:
https://wx1box.org/wp-content/uploads/2023/07/QPF.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-1 and Day-2 Excessive Rainfall Outlooks:
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-1 and Day-2 Convective Outlooks:
https://www.spc.noaa.gov/products/outlook/day1otlk.html
https://www.spc.noaa.gov/products/outlook/day2otlk.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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