Severe Weather Coordination Message #2 – Tuesday July 4th 2023 Severe Weather and Flood Potential

Hello to all…

..Happy Independence Day/4th of July to all SKYWARN Spotters and Amateur Radio Operators. An active period of weather continues a time of many outdoor activities for the July 4th Independence Day holiday in Southern New England..
..On Monday Evening into Tuesday Morning, localized areas of Western Massachusetts and Northern Connecticut received another 1-4″ of rainfall with the hardest hit areas over Southeast Hartford into Tolland Counties of Connecticut and Northwest Hampshire into West-Central Franklin Counties of Massachusetts. Additional Thunderstorms and heavy rainfall is possible across portions of Southern New England particularly along and south of the Mass Pike today though all areas should monitor..
..The threat for strong to severe thunderstorms has decreased with heavy rainfall, urban and poor drainage flooding and frequent lightning as the main threat for thunderstorms late Tuesday Morning through Tuesday Evening but an isolated strong to severe thunderstorm cannot be ruled out in the region as a secondary threat. The Storm Prediction Center (SPC) has pulled the region out of marginal risk as any severe thunderstorms will be quite isolated but thunderstorms with heavy downpours and frequent lightning can occur in parts of Southern New England today..
..A Flood Watch is in effect through Late Tuesday Night for Northern Connecticut, Providence County RI, Eastern Franklin, Eastern Hampshire, Eastern Hampden, Worcester, North-Central Middlesex, Western Norfolk and Northern Bristol Counties of Massachusetts for excessive rainfall causing flash flooding in areas that receive persistent heavy downpours and thunderstorms and in areas that receive these persistent heavy downpours and thunderstorms that also had heavy rainfall from Sunday 12 AM through Tuesday Morning. The Flood Watch for Western Essex County has been canceled..
..SKYWARN Self-Activation will monitor the flood and isolated severe weather potential for Tuesday Afternoon and Evening..

An active period of weather continues for the July 4th Independence Day holiday. On Sunday through early Monday Morning, a swath of 2-4″ rainfall with isolated higher amounts occurred across Western, North-Central and Northeast Massachusetts and North-Central Connecticut with 0.50-2″ rainfall amounts across the remainder of Northern Connecticut and into parts of Norfolk, Middlesex and Suffolk Counties of Massachusetts. Rhode Island received the least rainfall and Southeast Massachusetts had between 0.10-1.2″ of rain with the higher amounts in Western Cape Cod. A detailed list of rainfall reports, flood reports and isolated severe thunderstorm wind damage can be seen here:

NWS Norton Amateur Radio and Non-Amateur Radio Spotter Reports Log:
https://wx1box.org/wp-content/uploads/2023/07/reports_7_2_23_7_3_23.pdf

NWS Norton Public Information Statement – Precipitation Reports:
https://wx1box.org/wp-content/uploads/2023/07/PNSBOX_7_3_23_Rainfall.pdf

On Monday Evening into Tuesday Morning, localized areas of Western Massachusetts and Northern Connecticut received another 1-4″ of rainfall with the hardest hit areas over Southeast Hartford into Tolland Counties of Connecticut and Northwest Hampshire into West-Central Franklin Counties of Massachusetts.The following is a report focused on this information and will be updated later this morning and posted as a post message regarding the heavy rainfall and localized flooding over the past few days:

https://wx1box.org/wp-content/uploads/2023/07/reports_7_3_23.pdf

For July 4th, the severe weather potential has lessened and the main threat from thunderstorms is frequent lightning and heavy rainfall leading to urban and poor drainage flooding. An isolated strong to severe thunderstorm cannot be ruled out but any coverage of severe weather will be quite isolated compared to the heavy rainfall, flooding and lighting potential. Key factors for today include:

1.) Amount of sunshine for heating and destabilization for today with ongoing shower and thunderstorm activity. Lessening shear and cloud cover is reducing the severe weather potential but thunderstorms with frequent lighting and heavy downpours remain possible in the region particularly along and south of the Mass Pike.
2.) Flooding will be contingent on whether the same areas get hit hard repeatedly with heavy downpours or if the heavy downpours occur in areas that have received significant rainfall from the early Sunday Morning to Tuesday Morning period
3.) Despite the severe weather potential lessening, flooding from heavy rainfall is a concern along with frequent lightning which could affect outdoor events.
4.) Not all areas will see a thunderstorm today. Some locations will and could see significant impacts while other locations may not see any activity. Staying weather aware and monitoring future forecasts, watches and warnings if doing outdoor events will be key to insuring safety and to make the right decisions regarding continuing with outdoor events.

SKYWARN Self-Activation will monitor the flood and severe weather potential for Tuesday. This will be the last coordination message as we shift into operations mode. Below is the NWS Boston/Norton Flood Watch statement, Area Forecast, Discussion, and Enhanced Hazardous Weather Outlook:

NWS Boston/Norton Flood Watch:
https://forecast.weather.gov/product.php?site=NWS&issuedby=BOX&product=FFA&format=CI&version=1&glossary=1&highlight=off

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

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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