Severe Weather Coordination Message #2 – Wednesday Evening 9/8/21-Thursday Evening 9/9/21 Severe Weather & Flood Potential

Hello to all…

..Isolated to Scattered Strong to Severe Thunderstorms are possible in three rounds across Southern New England, one during the Wednesday Evening timeframe, another round possible Thursday Morning and a final round Thursday Afternoon and early evening. Strong to damaging winds, hail, frequent lightning and heavy rainfall leading to urban and poor drainage flooding and possibly small river and steam flooding are the primary threats..
..The Storm Prediction Center (SPC) has expanded the Marginal Risk for severe weather to include Western, Central and Northeast Massachusetts, Connecticut, and much of interior Rhode Island for tonight into Thursday Morning with a slight risk for severe weather further west into Eastern New York..
..The Weather Prediction Center (WPC) has placed portions of Western New England in a marginal to slight risk of excessive rainfall for Wednesday Afternoon and Evening and Eastern Massachusetts and Rhode Island in a marginal risk for excessive rainfall for Thursday..
..Hurricane Larry will track well east of New England but could bring the risk for swells, rip currents and dangerous surf conditions along coastal beach areas of Southern New England later this week and this weekend and anyone going to coastal areas should avoid the rocks etc and be careful swimming in any coastal area beaches..
..SKYWARN Self-Activation will monitor the severe weather and flood potential for Wednesday Evening through Thursday Evening..

A strong cold front will slowly work its way through Southern New England late Wednesday Night through Thursday Evening. This cold front will bring with it the potential for some severe weather and flooding issues to portions of Southern New England. This cold front is what will keep Hurricane Larry well offshore of Southern New England but swells, rip currents and waves from Larry will affect coastal areas of Southern New England late this week and this weekend so any beachgoers going to area beaches should use caution going into the ocean waters. The headlines reflect the current thinking. Key factors include:

1.) The timing of the cold front through Southern New England and whether there is sufficient instability or sufficient jet dynamics to overcome marginal instability to allow for any strong to severe thunderstorms to develop.
2.) The potential for any training of thunderstorms to allow for potential flooding issues in parts of Southern New England. While the rainfall will be nowhere near the magnitude of the remnants of Ida, the recent rainfall and the potential for 1-2″ of rain with isolated higher amounts may cause renewed flood potential over portions of the area.
3.) It remains unclear particularly for Eastern New England whether the greatest potential for severe weather will occur Thursday Morning or more towards afternoon and evening. This will depend on how any shower and thunderstorm activity forms, what areas it affects and as we get into Thursday any sunshine that may allow for higher levels of instability. These aspects will be monitored closely.

SKYWARN Self-Activation will monitor the severe weather and flood potential for Wednesday Afternoon through Thursday Evening. Where the severe weather and flood potential could occur anytime in the Wednesday Evening to Thursday Evening timeframe, this will likely be the last coordination message as we shift into operations mode unless a significant change to the situation occurs and time allows for an update, Below is the NWS Boston/Norton Area Forecast Discussion, Enhanced Hazardous Weather Outlook, SPC Day-1 and Day-2 Convective Outlooks and WPC Day-1/Day-2 Excessive Rainfall Outlooks..

NWS Boston/Norton Area Forecast Discussion:

NWS Boston/Norton Enhanced Hazardous Weather Outlook:

WPC Excessive Rainfall Outlook:

SPC Day-1 Convective Outlook:

SPC Day-2 Convective Outlook:

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:
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