Severe Weather Coordination Message #2 – Wednesday 9/4/19 Severe Weather Potential

Hello to all…

..Isolated to scattered strong to severe thunderstorms are likely from north and west of a Boston to Providence line through much of Southern New England. Strong to damaging winds, heavy rainfall leading to urban and poor drainage flooding are the main threats but there is also a secondary risk of large hail and an isolated tornado..
..The Storm Prediction Center (SPC) has placed much of Southern New England from Windham County Connecticut, Middlesex, and western Essex counties of Massachusetts north and west in a slight risk for severe weather with a marginal risk for severe weather in Southeast New England except for Cape Cod and the Islands..
..Timeframe for severe weather is expected to be between 2-9 PM Wednesday and a Mesoscale Convective Discussion has been issued indicating an 80% chance of a watch for much of Southern New England.
..SKYWARN Activation with Ops at NWS Boston/Norton is likely between 1-2 PM Wednesday Afternoon..

Clearing is occurring across much of the marginal and slight risk areas late this morning allowing for increased instability. There will be strong winds aloft above what is required for severe weather potential with strong forcing and a trigger with a cold front in the region. The extent of the severe weather potential will be based on the level of instability. There will also be some turning in the atmosphere which may allow for an isolated tornado and large hail risk. Given the clearing trend and if it continues, this may allow for a fairly potent severe weather event particularly in the slight risk severe weather area and will be monitored closely. The headlines of the message depict the current thinking.

SKYWARN Activation with Ops at NWS Boston/Norton is likely between 1-2 PM Wednesday Afternoon. This will be the last coordination message on this event as we shift into operations mode. Below is the NWS Boston/Norton Hazardous Weather Outlook, Enhanced Hazardous Weather Outlook, SPC Mesoscale Convective Discussion, and SPC Day-1 Convective Outlook..

NWS Boston/Norton Hazardous Weather Outlook:
https://kamala.cod.edu/ma/latest.flus41.KBOX.html

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

SPC Mesoscale Convective Discussion #1924:
https://www.spc.noaa.gov/products/md/md1924.html

SPC Day-1 Convective Outlook:
https://www.spc.noaa.gov/products/outlook/day1otlk.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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