Severe Weather Coordination Message #2 – Monday 7/20/20 Severe Weather Potential

Hello to all…

..The potential for isolated to scattered strong to severe thunderstorms appears lower than it was yesterday and the Storm Prediction Center (SPC) has pulled Southern New England out of a marginal risk for severe weather. Weather models have handled the overnight isolated to scattered showers and general thunderstorms poorly, however, and may not handle activity for later this afternoon and early evening correctly..
..Will continue to monitor the potential for Isolated strong to severe thunderstorms this afternoon and early evening across Eastern Connecticut, Rhode Island and Eastern Massachusetts despite the lower risk for this activity than noted Sunday Evening. Strong to damaging winds, hail, frequent lightning and heavy downpours with urban and poor drainage flooding would be the main threats if any isolated strong to severe thunderstorms are able to develop. Best timeframe for any severe weather potential is 2-6 PM today..
..SKYWARN Self-Activation will monitor the severe weather potential for Monday Afternoon and Evening understanding the potential is lower than noted Sunday Evening..

Another day of intense heat and humidity will affect Southern New England Monday despite the unexpected isolated to scattered shower and general thunderstorm activity that occurred this morning. A cold front will swing through the area Monday afternoon and evening. The potential for severe weather is less than noted Sunday Evening but will still be monitored in case any isolated strong to severe thunderstorms can develop. The headlines depict the current thinking. Key factors include:

1.) The ability of the atmosphere to heat up given morning cloud cover and isolated to scattered shower and thunderstorm activity. Satellite imagery shows strong clearing and clouds thinning over the region so this should not be a significant factor.
2.) The amount of forcing or triggering in the atmosphere. This is strongest north of Southern New England.
3.) Drier air in the mid levels of the atmosphere may not allow strong to severe thunderstorms to develop and keep them to more lower topped showers or general thunderstorms. If models incorrectly diagnose too much dry air in the mid levels of the atmosphere, that would mean a better chance for strong to severe thunderstorm development.

SKYWARN Self-Activation will monitor the severe weather potential for Monday Afternoon and Evening. This will be the last coordination message on Monday’s severe weather potential. Below is the NWS Boston/Norton Area Forecast Discussion and Enhanced Hazardous Weather Outlook:

NWS Boston/Norton Area Forecast Discussion:
https://kamala.cod.edu/ma/latest.fxus61.KBOX.html

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

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
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