Heat & Severe Weather Coordination Message #1 – Heat Potential – Weekend of 5/21-5/22/22 – Severe Weather Potential Friday Night 5/20-Sunday 5/22/22

Hello to all…

..Intense Heat & Humidity is expected this weekend so use caution outdoors with any strenuous activities, drink plenty of liquids and find locations to cool off if out in the heat and humidity for an extended period of the time. There will also be the threat for isolated to scattered strong to severe thunderstorms on Sunday Afternoon and Evening in interior portions of Southern New England with a much lower chance of an isolated strong or possibly severe thunderstorm across Connecticut, Rhode Island and Southeast Massachusetts late tonight after 11 PM Friday Evening through 5 AM Saturday Morning..
..A Heat Advisory is now in effect from 8 AM Saturday to 8 PM Sunday for the entire NWS Norton Coverage area except for the East Slopes of the Berkshire, South Coastal Rhode Island and East and South Coastal Massachusetts for heat indices to 99 degrees..
..The Storm Prediction Center (SPC) has placed portions of interior Southern New England in a marginal to slight risk of severe weather for Sunday Afternoon and Evening for isolated to scattered strong to severe thunderstorms with strong to damaging winds, hail, frequent lightning and heavy downpours leading to urban and poor drainage flooding..
..SKYWARN Self-Activation will monitor the severe weather potential for overnight Friday and especially Sunday Afternoon and Evening..

Intense heat and humidity will affect Southern New England this weekend with heat advisories posted for most of the NWS Norton coverage area as posted in the headlines of the message. There are a couple chances for strong to severe thunderstorms with the greatest risk Sunday Afternoon and evening with a lower grade much more conditional risk overnight Friday Night.

For the Friday overnight potential, a mesoscale convective vortex or MCV is moving across Long Island and south of Long Island but is spreading heavy showers and isolated thunderstorms into Southern Connecticut. This is associated with the warm front which will move through the region overnight to bring the intense heat and humidity to the region. This complex along with instability moving in via an elevated mixed layer could bring a low chance of an isolated strong to possibly severe thunderstorm over Connecticut, Rhode Island and Southeast Massachusetts late tonight into the overnight hours and this will be monitored via SKYWARN Self-Activation.

A better chance for isolated to scattered strong to severe thunderstorms exists on Sunday Afternoon and Evening as a cold front moves through the region with high instability and sufficient wind shear in place. The key factor in the coverage and intensity of the strong to severe thunderstorms on Sunday will be the timing of the cold front close enough to peak heating for the severe weather potential to be realized. This will be better known as we get closer to Sunday in future model runs. Portions of interior Southern New England are in a marginal to slight risk of severe weather per SPC.

SKYWARN Self-Activation will monitor the severe weather potential for overnight Friday and especially Sunday Afternoon and Evening. Another coordination message will be posted on Sunday’s severe weather potential by 11 PM Saturday Evening. Below is the NWS Boston/Norton Heat Advisory Statement and Graphics, Area Forecast Discussion and SPC Day-3 Convective Outlook:

NWS Boston/Norton Heat Advisory Statement:
https://kamala.cod.edu/ma/latest.wwus71.KBOX.html

NWS Boston/Norton Heat Advisory and Heat Indices Graphics:
https://wx1box.org/wp-content/uploads/2022/05/heat_advisory.png
https://wx1box.org/wp-content/uploads/2022/05/Heat_Indices_Saturday.png
https://wx1box.org/wp-content/uploads/2022/05/Heat_Indices_Sunday.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

SPC Day-3 Convective Outlook:
https://www.spc.noaa.gov/products/outlook/archive/2022/day3otlk_20220520_0730.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
http://www.wx1box.org
Like us on Facebook – http://www.facebook.com/wx1box
Follow us on Twitter – http://twitter.com/wx1box