Severe Weather & Heat Coordination Message #3 – Extreme Heat Sunday 6/22/25-Tuesday 6/24/25 & Severe Weather Potential Sunday 6/22/25 PM Thru Evening

Hello to all…

..Extreme heat is expected to setup over the region Sunday through Tuesday. The highest heat days are expected to be Monday and Tuesday. Sunday could have high heat potential as well but current shower activity from a remnant Mesoscale Convective System or (MCS) may keep temperatures a bit cooler for Sunday but it will still be hot and humid presuming sufficient clearing develops. The main severe weather impacts overnight from this MCS was felt in Central New York State with over 69,000 without power as of 730 AM this morning..
..Any severe weather potential for today has shifted to Sunday Afternoon and Evening, should be isolated in nature, and will be contingent on cloud cover clearing to allow for sufficient heating and destabilization and any boundaries or trigger to tap into a very unstable atmosphere presuming clearing develops. Greatest risk would be in Western and Central Massachusetts and Northern Connecticut..
..The Storm Prediction Center (SPC) has continued portions of Western and Central Massachusetts and Northern Connecticut in a Marginal Risk of Severe Weather this Sunday Afternoon through early evening. Strong to damaging winds, hail, frequent lightning and heavy downpours leading to urban and poor drainage flooding are the main threats. The threat again is likely to be isolated..
..An Extreme Heat Warning remains in effect from 11 AM Sunday to 8 PM Tuesday Evening for the entire NWS Norton Coverage area except for Cape Cod and the Islands and the East slopes of the Berkshires for heat indices of up to 110 degrees expected. A Heat Advisory remains in effect from 11 AM Sunday to 8 PM Tuesday for Western Franklin, Western Hampshire and Western Hampden Counties for heat indices up to 100 degrees expected. Use caution with any outdoor activities, drink plenty of liquids and take frequent breaks from the heat in Air Conditioning when possible..
..SKYWARN Self-Activation with Amateur Radio Call-Up Nets are possible Sunday Afternoon and Evening. Pictures and videos of storm damage, hail, and flooding can be sent as a reply to this email, via our WX1BOX Facebook, X and Bluesky feeds or to the email address pics@nsradio.org with credit given to the spotter unless otherwise indicated..

The headlines depict the current thinking on the Extreme Heat Warning and Heat Advisory. Sunday’s high temperature profile will be contingent on clearing from the remnant MCS that hit the Central New York area the hardest during the overnight hours. It will likely be cooler than originally thought for Sunday but still hot and humid. Monday and Tuesday are a high confidence on intense heat and humidity so use caution if doing any strenuous activities outdoors or in non-Air Conditioned environments, stay cool and drink plenty of liquids.

Turning our attention to the severe weather potential, we are once again humbled on how modeling of MCS’ remains a low confidence forecast. Models were ranging from Northern to Southern New England on potential severe weather impacts and the impacts ended up being felt in Central New York with wind damage, large hail and flash flooding. Over 69,000 were without power centered in Central NY where the complex went through in the NWS Binghamton NY coverage area. The remnant MCS has brought showers to Southern New England and cloud cover. This cloud cover could preclude any later Sunday severe weather potential unless it clears out by early afternoon.

For the Sunday Afternoon and Evening timeframe, the severe weather potential will be based on the following key factors:
1.) Clearing for destabilization after the remnant MCS has moved through the area.
2.) Available boundaries or triggers in the atmosphere assuming clearing can develop to allow for high instability to break the cap in the atmosphere.
3.) Ability of factors 1 and 2 to take advantage of an Elevated Mixed Layer or EML that should remain over the region through this evening. At this time, activity is expected to be isolated or the cap may be too strong to break for the marginal risk area but bears watching as any thunderstorm development could quickly become severe if any activity can break the cap.

SKYWARN Self-Activation with Amateur Radio Call-Up Nets are possible Sunday Afternoon and Evening. Pictures and videos of storm damage, hail, and flooding can be sent as a reply to this email, via our WX1BOX Facebook, X and Bluesky feeds or to the email address pics@nsradio.org with credit given to the spotter unless otherwise indicated. This will be the last coordination message on the severe weather potential for Sunday as we move to a monitoring mode. Below is the NWS Boston/Norton Area Forecast Discussion, Enhanced Hazardous Weather Outlook and SPC Day-1 Convective Outlook:

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 Extreme Heat Warning/Heat Advisory Statement:
https://forecast.weather.gov/product.php?site=NWS&issuedby=BOX&product=NPW&format=CI&version=1&glossary=1&highlight=off

NWS Boston/Norton Enhanced Hazardous Weather Outlook:
https://www.weather.gov/erh/ghwo?wfo=box

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)
Email Address: rmacedo@rcn.com
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