The 22News Storm Team issued a Weather Alert for Friday afternoon and evening as western Massachusetts braces for the risk of strong or severe thunderstorms. A Severe Thunderstorm Watch was also posted for the Berkshires and remains in effect through Friday night.
That timing is what makes the alert matter now. People in the region are heading into a hot, humid stretch, then into a narrow window when storms could turn strong enough to prompt warnings, even though the exact communities most exposed beyond the Berkshires have not been spelled out. When a weather alert is issued for a day like this, it is because the atmosphere is primed for quick changes, not a slow-moving rain event.
The forecast points to a sharp swing after the storms pass. The sky clears overnight and the humidity lowers, with Saturday morning temperatures in the 60s. By afternoon, nearly 100% sunshine is expected, the air should be dry, and highs are forecast in the mid-80s to mid-90s with a west breeze. Saturday evening stays mostly clear, and temperatures are expected to fall through the 80s and into the low 70s before 11 pm.
There is one part of the outlook that cuts against the calm Saturday setup: strong or severe thunderstorms are already in the frame for Friday afternoon and evening, and showers and thunderstorms are expected again Sunday afternoon or evening. That makes the brief dry window important, but also temporary. The atmosphere will not stay settled for long.
The Storm Team says the ingredients for a severe thunderstorm can be remembered as SLIM: shear, lift, instability and moisture. That shorthand fits the forecast well. The air starts out hot and humid, the risk rises Friday, Saturday turns sunny and dry, and then the pattern bends back toward rain by Sunday afternoon or evening.
