Boston normally reaches 90° (or higher) 14 days in a year….yesterday was the first time this year. That's the 4th latest date for that to occur–normally our first 90° day happens on June 8th (the latest date is August 6th, 1908). We should easily hit 90° again this afternoon. In fact, I think it will be hotter than yesterday for most cities & towns as a westerly wind dries out the air just enough to allow temps to reach the low & perhaps even mid 90s!
As for summertime thunderstorms due to all this heat & humidity…..you need something to *lift* this hot & humid air to pop the summer storms. Draped across CT, RI and SE MA will be a very weak cool front (leftover from Sunday evening's storms) this boundary will be weaker than yesterday but likely still able to pop some isolated storms this afternoon. Nothing severe but heads up when heading out to the tennis courts, beaches, golf courses later this afternoon.
Tuesday is another hot day for southern New England with 90° within reach by afternoon. The difference will be the thunder threat. A more potent cool front will charge into New England late tomorrow afternoon and this front will pop a scattering of showers & storms across the region. Far from a washout but a higher chance of summer storms than today.
In any event, this front sweeps the excessive heat & humidity out to sea by Wednesday–and beyond—setting the table for some fantastic summer weather. If this is your vacation week, I want your secret–great pick!