Boston reached 90 degrees already by noontime, making Monday the second day of our second heat wave of the season.
Tuesday and Wednesday are also expected to hit or surpass 90 degrees before a cold front moves through.
Monday evening, we will continue to have heat index numbers in the 80s. Overnight lows dip into the 70s, but it remains humid. Any pop-up storms or showers will dissipate once the sun sets.
Tuesday will be just as hot and humid, with highs in the low to mid-90s and heat index values approaching 100. There is a slim chance for a pop-up shower or storm in the heat of the afternoon again, but most of us stay dry. The mountains will see more widespread storms in the afternoon as a cold front approaches.
Wednesday looks to be just as humid, with highs around 90, even with the cloud cover. A cold front will be draped across northwestern New England Tuesday into Wednesday and will sink southeastward during Wednesday night. This front will trigger widespread showers and storms for northwestern New England Wednesday, then for southeastern New England Wednesday night into Thursday morning. The front may linger just to our south, so more clouds are expected there Thursday as we dry off.
High pressure builds in from the Great Lakes and we will be less humid with cooler highs in the low 80s Thursday and Friday. More sunshine is in store for the weekend as our highs will be in the low to mid-80s both Saturday and Sunday.
Next week, we have chances for pop-up storms Monday, Tuesday and Wednesday. Sometime Tuesday or Wednesday, a cold front will move through. Highs remain in the low to mid-80s through all of next week.