Boston MA weather: Pleasant air, chance of isolated shower

The new, delightful air for New England will get a reinforcing push from Canada as a new cold front crosses New England from northwest to southeast Monday.

Although this front will deliver some scattered showers and maybe even a rumble of thunder in the mountains to the lakes of New England – and an isolated late day to early evening shower as far south as the Mass. Turnpike – these won’t ruin a great-feeling day. In fact, for most of New England, the majority of the day is spent under a blend of sunshine and fair weather clouds with a light northwest wind that tends toward a gentle sea breeze, and even on Cape Cod where a southwest wind increases a bit late in the day, wave heights will remain a foot or less.

The drier air – dew point temperatures measuring the moisture in the air only in the 50s, versus 70s in tropical air last week – will afford a cool overnight Monday night with low temperatures in the 50s for many, and even some 40s in cooler spots of northern New England! Tuesday brings another exceptionally comfortable day with lots of sun, some late-day puffy cumulus clouds that could yield an isolated sprinkle or non-impactful brief shower with highs in the 70s, then an even cooler night than Monday night, with overnight lows dipping into the 40s in even some of the cooler, rural valleys of northern and central Massachusetts!

The pleasant and bright weather continues Wednesday, and most of Thursday, though slowly increasing humidity aloft Thursday late day to evening could touch off an isolated shower. Friday is really the day the humidity increases – dew point temperatures rise to the 60s again, and this encourages renewed scattered shower, downpour and thunderstorm growth as a large jet stream level disturbance arrives overhead.

Right now, the biggest forecast question is how long that disturbance lingers overhead. Our exclusive NBC Forecast System still holds a 70% chance of some showers cropping up Saturday, which is certainly possible, but we are a bit more optimistic the disturbance will just barely nudge east of us by Saturday – we’ll keep you posted, though even if some showers pop up they shouldn’t ruin the day, then Sunday looks good with seasonable temperatures returning from the weekend into next week – highs generally either side of 80 degrees in our exclusive First Alert 10-day forecast.