Though Monday didn't dawn all that humid for New England, the passage of a warm front during the day will mark an influx in deep, tropical humidity that will create an oppressively humid feeling by Monday afternoon.
The increase in humidity comes ahead of an upper level disturbance that arrives during the late day and evening, preceding what is technically a "cold front," but is unlikely to deliver any cooling Tuesday - just a decrease in humidity.
Nonetheless, the transition from Monday's humidity to Tuesday's reprieve will likely be marked by a line of showers and thunderstorms from west to east across New England, Monday late afternoon to evening, respectively.
Though some scattered, renegade showers may develop ahead of the main line in our increasing humidity, Western New England near the New York state line is likely to find storms with the "main event" sometime around 3 p.m., while eastern communities like Boston will wait until 6 or 7 p.m. The forecast radar image in this post depicts the likely radar image around 5 p.m. this evening.
As has been the case lately, developing Monday afternoon and evening storms will feed off ample heat and humidity - with high temperatures in the 90s and dew point temperature in the 70s for Southern New England - and likely will create at least pockets of damaging wind capable of downing trees, limbs and power lines. With any thunderstorm - severe or not - lightning is a real danger, and that's why you always hear our NECN Weather Team reminding viewers: "When thunder roars, go indoors," based on the premise that if you're able to hear thunder, that means you're close enough for the lightning to be a threat.
Of course, when severe storms threaten, that means damaging wind - 58 mph gusts or stronger - and/or large hail - 1" or larger - is closing in on your area. Be ready to seek shelter indoors, away from windows, if a warning is issued for your area.
Though storms exit east early Monday night, humidity will linger into Tuesday morning, making for a very uncomfortable night for sleeping in New England before drier air arrives Tuesday mid-morning, resulting in a much more comfortable afternoon 24 hours from now, along with a greatly diminished storm threat, save for a few showers in Northern and Central Maine Tuesday morning through early afternoon.
Of course, in this pattern, a decrease in humidity doesn't necessarily mean the end of the heat. In fact, while Tuesday will be less humid in the air that is technically behind a "cold front," there really is no cooler air - simply drier.
Dry air is capable of warming quickly and effectively with sunshine, and we actually think Tuesday's high temperatures may reach a degree or two hotter than Monday!
Overall for New England, with some local variability depending on sea breezes and the like, 90 degree heat is expected to continue through Thursday, before an increased chance of showers and thunder marks a decrease in temperature Friday through Sunday.