This is hands down likely to be the hottest and most uncomfortable stretch of 2016. Today will reach the mid to upper 90s under sunny skies and WSW winds near 5 mph. Don’t expect any relief at the coast, except maybe a very minor knock down to the low 90s right at the water but not much else. To get any real coastal relief you have to go to the south coast of MA/RI/CT where highs will be in the mid 80s, and even then, the low 90s may get very close to the south coast of MA. The closest to relief in our part of the region will be Cape Ann, in the upper 80s to around 90 degrees.
Dewpoints will be in the mid 60s to low 70s today. This combination will create an extremely dangerous situation, and if not for the intrusion of some slightly drier air (but still nonetheless uncomfortably humid air) into Northern MA, we would probably be under excessive heat warnings and not heat advisories. A heat advisory is in effect until 7 PM today for northern CT, northern RI, and much of MA except the South Coast, Cape Cod, the Islands, and areas west of the I-91 corridor. A heat advisory is also in effect for southern NH and York County, Maine until 7 PM *tomorrow*, and one might be issued for tomorrow in the areas that do not have one for tomorrow as of now.
This combination of high heat and humidity will produce heat index values of 100-105, and heat exhaustion and heat stroke are possible for those who spend significant time outdoors tomorrow (especially if exerting physical work). If working outside, take frequent breaks and drink lots of water. If possible, stay in an air conditioned area, stay out of the sun, and check in on relatives and neighbors (particularly the elderly).
This graphic is on the National Weather Service’s national heat safety site, and it nicely describes the differences between heat exhaustion and heat stroke.
Similar conditions are likely tomorrow and perhaps Saturday as temperatures reach the low to mid 90s Friday and possibly Saturday, and dewpoints are in the low to mid 70s both days. There is a little less confidence on temperatures for Saturday: the GFS and NAM portray a backdoor cold front (remember those?) Saturday afternoon/evening.
Today there is also a chance of scattered showers and storms south of the MA Pike, with a very low possibility of an isolated renegade cell or two north of the Pike. Either way, I’m not expecting anything widespread. There could be some more showers and storms tomorrow, though, and the SPC has placed a marginal risk of severe storms in VT, NH, and much of Maine, as well as northern Essex county in MA. These shower and storm chances continue over the weekend, with the potential for more widespread storms Sunday into Monday with a heavy rain threat – I’ll discuss that more tonight or tomorrow.