Get that A/C in right now! That is what I would suggest to anyone who has yet to put their A/C in. You will definitely need it the next several days. We are going from 50s/60s straight to middle 90's tomorrow afternoon. Tomorrow I am going for a high of 94 degrees in the city of Boston. The Cape will be cooler, as through much of this heat wave, as they will be in the upper 70's to low 80's throughout this first official heat wave for SNE. So, if you want a place to escape the heat, go to the Cape and the Islands because they will get use of natural air conditioning, but they will not be able to escape the humidity that will skyrocket after tomorrow's strong late afternoon storms. Everyone is fair game for a thunderstorm and downpour tomorrow afternoon say after 5PM. It may actually consolidate into a line of thunderstorms that could produce heavy rainfall, strong gusty winds, and vivid lightning. That will pass to allow for a stuffy night tomorrow night. Lows will have a hard time getting out of the upper 60's to low 70's.
Sunday is more of the same with highs getting into the middle 90's once again. It may be a degree or two hotter than Saturday as there will be less of a chance to cool from clouds and thunderstorms, but the threat will still be there, just minimized. The humidity will be high on Sunday and once again we will not cool down overnight. Low temperatures will hover in the middle 70's in Boston and around 70 in the suburbs.
Then we will have the hottest day of the past couple of summers. I am going for an all out 100 degrees for a SNE average. Some of the latest guidance has come back from this extreme heat idea, but I am still going for it unless we continue to see evidence to reduce these numbers. However, for now, I am going upper 90's to around 100 degrees in Boston, metrowest will likely come between 98-102 degrees. Again, escape to the Cape where they will be 'cool' into the middle 80's. I do not think we will see thunder because the air above us will be so warm that there will be no instability, just one uniform HOT airmass forming a 'cap.' This 'cap' will save us from afternoon thunderstorms. We will probably just stay sunny and baking all day long. Tuesday is the last real hot day, middle 90's, before late afternoon thunderstorms, likely severe, move across SNE to bring back some more seasonable air.
Last words, put in that air conditioner tonight!