High Heat, Humidity and Storms

Steam bath material yesterday as the high in Boston hit 96 degrees. Factor in a dew point of 72, and the heat index (what it feels like) hit a stuffy 105.

Today, we’ll do it again as highs reach the mid 90s and the heat index cracks 100.  A heat advisory is in place for much of southern New England from 11am-7pm.  Although it’ll very much feel like yesterday, there is one difference that stands out and is something to watch for.  That difference is a better chance for storms.  I don’t expect everyone to get hit, but by mid afternoon, scattered thunderstorms develop and remain hit or miss across the area into the early evening before fading out. A few of the storms could be on the strong side with strong wind gusts, however, the main threat from storms will be frequent lightning and downpours. The atmosphere is loaded with water vapor, so any storm that does form will have a high opportunity to produce plenty of rain. If those storms are slow to move, localized flooding is possible. So while many would love to see an inch or two of rain on the lawn, you just don’t want to see it in a 30-45min time span. Again, the high amounts are localized, so not all towns will see it.

The forecast for tomorrow is a bit tricky… ok, a lot tricky. A backdoor cool front will try to slide in from the northeast, changing the wind direction to the northeast for part of the area.  That would hold temps down quite a bit across eastern Mass compared to today. It’s likely that tomorrow afternoon, temps near the coast, including the city of Boston are only in the 70s to near 80.  Inland, it’ll be warmer, west of 495, high 80s to near 90 is still possible. Where the northeast wind meets southwest, that’s the best chance for scattered storms to develop. That best chance will be inland. Like today, locally heavy rain is the highest risk.

Sunday, the heat is on.  Low to mid 90s.  The risk for afternoon/evening storms is there too as a cold front slides in later in the day.  Stop me when this sounds familiar… the atmosphere will have plenty of moisture to work with, so locally heavy rain in any storm that forms is likely.

I know, I know, the weekend forecast sounds iffy with the storm chance.  Bottom line, keep an eye to the sky, but there will be a lot of dry hours too.

@clamberton7 -twitter