Hopefully you enjoyed the break from the heat and humidity this week because the comfortable air is about to be a distant memory with heat and humidity setting up shop the next two days. A heat advisory has been issued for Thursday and Friday — really it’s Friday that’s the dangerously hot day with feels like temperatures as high as 103°!
Thursday is still a hot day, don’t get me wrong. But Thursday is a somewhat bearable heat (in my opinion). Temperatures will be in the lower 90s… hot but doable. Dew points will be in the mid 60s… so a bit muggy, yes, but it’s not tropical air. Combine the two together and feels like temperatures will be 95-100°. But we’ll also have a breeze on Thursday which will keep the air moving, it’s not a stagnant hot air mass overhead.
Friday is the rough day. Temperatures alone will climb to the mid and upper 90s and the humidity will be almost tropical. So when you combine those two, feels like temperatures will climb to 100-103°. While the wind won’t be totally calm, it will be less than Thursday. Storms will arrive in the late afternoon and evening Friday and that will start to break down the heat and humidity for the weekend. In fact the weekend forecast is pretty nice — especially Saturday.
The storms will also help break down the humidity, but it’s not going back to the 40s like we had this week. We’ll likely start off Saturday morning a bit muggy, with falling dew points as drier air works in through the day. Sunday is a comfortable day, but looks like we’ll have to dodge a few storms Sunday (likely favoring the afternoon).
Does it seem like we’ve had a lot of humidity this year? Well it’s not your imagination. I guess the bright spot is it’s better than last year when we tied a record for most tropical days (dew points 70+) in the month of July. While we will fall short of last year’s mark, we’ve still had our fair share this year. This graph is a plot over the last 50 years (doesn’t include this July as it’s not over yet) showing how many July days had a dew point hit or exceed 70°. While every year might not be a record, the tropical days are becoming more common. Compared to 50 years ago, Boston is averaging five more days with tropical humidity just in the month of July! That’s a sign of a warming planet. Warmer air can hold more water vapor and water vapor is humidity. Warmer days are often more humid days.
