PM Update: Heat advisory for the District and east Saturday, with a heat index of 105-plus possible
A cold front is set to deliver storms late Saturday and eventually somewhat cooler air.
Our heat wave has reached six days in length and we’re going to make it a week straight tomorrow. Highs in the low and mid-90s are a handful above normal. Other than a slight chance of an isolated storm this evening, it’ll remain dry tonight and through a good chunk of Saturday until storms threaten late. Sunday might not be as wet as it once seemed.
Through Tonight: An isolated storm may pop up before sunset. I’d not even expect that at this point, though. Skies are partly to mostly clear overnight. Lows range across the 70s as higher humidity sloshes back into the area. Winds are light from the south and southwest after dark.
Tomorrow (Saturday): It’s another hot one with lots of sunshine. Our slight respite in super-high humidity is over with dew points past 70. As air temperatures reach the low to mid-90s, heat index values may near or even surpass 105 degrees for a time Saturday afternoon, prompting the heat advisory the District and points east. It’s the first heat advisory of the summer for D.C. proper. Amid the humidity, showers and storms erupt as the afternoon wears on, probably lasting into the evening, and maybe longer. Any storm could be strong, with heavy rain, lightning and possibly some damaging wind.
Sunday: We’re looking a bit better to end the weekend than we initially did. Latest weather modeling suggests a front will get far enough south to let us dry out a bit. Still, some showers are possible, but they may end up mainly south and east. We’ll need to keep an eye peeled for more shifts, just in case. The heat wave should break, with highs heading for the mid- to upper 80s.
https://www.washingtonpost.com/weather/2021/07/16/pm-update-heat-advisory-district-east-saturday-with-heat-index-105-plus-possible/?