D.C. area forecast: Heat wave in high gear ahead of potential weekend storms

* Code orange air quality alert Wednesday: unhealthy for sensitive groups *

Today’s Daily Digit

A somewhat subjective rating of the day’s weather, on a scale of 1 to 10.

3
Too hot, too humid, and now bad air. But could be (has been) worse during summer in DC.

Express Forecast

Today: Mostly sunny, hot and humid. Highs: Mid-90s.

Tonight: Very warm and muggy. Lows: 70s.

Tomorrow: Partly to mostly sunny, hot and humid. 20-30% chance of p.m. t’storm. Highs: Mid-90s.

FORECAST IN DETAIL

Our mid-July heat wave gets a little worse today with code orange air quality. I don’t want to over-dramatize the heat and humidity – it’s the kind of stuff we see at some point almost every summer, and sometimes worse. But the timing is just plain cruel for those of you in Prince George’s County affected by the water outage. And it’s worth reminding everyone to stay hydrated and, if you have to be outside, to take breaks indoors in the air conditioning. The heat relents by the second half of the weekend.

Temperature Map

Temperatures: Latest D.C. area temperature map. See interactive map on our Weather Wall.

Today (Wednesday): We’re looking at pretty much identical conditions to yesterday. That means mostly sunny skies, moderate to high humidity, and highs in the mid-90s. The combination of heat and humidity should have the afternoon heat index topping out near 100-105. Winds are of little to no help, blowing lightly from the north through morning, perhaps shifting to come from the south during the afternoon. Just a 20% chance or less for an afternoon thunderstorm. Enjoy? Confidence: Medium-High

Tonight: With daytime temperatures so high, there’s only so much they can drop. And so we find ourselves once again with a very warm and muggy night, with just a slight chance of an evening thunderstorm and overnight lows from the low-to-upper 70s (suburbs to city). Confidence: Medium-High

For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend…

Tomorrow (Thursday): Same heat, same humidity. Main difference is a bit higher chance of an afternoon thunderstorm, but still only in the 20-30% range. Otherwise, we’re talking partly to mostly sunny with highs in the mid-90s again, and with that afternoon heat index climbing to near 100-105. Winds stay light from the west/southwest. Confidence: Medium-High

Tomorrow night: After a 20-30% chance of an evening thunderstorm, it’s a repeat of tonight with partly cloudy skies and muggy lows in the 70s. Confidence: Medium-High

A LOOK AHEAD

If anything, we probably turn the heat up a notch on Friday. Highs head for the mid-to-upper 90s, and with high humidity the afternoon heat index makes a run at 105-110. Afternoon/evening thunderstorm chances remain in the 20-30% range with Friday night lows in the 70s to near 80. Confidence: Medium

The weekend brings some changes as a cold front approaches and moves through. Saturday still looks quite hot and humid with highs in the low-to-mid 90s, and Saturday night lows in the 70s. But Sunday should be somewhat cooler, in the mid-80s to near 90 for highs. With the front in our vicinity, we’ll want to prepare for a 40-50% chance of showers and thunderstorms on Saturday, and perhaps a chance of showers and storms on Sunday as well if the front remains close by. Confidence: Low-Medium

Also on Capital Weather Gang

PM Update: Staying hot and humid with declining air quality