FORECAST IN DETAIL
Heat wave No. 1 of the season has a real punch to it with yesterday’s high of 97 in D.C., a record for the date, and about the same expected today. With the heat we’ve got humidity, and that means a heat index treading in triple-digit territory. Tomorrow’s not quite as hot, though 90 is still in play with a better chance of storms. Then Friday and the weekend feature cooler 80s, though for a change it may not be storm-free for our Saturday and Sunday.
Today (Wednesday): It’s a true scorcher as today’s heat should match yesterday’s, and may outdo it in some spots. After a slight chance of an early-morning shower or thunderstorm, partly to mostly sunny skies send temperatures soaring toward afternoon highs in the mid-to-upper 90s. And with moderate to high humidity, the heat index should max out in the upper 90s to low 100s. Winds from the west near 10 mph warm the air as they flow downhill, helping the heat reach its full potential. Watch for a 25% chance of a thunderstorm in the late afternoon or evening. Confidence: High
Today’s record highs in play are 97 at National (1944), 94 at Dulles (2007), and 97 at BWI (1957).
Tonight: Unless a thunderstorm comes to fruition where you happen to be (25% chance), evening temperatures are slow to fall in the hot and muggy air. A complex of strong to severe thunderstorms could approach or arrive from the west-northwest during the overnight, as lows settle in the rather toasty 70s under partly cloudy skies. Confidence: Medium
For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend…
Tomorrow (Thursday): This could be one of those days where we see two rounds of thunderstorms come through, one during the early-to-mid morning and another during the afternoon into evening. Overall, any given location has a 60% chance of seeing a storm at some point during the day, and again some storms could be strong to severe. It’s not quite as hot, but still plenty humid with partly sunny skies and highs in upper 80s to low 90s. Confidence: Medium
Tomorrow night: Any evening storms (50% chance) should tend to clear out for the overnight. The evening mugginess eases some overnight as a breeze from the north begins to bring in a bit less humid air. Lows are still on the warm side, though, in the upper 60s to low 70s. Confidence: Medium
A LOOK AHEAD
Light winds from the north draw in cooler and less humid air for Friday. Let’s not get too carried away, though. The day still has a summery feel with partly sunny skies, low-to-moderate humidity, highs in the mid-80s, and a 30-40% chance of a shower or thunderstorm. That same shower/storm chance continues into Friday night as lows retreat to the 60s. Confidence: Medium
A stalled front and onshore flow seem likely to provide at least partly cloudy skies this weekend with a 40-50% chance of showers and storms at least through Saturday into Saturday night. We may or may not see precipitation chances drop a bit on Sunday, with highs both days in the 80s with moderate humidity. Confidence: Low-Medium