Remember May and June, and all of the torrential rain? Ellicott City catastrophically flooding for the second time in two years, and Frederick overflowing with water? That is absolutely over now. Seemingly overnight, two months of often-unfathomable rainfall ceded to sunny, hot days and parched lawns.
Since June 27, the last day of rain, Washington has received zero measurable precipitation, as measured at Reagan National Airport. That’s 14 days in a row, and it’s really strange — especially since the season that’s supposed to deliver afternoon showers and thunderstorms like clockwork is not yet over.
“This stretch we are in now is about as dry as it gets this time of year” in Washington, according to Ian Livingston, our local climate guru. He’s specifically taking into account the fact that we’re still in the peak of summer thunderstorm season.
Going beyond “strange” and getting a little more technical, Washington is in a “flash drought” — a short period of high temperatures and rapidly decreasing soil moisture. There are two kinds of flash droughts: those caused by heat waves and the ones caused by lack of rainfall.
Washington’s flash drought is both. Not only has it not rained for two weeks, but temperatures also soared into the upper 90s during the first week of July. The heat index spiked to 110 degrees. Temperatures didn’t drop below 80 degrees for 111 hours — the capital’s fourth-longest stretch on record.
So yes, it hasn’t rained in a while. But the extreme heat has also been leeching moisture out of the ground at the same time.
“I’ve seen pictures in the Metro of ground cracking where it’s so dry,” said Jason Elliott, a hydrologist at the National Weather Service in Sterling, Va.
Elliott said it’s not super uncommon to have a two-week period in the summer with no rain — “We just happen to be in an area that’s missed everything” — but the swing from one extreme to the other is strange.
“It’s weird to have a relatively short-term surplus and then a short-term nothing,” Elliott said.
The longest Washington has ever gone in the summer months of June through August without measurable rainfall was 25 days in 1995, ending Aug. 31. But that streak carried through Sept. 8, for a total of 33 rain-free days.
There was also a streak in 1988 that is comparable with this one in terms of timing. It didn’t rain between June 18 and July 10 that year.
Because of the incredible rainfall in May and June, Washington is still in a surplus on the year. We’d have to go without rain until Aug. 18 for a deficit to begin. In that respect, things are still pretty good. Deep soil moisture is still above average, especially west of the Beltway. But shallow soil moisture — the kind that matters for your lawn and garden — is below normal and dropping every day we don’t get any rain.
Rain is far from certain over the next week. There’s a very slight chance Washington will get hit with a shower or weak thunderstorm Thursday afternoon. The weekend is looking increasingly dry, and the next chance of rain is Monday or Tuesday, when a cold front comes through, and with each passing day, that front seems to get drier and drier in the forecast.
Beyond that, we will have to wait until late next week, at which point Washington could be closing in on its longest streak of rain-free days during the summer.
Capital Weather Gang’s Ian Livingston and Meriel Carney contributed to this report.