The Washington PostDemocracy Dies in Darkness

D.C.’s flip from bone-dry to waterlogged is the most extreme on record in July

Percent of normal rainfall in the first 14 days of the month, and over the past week. (National Weather Service, adapted by CWG)
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Somehow, it was just 10 days ago that we declared: “Washington has seen no measurable rain so far this July. That’s a record.” It’s been said — and proved — that droughts end in floods. We’ve seen that first hand.

The city has now recorded 9.19 inches of rain in July, all coming in the past eight days. Nearby locations have even seen totals in excess of one foot, including 16.55 inches near Dunkirk, Md.

We can now say that the flip from wet to dry is historic. It’s the biggest flip on record from the first half to the second half of July.

For the calendar year, this enormous switch from dry to wet only ranks behind the big reversals in June 1972 and 2006 (June 2006’s weather pattern was very similar to this year’s).

This year, Washington’s average daily rainfall leaped from zero inches between July 1 and 15 to 0.57 inches between July 16 and 31 (if no more rain falls). This massive increase edges past the next biggest change in 1969, from 0.02 inches to 0.57 inches. We’ll pull further away from 1969 with any additional rain during the next five days.

The flip from dry to wet has been even more astonishing in Baltimore.

The first half of July in Baltimore delivered slightly more rain than in Washington, with 0.05 inches tallied. The second half has already seen 15.38 inches! That’s a change of 15.33 inches from the first half to the second, obliterating the previous biggest July flip of 5.75 inches way back in 1897.

Retired National Weather Service climatologist Robert Leffler tells a similar tale from Damascus, Md.  “We probably just lived through the most extreme switch from dry-to-wet in the 43-year Damascus, Md., station history,” he said in an email. “We observed 26 days (June 26 to July 20) with only 0.31 inch rain (at highest sun angles of year) to 9.00 inches in next 5 days (July 21-25).”

Thanks to all of the rain, mainly in the past eight days, Washington and Baltimore have both registered their wettest second half of July on record. In Washington, the 9.19 inches in July’s second half surpasses 9.12 inches in 1969. If it’s going to rain so much, we might as well be able to brag about it?

Even after the record dry first half of the month, July now ranks as seventh-wettest on record in Washington overall. Of course, compared with Baltimore’s 15.43 inches this month, the record, it might feel like we’ve barely seen a drop. It’s so wet, everywhere.

And could there be more to come? It looks that way, even as we fight the calendar (only five days remain in the month following Thursday).

While Thursday is dry and sunny, our time with no rain seems to be rather limited per the forecast. The local outlook from the National Weather Service is a bit ugly for rain-weary Washingtonians by early next week. From Monday through Wednesday (that’s the first of August), we see “showers and thunderstorms likely” as the headline.

How much more falls is certainly up for debate. It seems unlikely to be as much as we just saw, but it could certainly push our numbers higher as we close the month.

Jason Samenow contributed to this report.