May rainfall topped 8 inches for just the third time on record in Baltimore

Baltimore's official rain gauge surpassed 8 inches last month, making it the region's third-wettest May on record.

May was only wetter here in 2009 and 1989, when precipitation totaled 8.42 and 8.71 inches, respectively.

Last month’s temperatures made it Baltimore’s fifth-warmest May on record, averaging just shy of 70 degrees.

May also was Baltimore’s wettest month since June 2015. That month, 13.09 inches of rainfall broke a record set the month of deadly Hurricane Agnes in 1972.

Officially, the wettest day came May 15, when 1.63 inches of rain fell at Baltimore-Washington International Thurgood Marshall Airport, the region’s point of record.

But even heavier rain fell elsewhere around the region, of course — more than 10 inches was reported in Catonsville and 8 inches in Ellicott City on Sunday, causing devastating flooding.

The month’s weather was marked by a persistent pattern in which frontal boundaries remained draped over the region. That allowed tropical moisture to flow northward only to be wrung out over the mid-Atlantic.

Until this month, drought had been developing across parts of Maryland. Now, precipitation is running a couple inches ahead of normal, with 18.76 inches at BWI since January.

Climate forecasts for June show continued chances for wet weather. The U.S. Climate Prediction Center in College Park predicts as much as 50 percent chances of wetter-than-normal conditions (compared to an assumption of equal 33 percent chances of dry, normal or wet conditions).

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