Making Up for Lost Ground

NOAA Expects a Significant Warm up for the Eastern U.S.

Until recently, Mid-Atlantic residents had been languishing in drier than average conditions since August 2015.  In that time, a double-digit rainfall deficit developed and that led to drought conditions for parts of the DC Metro Area.  Fortunately, there has been a wetter than average weather pattern during the last few weeks that’s helped alleviate the drought conditions while also putting a dent in the rainfall deficit.

Through April 30, the rainfall deficit had swelled to 13.75” at National Airport over the previous 21 months.  The rainfall deficit from May 1, 2016 through April 30, 2017 had grown to 8.48”.  Area residents who feel the weather has been rather gloomy in the Nation’s Capital the last few weeks would be correct.  There has been measurable rain on six of the first 13 days this month with rain on both weekends.  In fact, there has been 4.67” of rain in Washington, D.C. just since April 20.  By comparison, only 3.43” of rain occurred during all of February and March combined.

More rain is still needed, though, to continuing making up the rainfall deficit in Washington, D.C.  Gardeners are happy, though, that the so-called pendulum has swung the other way with above average precipitation so far this month.  Although NOAA expects the upcoming week to be drier than average for much of the eastern United States, they indicate an above average chance for a wetter than average week starting May 20.

With the 3.81” of rain that has already occurred this month, Washingtonians are close to meeting May’s average of 3.99” for the entire month.  To add to that, the 1.75” of rain that occurred at National Airport on May 5 was DC’s wettest day since June 27, 2015 (2.75”).  Despite having such a wet first half of the month, a small majority of recent Mays have been drier than average.  There have been 13 drier-than-average Mays since 1997 in the Nation’s Capital.  Meanwhile, three of the 10 wettest Mays on record in the Nation’s Capital have also occurred in the last 20 years. 

We can compare this May to last May which was not only wetter than average but was cooler than average.  However, no strong correlation exists between a wet and cool May and what the summer weather will be like.  While last May was both cooler and wetter than average in the Nation’s Capital, Washingtonians experienced a very hot summer with July, August and September 2016 all finishing among the hottest on record in the Nation’s Capital. 

For those of you longing for warmer and drier weather conditions, the upcoming week is looking a lot warmer and drier across the DC Metro Area.  In fact, temperatures will feel more like Independence Day by the middle of the week as temperatures approach 90° degrees in the Nation’s Capital.