Rainfall Deficit: Mid-April Update

NOAA's National Precipitation Outlook for April 23-27

The first half of April had some impressive weather in the Nation’s Capital.  Washingtonians saw 1.76” of rain through April 17.  Although that’s an average for the first 2.5 weeks of April, it doesn’t help DC make up any ground in its ongoing rainfall deficit.  Since August 1, 2015, Washingtonians are more than 13” below average in terms of rainfall.  The deficit is nearly 9” just since September 1, 2016.

People can look to other parts of the country for encouraging drought-related news.  The multi-year drought that dominated headlines the last several years along much of the West Coast recently ended.  There was record rain and mountain snowfall in many parts of California, in particular, during this past winter.  That helps show that drought conditions can end quickly if there is a favorable shift in the weather pattern.  NOAA’s Climate Prediction Center says there is a high potential for above average rainfall in the Mid-Atlantic Region over the next 6 to 10 days. 

Temperatures were significantly warmer than average so far this month.  Through April 17, this month’s average temperature (combining daily high and low temperatures) is 62.3 degrees at National Airport, well above the April average of 56.8 degrees.  In fact, that would put this month among the warmest Aprils on record if it were to continue for the rest of the month.  It was 89 degrees on Easter Sunday (April 16), which was the warmest day in the Nation’s Capital since September 23, 2016 (90 degrees).  Sunday was also DC’s warmest April day in more than four years since April 10, 2013 (91 degrees).

In addition to summer-like warmth, this month also saw some fleeting moments of chilly, March-like weather.  The high/low temperatures of 51/42 degrees on April 7 were more characteristic of early March.  Two very rare tornadoes occurred within the District of Columbia on April 6.  Also, a significant amount of rain occurred on April 6 (1.57”) making it the wettest day in Washington, D.C. since December 23, 2015 (1.67”).

There is still a lot of uncertainty about how this month’s weather will rank historically in the Nation’s Capital.  Temperatures won’t likely finish as far above average as they have been so far this month.  However, this month remains well-positioned to finish warmer than average for the tenth consecutive year.