Major Shift in the Weather Pattern

U.S. Capital  (July 4, 2016)

Although a few days late to arrive, more typical July-weather has begun to make its presence felt across the Mid-Atlantic Region.  On both July 3 and 4, the high temperatures were only 74 degrees at National Airport, the official weather reporting site for the Nation’s Capital.  That made this Independence Day the coolest since 1941 in Washington, D.C. according to the Capital Climate blog.  Baltimore, Maryland also had its coolest July 4 since 1979, with a high temperature of only 73 degrees.  Such temperatures are more characteristic of the first half of May rather than early July.

It was also a wet July 4^th holiday with 0.31” of rain officially at National Airport, though not as wet as past Independence Days.  The combination of cool and wet weather put a damper on many Independence Day plans.

However, a major shift in the weather pattern is bringing summer-like heat and humidity to the Mid-Atlantic Region, with the hottest weather of 2016 on tap the next few days.  Today’s high temperature of 91 degrees gave Washingtonians their first 90-degree day since June 21.  My colleagues and I on the WUSA9 weather team expect high temperatures to continue to be in the low to mid-90s every day through Sunday, with a few upper 90s possible in spots. 

Such a streak would easily meet the criteria for a “heat wave,” which is at least three consecutive days at or above 90 degrees.  The longest streak of 90 degree heat so far this year was a modest three day stretch from June 19 – 21.  National Weather Service data indicates that Washington, D.C. hasn’t had a streak of five or more consecutive days in the 90s since August 15 – 19, 2015.

Through July 5, 2015, Washingtonians had suffered through 19 days at or above 90 degrees.  However, for the same period this year, there have only been six-90 degree days.  Washington, D.C. averages 36 days of at least 90 degrees in a given year and there was a total of 52 such days last year so this streak of 90 degree temperatures will not only make beach-goers happy, but will also help the Nation’s Capital catch up.  Washington, D.C.'s hottest temperature so far this year was 96 degrees on June 11.