The Hottest Week in Four Years

July 25 Record Highs  (Source: WUSA9)

Washingtonians multi-year streak without triple-digit heat came to an end on July 25, 2016 when the high temperature reached 100 degrees.  Today marks the fourth anniversary of the last time thermometers in the Nation’s Capital reached the century mark.

Extreme heat has led to the issuance of heat advisories and excessive heat warnings from North Dakota to Louisiana to New York over the last week.  That includes cities in the I-95 corridor from Washington, D.C. to New York City.  Dulles Airport in northern Virginia set a new record high of 100 degrees on July 25.  Baltimore also reached 100 degrees, tying its record for the date.  Newark, New Jersey set a new record high of 99 degrees on July 25, while Philadelphia tied its record high of 96 degrees. 

During the current heat wave some may have heard the term “heat dome.”  That’s a fancy term used to describe a sprawling area of high pressure that’s dominated the weather across much of the Central and Eastern United States.  High pressure is characterized by sinking air which suppresses cloud development and facilitates the hazy, hot and humid conditions.  However, it’s not a new phenomenon as sprawling areas of high pressure typically dominate much of the United States during the summer months.

Meanwhile, the intensity of the current heat wave has been the most significant since 2012 for the Mid-Atlantic Region.  A “heat wave” is defined as a minimum of three consecutive days with temperatures of at least 90 degrees.  DC’s current heat wave began on July 21 and is poised to continue until this weekend.  That would give July 2016 a total of 23 days of 90-degree heat, one of the highest such totals on record (July 2011 had the most 90-degree days in a calendar month in the Nation’s Capital with 25).

That’s why it’s so important to drink plenty of water, spend time in air conditioning and do any outdoor errands or chores early in the day or after dark.  My colleagues and I on the WUSA9 weather team will keep you apprised of the latest weather forecasts both on-air and on the free app for your mobile devices.