SPECIAL REPORTS FROM OUR FORECASTERS

The Northeast U.S. Heat Wave of 2011

By Lead Forecaster Jason Mitchell of the Capital Region

July 25, 2011 (Huntingdon, MD) A historic heat wave gripped the Mid Atlantic and Northeast United States from Thursday July 21 through Sunday July 24. Although this portion of the country experienced several heat waves during the 2010 summer, no heat wave that year compared to the magnitude of this one. It was not just the heat, but the humidity that separated this heat wave from many others in recent years. Computer models began showing the potential for dangerous heat over a week in advance, and forecasters at the National Weather Service and other weather sources began mentioning the potential many days before the heat wave. Temperatures were just below record values Thursday, with many locations in the Mid Atlantic reaching the upper 90s for high temperatures.

The most intense portion of the heat wave peaked on Friday, with most airports from Washington, D.C to Portland, Maine breaking daily records. Newark, New Jersey and Washington Dulles International Airport reached all ALL-TIME record highs of 108° and 105°, respectively. Baltimore Washington International Thurgood Marshall Airport reached 106°, with a heat index (combining the heat and humidity) of 118°. Although Washington National Airport fell just shy of a daily record at 101°, the heat index reached a whopping 121°. Uncharacteristically, New England was no place to escape the heat.  Portland International Jetport reached 100°, and Concord, New Hampshire also reached 100°. Temperatures Friday night failed to drop to comfortable levels, with most of the Mid Atlantic remaining above 80° for most of the night. The farthest the temperature dropped to at Washington National Airport Saturday was 84°, which tied for the warmest low temperature ever recorded for Washington, D.C.  

After such a warm start to the day, Washington, D.C. went on to break a daily high temperature and reached 102°. Although not official, The Washington Post reported a possible heat related death Saturday in Northwest Washington, D.C. By Sunday, the extreme heat loosened its grip on the region. A meteorologist from the local National Weather Service covering the Washington, D.C. put the heat wave this way on Friday evening, “It is pretty amazing to see much of New England experienced temps almost the same as Washington National Airport [Friday]. But in my 17 years here I do not recall seeing widespread heat index values of 115-120 in the Mid Atlantic. Hopefully this is one for the record books that won’t be topped for many years.” Clearly, for much of the Mid Atlantic and Northeast a heat wave of this magnitude had not been seen in decades.