It’s unanimous among several private weather companies and the National Weather Service: Washington is in for a hotter than normal summer.
One of the strongest El Niños on record is on its way out and, often, summers following major El Niño events have simmered in the Mid-Atlantic.
“The strong El Niño we had last winter is quickly transitioning into a La Niña,” said David Samuhel, senior meteorologist at AccuWeather. “In years past when this has happened, Washington D.C., and much of the rest of the country have experienced hot and dry summers.”
AccuWeather is predicting D.C.’s summer temperature to average 2.5 degrees above normal, with 46 90-degree days in the summer months of June, July and August, compared with the average of 31.
Todd Crawford, the chief meteorologist at the Weather Company, which runs Weather.com, is also forecasting a hot summer for the District. He’s calling for temperatures 1.5 degrees above normal with 45 days at or above 90 degrees. He also pointed to a “very abrupt” change from El Niño toward a La Niña as one rationale for the hot summer forecast. But he cautioned this change doesn’t by itself guarantee a hot summer in the D.C. area.
Data support Crawford’s argument. While the summers following several recent major El Niños were quite hot in D.C. (2010, 2003 and 1988), the summers following several others (1992, 1998 and 2003) had average to below average temperatures.
Still, Crawford sees reasons besides the fading El Niño to support his hot forecast. “[T]he coastal Atlantic sea surface temperatures are unusually warm, and given prevailing summer flow patterns off of the Atlantic, these warmer temperatures effectively act as an offset to summer temperatures, especially manifesting as elevated nighttime temperatures,” he said.
Joe Bastardi, the lead seasonal forecaster at Weather Bell Analytics, says both the “bounceback” from El Niño and “warm water surrounding the U.S.” will lead to the nation’s hottest summer since 2012. He’s calling for an astonishing 60 days at or above 90 degrees in D.C., which would rank as the third most on record.
Forecasters are split on how humid it will be in the region. The Weather Company’s Crawford thinks the warm ocean temperatures nearby will tend to elevate humidity levels while AccuWeather’s Samuhel thinks conditions will be drier than normal and humidity “will not be as oppressive as it could be.”
The National Weather Service does not offer the same specifics as private forecasters in its summer outlook but favors above-normal temperatures in the Mid-Atlantic and Northeast and near-normal precipitation.
Since 2010, the D.C. region has experienced its hottest six-year summer period on record, including its hottest three summers on record in 2010, 2011, and 2012. In four of the six summers, D.C. has logged at least 50 days at or above 90 degrees, including 52 in 2015.
Capital Weather Gang will issue its detailed summer outlook for the D.C. area by late May.