Moist air is being funneled north due to a high-pressure system off the East Coast, making it feel like Florida across the Mid-Atlantic and Northeast.
Testing popular cooling gadgets for hot weather
Discover how wearable cooling tech, handheld fans and innovative cooling devices can help you stay cool, comfortable and safe during extreme heat.
Much of the East Coast is so humid, it feels just like Florida as August heat drags on in an unusually long and intense stretch.
As of Aug. 8, a stretch of the country in the eastern Mid-Atlantic from Virginia through Philadelphia, and into the New York City area through southern New England has seen high humidity combined with temperatures in the 90s, AccuWeather Senior Meteorologist Bill Deger told USA TODAY. The humidity has been making the temperature feel closer to 100 to 105 degrees, he said.
It’s not over yet. While areas north of the Philadelphia and NYC metro area will see a brief reprieve Aug. 9 before returning “right back into the sauna,” the humidity will be unrelenting in the southern Mid-Atlantic through Aug. 12 or 13, Deger said.
“If you take a look at the humidity right now in Florida, it’s pretty similar to what we have in the eastern Mid-Atlantic,” Deger said. “It’s basically just transportation of that moisture that’s always in place over the Southeast further north.”
The weekend forecast has temperatures in the 90s along a stretch from the Washington, DC, region up through New York City, with feels-like temperatures in the high 90s to triple digits, the Weather Prediction Center said. Heat advisories were in place on Aug. 8.
Scattered showers in the Central and Eastern U.S. are also expected, according to the National Weather Service. The thunderstorms, coming mostly in the late afternoons and evenings according to AccuWeather, may limit how hot it gets, but will highlight the oppressive humidity.
Why is it so humid in the East?
The steamy weather in the East is coming from moisture being funneled up along the East Coast from the South due to the presence of a high-pressure system off the coast, Deger said.
The system is known as a Bermuda high, an area of high pressure that can find itself anywhere between the East Coast and Bermuda in the open Atlantic Ocean. Because air flows clockwise around pressure systems, when the Bermuda high camps out just along the coast, moisture will flow northward and everyone to the west of the pressure system will experience muggy weather this time of year, he said.
Though a stretch of high humidity isn’t unheard of and might happen once or twice in an average summer, or not at all in a cool summer, what sets this situation apart is its intensity and how long it’s been going on, Deger said.
Prolonged periods of high humidity can be a real strain on the body, particularly for those who are more sensitive to heat illness or who don’t have access to quality air conditioning.
“Your body is looking for that relief at night from cooler temperatures, and it’s just not happening because the humidity is so high, and it keeps those overnight lows above average for this time of year,” Deger said, noting that lows have struggled to get below the mid- or even high-70s at night.
Above-average temperatures for coming weeks
This stretch of humidity should come to an end in the middle to end of next week, Deger said. But forecasters say much of the southern half of the country will still be facing above-average temperatures for the next six to 10 days.
According to the Climate Prediction Center, Southern states in a stretch from Texas through Florida will have the highest chances of above-average temperatures, but chances favor high temperatures for most of the lower half of the country.
Hot, dry temperatures fueling Western fires
The opposite kind of heat has taken hold in several Western states, where high temperatures and low humidity are combining to set the stage for raging wildfires.
“Hot and dry weather will support elevated wildfire conditions across the northern Intermountain West, which will allow for rapid fire spread,” the weather service said in an Aug. 8 outlook.
Major fires have been burning in states including Oregon, Washington and Utah. The National Interagency Fire Center said earlier this week that the Pacific Northwest was seeing the largest fire activity. Across the country, there are 97 large fires being battled by firefighters, the agency said on Aug. 8.