Long Island's air should improve by weekend, but depends on winds and wildfires, NWS says

Shifting winds and the breadth and direction of the Canadian wildfires are the major factors in whether air quality will be improving this weekend, capping several days when the Northeast's air was infused with tiny particles of ash, the National Weather Service said.

A thick column of smoke had settled over Long Island and the Northeast this week due to a stagnant low-pressure system that had been off the coast of Maine with winds blowing smoke counterclockwise, said John Cristantello, a lead meteorologist for the National Weather Service in Upton.

“We’re in the direction of where winds are traveling and it’s picking up smoke from southwestern Quebec and Ontario and funneling it south,” he said. “It depends on the magnitude of the smoke and how widespread the fire is and where the smoke is coming from.”

The low pressure over New England is funneling winds south, Cristantello said. The winds trapped the smoke in what is known as an Omega Block where high pressure over the Midwest plain states and central Canada and a low-pressure system over the Northeast drew out equal areas of pressure to upper levels in the atmosphere — resulting in stagnant weather for Long Island and the region.

The smoke could clear out of the region Saturday or Sunday as the low-pressure system dissipates and redirects the winds southwest. Winds shifted slightly Thursday directing the worst of the smoke over Central Pennsylvania, Cristantello said.

 “Last week was a more consolidated wildfire. It was nothing like we’re seeing now,” Cristantello said. “I think what’s happening is the low pressure drifted west and directing smoke a little bit more to the west. It’s a subtle system that can redirect the smoke.”

He said the winds won’t be as aligned after the smoke leaves the region, but may move west before moving south over the Mid-Atlantic.

“It’s still possible it could be hazy, but that area of low pressure moving farther out to sea and we won’t have the winds directly right over us,” Cristantello said. “Eventually those winds may steer it back east to our south.”

Accuweather Senior Meteorologist Alan Reppert said it's possible New York and the Northeast could see smoke from wildfires in the future. But short-term forecast models show the air improving next week with a chance of rain on Monday. 

"It's not likely we’ll see the dramatic intensity (of smoke) we saw," he said. "The rain for New York would help wash any pollutants out of the air and move the airmass along as well."

By John Asbury

john.asbury@newsday.comJohnAsbury

John Asbury is a breaking news and general assignment reporter. He has been with Newsday since 2014 and previously worked at The Press-Enterprise in Riverside, California.