Wildfire smoke disrupted life in Philly this week and will linger Friday, but forecasters say the weekend should be decent

While it may not be entirely smokeless, forecasters said Thursday that the punitive siege of disruptive haze imposing something akin to surreal snow days on the Philly region was likely to yield to an overall decent weekend.

As a bonus, come Monday, the parched foliage might even get a healthy dousing of rain, a phenomenon almost as rare as blue skies these days around here.

“It seems like things are gradually on the up and up,” said Alex Dodd, a meteorologist with the National Weather Service Office in Mount Holly.

Unhealthy smoke levels are forecast to persist Friday, with yet another air quality alert in effect, and those with respiratory and heart conditions are urged to be especially careful.

» READ MORE: Philly schools to shift to virtual instruction Friday as air-quality issues continue

Philadelphia School District buildings will be closed to students Friday, with classes held virtually.

But the particulate levels are not expected to rival the extremes of late Wednesday and early Thursday.

The impacts were evident. Officials urged people to stay indoors. And on the day after the Phillies experienced their first “smoke out” in their 140-year history, such vaunted institutions as Longwood Gardens and the Philadelphia Zoo closed. So did others, including the Shofuso Japanese Cultural Center, Eastern State Penitentiary, and the African American Museum of Philadelphia. Some restaurants suspended al fresco dining. Trash collections were halted.

» READ MORE: Stephen Starr and other restaurant owners shut down outdoor dining in Philadelphia, New York, and Washington, D.C., because of smoke

Something closer to normality was expected to resume Friday. But smoke levels continued to vary subtly Thursday — as did the opinions of computer models, some of which are almost as fallible as humans.

“This is almost like a snowstorm for us,” said Dominick Mireles, director of Philadelphia’s Office of Emergency Management. “We have a bit of a prediction, we understand how bad it could be, but the timing varies.”

But by day’s end Thursday, the consensus among humans and the machines was that the worst was over. “It’s going to get better,” said Dave Dombek, senior meteorologist with AccuWeather Inc.

One mark of a noxious air mass is when “unhealthy” constitutes a significant improvement.

The air quality was poor enough Wednesday night and Thursday morning to push Philly from the “very unhealthy” purple range to the “hazardous” maroon.

Those levels haven’t been seen around here in at least 15 years. A figure of 50 or lower is considered “healthy;” “very unhealthy” levels range from 201 to 300, and “hazardous” is 301 and higher.

Not surprisingly, emergency departments throughout the region were on alert for an influx of patients, but by late afternoon, most had not seen an increase in cases. Doctors warned that the danger hasn’t passed for those vulnerable to poor air quality: Inflammation can take a few days to build up before becoming problematic for people with asthma.

“I am wondering what tomorrow and the next day will bring,” said James Reingold, the chair of the department of emergency medicine at St. Christopher’s Hospital for Children. “And I definitely feel like I’m holding my breath for the weekend.”

It remained unclear precisely how long it would take to rout the smoke completely, but meteorologists said the winds of change will be blowing soon.

The prospects looked good for Sunday’s annual Odunde Festival, one of the largest African American street festivals in the country, which regularly brings 500,000 people to 15 city blocks in Philly. Bumi West, the CEO of Odunde Inc., advised people to follow Odunde on Instagram for any last-minute updates.

The forecasts on Thursday indicated that smoke shouldn’t be a major issue on Sunday, but AccuWeather’s Dombek cautioned that the smoke computer models do have their limits beyond 24 hours.

The smoke is being driven southward from the Quebec fires by a stubborn area of low pressure that was centered near the Maine-New Hampshire border late Thursday. Winds circulate counterclockwise around those storm centers, so areas to the west and south of the center experience winds from the north and northwest.

» READ MORE: Wildfire smoke hasn’t packed Philly’s emergency departments with patients, but physicians say the risk isn’t over yet

Winds from the north are unusual in June, when the prevailing breezes are typically from the southwest.

It so happened that the densest path of the smoke drove right through the heart of one of the nation’s densest population corridors, shrouding New York, Philadelphia, and Washington, D.C., in an acrid haze.

“This thing has been persistent,” said Dombek.

Such persistence would be a climate change signal, said John Gyakum, an atmospheric researcher at Montreal’s McGill University. So, too, the unprecedented fires in the province.

To date about 1.6 million acres of Quebec woodlands have burned, according to the Canadian government. The average over the last 10 years for the year to date is 3,300. A beetle infestation probably resulted is mass amounts of deadwood being added to the fuel supply, said Amy Freeze, meteorologist with Fox Weather.

The smoke those blazes produced extends from the surface all the way up to 20,000 feet in the atmosphere, Dombek said.

One positive sign for our future smoke inhalation is that the number of active fires did decline, from 149 Wednesday to 133 on Thursday, but a far more important development for the career of Philly’s air quality is the impending shift of winds.

That storm system is forecast finally to move away, and the winds are forecast to blow from the west late Saturday and from the south Sunday.

Dombek said the “sky won’t be pristine,” but the smoke should be thinning out, some sun will be visible, and temperatures are expected to be in the 70s Saturday and well into the 80s Sunday.

Overall, he said, “We have a decent weekend shaping up.

“We’ve experienced the worst.”

Inquirer staff writers Zoe Greenberg, Abraham Gutman, Michael Klein, Frank Kummer, Max Marin, Nick Vadala, Kristen A. Graham, and Aubrey Whelan contributed to this article.