The dirty white haze that drifted into the Philadelphia region yesterday from Canadian forest fires is expected to begin to dissipate tomorrow, the National Weather Service in Mount Holly said today. "There will be some improvement Monday," said meteorologist Jim Eberwine, with winds blowing "from west to east."
"So unless we get fires from Ohio," he said, the air quality and the sky color should be improving.
The Associated Press reported today that at least 50 fires - caused by lightning - had destroyed up to 148,200 acres of forest in a region of Quebec near James Bay, 500 miles north of Montreal.
The smoke was moving at 12,000 feet above sea level and should not cause health problems, an NWS official in Albany, N.Y., told the AP.
A wind shift yesterday had caused the Canadian smoke to move south, forming a plume 500 miles long and 300 miles wide from Michigan to Massachusetts.
In Mount Holly, Eberwine said the shift was very unusual.
"Normally, this time of year, you don't get northerly winds - winds from the north."
In fact, any strong winds are unusual, Eberwine said.
"Usually, we're in the dog days, stagnant air."
Not this weekend.
"We can smell it here in Mount Holly," he said of the Canadian forest smoke.
The irony is that last week the weather observers were looking forward to an expected shift from the normal wind patterns, a shift to refreshing winds from the north.
"We had a heat wave last week," Eberwine said, "and during that heat wave we were heralding the arrival of a nice, clean, fresh northerly flow."
And that held true, he said, for Friday and early yesterday.
Eberwine and his colleagues were a bit concerned when the skies turned sooty yesterday, he said, fearing the reaction would be, "the weathermen got it wrong again."
Apart from diminishing sunburns, Eberwine said the major effect of the haze was that it probably grounded small airplanes that do not carry sophisticated navigational equipment.
"It's a real hazard to aviation," he said. "The visibility is almost down to nothing."
Contact Walter F. Naedele at 610-313-8126 or wnaedele@phillynews.com.