All week long, wildfire smoke swirling to the east from Minnesota and Ontario has darkened skies, ruined outdoor plans and sent air quality plummeting for millions of people across the United States and Canada.
The plume of smoke far above the Earth’s surface has not gone away on Saturday, but where and when it sends pollution to the ground this weekend will shift considerably by the hour.
Amid the hard-to-pin-down forecast, air quality warnings and alerts remained in place across many of the affected states and provinces.
Some places that saw a reprieve on Friday, including parts of Minnesota, Wisconsin and Michigan, are likely to endure the smoke again on Saturday as shifting winds pull the densest smoke back to them. Forecasters warned that the air quality would once again worsen and limit visibility on lakes and roads across the Upper Midwest.
In New York City and other parts of the Northeast, another weather system moving through on Saturday brings a different complication: the chance of severe thunderstorms.
Those storms could deliver enough rain to cause flash flooding throughout the day on Saturday. The worst are expected in the afternoon, the National Weather Service said, warning that high winds could bring down trees and power lines and that even a tornado would be possible.
While the thunderstorms could help knock some of the smoke out of the air, the smoke itself complicates the forecast: It can block sunlight, keeping temperatures cooler at the surface and preventing storms from rising and intensifying.
Whatever smoke isn’t brought down by rain could disperse into a lighter haze or clear out completely Saturday night.
