More than 50 million people in the Northeast and Mid-Atlantic are at risk for severe weather this weekend as Canadian wildfire smoke continues to impact air quality. 

A severe weather threat is in effect from the Ohio Valley through the Mid-Atlantic and Northeast. Residents of towns and cities, including New York City, Philadelphia, D.C., Pittsburgh and Cleveland, could see damaging winds, large hail, isolated tornadoes and flash flooding.

The National Weather Center said Northeast residents face the potential for scattered flash flooding from D.C. to Boston, with rounds of storms are possible ahead of a cold front moving into the region. Urban areas with high runoff will be the most susceptible to flash flooding. New York City has a flood watch in effect as the city braces for thunderstorms and high wind gusts.

Heavy smoke from wildfires blazing in Canada and Minnesota engulfed large swaths of the Midwest and Northeast U.S. this week, impacting air quality as millions of people are exposed to hazardous levels of air pollution. The blanket of smoke has affected at least 19 states. 

Conditions are expected to improve in the East as the cold front moves through. Tens of thousands of fans gathering for the World Cup final could see improved smoke conditions for the Spain vs. Argentina game on Sunday. 

MLS analyst and former professional soccer player Sacha Kljestan told CBS News that if the rain doesn’t help clear away air quality, he does think it might be “a concern” for the game.

Kljestan said he doesn’t see FIFA changing or postponing the final, but poor air quality could “slow the game down.”

Further afield in Texas, conditions continue to improve after deadly, devastating flooding, although some rivers are still running high. Two feet of rain fell across central Texas in just days, and recovery efforts are ongoing. Similar storms last year led to the deaths of over 100 people. 

Texas resident Kat Stafford said the rain washed away everything inside the business where she works. 

“I’m trying to dry out the main documents, papers and stuff, financial documents,” Stafford told CBS Saturday Morning. 

In other places, roads are still impassable, so the Texas National Guard has taken to the skies for rescues and medical transports.