The striking yellow-gray wildfire smoke that blanketed the northeastern U.S. this week is expected to intensify in some areas Thursday, though forecasters believe the unhealthy—and in some cases hazardous—air quality from Canadian wildfires will improve in the Northeast as early as Thursday night before shifting West.
The Lower Manhattan skyline was obscured by hazy skies on Wednesday from wildfire smoke in Canada.
Poor air quality will linger in Philadelphia, where the air quality index topped 325 Thursday morning—considered “hazardous” by the Environmental Protection Agency—and the city’s Department of Health warned “everyone is likely to be affected,” suggesting residents stay inside and reduce physical activity.
New York City’s air quality improved slightly from Wednesday, when a thick cloud of orange haze forced schools to cancel outdoor activity and the New York Yankees and New York Liberty to cancel their home games, though it’s air quality index is still in the EPA’s “very unhealthy” range, meaning people with lung or heart disease, as well as older adults and children should avoid outdoor physical activity, according to the EPA.
An air quality advisory is in effect through midnight in Buffalo, where the National Weather Service warns being outside will be “quite unhealthy, especially for sensitive groups.”
The wildfire smoke will also linger on Thursday over Baltimore and Washington D.C., with levels of smoke considered “unhealthy” stretching as far north as upstate New York and western Massachusetts, and as far west as Michigan.
Residents in Pittsburgh, meanwhile, can expect a slight improvement in air quality Thursday, with the index level dropping from an “unhealthy” code red to code orange, considered “unhealthy for sensitive groups.”
In central Pennsylvania, the NWS urges people to avoid going outside, amid “hazardous” and “very unhealthy” air quality, with the worst effects over Harrisburg, according to Air Now.
Improved air quality in the Northeast, and worse conditions in the Midwest. The worst of the air pollution is expected to shift west over the Ohio River Valley on Friday, the NWS stated in an update on Wednesday, warning people against staying outside and urging people to wear masks outdoors. Thick clouds of smoke that covered New York Tuesday and Wednesday are expected to move over Ohio, southern Michigan and Indiana on Friday and into the weekend, according to Cincinnati NBC affiliate WLWT meteorologist Kevin Robinson, as a high pressure system in the northern Plains states drives winds south and west, Accuweather reported. Wind patterns could also make conditions worse on Friday in Toronto, Cleveland, Detroit and Pittsburgh, while a shift in weather patterns could bring the haze back over the mid-Atlantic this weekend before southerly winds force the smoke back north over Canada early next week, according to AccuWeather meteorologist Brett Anderson.
Limited visibility from thick clouds of smoke also prompted the Federal Aviation Administration to paused all flights into and out of New York City’s LaGuardia airport, Thursday morning and said it’s “likely” the agency will “manage the flow of traffic” at airports throughout the East Coast, including in Charlotte, Philadelphia, Washington D.C., and New York City’s JFK airport. The FAA had issued a ground stop for arriving flights at LaGuardia Wednesday afternoon, causing widespread delays.