Pittsburgh wildfire smoke forecast
The map above shows NOAA HRRR-Smoke near-surface PM2.5 for the next 48 hours, updated hourly, with active fires from NIFC and live AQI from EPA AirNow monitors. It opens over Pittsburgh.
Pittsburgh sits where the Allegheny and Monongahela rivers meet, in a network of steep, narrow river valleys cut a few hundred feet below the surrounding plateau. Those valleys trap cold air readily, which is why the region has a long-standing particulate problem independent of wildfires and why imported smoke settles into the valley floors rather than dispersing evenly.
Where the smoke comes from
Canadian fires on northwesterly flow are the source of the severe episodes, the same air mass that affects the rest of the Northeast. What differs here is what happens after it arrives: the river valleys concentrate it, and industrial PM2.5 in the Monongahela valley adds to the total.
How long it lasts
The regional smoke leaves with the synoptic pattern, but the valley inversions release more slowly than the surrounding plateau does, so low-lying neighbourhoods lag the general improvement by hours. Readings across the metro can differ substantially by elevation during the same episode.
Past smoke events
The June 2023 Canadian smoke episodes put Pittsburgh among the worst readings in the country on several days, and the region recorded repeated alerts through that summer.
Running, riding, and trailheads
The riverfront trails and the Great Allegheny Passage run along the valley floors, exactly where smoke concentrates. The parks up on the plateau, including Frick and Schenley, sit a few hundred feet higher and often clear earlier on an inversion morning.
Reading the map
Most of this smoke starts in Canada, so switch the map to the ECCC FireWork model, which resolves Canadian sources HRRR-Smoke can underplay. Compare the two with the layer toggle.
Near-surface is the product that maps to what you breathe and to AQI, not the high-altitude column that only tints the sunset. A sky that looks bad and a monitor that reads fine are usually both correct, and they are describing different layers of air.