Why is NYC air quality bad today? Here's one theory.

NEW YORK -- If you think something seems off with the air quality today in New York City, you're not wrong. But what's causing it? One possible reason for bad air quality in the city is a fire that broke out yesterday afternoon in Lancaster, Pennsylvania, where air quality is notably unhealthy. Why would a fire more than 150 miles away from New York City affect the air quality around here? A simple explanation could be the phenomenon known as cold air inversion.

Several key weather ingredients fell into place as the Lancaster fire developed: considerable snow cover west of I-95, a frigid air mass, a light southwest wind, and mostly clear skies allowing radiational cooling to occur. When these come together, cold, dense air dominates at the surface, and lighter, warmer air hovers immediately above. So, the relatively cold air at the surface cannot escape into the atmosphere.



After the fire started and day turned into night, the Earth's surface cooled rapidly. The trapped cold, dense air blocked smoke from rising and kept it close to the surface. Then, the southwest wind carried it gradually into the Tri-State Area.

The Air Quality Index (AQI) map supports the movement of the smoke. It shows high and unhealthy levels near and just east of where the fire started, and levels getting healthier closer to the Tri-State Area. Temperatures came up a little short of freezing on Thursday, but we could finally break the mark today ! Friday morning, temperatures were in the 20s, teens and single digits again.

Fortunately, the weather will run about 5 degrees warmer today with highs around 33 in NYC. If we get there, it would be the first time we find ourselves above freezing since Sunday. Tonight will be another very cold one, with temperatures falling back into the teens and single digits.

So have a warm coat handy! Saturday, we'll retreat ever so slightly as we'll find ourselves on the cold side of a front. Thankfully, we'll still make a run for the freezing mark by the afternoon. Sunday is the payoff as temperatures return to normal.

Yes, some disorganized snow showers will sweep through our northwest suburbs, but it should remain quiet for the most part. Other than that, there's not much in the way of active weather over the next several days. We won't see anything substantial, be it rain or snow, until the middle of next week.

That's been the pattern this January. Unfortunately, it will only further exacerbate the drought situation across the Tri-State Area..