Forecast Discussion:
Wintery precipitation will spread over the forecast area during Tuesday afternoon turning to rain in the Philadelphia metro area by evening. Locations north and west of Philadelphia will see a longer duration of wintery precipitation and a Winter Storm Watch has been issued. With temperatures near freezing, the precipitation forecast remains uncertain and, if you plan to travel Tuesday or Wednesday, please monitor the latest NWS forecasts. Light winds overnight Monday will eventually settle into the northeast by Tuesday afternoon. With warm air aloft, vertical mixing will be limited and, while we will start Tuesday with good air quality, scattered locations will reach the moderate range by later in the afternoon.

Extended Forecast:
Rain, heavy at times, is likely for Wednesday and this will limit fine particle accumulation with good air quality expected. A cold front, bringing windy conditions and a dry, cleaner air mass, will arrive Wednesday evening and Thursday will be breezy, cool and dry with good air quality. -Ryan