Current Conditions: A strong high pressure system over the Mid-Atlantic states is producing sunny skies and mild air this Wednesday afternoon. A morning inversion resulted in elevated fine particle (PM-2.5) levels, and limited mixing this afternoon is keeping overall PM-2.5 in the moderate range. Tonight, another inversion will develop, and fine particle pollution will tend to get trapped close to the surface once more. *** Thanksgiving Day forecast: An Air Quality Action Day will be declared for the day Thursday!! PM-2.5 will end up being highest prior to noon, with slightly better air quality during the afternoon. PM-2.5 concentrations will reach code ORANGE, especially in and around the Lancaster area. Otherwise, skies will be mostly sunny with a mild afternoon. *** Friday’s forecast: A weak cold front will bring more clouds and rain showers to the region Friday. PM-2.5 concentrations will still be elevated during the morning Friday, but increasing afternoon west to northwest winds should keep average concentrations down in the moderate range. |
