Today's ozone is forecasted to remain lower as rain has already arrived. The rain will move out of the area later this evening, and Saturday will be mostly dry, besides a few isolated cells that could form in the afternoon. Rain returns Saturday evening and it will be more widespread than today, and this will once again drop daily ozone values. The rain will end late Sunday/early Monday, and the drier conditions will bring an increase in ozone levels through early next week.

PM10 is already seeing lower values than normal this morning as rain has begun. The scattered thunderstorms will continue through at least the late afternoon. There may be isolated cells Saturday afternoon, but overall there will be dry conditions with lighter winds, and PM10 will remain in the Good AQI range. More steady rain arrives Saturday evening, and this is forecasted to keep the dust concentrations lower once more into Sunday. Drier conditions return on Monday, and there will be a gradual increase in daily PM10 values, including increases from local activity in the mornings.

Daily PM2.5 values will have similar daily trends to PM10. When the drier conditions come with the cooler temperatures early next week, more wood burning is expected and this could stay near the surface which will increase daily PM2.5 values.

- A. Hermansen
ADEQ Meteorologist