After a fairly quiet week, the weather pattern over the western U.S. will enter into an active phase again.

Today (Friday), a low-pressure wave advancing into Arizona will kick things off, bringing in cooler air and a brief pulse of moisture that will give Phoenix some rain chances this afternoon. In fact, gusty thunderstorm winds out the south are looking more and more likely. These winds could result in brief blowing dust, then help initiate rain. Any rain will help to drop dust (PM10) levels back down.

Then for Saturday and Sunday, things will calm down a bit. The main weather story will be much cooler temperatures (highs in the low/mid 70s) in the wake of today's wave. Cloud cover should also linger into Saturday, then clear up more by Sunday. During this time, local PM2.5 (smoke) levels could be elevated a bit more in the mornings/evenings because of the cooler temperatures (i.e. more stagnant, increased fireplace usage, weekend activities).

Then by Monday, PM10 will likely increase in the morning from local activities, namely in the industrial area south/southwest of Phoenix. PM2.5 should also be elevated from local activities in the morning and evening. But by Tuesday, our next weather system will arrive, bringing in another round of rain. Better air quality is thus expected on Tuesday.

Check back again on Monday morning for the next Phoenix Air Quality Forecast.

- M. Graves
ADEQ Meteorologist