A classic wave of monsoonal thunderstorm/rain activity swept through the Valley yesterday, this time from the northeast. A line of gusty winds led the way, resulting in gusts of 68 mph at Sky Harbor. Dust was also kicked up, with a handful of PM10 monitors seeing decent spikes in dust levels. Rain quickly followed though, knocking down dust (rain was mostly in the East Valley). Most monitors remained in the Good AQI category for PM10.

Regarding the new Phoenix Dust Storm Scale, last night's dust event was only a "Category 1."

Looking ahead, we will have the potential for a repeat wave out of the northeast this evening/night. A low-pressure disturbance from the east will provide the needed atmospheric assistance for this. Details are hard difficult to pin down, as always, but brief blowing dust may be possible.

After today, the monsoon does finally look to calm down a bit, at least for the Valley. Instead, we'll have to contend with the heat. Temperatures above 110°F look likely, and the National Weather Service has issued an Extreme Heat Watch for Thursday-Monday.

During this time, we'll have to watch ozone, as the drier, sunnier, and calmer conditions will favor local ozone formation and build-up. An Ozone High Pollution Watch has been issued for Friday.

Lastly, PM10 and PM2.5 (smoke) will return to being mostly locally driven, though the recent rain should help to limit PM10 levels.

Check back again tomorrow morning for the next update!

- M. Graves
ADEQ Meteorologist