Dust Risk-Based Forecast | Pinal County

Thursday

Stagnation: Light stagnation

Wind: Light becoming west to west-northwest 5-12 mph, evening outflows (gusts over 30 mph) possible

Friday

Stagnation: Light stagnation

Wind: Light becoming west 5-10 mph

Saturday

Stagnation: Light stagnation

Wind: Light becoming west to west-northwest 5-13 mph, evening outflows possible (gusts over 30 mph)

Sunday

Stagnation: Light stagnation

Wind: Light becoming west to west-northwest 5-13 mph, evening outflows possible (gusts over 40 mph)

Monday

Stagnation: Light stagnation

Wind: Light becoming east to southeast, evening outflows possible (gusts over 30 mph)

Forecast Discussion:

An outflow event last evening brought blowing dust and elevated PM10 concentrations to the area, first time in quite some time (July 21st/22nd). The Stanfield monitor exceeded the PM10 health standard for the first time in 2020 due to the blowing dust (24-hr avg. 158 ug/m3/health standard 155 ug/m3). The chances continue for scattered evening cell development today and even more so on Thursday. Additionally, the area hasn't received much rain lately and so any outflow winds will generate more blowing dust and it's possible that the PM10 concentrations could again reach or exceed the health standard. Thursday's highest forecasted PM10 levels have been increased into range for high dust risk due to the possibility for blowing dust. Less in the way of outflow winds on Friday bring a moderate dust risk. The blowing dust chances increase a bit for Saturday, though still have a moderate dust risk forecast (subject to change, check back tomorrow). Sunday looks to be a more active weather day as high pressure builds north of the state and a little bit close to the favorable (for Monsoon storm activity locally) Four-Corner area. Expect better chances for widespread blowing dust and elevated PM10, thus have a high dust risk Sunday. Monday's high dust risk is mainly due to the easterly wind component which usually means higher PM10 concentrations at Hidden Valley. Check back tomorrow for an updated dust risk forecast.

- S.DiBiase
Pinal County Air Quality Meteorologist