Dust Risk-Based Forecast | Maricopa County

Tuesday

Stagnation: Morning and evening stagnation

Wind: West-southwest winds of 10-15 mph

Wednesday

Stagnation: Morning and evening stagnation

Wind: Light southwest winds of 5-15 mph

Thursday

Stagnation: Morning stagnation

Wind: Light southwest winds of 5-15 mph; gusty outflow winds possible in the afternoon

Friday

Stagnation: Morning stagnation

Wind: Light southwest winds of 5-15 mph; gusty outflow winds possible in the afternoon

Saturday

Stagnation: Morning and evening stagnation

Wind: Light southwest winds of 5-15 mph

Forecast Discussion:

No way to sugar coat it: it's hot! The high temperature in Phoenix on Saturday was 115 degrees, and yesterday it was a record-setting 116. Even the low temperatures have been warm, with the temperature at Phoenix Sky Harbor not dropping below the 90-degree mark since the morning of July 7th!

This record heat is being brought to us courtesy of a very strong area of high pressure, with the center elongated from about the Arizona/California border back east into the panhandle of Texas. This pattern has also allowed moisture to move into the region from the southeast resulting in thunderstorms across northern, eastern, and southern Arizona this weekend. Phoenix stayed dry, but an outflow did move into the East Valley yesterday, bringing some dust to the area.

Today and tomorrow, the high will begin to weaken and slowly shift eastward, centering itself over Texas. This shift will result in a drier southwest flow across Arizona, which will lower the chance of thunderstorms statewide. The weakening high will also result in a slight "cool down" with high temperatures lowering into the 107-109 degree range tomorrow through the end of the week. Hard to say cool down with temperatures still near 110 degrees, but compared to the 116 this weekend it will be "cooler."

Late Wednesday into the weekend, the high will slowly expand back toward the west, allowing for a southerly flow to re-establish itself over Arizona, which is forecast to increase moisture. Couple this increase with a few hard to time disturbances moving into the area and thunderstorms chances will increase statewide.

Right now, Phoenix looks to have at least a slight chance of storms Friday and Saturday, with a better chance of dust on Thursday. Will continue to watch as this pattern develops.

As for air quality, ozone remained below the federal health standard this weekend and with the breezy afternoons forecast to continue, expecting this trend to continue as well. We are increasing PM-10 concentrations on Thursday and Friday afternoon due to the dust threat, but the 24-hour averages are forecast to remain below High Pollution Advisory criteria.

Have a great Monday!

- M. Pace
ADEQ Meteorologist