Dust Risk-Based Forecast | Maricopa County

Friday

Stagnation: Morning and evening stagnation

Wind: Westerly winds of 5-15 mph

Saturday

Stagnation: Morning and evening stagnation

Wind: Mainly light winds. Gusty winds possible with any storms

Sunday

Stagnation: Morning and evening stagnation

Wind: Mainly light winds. Gusty winds possible with any storms

Monday

Stagnation: Morning and evening stagnation

Wind: West-southwest winds of 5-10 mph

Tuesday

Stagnation: Morning and evening stagnation

Wind: West-southwest winds of 5-10 mph

Forecast Discussion:

The weather pattern this morning has many pieces to it: (1) A disturbance is moving through the southeastern portion of the state, bringing some rain and copious cloud cover to that area. (2) High pressure has shifted east and is centered over El Paso. (3) A trough of low pressure is moving through the Great Basin with an axis running from Southern California up through Western Montana. (4) Last, but not least, a prominent ridge of high pressure is just off the West Coast of the United States.

All of this will impact the weather in the Valley of the Sun over the next five days. First and foremost, the disturbance moving through southeastern Arizona and the position of the high over El Paso have helped increase moisture across the area. At the same time, a piece of energy will break off the trough and dive southward and center itself just southwest of Arizona tomorrow as it wraps around the side of the high off the West Coast. This weekend, the low will slowly move back toward the east-northeast. This pattern will result in the chance of showers and thunderstorms later this afternoon through at least Monday. Chances will be slight throughout this period, with the best chances being tonight as the system drops southward and again late Saturday through Sunday as the low moves back through the state. For the most part expecting storms to remain isolated in the Valley, with storm totals remaining below a quarter of an inch.

This pattern shifts will also result in afternoon high temperatures dropping into the mid-90s tomorrow through the first part of next week! We might even see temperatures in the upper 80s to low 90s Sunday, depending on how much cloud cover there is.

Ok, what about air quality? Yesterday, ozone certainly jumped up, with one monitor reaching 100 AQI, just shy of the federal health standard. Today will raise ozone slightly back into the low Moderate AQI category before dropping into the Good AQI category tomorrow into the weekend, given the increase in clouds, slight rain chances, and better ventilation with the low moving overhead. As for PM-10, expecting is to rise in the Moderate AQI category today with increased values this morning and the chance for some isolated blowing dust later this afternoon. Tomorrow into the weekend, forecasting PM-10 to lower in the Good AQI category; however, would not be surprised to see some isolated pockets of blowing dust with any storms that form.

Overall, an interesting weather pattern to watch over the next several days!

- M. Pace
ADEQ Meteorologist