Air Quality / Weather
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Without wind and with the cold inversion layer, the Valley of the Sun's air becomes unhealthy, even hazardous to breathe.
There is really no excuse for this type of terrible air quality.
Ozone is definitely the big story this week. Concentrations have pushed into the middle to upper part of the Moderate range over the past 48 hours. Models suggest we could see one or two monitors approach the health standard on Friday. Thus, we are issuing an Ozone Health Watch for Friday. History shows that the day after such an event usually sees lower concentrations. PM10 levels continue to be mostly in the Good range with one or two local monitors (West 43rd and South Phoenix) in the lower Moderate range. Daytime highs will hold steady between 106-111°F Friday through next week as high pressure maintains its position to the south. We're watching the long-range models for an indication of when the monsoon shift may occur. We are starting to see some signs of high pressure migrating north near the Four Corners around the 16th to the 21st of June. Thunderstorm activity may begin to pop up in Arizona's mountains around that time, but wide-spread moisture will likely hold off until the end of June.