Wednesday, June 29, 2016

The Monsoon and Unhealthy Ozone

Staff Writer, Nathaniel Diaz 
Weather / Air Quality

Ozone will be a problem again in the unhealthy range. So people with respiratory issues should limit activity. Healthy people should take caution as well. 

Will the monsoon come and alleviate the unhealthy air quality?
Forecast Discussion: Ozone has been exceptionally high the past couple days as a monsoonal high pressure has persistently remained over the Four Corners region. This system has resulted in an easterly, upper-level flow over the Valley, which acts to "lock" ozone over central parts of the Valley and allows it to accumulate. Nine Valley monitors exceeded the health standard yesterday. Looking ahead, a ridge of high pressure is forecast to remain situated over the Southwest for the next several days. Consequently, the atmosphere over the Valley is expected to be stagnant and support ozone accumulation. Hence, the ozone High Pollution Advisory (HPA) has been extended into Thursday. It is likely that an HPA will be issued for Friday, depending on timing of thunderstorm activity. Regarding thunderstorms, thunderstorms are likely to develop each day over the higher terrain in southeast Arizona and to the north/northeast of Phoenix. Due to the very moist atmosphere over much of south central Arizona, these storms will have to the potential to reach the Valley. For today, there is agreement in high resolution models that a strong outflow could impact the Valley from the south later this afternoon. This would result in blowing dust impacting the Valley. Elevated PM-10 is thus possible this evening. Any rain will help to shut down PM-10. Blowing dust will continue to be a possibility each afternoon/evening this week. Check back tomorrow for the next air quality forecast...
Storms are expected around the metro area for the next few days and into the first of July.  

Hopefully these storms produce enough rain to clean the air, wet the land, and keep ozone at bay.

Source: AirNOWWeather Underground