Tuesday, May 13, 2014

Windy, Dry Conditions May Create Another Dust Event

Staff Writer, DB Holmes
Weather / Air Quality

When will this wind end? Not for the next 48 hours or so. Phoenix can expect windy conditions to persist with PM 10 and 2.5 particles being kicked up again.
Forecast Discussion: What an impressive dust event we saw Sunday morning. Contrary to some media reports out there, this was not a localized event. This was not a "dust storm". This was not isolated to Arizona. A large trough of low pressure moved through the western U.S. The leading edge of the cold front churned up an impressive amount of dust extending from the desert valleys of California and Nevada, through Baja, and finally northeast through Arizona and New Mexico. Looking at concentrations from monitors to the west, California was hit hard with dust first on Saturday morning. Around 10pm Saturday night, it was Las Vegas that got hit. Yuma saw concentrations spike around midnight. Then dust moved into the Phoenix area around 2 am on Sunday. The cold front continued east through the early morning hours, and by 11 am, levels and visibility improved significantly. About the same time our air cleared, Albuquerque, NM got slammed. This was a major dust event that could not be prevented on a local level no matter what control measures were in place. Nature vs. Man, and Nature won easily. As of 10am Monday morning, Phoenix-area PM10 levels are back in the Good range. Looking ahead, high pressure will move overhead this week, pushing daytime into the triple digits by Wednesday and Thursday. Unfortunately, we may see some more dust on Wednesday, this time from the east. Concentrations, however, should not result in an exceedance here in the Valley. Expect ozone levels to increase as well under sunny skies. The northeast and east winds could trap ozone and precursors in the Valley by mid-week, sending levels well into the Moderate range.
Anyone with respiratory issues may want to wear a mask or stay indoors with a good air filter. 

Source: AIRNow