[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Wednesday, May 16, 2012

[forecasts@lists.azdeq.gov]

Health message for Tuesday May 15: Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors.

Health message for Wednesday May 16: Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors.


Synopsis and Discussion
*AN OZONE HEALTH WATCH REMAINS IN EFFECT TODAY*
OZONE:  Local ozone levels reached their highest readings so this far this season on Monday but ozone production was likely augmented by combustion by-products contained within the dense blanket of smoke that arrived overhead around 1:00 p.m. yesterday.  Gusty winds currently in progress should steer most of any additional smoke away from the metro area today.  As of noon hourly ozone readings were elevated over much of the forecast area and at 78 parts per billion were in excess of the 8-hour health standard at the Humboldt Mountain site; as a result the Health Watch issued for today will remain in effect.  A westerly wind regime is forecast to resume over the area by Wednesday afternoon and under normal circumstances local ozone levels would subside into the mid-moderate range of the Air Quality Index or lower.  However, with the potential for additional - but much less serious - smoke intrusions, highest forecast AQI levels will be set at just below health watch criteria for at least one more day. 

PARTICLES:  Low-level winds are forecast to keep the bulk of smoke from Arizona wildfires out of the Valley the next few days although overnight drainage flow may channel some over portions of the metro area.  A strong ridge aloft will remain over Arizona the next few days although a weak disturbance will move west to east over the northern portion of the state today and Wednesday.  On Friday the southern end of a sizeable trough in the mid-latitude storm track will likely bring a significant increase in winds to the Valley and some areas of blowing dust are possible during the afternoon.


For more information, please visit our Web page:
www.azdeq.gov/environ/air/ozone/ensemble.pdf 

For transportation alternatives:
www.valleymetro.org 


If you have any questions or comments regarding this forecast please contact:

Mark Shaffer, Communications Director
Arizona Department of Environmental Quality
Office of Communications
1110 W. Washington St., Phoenix, AZ 85007
(602) 771-2215
ms15@azdeq.gov