[ADEQ Forecasts] ADEQ Issues a Particulate Matter (PM10) High Pollution Advisory (HPA) for the Phoenix Metro Area for Friday, May 25, 2012

[forecasts@lists.azdeq.gov]

Health message for Thursday May 24: Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors.

Health message for Friday May 25: Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors.


Synopsis and Discussion
*A PM10 HIGH POLLUTION ADVISORY HAS BEEN ISSUED FOR FRIDAY MAY 25*
OZONE: On Wednesday ozone concentrations at the majority of local monitoring sites fell into the good range of the Air Quality Index for the first time in several weeks but it took wind gusts of 30 mph to do it. At noon today hourly ozone concentrations in parts per billion were in the 40's and 50's at all sites.  An intense weather system is poised to deliver even stronger winds on Friday and early Saturday so additional decreases in ozone levels are forecast to occur Friday with a rebound possible on Saturday as winds aloft become conducive to transport from the west.
 
PARTICLES: The approach and arrival of an unseasonably strong upper level trough and dry surface cold front in the mid-latitude storm track will lead to a lengthy episode of strong and gusty gradient winds in the Phoenix metro area.  Sustained southerly winds within the 5-10K' layer above the corridor between Casa Grande and Phoenix are forecast to be in the 30-40 mph range from daybreak on Friday thru the overnight and into the morning hours on Saturday.  As a result there is currently a strong potential for not only periods of localized blowing dust but also for transported dust from Pinal County to overspread the area by late morning and continue into the afternoon and evening hours.  The last significant rainfall event in the Valley was on March 18 and dust raised from winds on Wednesday still lingers overhead.  For these reasons a PM-10 High Pollution Advisory has been issued for Friday.  A significant volume of dust may persist over the metro area on Saturday and a Health Watch for that day is possible.


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