[ADEQ Forecasts] ADEQ Extends Today's Ozone Health Watch for the Phoenix Metro Area through Tuesday, May 15, 2012

[forecasts@lists.azdeq.gov]

Health message for Monday May 14: Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors.

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


Synopsis and Discussion
*TODAY'S OZONE HEALTH WATCH HAS BEEN EXTENDED THRU TUESDAY MAY 15 *
OZONE:  On Sunday five area ozone monitors registered unhealthy concentrations and was the sixth day of the season thus far with at least one exceedance of the ozone standard within the ADEQ forecast domain.  Above average daytime high temperatures and minimal cloud cover have made for very efficient ozone production recently while low-level wind flow over and to the west of Valley has at times been conducive to an influx of additional ozone and/or its precursors from the west the since last Thursday.  However, the wind-flow has now have shifted out of a more favorable direction and this should allow ozone levels to drop a bit at most parts of the metro area by Tuesday; however, the current Ozone Health Watch has been extended thru tomorrow.  Due to prevailing winds locations such as Cave Creek and Humboldt Mountain are forecast to bear the brunt of high ozone problems beginning on Tuesday.  

PARTICLES:  Although dense smoke from several wildfires north and northeast of the metro area can be seen at times, thus far only visibilities have been impacted in the downtown area with PM-2.5 (fine particle) levels still in the good range of the Air Quality Index at all monitors.  Although daytime winds will tend to steer smoke away from the Valley beginning Tuesday, there will still be the potential for nighttime drainage flow to move smoke from the higher terrain toward the metro area and this situation will be monitored for possible health impacts.  A strong ridge aloft will remain over Arizona most of this week although a very weak trough will move west to east over the northern portion of the state Tuesday and Wednesday with an increase in southeast to southerly winds in the Phoenix metro area both mornings. Even so, little if any dust is expected with PM-10 (coarse particle) levels in the good range of the AQI.


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