[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Wednesday, August 17, 2011

[forecasts@lists.azdeq.gov]

Health message for Tuesday, August 16:  Unusually sensitive people
should consider reducing prolonged or heavy exertion outdoors. 

Health message for Wednesday, August 17:  Unusually sensitive people
should consider reducing prolonged or heavy exertion outdoors. 
 

Synopsis and Discussion
OZONE:  Actual peak local ozone levels the next few days will likely be
determined on the balancing act between opposing production and
accumulation factors.  Afternoon high temperatures at or near 110
degrees F, a drop in afternoon gradient winds, and steering flow
conducive to outflow boundaries from the northeast and east will
contribute to an increase in both production and accumulation.  Daytime
cloud cover left behind from convective clouds and thunderstorm activity
- always difficult to predict - would strongly impede or delay ozone
production.  Since an upswing in summer monsoon activity is being
forecast, more weight is currently being given to the subtractive half
of the equation for Wednesday but with an Ozone Health Watch still being
considered for Thursday.  
PARTICLES:  Another outflow boundary from distant thunderstorm activity
reached the southeast Valley Monday evening with wind gusts of 30 mph
and reductions in visibilities to as low as four miles in blowing dust.
Even so, this appeared to be highly localized event since nearby air
quality monitors did not record any high hourly PM-10 levels. Active
summer monsoon weather is forecast to be on the increase during the next
few days over or in the vicinity of the Phoenix metro area.  As a
result, thunderstorm outflow boundaries from even distant thunderstorms
will pose a risk for periods of dense blowing dust and unhealthy PM-10
levels thru this forecast period - especially over the east and
southeast portions of the Valley.  Otherwise, winds are forecast to be
relatively light.  


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:

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