[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Thursday, August 11, 2011

Wed Aug 10 12:33:33 MST 2011

Health message for Wednesday, August 10: Unusually sensitive people
should consider limiting prolonged exertion outdoors.

Health message for Thursday, August 11: Unusually sensitive people
should consider limiting prolonged exertion outdoors.

Synopsis and Discussion
High pressure continues to loom south of Arizona, in a not-so-favorable
Monsoon position.  The current southwest-to-northeast flow is pulling in
more dry air than moist air.  This has limited the thunderstorm activity
in recent days.  Models suggest the deserts will see a 10-30% chance of
showers across the deserts through the weekend, including the Phoenix
forecast area.  Unfortunately, there is no clear Valley-wide rain event
forecasted, so we'll likely continue to see isolated storms capable of
producing blowing dust.

Speaking of dust, PM10 and PM2.5 levels have been really good the past
few days with the highest levels buried nicely in the GOOD range of the
Air Quality Index (AQI).  Ozone has been in that range at most sites
with the exception of Queen Valley.  This may be an instrument issue as
it doesn't make much sense to have Queen Valley significantly higher
than nearby locations.

With thunderstorms possible south of the forecast area each day, we'll
probably see PM10 levels increase a bit.  Hopefully levels won't
threaten the health standard.  Ozone levels should continue to be the
highest in the east and northeast part of the forecast area under the
southwest-to-northeast flow.  

Check back tomorrow for more.  Until then, have a good day!  -J.Paul

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

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