[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Wednesday, September 21, 2011

[forecasts@lists.azdeq.gov]

Health message for Tuesday, September 20: Unusually Sensitive People
should consider limiting prolonged exertion outdoors.

Health message for Wednesday, September 21: Unusually Sensitive People
should consider limiting prolonged exertion outdoors.


Synopsis and Discussion
NOAA's ozone model continues to suggest wide-spread ozone exceedances
today and tomorrow.  We know enough from actual concentrations vs.
modeled concentrations to not fully believe the model.  Two monitors
(Cave Creek and Humboldt Mountain) reached the lower moderate range of
the Air Quality Index (AQI) on Monday.  While Humboldt Mountain is
slightly higher at 11am than it was 24 hours earlier, most other
monitors are lower than their respective levels the day before.  This
provides enough information to rest assured that exceedances are not
likely the next few days.  As a result, we will keep the forecasted
maximum ozone levels in the mid moderate range through Thursday.

With high pressure firmly in place to the northeast, dry air continues
to drop into Arizona.  This will keep thunderstorm activity dormant
through the end of the week.  Thus, no major dust events are expected
through at least Friday.  Now some moisture is poised to move in
Saturday and Sunday, increasing the possibility of distant thunderstorms
and resulting dust.  We will watch this closely the next couple days to
see if we need to raise the forecasted PM10 levels.  Until then, most
particulate monitors should remain in the good range with one or two
possibly reaching the lower moderate category.

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


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