[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - July 9, 2011

Fri Jul 8 12:13:47 MST 2011

Health message for Friday, July 8: Unusually sensitive people should
consider limiting prolonged exertion outdoors.

Health message for Saturday, July 9: Unusually sensitive people should
consider limiting prolonged exertion outdoors.

Synopsis and Discussion:
Ozone concentrations exceeded the standard again in the far east part of
the Valley.  Queen Valley registered 101 on the Air Quality Index (AQI),
its second exceedance in as many days.  Models suggest much lower levels
are expected across the forecast area through the weekend with the same
east-southeast region expected to have highest levels.  
PM10 continues to be an issue in parts of the Valley.  Both Higley and
West Chandler exceeded the standard again Thursday due to another
thunderstorm-generated dust event around 11 pm.  Other parts of the
forecast area did see an increase in particulates overnight as the weak
out flow boundary continued west and north, but nothing compared to what
Higley and Chandler experienced.  We need a significant rain event
across the entire Valley to clear the air and stabilized the loose dirt
on the streets and in the open deserts surrounding the Valley.  That
doesn't appear to be coming any time soon.  Forecast models suggest some
showers may make it into parts of the Valley following additional dust
fronts each night through Monday.  Unfortunately, these showers will be
spotty at best with totals less than a tenth of an inch.  Then the storm
track pulls east into New Mexico Tuesday and Wednesday.  This break in
the action could last 10 to 14 days, prolonging the time without the
much need soaking rains while increasing the risk of more dust storms
upon the pattern's return.  
Check back on Sunday for the latest.  Until then, have a great weekend!

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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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