[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Thursday, August 18, 2011

Wed Aug 17 12:59:05 MST 2011

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

Health message for Thursday, August 18:  Unusually sensitive people
should consider reducing prolonged or heavy exertion outdoors. 

Synopsis and Discussion
OZONE:  Considerable cloud cover held local ozone levels down on Tuesday
but today is starting out under mostly sunny skies.  This, along with
rather subdued gradient winds, should support highest ozone
concentrations reaching the upper moderate range of the Air Quality
Index.  Winds aloft are now being advertised to become westerly thru a
deep layer by Thursday morning.  Since this component aligns with the
typical upslope flow this time of year, higher afternoon winds are
forecast to resume tomorrow and continue thru the weekend.  This
situation usually means that highest ozone levels will occur over the
far eastern Valley and at this time are forecast to be in the
mid-moderate range of the AQI.  
PARTICLES:  Another outflow boundary from thunderstorm activity impacted
parts of the Valley Tuesday evening with wind gusts as strong as 36 mph
and reductions in visibilities to as low as two miles in blowing dust.
This contributed to a max hourly PM-10 concentration of 591.2ug/m3 at
the Higley monitoring site at 8:00 p.m.  Active summer monsoon weather
will continue over or in the vicinity of the Phoenix metro area thru
Friday followed by a brief lull as dry westerly winds aloft occur.
Moisture will be on the increase again by Monday.  As a result,
thunderstorm outflow boundaries from even distant thunderstorms will
continue to pose a risk for periods of dense blowing dust and unhealthy
PM-10 levels the next few evenings. 

For more information, please visit our Web page:

For transportation alternatives:

If you have any questions or comments regarding this forecast please

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

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