[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Tuesday, July 19, 2011

Tue Jul 19 12:22:46 MST 2011

Health message for Tuesday, July 19:  Unusually sensitive people should
consider reducing prolonged or heavy exertion outdoors. 

Health message for Wednesday, July 20:  Unusually sensitive people
should consider reducing prolonged or heavy exertion outdoors. 

Synopsis and Discussion

OZONE:  An ozone-trapping easterly wind regime was in place over the
Valley on Monday as illustrated by highest ozone levels being reported
from locations such as Dysart, Glendale, and West Phoenix.  Fortunately,
some cloud cover and the arrival of gusty outflow winds by around 4:00
p.m. interrupted what would likely have been unhealthy levels at some
locations in the central city area.  Another possible episode of
easterly flow is possible early next week; until then, winds in the
5-10K' layer are forecast to become increasing westerly into the weekend
due to the approach of the southern end of an upper level trough.  This
situation typically improves ozone dispersion and lessens the potential
for unhealthy ozone levels, but elevated ozone concentrations are likely
to continue especially over the northeast and east portions of the
Valley the next few days.    

PARTICLES:  Another thunderstorm outflow boundary arrived over the metro
area from the southeast Monday evening with wind gusts up to 45 mph and
visibilities as low as 1/4 mile in dense blowing dust.  The highest
hourly PM-10 concentration was 2,861.1ug/m3 at the South Phoenix
monitoring site at 6:00 p.m. There is a chance for summer monsoon
thunderstorm activity over or near the Phoenix metro area thru
Wednesday, followed by a short break in the summer monsoon circulation
pattern as southwesterly flow aloft occurs.  As was the case on Sunday
and Monday, periods of dense blowing and/or transported dust generated
by convective storm outflow boundaries are possible today and Wednesday
- along with a moderate risk for unhealthy PM-10 levels.   

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

More information about the Forecasts mailing list