[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Friday, November 06, 2009

[forecasts@lists.azdeq.gov]

For more information, please visit our Web page:
http://www.azdeq.gov/ensemble.pdf

For transportation alternatives:
http://www.valleymetro.org


Health message for Thursday, November 5: Unusually sensitive people should consider limiting prolonged outdoor exertion. 

Health message for Friday, November 6: No health impacts are expected. 


Synopsis and Discussion
High pressure will weaken a bit as an area of low pressure becomes cut off and moves east along the Arizona/Mexico border Saturday.  This will do little in the way of wind or moisture, but it will help lower our afternoon temperatures by about 5 degrees or so.  That low quickly moves away from the region by Sunday, allowing a weak ridge to return to the area.  This will push desert temperatures to the upper 80s once again by Monday.

It's now been 60 days and counting since our last measurable rain, going back to September 5.  This lack of moisture has allowed the surface to completely dry out.  Any activity that disturbs the dry, crusted dirt (such as driving on unpaved roads, construction and earth-moving operations) will easily send the dust into the air.  Weak early-morning inversions trap the pollutants (including vehicle emissions) near the surface.  The lack of winds means that this accumulating pollution has a very difficult time dispersing horizontally.  All of this adds up to the elevated PM-10 concentrations we've been seeing the past several days.  Despite overnight temperatures only in the lower 60s, it's also evident that fireplace activity is beginning to take place in some neighborhoods as local PM-2.5 (finer particles) levels are also starting to climb into the "Moderate" range.  With no clearing rains in forecast for at least another week, local air quality will likely continue to deteriorate.  It's a good idea to reduce you speed while driving on unpaved areas, refrain from using outdoor fire pits and chimineas, as well as residential fireplaces where possible.  Hopefully this can help keep us from seeing concentrations reach unhealthy levels before the next clearing system.

Check back on tomorrow for the latest on your coming weekend's weather and air quality.  Until then, have a good day!  -J.Paul  


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

 
 

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