[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Wednesday, April 21, 2010

[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 Tuesday, April 20: Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors. 

Health message for Wednesday, April 21: Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors. 


Synopsis and Discussion
A strong trough of low pressure heading towards Arizona will dramatically affect the weather over the next few days.  Afternoon desert temperatures will hit a high of around 90°F on Tuesday, but much cooler air will move in overnight.  Cloud cover along with increasing winds on Wednesday will keep temperatures in the mid to upper 60s.  As the trough rams into the slowly exiting ridge of high pressure, the steep gradient (the pressure difference over a horizontal distance) will result in strong afternoon winds on Wednesday.  Sustained around 20 mph out of the south during the afternoon, Valley gusts could reach 30 mph at times.  

It has now been 28 days since the last significant rainfall in the Phoenix forecast area (going back to March 23rd), so the ground is sufficiently dry.  It won't take much to get the surface dust airborne.  Thus, we expect PM10 concentrations to reach the mid "Moderate" range on Wednesday with PM2.5 levels in the lower part of that category.  There is an outside chance of a passing shower or two which would help reduce Wednesday's particulate situation, but it's tough to put any money on that right now.  

Ozone will have a very difficult time setting up due to the winds, and along with the lack of available sunshine, we expect maximum ozone concentrations to stay in the "Good" range.  

Weather conditions improve a bit on Thursday with decreasing clouds and winds along with increasing sun and temperatures.  We should see highs in the upper 80s by Saturday.
  
Check back tomorrow for the latest information.  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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