[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Tuesday, October 20, 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 Monday October 19: Unusually sensitive people should consider reducing prolonged or heavy exertion. 

Health message for Tuesday October 20: Unusually sensitive people should consider reducing prolonged or heavy exertion. 


Synopsis and Discussion
A somewhat stagnant air mass situation along with elevated surface moisture levels are contributing to a pretty significant Valley Brown Cloud this a.m. (http://www.phoenixvis.net/). Although local hourly PM-10 (coarse) and PM-2.5 (fine) particle levels are up noticeably at some monitors from 24 hours ago, readings are comparatively low (<120ug/m3 for the former and <20ug/m3 for the latter).  Per AMDAR sounding data surface-based inversion strength was moderate at 4-5 deg C but shallow to only ~1100'.  At 10:00 a.m. metro airport dew point temperatures were in the 45-55 deg F range - probably the principal reason for the increase in visibility degradation.  Thankfully, a noticeable increase in winds is expected in the local forecast area on Tuesday with the approach and passage of a mostly dry upper level trough and surface cold front in the mid-latitude storm track.  Gusty winds and much cooler temperatures will be the main impacts, although some blowing dust is possible during the afternoon hours.  In its wake high pressure will build over the Great Basin and bring several days of north to northeasterly breezes.

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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