[ADEQ Forecasts] ADEQ Daily Air Quality Forecast For Wednesday, September 23, 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 Tuesday, September 22: Unusually sensitive people might want to consider limiting prolonged or heavy exertion outdoors.

Health message for Wednesday, September 23: No health impacts are expected.


Synopsis and Discussion
*A PM-10 HEALTH WATCH REMAINS IN EFFECT FOR TUESDAY, SEPTEMBER 22, 2009*
Snow in the Colorado Rockies, Freeze Statements for the mountains of Arizona... That's the result of the latest are of low pressure to affect the region.  Many people who were expecting a cold front to move through the region today probably slept through it.  The "back-door" cold front increased winds out of the northeast to around 15-20 mph across the Phoenix forecast area around 5 a.m. Tuesday morning.  At the same time, dew points plummeted from 40 degrees to 14 degrees in Phoenix in just one hour.  This super dry air will allow overnight temperatures to dip into the upper 60s in outer lying areas of the Valley the next three nights.  The responsible low over Colorado will begin to open up Friday morning, joining the main jet stream.  When that happens, high pressure over California will regain control of Arizona's weather, warming afternoon desert temperatures from the upper 90s to around 102°F by the weekend.  As far as winds go, Tuesday morning was the strongest they'll get this week.  In fact, as the low pressure system weakens and moves away from the region and high pressure moves closer, winds will be nearly calm with increasing overnight inversions.  

Air quality-wise, a PM-10 health watch and Maricopa County-issued No Burn Day remains in effect for Tuesday due to the morning winds that kicked up some dust this morning.  As the inversion sets in later this evening, we could see a secondary spike in concentrations causing the 24-hr average to approach the health standard.  Lighter winds and increasing mixing heights Wednesday through the weekend should slowly allow any suspended dust to mix and/or settle out, resulting in "Good" range particulate levels.  Ozone concentrations are not expected to break into the "Moderate" range until at least Friday if not later.

Check back on tomorrow for the latest.  Until then, have a good day!

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

 

**********************************************************************
NOTICE: This e-mail (and any attachments) may contain PRIVILEGED OR CONFIDENTIAL information and is intended only for the use of the specific individual(s) to whom it is addressed. It may contain information that is privileged and confidential under state and federal law. This information may be used or disclosed only in accordance with law, and you may be subject to penalties under law for improper use or further disclosure of the information in this e-mail and its attachments. If you have received this e-mail in error, please immediately notify the person named above by reply e-mail, and then delete the original e-mail. Thank you.