[ADEQ Forecasts] ADEQ AIR QUALITY FORECAST FOR THURSDAY, MAY 21, 2009

[forecasts@lists.azdeq.gov]

http://www.azdeq.gov/ensemble.pdf

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

Health message for Wednesday, May 20: Unusually Sensitive People should
consider limiting prolonged or heavy exertion outdoors.  

Health message for Thursday, May 21: Unusually Sensitive People should
consider limiting prolonged or heavy exertion outdoors.  

Synopsis and Discussion
   Morning cloud cover left over from overnight storms that developed
will persist well into the afternoon hours across the south-central
deserts.  A good fetch of moisture continues to stream north into the
state from Old Mexico.  This will keep an active threat for afternoon
mountainous buildups and late evening lower desert thunderstorms.  Any
kind of break in the clouds will only enhance the energy needed for
storm development later this afternoon.  Rain totals in the Phoenix
forecast area are not expected to exceed a quarter of an inch, while
most places will be lucky to even see a Trace (less than 0.01 inches). 
   The added moisture has been just enough to cancel the affects of
storm outflow-generating dust.  This has resulted in particulate
concentrations in the "Good" range here in the Phoenix forecast area.
This should continue into the weekend.  Wednesday's cloud cover will
likely repeat again on Thursday and Friday mornings, keeping maximum
ozone production well below its potential.  Thus, the highest ozone
concentrations should drop into the lower "Moderate" range through the
remainder of the week.  
   This monsoon-like pattern will taper off by Sunday as the high
pressure system pulls east allowing much drier air to move in from the
west.  The tradeoff of the lower humidity will be warmer temperatures,
with afternoon desert highs reaching the triple digits once again by the
early to middle of next week.  Check back tomorrow for any changes in
the forecasted weather and resulting air quality.  Until then, have a
good day!  -J.Paul

**********************************************************************
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.