[ADEQ Forecasts] ADEQ AIR QUALITY FORECAST FOR FRIDAY, MARCH 20, 2009

[forecasts@lists.azdeq.gov]

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

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

Health message for Thursday March 19: Unusually sensitive people should
consider reducing prolonged or heavy exertion outdoors.  

Health message for Friday March 20: Unusually sensitive people should
consider reducing prolonged or heavy exertion outdoors. 

Synopsis and Discussion
Per local ACARS sounding data the overnight formation of another
moderate (6-7 deg C) surface-based radiation inversion - this one
extending to over 2100' - contributed to more elevated to excessively
high hourly coarse particle (PM-10) levels this morning.  Thru 9:00 a.m.
the highest monitoring site readings included 75.4ug/m3 at Buckeye,
88.5ug/m3 at Greenwood, 99.0ug/m3 at Higley, and 115.5ug/m3 at Durango.
Doubly troubling were the 352.9ug/m3 and 557.4ug/m3 concentrations at
West Forty Third ending at 6:00 a.m., since a high wind event looks
likely for Sunday.  The warm upper level ridge that has been over the
local forecast area this week will move east on Friday and an intense
trough in the mid-latitude storm track will approach the area on
Saturday.  A strong frontal passage will occur on Sunday accompanied by
strong and gusty winds over a lengthy period of time. Winds aloft over
the Valley are currently projected to be in the 45-50 mph range in the
5K-10K' layer by Sunday afternoon and strong cooling with the front will
help some of this momentum mix to the surface; winds at the 18K' level
may be in excess of 120 mph! Since no significant rain has fallen
locally since February 10 and "ambient" PM-10 levels are already
elevated, this scenario has a strong potential for generating large
volumes of blowing as well as transported/suspended dust locally as well
as from southeast CA and southwest AZ.  As a result, look for a PM-10
Health Watch or High Pollution Advisory to be issued for this event.
-Reith  

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