[ADEQ Forecasts] ADEQ Issues an Ozone Health Watch for the Phoenix Metro Area for Tuesday, July 21, 2009

[forecasts@lists.azdeq.gov]

For more information, please visit our Web page:
http://www.azdeq.gov/ensemble.pdf

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Health message for Monday, July 20: Unusually sensitive people should consider limiting prolonged or heavy exertion outdoors.

Health message for Tuesday, July 21: Unusually sensitive people should consider limiting prolonged or heavy exertion outdoors.


Synopsis and Discussion

*An Ozone Health Watch has been issued for Tuesday, July 21st*

Particulate matter pollution continues to be the area of focus for this forecast period.  While none of the Phoenix area PM10 monitors exceeded the health standard yesterday, particulate pollution was elevated once again due to another round of thunderstorms and blowing dust.  Today could be a repeat performance of yesterday evening as the atmosphere remains fairly unstable and moist.  However, the steering flow has shifted and is now out of the west, which should help prevent the large dust storms that we saw Friday and Saturday from reaching the Phoenix area.  Any blowing dust that does occur today will likely originate from local storms which tend to be smaller dust producers.  Nonetheless, elevated particulate pollution in the form of blowing dust remains a possibility once again today.  We should get a break from the dust Tuesday and Wednesday as the ridge of high pressure reorganizes and begins to shift to the north.  As it does so, an easterly steering flow will return later in the week.  Meanwhile, ozone concentrations at many Valley monitoring sites this morning are higher than this time yesterday.  With maximum ozone concentrations reaching the upper Moderate category of the Air Quality Index (AQI) yesterday, it will not take much of an additional increase to exceed the standard.  Taking the current ozone concentration data into consideration, in conjunction with uncertainties in thunderstorm outflow boundaries for today and tomorrow, an Ozone Health Watch has been issued for Tuesday, July 21st.  Check back tomorrow to see if additional Health Watches will be needed for the second half of the week. 


If you have any questions or comments regarding this forecast please contact:
The 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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