* WHAT...Flash flooding caused by excessive rainfall is possible.

* WHERE...A portion of south central Arizona, including the Phoenix Metro, all of Gila and Pinal Counties, and much of Maricopa County.

* WHEN...From Saturday afternoon through late Saturday night.

* IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations.

* ADDITIONAL DETAILS... - Increasing moisture and atmospheric instability will combine with an approaching weather system to promote scattered thunderstorms capable of producing heavy rainfall from late Saturday afternoon through Saturday night. Training of storms could result in localized rainfall amounts of over two inches within the watch area. - http://www.weather.gov/safety/flood

AQAPSR The Arizona Department of Environmental Quality (ADEQ) has issued a PM-10 High Pollution Advisory for the Phoenix Metro Area through Saturday. An episode of strong and gusty winds is forecast to generate widespread blowing dust that may result in local PM-10 concentrations that pose a health risk. Adverse health effects increase as air quality deteriorates. Coarse particulate matter - also known as PM-10 - is an air contaminant that can aggravate heart and lung disease conditions, especially in older adults, children, and those with asthma. A decrease in physical activity is recommended. Consolidate your travel, stabilize loose soils, slow down or avoid travel on dirt roads, reduce or eliminate fireplace use, and avoid using gas-powered lawn equipment. For details on this High Pollution Advisory, visit the ADEQ internet site at www.azdeq.gov/forecast/phoenix or call 602-771-2300.