* WHAT...Flooding caused by excessive rainfall is expected.

* WHERE...Northeastern Pima County in southeastern Arizona...

* WHEN...Until 430 AM MST.

* IMPACTS...Minor flooding in low-lying and poor drainage areas. Overflowing poor drainage areas. Some low-water crossings may become impassable.

* ADDITIONAL DETAILS... - At 225 AM MST, Doppler radar indicated heavy rain due to thunderstorms in the Tucson area. Two areas of heavy rain have occurred, the first extending from south of downtown through much of midtown and a secondary area on the west and northwest sides, including portions of Marana. Minor flooding is ongoing or expected to begin shortly in the advisory area. Between 0.5 and 1 inch of rain has fallen. - Some locations that will experience flooding include... Tucson, Catalina, Oro Valley, Marana, Davis-Monthan Air Force Base, Casas Adobes, Drexel Heights, Flowing Wells, South Tucson, Tortolita, San Xavier Community, Saguaro National Park West, Tucson Mountain Park, Catalina Foothills, Catalina State Park, Tucson Estates and Valencia West. - This includes the following highways... Interstate 19 between mile markers 58 and 63. Route 86 between mile markers 162 and 171. Route 77 between mile markers 70 and 85. Interstate 10 between mile markers 239 and 265. This includes the following Flash Flood Prone Locations... Manville Rd at Brawley Wash, Santa Clara Ave at El Vado Wash, 1st Ave north of Fort Lowell Rd, Stone Ave at Mabel St, Alamo Wash between Speedway and Grant, Twin Peaks Rd between Sanders and Sandario, Silverbell Rd near Ina Rd, Camino De La Tierra at the Rillito River, Camino de Oeste from Sweetwater to Gates Pass, Ironwood Hills Dr from Shannon to Camino de Oeste, Mission Rd from Valencia Rd to San Xavier Rd, Overton Rd at Canada del Oro, Snyder Rd from Kolb Rd to Sabino Canyon Rd and Sunset Rd west of Camino de Oeste. - http://www.weather.gov/safety/flood