* WHAT...Flash flooding caused by excessive rainfall will be possible. * WHERE...Portions of northwest Arizona, including the following areas, Hualapai Mountains, Lake Havasu and Fort Mohave, Lake Mead - AZ side, Lake Mohave - AZ side, Northwest Deserts and Northwest Plateau, southeast California, including the following area, San Bernardino County-Upper Colorado River Valley, and Nevada, including the following areas, Lake Mead - NV side, Lake Mohave - NV side, Lincoln County and Northeast Clark County. * WHEN...Now through late Sunday night. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. Low-water crossings may be flooded. * ADDITIONAL DETAILS... - Moderate to heavy rain is possible at times. Between a half an inch and an inch of rain will be possible. With saturated soils and significant run off expected, flash flooding may occur. - http://www.weather.gov/safety/flood