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

* WHERE...Portions of northwest Arizona, including the following areas, Lake Havasu and Fort Mohave, Lake Mead National Recreation Area and Northwest Deserts, southeast California, including the following areas, Death Valley National Park, Eastern Mojave Desert, Owens Valley and San Bernardino County-Upper Colorado River Valley, and southern Nevada, including the following areas, Lake Mead National Recreation Area, Las Vegas Valley, Northeast Clark County, Southern Clark County and Western Clark and Southern Nye County.

* WHEN...From 10 PM PST /11 PM MST/ this evening through late Tuesday 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... - A storm system will move in late tonight with areas of heavy rain spreading across much of the Mojave Desert and Northwest Arizona. Embedded thunderstorms are also expected which may produce locally heavier rainfall. Combined with the wet soils from the weekend storm system...storm run off will happen quickly and may lead to rapid flooding of sensitive basins. - http://www.weather.gov/safety/flood

* WHAT...Sub-freezing temperatures dropping to 30 to 32 possible for the first time this season.

* WHERE...Western Clark and Southern Nye County including Pahrump and Amargosa Valley.

* WHEN...From late Tuesday night through Wednesday morning.

* IMPACTS...Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing.