By Dave Toplikar

Published Sunday, July 20, 2008 | 7:22 a.m.

Updated Tuesday, Oct. 28, 2008 | 10:15 a.m.

Be prepared for some periods of heavy rain today. And watch out for flooding while you drive.

The National Weather Service forecasts a 40 percent chance of showers and thunderstorms today for Las Vegas and has placed most of southern Nevada in a flash food watch.

The flash flood watch will last from 11 a.m. through this evening and covers parts of northwest Arizona, California and Nevada.

The Nevada area includes the Las Vegas Valley, Lake Mead National Recreation Area, northeast, western and southern Clark County, Sheep Range, the Spring Mountains-Red Rock Canyon area and southern Nye County.

The weather service said lots of moist and unstable air that moved in from the southeast will lead to scattered thunderstorms across the region with the potential of bringing between 1 to 2 inches of rain per hour.

Some of the storms could produce even more intense rainfall, the weather service said.

Thunderstorms will move slowly to the north and could redevelop over areas that have already received significant rainfall, especially near higher terrain, the weather service said.

Skies this morning were mostly cloudy, with temperatures in the 80s. Today's high will be 98 degrees, the weather service said. Saturday's high was 109 at McCarran International Airport.