Tropical storm changes Las Vegas weather

By Mary Manning

Sunday, Aug. 24, 2008 | 3:23 p.m.

A tropical depression that became Tropical Storm Julio off the southern tip of Baja overnight may change the hot, dry weather pattern forecasters had predicted for the next week.

The National Weather Service said clouds had built up in northwestern Arizona and in San Bernardiino County, Calif., over Saturday night.

By this afternoon dark towering clouds had built up in far southern Nevada, near Laughlin, and Needles, Calif.

The high temperature in Las Vegas was 106 degrees at 3 p.m., the weather service said.

For the rest of the afternoon and evening there is a chance of thunderstorms mainly over the southeastern part of the valley, including Lake Mead, Boulder City and Henderson.

By Tuesday the moisture from Julio could increase chances of a thunderstorm in the Las Vegas Valley, if the moisture continues to stream northeast across the southwestern states, the weather service said.

Typically the southwestern flow of moist air, called the Southwest Monsoon, lasts from July through mid-September, when chances of thunderstorms and flash flooding are greater than at other times of the year. the weather service said.