Flash flood watch called for today

Wednesday, Aug. 25, 1999 | 9:44 a.m.

The National Weather Service issued a flash flood watch today until 9 p.m. for the Las Vegas Valley.

Forecasters predicted a 70-percent chance of showers or thunderstorms that could produce 1 to 2 inches of rainfall an hour.

The weather service issued the flash flood watch after thunderstorms struck Southern Nevada on Tuesday afternoon, raising humidity levels.

Meteorology technician Steven Downs said McCarran International Airport, where official weather service records are made, measured 0.04 of an inch of rain by 6 p.m. Tuesday.

The total rainfall for Southern Nevada has reached 3.38 inches so far this year. Total rainfall for a typical year is 4.12 inches.

The Las Vegas Valley and the Southwest normally experience a wetter weather pattern from early July through mid-September. Known as the Mexican monsoon season, the winds tend to blow from the south or southeast, bringing moisture into Arizona, Southern Nevada and Southern California.

This summer the monsoon started on time with the first storm July 8-16 bringing a presidential disaster declaration for Southern Nevada after $20.5 million in damages occurred to public structures and property.

Overnight the weather service began to pay more attention to former hurricane Bret, which drenched Texas in heavy rains. If Bret's rains continue to move westward, the moisture could feed into the Mexican monsoonal flow, adding more rain and thunderstorms in Las Vegas later this week and through the weekend.

Forecasters also said that the extra clouds may keep Southern Nevada cooler, reducing the risk of thunderstorms.

Arizona and New Mexico may bear the brunt of the heaviest rainfall, leaving Southern Nevada unfazed.

Temperatures in Southern Nevada are expected to soar into the 105-degree range, combining heat with higher humidity. Today the high was expected to reach 100 degrees.

It's the heated air rising that boosts chances for those cloudbursts in the Las Vegas Valley.