Flood watch expected as thunderstorms threaten

Thursday, July 15, 2004 | 9:45 a.m.

The weather service issued a watch on Wednesday for southern Clark County and the Lake Mead National Recreation Area through 9 p.m.

A watch does not mean it will flood, but as the moist monsoonal flow from Mexico streams northward, the chance of downpours in the afternoons and evenings continues.

People traveling in a flood watch area should keep their eye on the weather, as the threat of heavy downpours and flooding is possible. If conditions are ripe for a thunderstorm, a flash flood warning could be issued.

The weather service has issued flood watches for Northwest Arizona, including all of Mohave County, and Southeast California, including San Bernardino County east of Barstow as the result of atmospheric destabilization and the increasing moisture.

This year's monsoon has been slow to arrive in Southern Nevada.

Wednesday's temperature reached 99 degrees, five degrees lower than Tuesday, weather service meteorologist Jon Adair said.

Today's high is expected to reach 103 degrees.

Lows will range in the lower to mid 80s, Adair said.

Sprinkles fell in the northwest valley and in Henderson Tuesday evening, but nothing was measured in Las Vegas, Adair said.

More raindrops fell on Mount Charleston, but nothing was measured.

Weather officials warned that the storms developing south of Nevada could produce locally heavy rain because they are moving so slowly.

The moist, warm air mass called the Southwest monsoon could continue into the weekend, Adair said, keeping a chance of afternoon and evening thunderstorms possible in the Las Vegas area.

Monsoonal moisture can trigger thunderstorms from mid July to mid September.

Even the weather service isn't immune to temperature fluctuations. The weather service Doppler radar system's air conditioning failed on Tuesday, leaving meteorologists without one way to track storms. It took until late Wednesday afternoon before repairs were completed, Adair said.