Flash-flood watch through 9 tonight

Wednesday, July 24, 2002 | 11:05 a.m.

The National Weather Service issued a flash-flood watch this morning for Clark County that extends through 9 p.m.

A watch means that flash floods are possible but not eminent, as thunderstorms are expected to roll in from the south through the afternoon.

"We have no reports of flooding at this time, but the conditions are there that we can get some heavy rain during the day," National Weather Service Meteorologist Larry Jensen said.

Isolated thunderstorms are expected today into this evening with a 50 percent chance of heavy rain. The high temperature is expected to reach about 100 degrees with the cloud cover.

Intense thunderstorm cells can produce heavy rains and lightning in a short period of time, Jensen said. Forecasters will issue a flash flood warning if there is the possibility of a flood.

Heavy rain and possible flooding is most likely to hit the northeast section of the Las Vegas Valley, the National Weather Service forecast said. The slow-moving thunderstorms developed in Arizona Tuesday night.

The first wave of storms pushed west from Arizona and sparked showers over the far eastern end of Lake Mead late Tuesday, forecasters said.

A second surge of moisture from Mexico was also expected to push into Southern Nevada from Mexico this morning.

The thunderstorms are part of the seasonal Southwest monsoon that occurs between July and September, National Weather Service meteorologist Charlie Schlott said.

The Clark County Regional Flood Control District has made extensive flood control improvements to offset the chance of flash floods, including 53 detention basins and 280 miles of channels and underground storm drains, spokeswoman Betty Hollister said.

"But there is still a chance of flooding in places that we haven't made improvements in, so people need to make smart decisions and not take any chances," Hollister said.

Hollister warned drivers to stay off the roads as much as possible if heavy rains hit today and to "absolutely not drive through flood water."