Thunderstorms crackle into Las Vegas Valley, bringing heavy isolated downpours

By Mary Manning (contact), Tim Richardson (contact), Dave Toplikar (contact)

Published Saturday, July 26, 2008 | 8:16 a.m.

Updated Saturday, July 26, 2008 | 1:14 p.m.

Light rain continues to be possible across the Las Vegas Valley today, but rain that soaked southeastern portions of the region this morning was anything but light — some areas reported a half-inch or more by 1 p.m.

Thunder and heavy rain stormed into the area this morning, settling along the Interstate 215 and U.S. 93 corridor. The downpours prompted the National Weather Service to issue a flood advisory for the Lake Mead area, although forecasters said the threat for signficant flooding diminished after 8:15 a.m.

A flood advisory then was extended to cover most of the Valley. Forecasters said the heaviest rain was reported across Silverado Ranch, Green Valley and other parts of Henderson.

"Minor flooding of roadways and rapidly running washes are likely in these areas," the weather service said.

By 1 p.m. today, McCarran International Airport recorded about 0.05 of an inch of rain. But other rain gauges around the Valley measured more, according to WeatherUnderground's network of small weather stations across the Valley. WeatherUnderground reported that the Jean Airport had heavy rain about 12:15 p.m., with 0.63 of an inch of rain in about an hour. Also, at 12.12 p.m., an automated gauge near the Pittman-Pecos channel recorded 0.59 of an inch in about an hour, WeatherUnderground reported.

Morning storms grew along the Lower Colorado River and extended as far away as Mesquite, which is about 60 miles northeast of Las Vegas.

At 1 p.m., it was 93 degrees at the official weather station based at McCarran International Airport. With daytime highs predicted to reach 102 degrees, the showers and thunderstorms may shear a few degrees off those forecast highs, the weather service said.

However, if the sun comes out later this morning into this afternoon, that could trigger more thunderstorms through this afternoon and evening.

The storms this morning developed south of the Valley over the McCullough Range and moved northeast at about 20 mph. As storms clipped the southeastern Valley, they brought along brief periods of heavy rain, gusty winds and the threat of small hail, forecasters said.

Despite the damp beginning to the day, the weekend won't be a washout.

The weather service said rain likely will develop in areas south and east of Interstate 15 -- and even that area has only a 20 percent chance of rain.

Rain chances will stick around Sunday, mainly after 11 a.m., with the high topping out at 104. Forecasters said drier air will develop across the region Sunday and push monsoon moisture into Arizona during the middle of next week.

A disturbance moving across northern Arizona today is bringing favorable conditions for thunderheads before dawn in that area, the weather service said.

McCarran has recorded 0.05 inches of rain this month, although storms earlier this month dropped more than an inch of rain in a single day in parts of Clark County.

Weather service records indicate the average high on today's date at McCarran is 104 degrees.

Temperatures are expected to stay at 100 degrees or higher into next week with a chance of thunderstorms each day.