El Nino could dampen LV winter

Wednesday, Aug. 25, 2004 | 9:34 a.m.

National weather experts say there is a slight chance that the Southwest, including Southern Nevada, could experience above-normal rainfall this winter.

Winter rains would be a welcome change from the five-year drought that has gripped the Las Vegas Valley and most of the Southwest.

The National Weather Service's Climate Prediction Center on Tuesday issued a forecast for a weak El Nino, a phenomenon that occurs when the Pacific Ocean's waters warm up near the equator around Christmas, which creates more clouds over Southern California and Southern Nevada.

The key term in the forecast is "mild," climatologist Larry Riddle of Scripps Oceanic Institute in San Diego said.

"I would say the prediction is for a very, very mild El Nino," Riddle said.

The coming winter and early spring indicate Pacific Ocean waters at least a degree warmer, he said, which favors the return of the El Nino.

"The fact that an El Nino is in progress, that does expand the range of possibilities," Riddle said.

The prediction, though, doesn't guarantee a rainy winter.

"Hey, you know, if we could answer that question, we wouldn't be working for a living and we'd be rich," Riddle said.

At the National Weather Service in Las Vegas, meteorologist Charlie Schlott said it would take another month or two before forecasters can agree on the extent of an El Nino.

"It would be nice if it materialized," Schlott said.

However, based on what the climate center reported, this El Nino won't match the wet years of 1997-98, Schlott said.

"We'll see how it develops over the next few months," Schlott said.

Some forecasts have indicated above-normal precipitation this winter. "It's kind of in the embryonic stages right now," Schlott said.

What the Southwest needs is a heavy snowpack in the Rocky Mountains, on the western slopes.

"We've got to get the snowpack up north," Schlott said.

Then, when snow melts in the spring, the water feeds the Colorado River, the source of 90 percent of the Las Vegas Valley's drinking water.

It will take two or three years of above-normal snowfall in the Rockies to break the drought down here, Schlott said.

The signs of a possible El Nino appeared first from weather buoys strung across much of the Pacific, stretching from New Guinea to the Galapagos Islands, and detecting warmer surface waters.

Normal easterly winds that blow across the Pacific at the equator in mid-June and early July had weakened, another indicator of El Nino conditions.

Peruvian fishermen named the weather phenomenon El Nino, for the Christ child, after noticing changes in fish populations around Christmas Day when ocean waters grew warmer.

El Nino can affect weather worldwide, producing strong storms in California and droughts in Indonesia, Australia and Africa, the center said.

In the last strong El Nino in 1997-98, fish normally found in warmer waters -- great white sharks and yellowtails -- were swimming off the Alaskan coast.

There are costs associated with strong El Ninos, the center noted. The 1997-98 El Nino caused an estimated $20 billion in damages around the globe.