Strong El Niño storms set to hit region next week

A series of three strong storm systems is set to sweep into Arizona Monday, all fueled by El Niño.

Prescott should get mostly rain, according to the National Weather Service.

The city could get as much as 1.5 inches of rain during the first two storms systems Monday through Wednesday, leading the Weather Service to alert the public to possible flooding on Thursday and Friday as a potentially even stronger system hits.

The second storm system, which should hit Tuesday and Wednesday, should be the coldest, with snow levels dropping as low as 5,000 feet. The Weather Service still doesn't expect downtown Prescott to get any snow accumulation, but surrounding higher-elevation areas could see snow buildup.

A warmer and possibly the most powerful third storm on Thursday and Friday could melt higher-elevation snow and send extra water flowing down streams, prompting the Weather Service to caution the public to prepare for flash flooding.

"We are a little concerned about creeks and rivers coming up," said Dave Vonderheide of the National Weather Service office in Flagstaff.

He said it's too early to forecast how much rain and snow the third storm might produce.

Driving in the high country could be quite hazardous next week, the Arizona Department of Public Safety warns.

The Weather Service is forecasting that the first storm could produce 2-6 inches of snow at elevations between 6,000 feet and 7,000 feet, and 6-10 inches at higher elevations.

The second storm could bring another 4-10 inches of snow at elevations of 5,500-6,500 feet, with 8-12 inches above that.

El Niño, which consists of a periodic warming of the Pacific Ocean's equatorial zone, tends to bring more precipitation to Arizona winters. It already helped boost December precipitation to above-average numbers in Prescott, and now it's really kicking in.

"It's a major shift in the weather pattern," Vonderheide said. "It looks like it's trying to lock in now."

Drought-stricken Arizona probably can use all the precipitation that El Niño can dish out.

The Weather Service recently published an analysis of northern Arizona weather in 2009, including weather at the Prescott airport.

The Prescott airport recorded its 10th driest year in its 70-year period of record in 2009, with 10.31 inches of precipitation. It was the eighth driest for Seligman and fifth driest for Bagdad.

The same rankings apply to last year's summer monsoon. The Prescott airport received 4.34 inches of rain.

The Prescott airport's 7.77 inches of precipitation in 2009 was 11.12 inches short of the 30-year normal between 1971 and 2000. The maximum temperature was 2.1 degrees above normal, and the minimum temperature was 4.7 degrees above normal.

Cottonwood, Sedona and Seligman also saw below-normal precipitation and above-normal temperatures, but the differences weren't as strong as in Prescott.

While the Weather Service didn't list Prescott in its snowfall statistics, it listed huge drops in the 2009 snow levels for most areas on its list compared to the sites' 30-year normals. The Grand Canyon's North Rim was the worst, at 70.7 inches below normal snowfall.

The Weather Service also listed some weather extremes for Prescott. Its hottest day was 102 degrees on July 17, its coldest day was 9 degrees on Dec. 4, its highest precipitation was 2.12 inches on Dec. 8, and its snowiest day was one inch on Dec. 23.

To see the entire report - and keep up with next week's weather forecasts - visit the Weather Service website for Flagstaff at www.wrh.noaa.gov/fgz.