Leave an empty water glass outside during the next few days, and there’s a good chance it’ll be half-full. But will the rain and snow forecast to fall on Arizona make a dent in the drought?
Weather experts said Wednesday the outlook is a glass half-empty.
The first serious precipitation of the winter is forecast to arrive today, dropping up to a half-inch of rain in the Valley by Saturday.
Meanwhile, the National Weather Service offices in Phoenix and Flagstaff are considering snow advisories or winter storm watches for some areas beginning Friday night.
What’s happening is a surge of tropical moisture entering Arizona ahead of a cold, lowpressure system from the Pacific Northwest.
Once the storm pushes east by early Sunday, left behind will be perhaps the coldest air of the season. Low temperatures on Sunday and Monday mornings will dip below freezing in all but the warmest desert locations.
In addition, the duration and severity of the freeze could damage frost-sensitive outdoor plants and shrubbery, and could cause exposed water pipes to burst. This is the beginning to Arizona’s wet winter, right? After all, this is an El Niño year and those are notable for above-average precipitation levels in the winter across the Southwest. Not so fast, say the experts. “One storm does not mean El Niño’s rolling in here and we’re going to be soaking,” Weather service meteorologist Austin Jamison said Wednesday in Phoenix.
Tom Kines, a senior meteorologist with AccuWeather, had even worse news: The El Niño is fading.
An El Niño is marked by warmer-than-usual water in the tropical Pacific Ocean. The current change in temperature, called an oscillation, was never that strong to begin with, and now a number of forecasts employed by federal climate experts are predicting an end to El Niño conditions by the start of summer.
“That’s one reason why weather is starting to shift nationally,” Kines said.
On Monday, AccuWeather released a statement declaring the unseasonably warm winter experienced by much of the country is likely to “turn on a dime.”
If AccuWeather is accurate, then Arizona is about to get caught in a climatological dry squeeze.
During the typical El Niño, the Southwest sees less precipitation than usual in the fall.
And that’s borne out so far. Since Oct. 1, less than six-tenths of an inch of rain has fallen at Phoenix Sky Harbor International Airport, the Valley’s official gauge, which is 21 percent of normal.
Also, the state has about 38 percent of the average snowpack, according to the Arizona Basin Outlook Report released this week by U.S. Department of Agriculture’s Natural Resources Conservation Service.
But winters without an El Niño are less likely to have above-average rainfall.
No rain in the fall, no rain in the winter. For a state locked in a drought that’s lasted more than 12 years, this is bad news.
“Hopefully, we’re wrong, for your sake,” Kines said of the Valley. “We know you need the moisture.”
Waiting for snow
Percent of average snowpack levels as of Jan. 1 at Arizona locations: San Francisco Peaks 32% Grand Canyon 33% Salt River Basin 38% Verde River Basin 40% Upper Gila River Basin 40% Little Colorado River Basin 41% Chuska Mountains 41% Central Mogollon Rim 52%
SOURCE: NATIONAL WEATHER SERVICE