Winter Forecast: La Nina Returns, Southern Drought Persists
Spotts, Pete, The Christian Science Monitor
Last winter - with its droughts, tornado outbreaks, heavy snows, and floods - was a tough one in different ways for millions of people. Be prepared for more of the same this year.
Last winter, with its droughts, tornado outbreaks, heavy snows, and floods was a tough one in different ways for millions of people.
Be prepared for more of the same this winter and into early spring, say forecasters with the National Oceanic and Atmospheric Administration.
The agency's seasonal outlook for the coming winter calls for cooler-than-normal temperatures up and down the West Coast and across the northern tier from the Pacific Northwest through the Great Lakes Region. The southern tier is expected to see warmer- than-normal temperatures from the eastern half of Arizona though western Mississippi.
More challenging for the already parched southern tier is the precipitation outlook. From southern California to the southern Great Plains and into the Southeast US, the southern half of the country is expected to be drier than normal, which would reinforce an already devastating drought centered on Texas and into New Mexico, Oklahoma, and spilling into neighboring states.
Ninety-one percent of Texas, 87 percent of Oklahoma, and 63 percent of New Mexico are experiencing either extreme or exceptional drought conditions - the designations given the two most-severe rankings, according to David Brown, climate services director at the National Weather Service's southern regional headquarters in Ft. Worth, Texas.
For the 12-month period ending Sept. 30, sections of southeast Texas saw rainfall totals up to 30 inches below normal, he says. The water level in Lake Travis, a popular recreation spot northwest of Austin, is 30 feet below normal.
Along with the exceptional drought and high temperatures throughout the summer texas lost more than 3.5 million acres to wildfires this year.
"It would take upwards of 10 or 15 inches of rain in many areas to make an appreciable improvement in the drought situation," he says. Given the outlook for this winter, "the likelihood of seeing that kind of relief here in the southern plains is pretty low."
Forecasters attribute the general trends expected for temperatures and precipitation to La Nina, one half of a cyclical shift in sea temperatures and atmospheric pressure across the tropical Pacific. El Nino forms the other half.
Under La Nina conditions, warm surface waters in the tropical Pacific migrate west, allowing cold water from deep in the eastern Pacific to reach the surface along the west coast of Central and South America and fill in behind the departing warm water. …