Washington, DC Oct. 26 (AP by Randolph E. Schmid)--The weather phenomenon called La Nina--Spanish for little girl--may seem like sugar and spice to Southern states where she is promising a mild winter. But forecasters expect her to be bratty to the Northwest and Great Lakes.
La Nina will change the strength and pattern of the Pacific jet stream over North America, said D. James Baker, head of the National Oceanic and Atmospheric Administration.
The result will ``give us a warm and dry winter in the southern half of the nation but more snow and rain in the Pacific Northwest and Great Lakes,'' Baker said Tuesday as the agency issued its winter weather forecast.
``We expect considerable month-to-month variation in temperature, rainfall and storminess in the Central, Northern and Eastern states, which means days of warmer than normal temperatures followed by bouts of bitter cold,'' he added.
La Nina is a periodic cooling of a large area of the tropical Pacific Ocean. It can alternate with an ocean warming called El Nino. Both can have impacts on weather worldwide.
In Southeastern areas plagued by drought last summer the outlook is for normal to below normal moisture in coming months, said Louis Uccellini, director of the National Weather Service's National Center for Environmental Prediction. That may be a boon, however, to flooded areas of North Carolina, permitting the ground to dry, he said.
``Over the past decade we have improved the forecasting of La Nina and El Nino so that we can now predict these events and their expected climatic impacts on different regions with 70 to 80 percent accuracy a year before they occur,'' said John J. Kelly, director of the Weather Service. The service is part of the National Oceanic and Atmospheric Administration.
The annual Weather Service forecast came a day after NASA researchers in Pasadena, Calif., issued their own similar forecast calling for a wet winter across the Northwest and a dry one in the Southwest.
The regional winter forecasts from the National Weather Service were:
-Alaska: Colder and drier than normal.
-Hawaii: Colder and wetter than normal.
-Pacific Northwest: Above-normal precipitation and increased storminess. Near-normal temperatures. Above normal snowfall.
-California: Below normal temperatures near the coast. Above normal precipitation in the north, below normal in the south.
-Southwest: Above normal temperatures, below normal precipitation. Below normal snowfall in eastern New Mexico.
-Northern Plains: Near normal temperatures and above normal precipitation. Significant arctic outbreaks likely.
-Rocky Mountain region: Near to above normal temperatures. Above normal precipitation in the north, below normal in the south.
-Midwest: Near to above normal temperatures as you go from north to south, above normal precipitation entire region. Above normal snowfall in upper Midwest.
-New England: Warmer than normal in southern New England; jet stream makes prediction uncertain in northern New England.
-Southern Tier: Warmer and drier than normal, with dryness most likely in New Mexico, south and west Texas and Florida. Below normal snowfall in northern Texas and central Oklahoma.
-Mid-Atlantic: Milder than normal with near normal precipitation east of the Appalachians.
-Ohio and Tennessee River Valleys: Warmer and wetter than normal. Increased number of heavy precipitation events and an increased risk of severe winter weather. Above normal snowfall.
-Great Lakes and Northeast: High degree of uncertainty. Considerable variability from week to week with above normal temperatures in southern areas and closer to normal in the north. Above normal snowfall in northern Great Lakes. Near normal precipitation south and east of the Appalachians, above normal elsewhere.
Copyright (c) 1999 The Associated Press