FOR IMMEDIATE RELEASE
Contact: Randee Exler, Ruth Barritt
A strengthening La Niña influenced weather patterns that sent Alaskan temperatures dipping to -74 F and wind chills to -90 F in late January and early February, and brought flooding and heavy snow to the West, warmth to the East, and extreme weather from South America to Asia, according to National Oceanic and Atmospheric Administration scientists.
In May 1998, a rapid cooling of the near equatorial waters in the central Pacific signaled the end of the 1997/98 El Niño and the beginnings of a La Niña. La Niña features colder-than-normal sea surface temperatures in the tropical Pacific Ocean. Many forecast models indicated this transition and that the La Niña would continue to develop. Now, six months later, scientists at the National Weather Service's Climate Prediction Center, a NOAA facility in Camp Springs, Md., say that the event has grown into one of the strongest La Niña episodes of the past 50 years.
"This La Niña provides the physical link between many of the unusual weather patterns seen recently in far-flung parts of the globe," said John Janowiak, a NOAA scientist. "While parts of Alaska have experienced severe cold, most of the lower 48 states, especially those in the southern tier, have enjoyed record breaking warm temperatures."
The Alaskan cold snap can be blamed on persistent winds bringing bitterly cold air from north of the arctic circle southward to Alaska. According to National Weather Service scientists, this circulation pattern is frequently associated with La Niña, which usually results in colder than normal winter weather over Alaska. Forecasters predicted the below-normal winter temperatures for Alaska as early as September.
Except for California, the rest of the
lower 48 states experienced a much warmer-than- normal November
1998 through January 1999. Temperatures in many states ranked
within the 10 warmest November-January periods of the century.
The United States, as a whole, experienced the third warmest
November-January of the past 104 years. As a result, the United
States, as a whole, saw a 10 percent energy savings, more than
a 20 percent savings over the southern-tier states, and a nearly
50 percent savings in Florida, according to the weather service.
The global La Niña impacts include heavy rains, severe storms, and flooding in southern Africa, drought in Kenya and Tanzania, flooding in the Philippines and Indonesia, and abnormal wetness in northern South America. The same regions suffered the opposite impacts during the 1997/98 El Niño.
As for the cold wave in Alaska, it lasted
from Jan. 26 to Feb. 13, during which time Fairbanks recorded
a record 19 consecutive days with a low temperature less than
Alaskans should not have let the last week's abnormal warmth make them too complacent. The National Weather Service's long-range forecasts indicate that the odds favor below-normal temperatures during the March-May time frame when La Niña impacts will still be in force.
Current forecasts, graphics and observations are available on the Internet at http://www.cpc.noaa.gov