NOAA SAYS EL NIÑO TO INFLUENCE U.S. WEATHER

December 12, 2002 — Last week’s early dose of snow and ice in the Southeast and along the East Coast may be a glimpse of weather to come during Winter 2002-03, thanks to a moderate-strength El Niño digging in its heels. Top weather and climate experts from NOAA today said El Niño will set the stage for increased storm activity across the South. (Click NOAA image for larger view of 2002-2003 winter outlook. Click here for high resolution version of this image. Please credit “NOAA.”)

At a news conference in Washington, D.C., NOAA officials updated its winter outlook, first issued in September, and said El Niño remains a key influence.

“This is a classic El Niño pattern,” said retired U.S. Navy Vice Admiral Conrad C. Lautenbacher, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator. “El Niño is one of the driving forces behind these kinds of winter storm systems, which develop in the South and head east. But in some cases this winter, these storms could bring more rain to parts of the East.” Lautenbacher added, “El Niño will shape weather patterns through spring 2003.” (Click NOAA satellite image for larger view of the development of El Niño taken Dec. 9, 2002. The warm sea surface temperatures in the eastern Pacific Ocean are represented in red. Please credit “NOAA.”)

El Niño occurs when sea surface temperatures in the equatorial Pacific Ocean remain above average for more than several months. This usually triggers a chain reaction of atmospheric and weather changes around the globe.

Based on NOAA’s latest El Niño forecast and its updated December-February winter outlook, forecasters said the nation can expect warmer-than-normal temperatures across the northern half of the country, wetter and stormier-than-normal weather across the south from California through the Carolinas, and drier-than-normal conditions in the northern Rockies and Midwest.

“Over time, these precipitation patterns can reduce lingering drought conditions that have plagued the southeast and southwest in recent years,” said retired Brig. Gen. Jack Kelly, director of the NOAA National Weather Service. However, he added, “Drought may intensify in the northern Rockies and parts of the Midwest.” (Click NOAA image for larger view of U.S. Drought Monitor for Dec. 10, 2002. Click here for high resolution version of this image. Please credit “NOAA.”)

Kelly said nine percent of the area east of the Mississippi River remains in drought, while 53 percent of the region west of the river remains in drought. In September, approximately 55 percent of each region was affected by drought.

“El Niño most strongly impacts U.S. weather patterns during the winter by shifting the jet stream and storm track toward the southern tier of the country,” said Jim Laver, director of the NOAA Climate Prediction Center. “As a result, increased storminess is expected across the southern U.S.,” said Laver.

The U.S. 2002/2003 winter outlook for December-February calls for:

• Warmer-than-normal temperatures across the northern half of the country.
• Equal chances for temperatures to be above normal, near normal, or below normal in the southern half of the continental United States.
• Drier than normal conditions in the northern Rockies, including Montana and northern parts of Idaho and Wyoming.
• Drier than normal conditions in the Midwest, including eastern Iowa, eastern Minnesota, Wisconsin, Michigan, Illinois, Indiana, Ohio and Kentucky.
• Wetter-than-normal weather pattern across the South from California to the Carolinas, including California, Nevada, Arizona, New Mexico, southwest Utah, southeast Colorado, Texas, Oklahoma, Kansas, southern Nebraska, western Missouri, western Arkansas, Louisiana, southern Mississippi, southern Alabama, Georgia, Florida, South Carolina and eastern North Carolina.
• States and regions in the continental United States not mentioned above will have equal chances for precipitation to be above normal, near normal, or below normal.
• Warmer and wetter-than-normal conditions in southern Alaska.
• Cooler and drier-than-normal conditions in Hawaii.

The CPC updates its El Niño Diagnostic Discussion and seasonal outlooks each month, and they are available online.

The CPC is one of the National Centers for Environmental Prediction, which is part of the NOAA Weather Service. The CPC predicts and monitors El Niño and also produces the nation’s official long-range outlooks and medium-range weather forecasts. NOAA Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories and operates the most advanced weather and flood warning and forecast system in the world, helping to protect lives and property and enhance the national economy. NOAA is an agency of the Commerce Department.

Relevant Web Sites
NOAA's Climate Prediction Center

El Niño/Southern Oscillation (ENSO) Diagnostic Discussion

El Niño to Play Role in Nation’s Fall, Winter Weather

Weekly El Niño/Southern Oscillation (ENSO) Update

Most Recent 2 Months Sea Surface Temperature Anomaly Animation

El Niño and La Niña-related Winter Features over North America

NOAA's El Niño Theme Page

NOAA's El Niño Home Page

CLIMATE FACTORS HELPING TO SHAPE WINTER 2001-2002

NOAA's CURRENT SEA SURFACE TEMPERATURE MAPS

ENSO Fact Sheet

ENSO Frequently Asked Questions

ENSO Tutorial

ENSO Recent Events

Sea Surface Temperature Outlook

ENSO Impacts by Region

NOAA's Storm Watch — Get the latest severe weather information across the USA

NOAA's Drought Information Center

Media Contact:
Carmeyia Gillis, NOAA Climate Prediction Center, (301) 763-8000 ext. 7163 or John Leslie, NOAA National Weather Service, (301) 713-0622