NOAA 2000-068
Contact: Cirtis Carey

Autumn Expected To Bring Continued Warmth For Portions of the U.S.

In the meteorological record books, summer 2000 will be remembered for the
devastating wildfires that scorched more than 6.8 million acres across the nation, the
searing temperatures and drought that plagued parts of the West and South, the historic string of rain-free days in Texas, which rivaled the Dust Bowl of the 1930s, and the cooler-than-usual temperatures in the East. For example, the Washington, D.C. area had its coolest summer since 1972, and the San Francisco Bay Area, by contrast, had hotter-than-usual temperatures, including a heat wave with record temperatures of up to 110 degrees.

Today, NOAA scientists declared that La Niña, the system mostly responsible for the weather extremes, is not a factor now and do not expect it -- or its climatic opposite El Niño -- to influence global weather for the next nine months.

The U.S. autumn forecast calls for the enhanced likelihood of warmer-than- normal temperatures in the Southwest, especially in the desert Southwest and in the Florida Peninsula. The likelihood of continued drier-than-normal conditions will prevail in the Southwest. The Northwest and the Central and Southern Plains will likely experience wetter-than-normal conditions, but not enough to eliminate the drought.

"For the first time in three years, global weather will not be impacted directly by either a strong El Niño or La Niña," said U.S. Secretary of Commerce Norman Y. Mineta. "This means a return to more normal weather, but it also means that long-term seasonal outlooks will be more uncertain without the firm influence of these climate cycles."

"Now that La Niña is history - we are at a turning point for our climate pattern," said NOAA Administrator D. James Baker. "This climate shift is one that we are continuing to study, but we know that without the influence of La Niña and El Niño, seasonal climate forecasting is more challenging."

El Niño occurs when sea-surface temperatures in the Equatorial Pacific are warmer than usual, and La Niña, when the water temperatures are cooler than normal. Both events influence the atmosphere and have ripple effects on weather around the world.

NOAA scientists also said a lesser-known, short-term climate phenomenon called the Madden-Julian Oscillation, is one of several atmospheric features that can impact the numbers and intensity of tropical storms. The MJO circulates from west to east around the globe, sometimes enhancing wind patterns favorable for rainfall. As the pattern approaches the Americas, other factors being equal, hurricanes are more likely to occur in the Gulf and Caribbean.

Retired Air Force Brig. Gen. Jack Kelly, director of NOAA's National Weather Service, said La Niña's exit will mean a return to more normal.

"Summer 2000 was one of transition, as La Niña faded but went out with a flourish," Kelly said, pointing to the recording-setting weather events. "Conditions to suppress wildfire activity will become more favorable, especially as we edge closer to the cold months."

With hurricane season at its peak, and with parts of the East receiving more rain than normal, Kelly warned of the severe flood dangers of land-falling tropical storms and hurricanes and urged residents to stay prepared.

"Every home, school, office, church or business along the East [and Gulf] Coasts should have a NOAA Weather Radio, and be prepared to respond when the warnings are announced," Kelly said.

Tom C. Peterson, chief of the Scientific Services Division at NOAA's National Climatic Data Center, said, "If we look at the year-to-date, January - August period, we find that the U.S. temperature is at record levels, though only slightly above the 1934 value." He added, "This is the 17th time the January-August period for the U.S. was above average in the last 20 years."