LEXINGTON, Ky. (January 22, 2003) – Early predictions about an El Nino winter in the Bluegrass had Kentuckians preparing for a warmer and dryer than normal winter. But January weather has been more cold and wet – so, what happened?
University of Kentucky Agricultural Meteorologist Tom Priddy said when NOAA released it’s 15-day lead monthly outlook for January 2003, the higher than normal sea surface temperatures that characterize El Nino’s appearance continued to indicate moderate El Nino conditions.
“As a result of that January outlook, forecasters placed a lot of weight on the past climatology of El Nino,” he said. “But that’s not what we are seeing. Milder-than-normal El Nino conditions during January in key parts of the Pacific are now leading forecasters down a different and bumpy road.”
Typical El Nino winters usually bring a stronger than normal low-pressure situation near an area of the North Pacific named the Aleutian Low. Priddy said the counterclockwise spin of the wind patterns over that area feeds stronger-than-normal, westerly airflow into Western Canada. The result is a decrease in the chance for Artic air to surge into the northern third of the 48 states.
“So instead of the normal bursts of Arctic air, a milder Pacific air mass replaces that,” Priddy continued. “The same air mass, coupled with a strengthening of the jet stream through the southern states (resulting in a well-established storm track there), normally means lower-than-normal temperatures for the Southeast.”
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EL NINO…page 2
So what happened to Kentucky’s predicted warmer-than-normal winter? Corey Pieper, UK ag. Meteorologist said we have a habit of blaming El Nino and that tradition should continue.
“It’s El Nino’s fault,” he said. “El Nino appears to be fading for the moment. The fact that sea surface temperatures near the South American coast are only slightly above normal really limits the atmosphere’s response to El Nino. We gave too much weight to the potential effects of El Nino, which turned out to only be a minor player in the January conditions.”
Priddy said that currently the climate prediction center stands by a weak return of warmer sea surface temperatures along the South American coast. Therefore, the updated long-range outlook shows near-normal temperatures and drier-than-normal conditions for February and for the period of February through April.
To date, the winter of 2002-2003 has been hard on agricultural interests in Kentucky with mostly cold and wet conditions, especially compared to previously mild winters. Near-normal temperatures in the outlook indicate a continuation of cold spells in the Commonwealth.
“A trend to drier conditions through May could provide mixed blessings,” Pieper said. “Most of the state is too wet moving into February and slightly drier conditions would be welcomed -- but not drier conditions through May...all the way into planting season. Fortunately, the June through August outlook is calling for near normal precipitation at this point.”
“When the jet stream moves away from Kentucky we will see a drier weather pattern move into the state,” Priddy said. “But as long as the jet stream stays south of Kentucky, and the axis of the jet stream trough is near or slightly to the west of the state, we will continue to experience cold, wet weather.”
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Writer: Aimee D. Heald 859-257-4736, ext. 267
Source: Tom Priddy, Corey Pieper 859-257-8803, ext. 245