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By Lana Robinson
Field Editor
Despite a forecast of a mild winter in the Old Farmer's Almanac, meteorologists are predicting a cold, wet winter ahead.
The main reason is a weak El Niño that's expected to strengthen this winter, shifting the jet stream and bringing enhanced storminess into Texas.
In October, state meteorologist George Bomar said, "I'm convinced that this winter is going to be significantly cooler, even colder than normal, and it's also going to be unusually wet."
Bomar was on the mark with earlier predictions of heavy rains and cooler weather in October, which inundated the West Texas cotton patch.
"September is normally one of the two wettest months of the year. We had plenty of tropical activity, well east of Texas. Summer didn't get underway until July, and we had a late-arriving autumn, so that pushed the rain into October," he explained.
The National Oceanic and Atmospheric Administration's 2004-2005 Winter Outlook calls for above-average temperatures in Alaska, much of the West and the northern and central Great Plains while lower-than-normal temperatures are expected in the Gulf Coast states, the Southeast and mid-Atlantic region. NOAA says there are equal chances of warmer, cooler or near-normal temperatures this winter in the Northeast, Midwest and parts of Southwest.
As Winter 2004-2005 approaches, NOAA scientists say the leading climate patterns expected to impact winter weather are: the El Niño/Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), the Pacific/North American pattern (PNA) and long-term climate trends. Scientists at NOAA's Climate Prediction Center (CPC) say these patterns are the physical basis for this season's winter outlook.
Water temperatures in the central-equatorial Pacific Ocean are warmer than average, indicating the early stages of a warm (El Niño) episode. Current departures indicate that the intensity of this episode is weak. Bomar said he did not expect the El Niño to be a force until early in 2005.
"Even if an El Niño were to pop up in the next 60 to 90 days, it probably wouldn't impact us. It would not have a bearing on us until we get into spring," he added.
Weak ENSO years, scientists say, tend to be associated with the positive phase of the Pacific/North American pattern. The positive phase of the PNA is often associated with weak El Niño episodes. The negative phase features a shift in the jet stream southward along the U.S. East Coast resulting in an increased number of extreme cold days, especially from the Great Plains to the Southeast.
During weak El Niño episodes the jet stream is stronger-than-average over the east-central North Pacific and over the Mid-Atlantic States, with greater-than-average storminess in the Aleutians/Gulf of Alaska and along the southeast coast of the United States. This results in warmer and drier than average conditions over western North America and cooler and wetter than average conditions over the Southeast U.S.
Bomar does not expect anything rivaling the bitter cold winters of 1983 and 1989, with extreme dips that essentially wiped out citrus trees in the Rio Grande Valley, but he does think the weather will be colder over the long term.
"With the weak El Niño, I expect, from December to January, a lot of chilly weather and a lot of wet weather," he said. "We could be in for a rambunctious spring and summer. I think we'll see a drop off in cyclones next year. We'll trade the summer high-level activity in the tropics for more tumultuous weather in spring. However, if we get an El Niño established, we'll get a totally different story."
