By Gary McManus, Climatologist
Oklahoma Climatological Survey


NORMAN - Last fall's forecast of El Niño by the Climate Prediction Center (CPC) seemed to spell good things for Oklahoma. After all, past El Niño episodes have at times brought the state healthy rain and snow totals. Following the catastrophic drought of the previous couple of years, including last winter's disastrous wildfires and failed wheat crop, any help would be greatly appreciated. And sure enough, Mother Nature responded with the 10th wettest December-January period on record in Oklahoma, dating back to 1895. The Panhandle enjoyed its wettest such period ever. The latest El Niño forecasts are far different, however. The CPC now predicts that the ocean temperatures in the pacific will revert back to normal, spelling an end to the latest El Niño episode. "Any El Niño-related effects over North America should be minimal during the remainder of the winter season," said Vernon Kousky, research meteorologist at the NOAA Climate Prediction Center. "A return to neutral conditions in the tropical Pacific is expected this spring." Does this mean a quick return to prolonged drought conditions for Oklahoma? Well, not so fast.

While a fairly decent El Niño did materialize over December and January in the equatorial pacific, this episode's impacts were hardly typical. Take Southern California, which has also been in extended drought conditions. During a normal El Niño winter, areas such as Los Angeles and San Diego could expect strong pacific low pressure systems to drop down along the coast and deposit lots of rainfall. Likewise, the Pacific Northwest should have been dry. This was far from the case, however, with drought conditions intensifying rapidly in Southern California and flooding rain and snow events in Washington and Oregon.

The star-crossed fortunes of the two regions came courtesy of a meandering polar jet stream. El Niño would normally steer this river of air that keeps the cold, dry air at bay farther to the north. Instead, a large high pressure ridge parked itself over Southern California, diverting the relatively warm moisture-laden storms over and around California, through the Pacific Northwest. Oklahoma, has still received an ample number of seemingly El Niño controlled storm systems, Given the atypical nature of El Niño impacts in other parts of the country, however, perhaps our good fortune has been due to some other far-flung weather phenomenon.

The latest February precipitation forecasts from CPC give much of northern and eastern Oklahoma a greater chance of below normal moisture, while southern and western areas of the state are given equal odds for above normal, below normal, or normal conditions. Drought conditions have improved dramatically over much of the state throughout the last several months. The drought lingers on in north central Oklahoma, however, deemed "severe" by the National Drought Mitigation Center.