The outlook for the upcoming winter months of December-January-February has been released by the Climate Prediction Center. The forecast is primarily based on a weak to moderate El Nino (warm ocean temperatures) persisting in the tropical Pacific Ocean through early 2005. While other parts of the country, particularly the West Coast, Southeast, and Northern Plains, have significant weather impacts related to El Nino, the Central High Plains’ weather has a rather weak response. While there is some tendency for above normal temperatures in southwest Nebraska, elsewhere in the Tri State area there is little temperature trend associated with weak El Nino events. As for precipitation, there is no climatological evidence that El Nino affects local precipitation amounts, and with no other atmospheric signals, there are equal chances that precipitation will be above, near, or below normal this winter.
Long range forecasts only apply to the average over a three month period. There will still be great day-to-day variability in the weather, which cannot be forecast accurately more than a week in advance. So, although the outlook calls for a chance of above normal temperatures over a time period measured in months, this does not mean that outbreaks of bitter Arctic cold cannot occur on smaller time scales such as days. For example, in January 2004 in Goodland, temperatures averaged over 3 degrees above normal for the month, but the mercury plummeted to 9 below on January 5th. In addition, because the influence of El Nino is relatively small in the area, there is still a chance that near normal, or even below normal, temperatures will occur over the three month period of December through February.
The table compares normal temperature and precipitation for the three month period of December to February to weak El Nino events. The winter of 1979-1980 was the last time a weak El Nino occurred, and that year average temperatures were near normal and precipitation was mainly above normal, though McCook had near normal precipitation. At the bottom of the table, all weak El Nino winters were averaged (a total of 6 have occurred since 1950) and the results reflect the current long range forecast. McCook and Hill City show a tendency to have above normal temperatures, while Goodland and Burlington actually show a tendency to be below normal. However, the departures from normal are relatively small at all locations. Average precipitation amounts have been above, below, and near normal, and no trend can be established during weak El Nino years. |
