Scorecard on winter weather forecast



A comparison of the observed temperatures and precipitation for this past winter (maps on left) with predicted temperatures and precipitation (maps on right) shows that the National Weather Service (NWS) temperature prediction was below par, but that the NWS precipitation forecast was ‘quite good,’ according to Don L. Gilman, chief of the NWS long-range forecast branch. The predictions, issued November 29, 1982 (Eos, December 14, 1982, p. 1211), covered December, January, and February.

NWS long-range forecasters had thought that frigid Arctic air would swoop far south to bring below-normal temperatures to the western United States. Instead, an east Pacific trough, which may have been the strongest since 1900, brought a strong influx of air from the west, according to Gilman. The intense, low-pressure anomaly in the east Pacific, with the strong westerly winds, teamed with heavy rains south and southwest of Hawaii and warm equatorial Pacific waters to bring warm, wet air to the western United States. The results (see maps): Throughout most of the country, observed temperatures were above normal (A) or normal (N), while observed precipitation was heavy (H) o r normal (no code). Below-normal temperatures (B) occurred only in a portion of the southcentral U.S. and the Florida Keys. Light precipitation (L) fell over two patches in the northern plains, in the Appalachian region, and along the Maine coast.