W E A T H E R
2007–08
To see color maps of the forecast, turn to page 80.
Our study of solar activity suggests that a La Niña will prevail this winter, resulting in above-normal temperatures in much of the country. The coming winter will be remarkable for its lack of any prolonged cold spells, especially if the La Niña strengthens. (Only if an El Niño or neutral conditions were to develop would there be any lengthy or extreme cold spells.) Snowfall will be below normal in most areas, the exception being a rather narrow swath extending from northeast Texas into northern New England. In short, the winter of 2007–08 will be the mildest for the country as a whole.
Spring will come relatively early in most regions. Summer will be hot in most areas, but continuing drought will lead to wildfire and water management challenges in Florida and in western states.
Overall, we expect that the coming year will be the warmest of the past century.
November through March will be milder June through August will be cooler than than normal, on average, in all areas, ex- normal in northern Maine and in an area except Florida, southern portions of the South- tending from the Great Lakes southward east and Deep South, and easternmost Texas. through the Ohio Valley and west ward Snowfall will be above normal from north- through most of the Heartland and Upper ern New England southwestward through Midwest, near normal in the Appalachians central Pennsylvania, the Ohio Valley, north- and the southern tip of Texas, and hotter than ern portions of the Deep South, and into normal elsewhere. Rainfall will be below northeast Texas, while rainfall will be above normal from the Pacific Northwest across normal from Los Angeles northward to cen- the Intermountain region, from the Upper Midwest south and eastward through the Ohio tral Oregon and eastward into western Valley, and in most of Florida. Rainfall else-Nevada. Elsewhere, precipitation and snow- where will generally be above normal. fall will be below normal.
September and October will be warmer
April and May will be warmer than normal, and drier than normal in most areas. The exon average, in all areas except Florida. Rain- ceptions will be Florida and the Southeast, fall will be below normal in Florida, the which will be cooler than normal, while the Southeast, Deep South, Ohio Valley, Lower Pacific North- and Southwest, Intermountain Lakes, and Texas–Oklahoma, and near or region, and portions of the Desert Southwest above normal in other regions. will have above normal rainfall.
How accurate was our forecast last winter?
Our forecast for the winter of 2006–07 resulted in our lowest verification scores ever, with a 61% accuracy rate on the monthly regional precipitation and a 49% accuracy rate on monthly regional temperatures. A coin toss would have beaten our monthly regional temperature forecasts by 1%. The reason our scores were so low was the exceptionally mild temperatures that persisted through much of December and the first two-thirds of January, before the turn to exceptional cold from late January through much of February. Had the cold period started a month earlier, our overall accuracy rate would have been over 75%. To our credit, we did predict that “most regions will have at least one mild month” and cautioned that “[i]f the El Niño fails to develop as expected, the very cold periods will be brief and most of the country will experience a mild winter overall, perhaps even a very mild winter.”
We expect to do much better in our forecast for the winter of 2007–08, as we are confident that above-normal temperatures will predominate whether the La Niña that develops is weak or strong.
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