The influence of La Nina is expected to wane during the last quarter of this year, with normal sea surface temperatures in the equatorial Pacific Ocean for much of the cold season to follow. As a result, a near normal weather pattern is expected to evolve for this fall and into the winter. this means that the more significant weather systems are likely to move from the North Pacific Ocean eastward across the U.S. with occasional surges of Canadian air. Ovearll, average to warmer than normal temperatures and near to drier than normal precipitation conditions are expected for autumn and the first half of next winter.

More specifically, the expected temperature pattern for the contiguous 48 states when averaged out over the fall and early winter is likely to show above normal temperatures for the Plains states and Gulf Coast states. Near normal temperatures are likely across the northern tier states, along the Pacific Coast and in the desert Southwest. Below normal temperature averages are indicated for the intermountain region of the West.

Precipitation occurring during the fall and the first half of winter is indicated to be generally near normal for most areas of the U.S. Any area receiving above normal rain/snowfall during this period of time is more likely to be in the Rocky Mountains and westward. This pattern may result in a less than normal amount of snow falling in the southern Great Lakes, the Ohio River Valley, and the central Appalachian Mountains.

During the second half of winter, from mid-January through March 2000, the movement of weather systems across the U.S. is likely to begin favoring above normal temperatures in most areas. This typically occurs with a decrease in the strength and/or the frequency of cold fronts moving through the central and southern portions of the U.S. The frequency of precipitation does not necessarily decrease in this case, although the amount of precipitation falling from any cold front or area of low pressure may generally decrease, particularly
in the South.