WWT Offers Early Preview for Fall-Winter Season

The El Nino event from the summer of 1997 is expected to continue through the autumn and winter seasons. An El Nino event typically lasts from 15 to 18 months. This pattern usually allows low pressure/cold front systems to move across the southern half of the United States on a regular basis. Another effect of the El Nino is to divert the polar weather systems north of the United States on a routine basis. Persistent or regular occurrences of high-pressure (pacific origin) in the northern half of the 48 contiguous states typically results from this.

The frequency of these low pressure/cold front systems across the Southern states is likely to accompany fewer surges of freezing weather from the north. Also, fewer snowstorms are presently indicated for the Northern states next winter since we expect most of the very moist air masses to remain in the south. We anticipate the snow that does fall in the Plains states to melt by a greater number of warming Chinook wind events than were noted last winter. Finally, fewer outbreaks of arctic air into the Central and Southern states are forecasted for next winter than were noted this winter.

More specifically, near normal to slightly above normal temperature conditions may occur in the Central and Northern Plains and Rocky Mountain states with only a few colder than normal periods. Near to above normal temperature averages are foreseen for the Midwest and the Northeast. We predict cooler than normal conditions for the Southern states with near normal temperature conditions in the states west of the Rocky Mountains.