Taking A Break from the Tropical Traffic Jam and Talkin' Winter

The winter of 2010 - 2011 was a tough one caused primarily by the La Niña pattern in the equatorial Pacific Ocean.  Water colder than normal is characteristic of La Niña winters.  The cold water is the result of a pattern change in the global atmosphere and a cause of the northern branch of the jet stream being dominant.

Last winter the southern jet was also very active bringing about the clash of warm moist air from the tropical Pacific with cold, polar air from northern Canada. The clash took place for the most part right over the tristate.

I am not going out on a limb yet, but the elements are there for another fairly rough winter. The La Niña pattern is being restablished over the equatorial Pacific with temperature anomalies (i.e. departures from normal) in the negative indicating cooler than average water. The blue areas below are the cooler areas.

Notice the large cool water pools north and south of the equator and the area right along the equator. When the water is cooler than normal in these regions less energy is transferred to the atmosphere and the southern branch of the jet is weaker than normal. The northern branch dominates guiding cold air into the Ohio Valley. At the same time mositure arrives from the Pacific causing a winter wetter than normal.

If enough cold air sneaks into the pattern it can be a white winter instead of wet.

Typically the La Niña or El Niño pattern does not set up until January. When it did last year it brought a snowy February. The La Niña dominated the spring resulting in the wettest 31 day period in Cincinnati history, ending May 3 with 15.96" of rain.

The video below has more.