In a preseason Weather Conference at The American Meteorological (AMS), National Center of Environmental Prediction (NCEP) Director Louis Uccellini warned this would not be an easy winter to make weather forecasts. 'Louie' as Dr. Uccellini does not mind being called, told of how challenging a La Nina winter can be. I just happened to be the front row, with my IPhone. Here is a brief video excerpt of Louie telling us why La Nina, cooler than normal water in the Pacific Ocean, makes winter forecasting in North America so difficult.
Obviously there are flaws in generalizations. Most glaring here is the forecast for dry weather in New Mexico and Texas, as the 4th snowstorm so far this winter moves into that region tonight, just 48 hours after the most recent blizzard.
One generalization is glaringly manifest this year though, the inability to prediction phasing of northern and southern stream short waves.
That phasing is so important, it makes a difference of whether, a storm stalls in the Gulf of Mexico, or comes up the coast and evolves into a New England Nor'easter for this Christams? The later was in yesterday's forecast, the former is now the call. Maybe it will change again. In the meantime we have a warm dry Thursday, rain and snow Friday (a few inches at the ski resorts, not much elsewhere). Then another pseudo-arctic front Saturday may produce snow from Maine to Massachusetts.. just like last Saturday/Sunday.