Winter outlooks vs. reality
Seasonal-forecast season underway; nature might find it all amusing.
AccuWeather is on record as calling for a snowy winter in the Northeast, with above-normal snowfall around here.
Other outlooks soon will follow, with the government due to release its forecast on Thursday. That one, issued by the Climate Prediction Center, typically is the least-specific.
The temperature and precipitation maps won't tell you much, but in the view of government meteorologists that's about as much as can be said in all honesty.
For any number of reasons, compared with short-term prediction, the art of seasonal forecasting remains in a cave-drawing phase.
Computer modeling has been of limited use in long-range forecasting, and those in the business look at correlations, "teleconnections," and longer-lasting phenomenon such as the cyclical cooling and warming in the tropical Pacific – La Nina and El Nino respectively.
Right now the signal in the Pacific is conflicted. In the spring, speculation centered on a monster El Nino for the fall and winter, but so far not much has been cooking out that way.
Winter around here often is driven by the career of the North Atlantic Oscillation, a fluctuation of air-pressure patterns over an area from Iceland to the Azores.
The NAO, however, isn't reliably predictable beyond several days. What's more, last winter the NAO generally was in a mode that would suggest a gentle winter in the Northeast.
Enough said.
The winter of 2013-14 ended up being another lesson in humility for forecasters.
AccuWeather predicted a third consecutive season of below-normal snowfall in Philly. Glenn Schwartz at NBC-10 called for 14-18 inches for the season.
At the end of the season, chief of forecast operations at the government's Climate Prediction Center, declared: "We had a rough winter, too."
As Penn State's Jon Nese, erstwhile Franklin Institute meteorologist, observed: "We keep discovering new pieces of the puzzle. But we still don't know how to fit those pieces together."