Joaquin: Europe rules?

Evidently European model is pulling off another forecast triumph.

The message was ominous, about the worst news possible for one of the nation's densest population corridors and developed coasts.

"A significant adjustment to the forecast has been made this afternoon," the National Hurricane Center reported at 5 p.m. Wednesday, "and this shows an increased threat to the mid-Atlantic states and the Carolinas."

The anxiety storm was predictable. But the hurricane center added a couple of important caveats, among them:

"However, confidence in the details of the forecast … remains low, since we have one normally excellent model that keeps Joaquin far away from the U.S. East Coast."

That computer model was run by the European Centre for Medium-Range Forecasts, viewed by many in the meteorological community as the world's best.

For an excellent treatise on computer models and why the European is better, we refer you to Glenn Schwartz's fine blog post.

Computer models depend on initialization – that is, observations that capture the initial state of the atmosphere. It's impossible to know what the atmosphere is going to do without knowing what it's doing now.

As Schwartz notes, the European does a better job at initialization. It was the European in 2012 that first nailed Sandy's counterintuitive jog to the west.

So why didn't the Hurricane Center just go with the European?

First off, unlike the visitor who was in Philadelphia last weekend, the European is fallible. In January, for example, it had Philly buried under 30 inches of snow; that didn't quite happen.

Plus, as late as Tuesday it was among the several models that had Joaquin slamming into the East Coast.

But it quickly broke ranks, said Andy Mussolini, and foresaw Joaquin's becoming a fish storm.

The hurricane center opted to stay with the consensus, noting in its various advisories that the outcome was highly uncertain.

One other important point, raised by William Lapenta, head of the National Centers for Environmental Prediction: It isn't over yet. Joaquin remains days away from the Midatlantic.

"One should never verify a forecast with a forecast," he said in a statement. That said, the European has done a better job on Joaquin's track so far, said Andy Mussolini, a meteorologist at AccuWeather Inc., the commercial service in State College.

AccuWeather tends to give more weight to the European, he said, but no model is perfect.

"I wish there was a computer model that was right all the time," he said. "That would make our life easier."