Models on Possible Bookend Northeast Snowstorm

So the computer forecast models have been waffling this week with a possible "bookend" snowstorm in the Northeast, to compliment the October snowstorm we had here in Central Pennsylvania last Fall. A bookend storm would satisfy the wooly worms, but meteorology doesn't usually work that way.

Nonetheless, this morning the models are coming together (GFS shown above, NMM below), both saying that a fairly widespread area of Pennsylvania and New York will see snow this weekend, and it will likely accumulate to several inches in higher elevations. And so in this morning's news team meeting here at AccuWeather, it was the first time that our meteorologists seemed excited about it, although Henry is still pessimistic; our forecast as of Friday morning has about 2.5 inches for the Johnstown, PA area on Sunday, followed by another inch or two Monday.

My experience with the models this season has taught me that the GFS and NMM models don't have a great track record of accuracy, though I don't have any proof of that. They may continue to waffle, although it's worth noting that the more-accurate ECMWF (European) model is also predicting heavy snow over western Pennsylvania.

Models aside, it certainly can snow this time of year. More than a foot of snow fell in PA & NY on April 23, 1986, nearly that on April 22, 1993; in Warren, OH nearly 3 feet fell on April 20th, 1901 with 13.5" at Pittsburgh! (if you want to go back into the Little Ice Age, you can find the ground covered in PA & NY in May 1774 and 1812). And remember it snowed here in Central Pennsylvania in May 2009:

I'd rather take what the GFS& NMM say with a grain of meteorological salt, and wait for the 4-KM WRF models to come in (they predict 48 hours ahead, so that won't happen until Saturday or Sunday morning (the models above are predicting the snow either Monday or Tuesday night). Stay tuned to the Pennsylvania Storm Chasers Group on Facebook this weekend for additional model updates from me. In the end, it will probably snow somewhere, at least a few inches, but I can't guarantee it will be in a populous area like the Fall snowstorm was.

For more meteorological discussion on the snow, check out Elliot's blog and Henry's report and Facebook Page.

But before we get excited about the snow, we have to get the front through Pennsylvania; it could feature a squall line of storms, but right now the 4-KM WRF says that the line will fade before it gets into the state and not reappear until it gets into southeastern PA (the lighter simulated radar is the later one):