How We Went From Little Snow to Major Storm Estimate | NBC 10 Philadelphia

How We Went From Little Snow to Major Storm Estimate

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    How Did We End Up With Big Snow Predictions?

    It looks like another Category 5 (crippling) storm on our Winter Storm Scale for a good bit of the area Sunday into Monday.

    EarthWatch Forecast: Crippling Snowstorm Approaches

    [PHI] EarthWatch Forecast: Crippling Snowstorm Approaches
    NBC 10's chief meteorologist Glenn "Hurricane" Schwartz gives his latest forecast, which anticipates 10 to 20 inches of snow for some parts of the Philadelphia region. (Published Saturday, Dec. 25, 2010)

    Snow could fall at 2 to 3 inches per hour plus thunder is possible at the peak of the storm Sunday evening -- during the Eagles game with near-blizzard conditions -- and overnight.

    There could also be moderate coastal flooding and beach erosion likely as well.

    Shovels? Check. Rock Salt? Check. Get Ready to Be Snowed in!

    [PHI] Shovels? Check. Rock Salt? Check. Get Ready to Be Snowed in!
    A crippling snowstorm is just hours away. It could dump a foot or more on parts of our region forcing emergency crews and average joes into preps. (Published Saturday, Dec. 25, 2010)

    How did we get to this point, when most forecasters even at 11 p.m. last night were calling for the storm to move out to sea, just "brushing" the area with a little snow (maybe)?

    As I've mentioned in previous articles, this has been a wildly inconsistent week for the world's computer models. Practically every one has flip-flopped at one time or other. First, it was the overall best model, the European, which had a major snowstorm predicted even early in the week. But it was the only model with that prediction; so many forecasters just ignored it (I have learned to never ignore the Euro when it says the same thing half a dozen times in a row).

    Then, the Euro flipped to the out-to-sea track Wednesday night and Thursday, two runs in a row. By that time, every model was well offshore, so we pretty much gave up on the storm Wednesday night.

    At the same the Euro was bailing out on the big snowstorm idea, the main U.S. model, the GFS, suddenly came to the big snowstorm solution. But since it was the only one suggesting it, most forecasters ignored it.

    The computer folks in Washington, D.C. even issued a statement saying that there were "Initialization errors in numerous diagnostic quantities… thus the specific predictions are in question." They were basically saying: "garbage in, garbage out," so ignore the model. I even put that statement up on the air Friday at 6 p.m.

    But everything changed Friday evening. Other models came on board the big snowstorm solution, and I upped my probabilities for a major snow for the I-95 corridor (the Philly area included) significantly. To my shock, it seemed no one else even mentioned the POSSIBILITY of a big snowstorm in Philadelphia.

    It was Christmas Eve and many people didn’t catch my 11 p.m. prediction for snow. So Christmas Day, there was the sudden shock of a big snowstorm for most people.

    As I write this Saturday afternoon, not a flake has fallen yet, so I won't come to any strong conclusions. But I've never seen anything this wild so close to the start of a big storm.

    Maybe just enough kids wished for snow on Christmas weekend.


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