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00Z Model Suite


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This NAM run has a far more impressive upper level jet coupling. I think this will end up a lot better than 18Z.

I dont know...I agree it looks a LOT better, especially at upper levels, but it would almost have to go ridiculously negative and back in from where it is to make any difference for DC, Baltimore, and Philly.

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I have read on here multiple times that past 48 the NAM is pretty worthless...or at least not that great of a model.

Is it possible, considering all the noted changes for the better up till 42, that this is just outside of the NAM's good range, and that explains it falling apart at that point?

Not really. All models get progressively worse as you go off into the future, including the NAM. Its accuracy doesn't just suddenly drop off significantly after a certain hour.

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Not really. All models get progressively worse as you go off into the future, including the NAM. Its accuracy doesn't just suddenly drop off significantly after a certain hour.

This isn't very true. The GFS goes out to 384 hours, so we should expect half of a model's run to USUALLY be fairly accurate. With the GFS, that would take us to 192, which is an interesting number, because that's where truncation occurs. With the NAM, the halfway point would be 42. I know the NAM doesn't truncate, but normally when you get more than halfway out in a model's run, the accuracy begins to decline sharply, almost like your car's gas gauge (on the older cars at least), when it gets near half.

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MUCH better low placement at 66, bringing snow to far eastern Md, far ne Va, De, and just touching Se NJ shore......BIG difference from 72 18Z

Very true. I know one means it's cloudy and the other means mostly sunny, but the results are VERY different. One run ago, the NAM was a miss by a LOT. This one is a near-miss. One more run with the same trend is a hit!

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Looks yet again like mystery vort energy kicks off another low and thunderstorm activity south of the Cape Hatteras low and robs from it. This would probably be a more impressive solution without those mystery vortmaxes over the Atlantic. The jet and energy overall look much more impressive this run than last.

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This isn't very true. The GFS goes out to 384 hours, so we should expect half of a model's run to USUALLY be fairly accurate. With the GFS, that would take us to 192, which is an interesting number, because that's where truncation occurs. With the NAM, the halfway point would be 42. I know the NAM doesn't truncate, but normally when you get more than halfway out in a model's run, the accuracy begins to decline sharply, almost like your car's gas gauge (on the older cars at least), when it gets near half.

Well yeah, I wasn't arguing that it decreases linearly the entire time the model runs. Rather, there is no given "hour" where it suddenly becomes terribly inaccurate.

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Looks yet again like mystery vort energy kicks off another low and thunderstorm activity south of the Cape Hatteras low and robs from it. This would probably be a more impressive solution without those mystery vortmaxes over the Atlantic. The jet and energy overall look much more impressive this run than last.

Convective feedback?

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