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January 28-30th Possible Nor'easter


Rjay
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4 minutes ago, Nibor said:

I don't know where this thought process came from but I wish it would go away.

 

 

https://ams.confex.com/ams/27WAF23NWP/webprogram/Handout/Paper273676/GFS4cycle_2015_NWP_Chicago_15A.pdf

 

All cycles have been steadily improved. • 12Z cycle is comparable to 00Z cycle. • 06Z and 18Z cycles are worse than 00Z and 12Z

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1 minute ago, Jt17 said:

And with 18z there isn't that much to even examine. Really the only sort of dramatic shifts were the GFS, Euro largely the same, some lesser models like Icon for example trended west, etc. really not much has happened today lol, just 1000s of anxiety filled messages across a few subforums. 

Right the GFS is the odd person out.  Also check the above PDF from the pros, it's pretty clear cut that the 6z and 18z have far lower verification scores, I'm not sure why anyone questions it anymore.

 

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This paper should be the go to for verification scores of the GFS.

 

In contrast to the NH, in the SH there is no systematic differences between the four cycles except that the 06Z cycle is slightly worse.

 

GFS 06Z and 18Z cycle are less skillful than the 00Z and 12Z cycles. • The difference in the NH is the largest

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• 06Z data count is always less (10~30%) than other cycles. • Even though the 18Z-cycle forecast score is worse than that of the 00Z cycle, 18Z conventional data count is not less than 00Z data count!

 

Note even though the total number of land soundings is almost the same among the four cycles, 06Z and 18Z have much less land RAOBs than the 00Z and 12Z cycles !

 

Among the four cycles, there is no difference in land Sfc and Marine Sfc data counts. • 18Z has the same amount of Aircraft data as the 00Z does, but has worse forecast skill scores. • 12Z has less Aircraft data than 00Z, but has similar forecast skill scores to 00Z. • Difference in Aircraft data cannot explain forecast skill differences between 00Z/12Z and 06Z/18Z cycles.

There is no difference in satellite data count among the four cycles. • 18Z and 00Z have the same amount of conventional data, but 18Z has worse forecast skills than 00Z. On the other hand, 12Z has less conventional data than 00Z, but 12Z and 00Z have similar forecast skills. • 06Z and 18Z cycles have 10 to 20 times less land rawinsonde observations than the 00Z and 12Z cycles. Is the lack of RAOBS responsible for the lower forecast scores of the 06Z and 18Z cycles? More investigation is required to understand its impact.

The forecast skills of GFS 06Z and 18Z cycles are not as good as that of the 00Z and 12Z cycles. what are the benefits of running these two extra cycles of forecast ?

 

06Z and 18Z cycles are significantly worse than 00Z cycle for forecasts up to 6 to 7 days.

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4 minutes ago, LibertyBell said:

This paper should be the go to for verification scores of the GFS.

 

In contrast to the NH, in the SH there is no systematic differences between the four cycles except that the 06Z cycle is slightly worse.

 

GFS 06Z and 18Z cycle are less skillful than the 00Z and 12Z cycles. • The difference in the NH is the largest

Are you talking about the one by Dr Yang in 2015?

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36 minutes ago, LibertyBell said:

It's true, someone posted the verification scores of the GFS and the 6z and 18z consistently ranked as the lowest.

So I’m sure saying that the “6z and 18z is less than useless” is a bit intentionally hyperbolic but even if the skill is lower than the other run times I think disparaging it is a bit silly, all things considered. 

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3 minutes ago, jdj5211 said:

GFS is off and running...one of the bigger runs of the season!  The weenie in me is pumped!

Well it would be nice to quickly reverse the trend. But wobbles often come in clusters of successive runs. I wouldn't be shocked if the GFS is similar or worse this run. But we can still recover from this point. By tomorrow and especially Wednesday it will be increasingly difficult to recover if the consensus is OTS.

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11 minutes ago, White Gorilla said:

I am prepared for any outcome... from cirrus to blizzard.  No expectations.  Just roll along with what is and what will be.  Tracking is still fun and interesting. 

This is awesome.  Literally the whole post, but especially "Tracking is fun and interesting."  sounds like a mantra from a self help audio tape for those with snow-related disorders.

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9 minutes ago, kat5hurricane said:

GFS is doing the windshield wiper thing. Went well east at 18z then back west at 00z. Still way too early to make any determination.

 

It would be nice to see the CMC somewhat hold serve since it sniffed out this thing first.

 

We still have a few days to track it. Alot more up and downs. 

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