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Pattern The Great December Dump

The differences between the Euro & GFS really are stark even at day 5. Euro digs our shortwave of interest into the southwestern US while the GFS progresses the wave out into the southern Rockies & phases w/ the longwave trough over the plains & south-central Canada.

Timing is everything in this pattern

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Webberweather53 said:
The differences between the Euro & GFS really are stark even at day 5. Euro digs our shortwave of interest into the southwestern US while the GFS progresses the wave out into the southern Rockies & phases w/ the longwave trough over the plains & south-central Canada.

Timing is everything in this pattern

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Webb, is timing ever not everything?
 
The GFS seems to be heading for a dud. I'm noticing one big error with the low that can be traced back even before 48hr. Notice that big low off the coast of CA and OR. The GFS has it subtlely further east so the energy phases and goes North well out of our way. The Euro luckily is much further west, so it becomes a cutoff low and digs.

Luckily we have the euro on our side and the usual problem of a sustainable high has high confidence according to Webb. I think models should cave to each other within a day or 2. Subtle changes are extremely important!
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Sleet City USA said:
Webb, is timing ever not everything?
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It's even more important here imo in this kind of pattern because the northern stream waves are moving very quickly in the mean stream flow. In a more classic -NAO pattern which decelerates the northern stream & the southern stream is often more prominent, our windows to fit a storm are typically larger although the air masses that come with them are marginal.
 
I’m ready to see what the GEFS has to say about this wether it will say the GFS is wrong or back the GFS
 
So the big takeaways that I got here is that the right pattern for a storm is coming and all we need is good timing. Honestly despite the fact that it's currently a day 6-8 affair and that the GFS is poop, I honestly think this should be watched and not dismissed, unless ofc everything goes poof on the next runs.

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Webberweather53 said:
It's even more important here imo in this kind of pattern because the northern stream waves are moving very quickly in the mean stream flow. In a more classic -NAO pattern which decelerates the northern stream & the southern stream is often more prominent, our windows to fit a storm are typically larger although the air masses that come with them are marginal.
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If you think about it in this manner: during -EPO/+TNH we have a stronger height and temperature gradient between us and central Canada, this height gradient means the jet stream is stronger and so are the corresponding winds >>> faster moving shortwaves. On the other hand, with -NAO and Baffin Bay blocks theres typically a “traffic jam” immediately upstream over North America that slows northern stream waves down a lot and the height gradient is also weaker. The subtropical jet (STJ) on the other hand is much stronger as -NAOs are often a symptom of El Niño or a sub seasonal convective boost from the Pacific & W hem which “juice” the STJ.
All of this really means the phase speeds of the waves in the two streams are often more comparable in -NAOs vs +TNH/-EPOs, thus there’s inherently a larger window of time for phasing &/or interaction between the polar and subtropical jet as long as their initial placement is roughly the same.
 
And I have seen this movie before. One model, this time the GFS, shows a storm in the long range, at least 14 days out, only for it to go poof, and then another model, this time the Euro, shows it out of nowhere inside 10 days. And then the one that showed it in the long range eventually shows the storm again when we get closer.
 
Brick Tamland said:
And I have seen this movie before. One model, this time the GFS, shows a storm in the long range, at least 14 days out, only for it to go poof, and then another model, this time the Euro, shows it out of nowhere inside 10 days. And then the one that showed it in the long range eventually shows the storm again when we get closer.
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Sounds familiar ??
 
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