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March or BUST! - Pattern & Model Discussion


Baroclinic Zone

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When looking at the upper air maps between the Ukie and Euro....Ukie has the northern stream a solid 100-150 miles W of the euro at 72 hours over Lake Superior.

 

That northern stream shortwave is currently just south of Alaska....it then takes a lonely journey over the Yukon and NW Territories before finally emerging over north Manitoba at the 48 hour mark at 12z Sunday....so this one could have some wrinkles given the path it takes. Maybe Chris has some insight on the sensitivity data...obviously the ridge out west is an important factor....perhaps more important than the northern stream shortwave itself. But don't be surprised if models don't handle this well because of how sparse the region is that the northern stream is navigating over the next 48 hours.

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4 minutes ago, rnaude241 said:

How big of a shift from 00z? 50-100 miles?

The precip shield probably jumped 200 miles NW from the 00z run looking at 96 vs 108....but this was caused by a mere 75 miles or so shift in the northern stream being west of 00z at 72 hours....so the changes early on get amplified later on the ground. I would say the ridge out west wasn't even quite as good as the 00z run so the position of the northern stream on this run is what was doing the leg work.

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3 minutes ago, dryslot said:

I consider a correction when you have the model showing a solution for a few runs only to shift on a run east or west, Then go back to what it had previously.

I think anything could be a correction if it ultimately proves to have reflected the actual outcome.  You kind of have to compare the output to the reality it’s modeling.  Otherwise it’s not a “correct”ion, it’s a change. 

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1 minute ago, JBinStoughton said:

I think anything could be a correction if it ultimately proves to have reflected the actual outcome.  You kind of have to compare the output to the reality it’s modeling.  Otherwise it’s not a “correct”ion, it’s a change. 

To technical.

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Agree with Will ... the "journey" the N/stream must take before plunging S to/over the Lakes may be sensitive to sparseness/assimilation and should bear in minds as having some importance...  

The western ridge handling during this PNA spike (I feel) is hugely important... It could come in suddenly more robust over the weekend (which I'm 'almost' suspecting it will but not fully so), and when/if that happens, obviously wave mechanics forces deeper digging downstream ... therein, effecting any phase potential/proficiencies. 

There are a lot of moving parts to the Sunday night through next Wednesday period of time.  

.. Said N/stream handling

.. The S/stream handling

.. The interaction between these two above being critically dependent upon the handling of either, individually then in unity.

.. The NAO's status is not abundantly clear, but the GEFs derivatives have the current -NAO decaying to a "tendency -NAO" ...  if that makes any sense. NCEP noted that tendency yesterday... and all that means is that we are not really in hurry here to lose it's influence/vestigially/entirely.  Which can effect matters along and off the EC in perhaps more subtle ways... 

..  This one I have just sort of realized this morning when studying the charts.  It seems the models are in limbo between that NAO handling and the faster flow that is hinting at taking back over from west to east across the N/A domain space. The NAO (west based negative) is a slowing influence... as these recent events have demoed rather nicely... But come early to mid week, the NAO's is relaxing toward said status, and it really more than just seems that proportionately... as that happens, the wave translations speeds (how fast S/W ripple along in the flow) is speeding up. That is bad for phasing; the S/stream simply outpaces the N/stream when that happens, because it doesn't give the N/stream time move south and begin subsuming.  It's really that the L/W morphology is slower than the S/W translation speed, and that mitigates union of streams... (there's a paper in this!)  I'm not ready to say this is all in error.  After all, the base-line state has been fast fast fast for years ... YEARs at this point. I have got no reason to presume that as the NAO's influence weakens (but not totally) that the flow may re-establish in concert - it certainly could and probably will.  However, it could also just mean reduction of stall chances...  

If the NAO's influence is weak, and the ridge in the west bumps stronger, the N/stream will dig fast and offset the speedier S/stream and we'd probably get a partial phase that way, with a correction toward somewhat more impact in the days to come. 

If the NAO's influence is bit more stronger, and the rest of all that is more true, ...then we could certainly get a slower system with have better phasing potential.. 

If the NAO's influence is weak, and the ridge in the west doesn't help out more so then we already have seen depicted in the models, we would likely end up with the flat wave with dim sun and gelid breezes in wait for the faux spring warm up over the following weekend.  Real entertaining!   However, I feel the +PNA spike should be more prepresented on the flow over N/A than all that, so I put this at 20% and some variation of the former two at 35 each.  The remaining 10% reserved for the fractals.  

 

 

 

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