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December 2019 Med/Long Range Disco


Bob Chill
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31 minutes ago, Ji said:
37 minutes ago, stormtracker said:
It’s the only one that far NW.  either it’s a pioneer or pure carp

I mean it gave us 5 inches at 00z last night. Its constantly overdoing something. Fv3 was stubborn last year but always need up being wrong. The model is broken

Did you see what the euro gave us 3 days prior to the storm?

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59 minutes ago, C.A.P.E. said:

Slight difference of opinion.

Beware the FV3 cold bias in the long range.

I would bet its wrong, it also has an over amplification bias and that is more in play here, but it's the solution it comes up with day 5 that leads to that day 10

48 minutes ago, jaydreb said:

Ok, I guess I’ll side with PSU and trade in next week’s 2-4”.  

The whole sacrifice thing is just a mental exorcise since we don't get to choose...but I would root for the GFS progression.  I doubt it is correct but if storm 1 phases with the TPV and pulls it under the block into a 50/50 position...that really does set up a classic HECS look.  

You can see the GFS scenario below

The GFS phases the system into the TPV in Canada.  This will amplify it, consolidate it, and pinwheel it east into a 50/50 location.  This also prevents the TPV from pulling west and feeling into the trough along the Pac.  

GFS1.thumb.png.766988464ed6570ec748f67cf7df8c93.png

GFS2.thumb.png.6498a4714612bf3eec9d86c0981fff38.png

GFS3.thumb.png.7056f72223a2b19f87a78294bae3196a.png

This sets up the HECS look with a massive 50/50 under the blocking and very little of the TPV left in Canada to interfere and or feed into the western trough.  That allows the energy out west to cut underneath.  

In the next post I will show what the euro does instead...

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Instead of phasing the euro suppresses the system and the TPV elongates and splits but the major piece retrogrades west and feeds into the PAC trough.  This pumps a full latitude ridge across north America and with no monster 50/50 its game over.  We would eventually recover as that ridge lifts and the pacific energy cuts under but that would take a week or so.  

Euro1.thumb.png.99c14ff026d1802d84b8a2d8ff0e2add.png

Euro2.png.a341190c9779144bd84cb947e5d8e88e.png

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Just now, psuhoffman said:

Unfortunately everything other than the gfs agrees with the euro progression so this is probably a moot point and we should root for whatever we can get from storm 1. 

Whatever is gonna happen will happen regardless, as we all know.

That was a nice discussion/illustration btw, but would have been better using the Ens runs rather than the op runs, which can and do change pretty dramatically from run to run..

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7 minutes ago, C.A.P.E. said:

Whatever is gonna happen will happen regardless, as we all know.

That was a nice discussion/illustration btw, but would have been better using the Ens runs rather than the op runs, which can and do change pretty dramatically from run to run..

I thought of that but since both ensembles generally agree with the respective op runs...and the features I was trying to show are clearer on the ops (not washed out) I went with that.  I wasn’t trying to endorse an op run at range as likely.  I suppose some will interpret it that way but oh well. 

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23 minutes ago, Bob Chill said:

Being honest with what I'm seeing... Ens are starting to converge on AN temps leading into and on Christmas. Still a lot of time for changes and not spiking any footballs but the pattern progression makes sense and imho it's becoming more likely as the days go by. 

Almost to be expected.  We will win the war if we lose the battle.  Doesn’t look like an inferno based on what I saw on 18z GEFS.  Not yet anyway.  

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Not sure the outcomes are really set in stone for the 12/21 threat period. 

Blocking will continue to evolve further and possibly even more significantly.   I realize the Euro has better verification scores but with a period of high model volatility I would be open to any outcome. 

There is also some downward coupling from the weakened pv, coming up in the next 10 days. Afterwards, it is appearing the vortex gains strength per Amy.  

 

 

 

 

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1 hour ago, Bob Chill said:

Being honest with what I'm seeing... Ens are starting to converge on AN temps leading into and on Christmas. Still a lot of time for changes and not spiking any footballs but the pattern progression makes sense and imho it's becoming more likely as the days go by. 

It may be unscientific, but if the Pac puke is inevitable, I kind of feel like I just want it to go ahead and get it over with so we can move on.  The bad thing is, there is no guarantee that we move on.

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29 minutes ago, frd said:

Not sure the outcomes are really set in stone for the 12/21 threat period. 

Blocking will continue to evolve further and possibly even more significantly.   I realize the Euro has better verification scores but with a period of high model volatility I would be open to any outcome. 

There is also some downward coupling from the weakened pv, coming up in the next 10 days. Afterwards, it is appearing the vortex gains strength per Amy.  

 

 

 

 

Massiello nailed the blocking episode mid month when he was all alone on that. Impressive. 

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17 minutes ago, cbmclean said:

CPC NAO outlooks range from "hmm" to "ugh" with a mean of "meh".

 

The December -NAO has become a Unicorn this decade.  There seems to be some support moving later in the winter for a decent -NAO period, but so hard to predict even at short leads, seasonal NAO calls even more challenging.  

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Just now, psuhoffman said:

Massiello nailed the blocking episode mid month when he was all alone on that. Impressive. 

Sorry for the ignorance on my part, but the blocking that you are referring to, I am not seeing anything showing up on the NAO forecast, and I was under the impression that it was the teleconnection most reflective of the kind of blocking we (eastern CONUS) like to see.  I did note a predicted nice little negative event on the AO, but I thoght taht teh AO reflected the strength (or lack thereof) of the polar jet stream.  Is it also conencted to "blocking"?

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3 minutes ago, psuhoffman said:

Massiello nailed the blocking episode mid month when he was all alone on that. Impressive. 

Yes, he gets these " not in consensus calls"  right a decent amount of the time .  I recall many of these the last 10 years. 

I wish he would put up when our KU window is. LOL  Also his mid December shoveling reference made about a month ago (  although not a forecast )  fits as well , with this past week's snows in areas to our East and NE. , and also what might be coming up next week too. Not bad. 

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Just now, psuhoffman said:

The h5 look matters a lot more than that chart. Guidance all agrees with a west based block. Unfortunately most guidance ruins it with a hostile pac.  

Well that is what confuses me.  The chart mentioned that it is defined at 500 hp as opposed to the older 1000 HP.hp.  So are you just saying that the index, at whatever level it is taken, only gives a very rudimentary approximation of the state of blocking?

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