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December Med/Long Range Disco


WinterWxLuvr

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GEFS is faster than the EPS. I suppose we should go with the rule of thumb that things are probably rushed as usual with an overall lw pattern shift. d11-15 mean on the GEFS is certainly not hideous. EPS is moving in the same direction but not in the same time frame. 

 

gfs-ens_z500a5d_nhem_3.png

 

Problem is that is still warm for us which I am guessing will be an ongoing narrative this winter....

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Problem is that is still warm for us which I am guessing will be an ongoing narrative this winter....

 

It is during that time frame for sure. But it's a bit of a stepping stone getting the pac in a better setup to get some cold air building in our source region (cold being a loose term. lol). Amplify things in the east and it can dump. I'm mostly looking beyond ens range because inside of the next 15 days aint very pretty. haha. 

 

Looking at last night EPS mean 850 temps starts looking MUCH better through d10-15 compared to the period before it. The short story is without an epo ridge, we are going to suck it unless we get a real -nao and/or ao. To my eyes, the progged drop in the nao is a byproduct of the big flat ridge in central Canada overlapping the nao domain space vs something more traditional. 

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Not sure where this post should go as it's not a true discussion of the medium/long range though right now I think the latest GEFS ense mean looks pretty hostile through the period and if anything has a more positive AO this run than the last few and also has a roaring, colder and deeper stratospheric vortex than normal which is not a good thing.  The run does show higher heights poking into AK which would probably be a good thing.  I'll be doing a 2 week outlook either Wed or Thur and will discuss the pattern more. 

 

This post is really an attempt to look at the anomaly pattern of all the enso events with and D-F ONI greater than 0.50, most but not all would be classified as Nino years so I've simplified the graphics and called composites Nino composites.  The first one I show is the Nino year composite 500h years with less snow than normal.  Note there were two general looks to the composites.  One with higher than normal heights across the polar region (a negative AO) and one with below normal heights (a positive AO).  It's easy to understand why the latter didn't produce much snow.  The cold air would tend to stay locked up in Canada.  The negative AO years are tougher to fathom.

 

post-70-0-43672600-1448906602_thumb.png

 

The second graphic is the snowy years.  The top graphic on the left is all the snowy NIno years except 1965-1966 which had a negative PNA and negative AO with its positive  anomaly across Greenland very similar to that of the other snowy years.  The bottom figure is another look at the composite for the non snowy years that had a negative AO.  One difference is that the snowy years had a stronger southern stream as seen in the larger negative height anomalies across the south.  The other difference was the lack of a strong negative anomaly south of the Aleutians. I'm not sure hwo significant that might be but found it interesting.

 

post-70-0-94742000-1448906720_thumb.png

 

The final graphic is 1997-1998.  The anomaly patterns weren't that different than for the good snow years though the positive anomaly across the north was not as impressive across Greenland and was concentrated more over Canada than the snowy years.  ALso the strong negative south of the Aleutians was a little farther east.  Temps across the northern U.S. into our area were toasty.

 

post-70-0-26614400-1448907251_thumb.png

 

So what am I saying,  even with a negative AO, a snowy winter in an El Nino year is not a given even with a nice strong southern storm track.  I'm a little worried about the AO this December as it looks like it will end up positive certainly for the 1st half of the month. 

 

HOw's this post for wasting your and my time? 

 

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Nice post, Wes. Reinforces the fact that Dec isn't looking like it starts off with good company in the history dept. We have a very long way to go to move towards any type of weak strat pv and stable blocking pattern. If it never happened this winter I wouldn't be surprised at all.

If we can't get rid of it, our best hope is for it to get shoved out of the Nao and EPO regions.

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Nice post, Wes. Reinforces the fact that Dec isn't looking like it starts off with good company in the history dept. We have a very long way to go to move towards any type of weak strat pv and stable blocking pattern. If it never happened this winter I wouldn't be surprised at all. 

It could happen. It will be a good test of Cohen though last year we didn't get a negative AO and the vortex was stronger than normal except it was more elongated and ridging developed and persisted over AK and western North America.  Not sure the stratospheric vortex being strong negates the possibility of getting a negative AO but it probably lowers the probability if it continues to stay strong like the ensembles are predicting.  I guess the good news is that we don't know how good the models are at predicting the strength of the vortex.  Still it looks like the 1st couple of weeks of Dec will be rough sledding. 

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It could happen. It will be a good test of Cohen though last year we didn't get a negative AO and the vortex was stronger than normal except it was more elongated and ridging developed and persisted over AK and western North America.  Not sure the stratospheric vortex being strong negates the possibility of getting a negative AO but it probably lowers the probability if it continues to stay strong like the ensembles are predicting.  I guess the good news is that we don't know how good the models are at predicting the strength of the vortex.  Still it looks like the 1st couple of weeks of Dec will be rough sledding. 

so you think we will be sledding soon but it may be a big rough?

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Nice post, Wes. Reinforces the fact that Dec isn't looking like it starts off with good company in the history dept. We have a very long way to go to move towards any type of weak strat pv and stable blocking pattern. If it never happened this winter I wouldn't be surprised at all. 

 

 

It could happen. It will be a good test of Cohen though last year we didn't get a negative AO and the vortex was stronger than normal except it was more elongated and ridging developed and persisted over AK and western North America.  Not sure the stratospheric vortex being strong negates the possibility of getting a negative AO but it probably lowers the probability if it continues to stay strong like the ensembles are predicting.  I guess the good news is that we don't know how good the models are at predicting the strength of the vortex.  Still it looks like the 1st couple of weeks of Dec will be rough sledding. 

 

Grit tweeted this out....yikes.  One positive is it can only get better.  

 

Edit:  I wonder if the lack of nino forcing in Nov helped this...now that Nino is kicking in we need that along with snow cover to do it's thing.  Looking at Cohen's precursor we atleast got the SLP over AK right but lacking Barents Sea/Siberia high.

post-2311-0-48635000-1448913140_thumb.pn

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There is just no end in sight of this crap pattern on the models, going to be a long month for us winter weenies most likely. I'd rather a winter with 1-2 big storms surrounded by warmth than a cold winter with a bunch of small nuisance type snows anyway, so if it turns out we get a month of winter and score one huge event, I'd be satisfied. 

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Tonights GFS in lala land looks ridiculous as you reach Day 11 and 12... winds up a 969mb SLP system in W MI with 516 DM heights... and is that part of the PV that shows up in Quebec on Day 13?

 

Yes, its la la land, but it looks interesting nevertheless... looking at the h5 maps, I think that we would be entering a bit more favorable pattern for us to get something if the GFS were right that far out in la la land... which the GFS does show at the end of the run re snow :lol:

 

EDIT:  It also looks like the GFS is finally bringing the cold air at the end of its run... nothing too wacky... but some -8 to -12 850 temps start showing up in the Northern Plains

 

Hopefully, I interpreted that run correctly... if I didnt please let me know ;)

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6z GFS says slow your roll player at the end of it's run and continues the s***show...perhaps the ensembles will provide some hope.  I am looking for anything at this point which will negate the need for open windows and shorts Xmas week.

 

:huh:

 

The end of the run to me is pretty decent

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Even before that, Bob.  you can see how the +NAO breaks down to finally get some cooler air to filter in.  That part has been so hostile of late and through next week.  Each day has this starting around the same point in time which might be a sign that it sees a change in pattern.  Its not constantly getting pushed back

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I don't think we get shutout, but I don't think we rock this month either.

 

A complete shut-out (0 snow or sleet) is rare, but no measurable has a 23% chance in any given year based on the entire historical record, and a 30% chance based on the 1981-2010 period.  Right off the bat.  This year those odds are elevated, for sure.

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I'm not mad at the fantasy -nao and 1050+ hp anchored over the GL ice cap on the gfs

 

gfs_mslpa_sd_nhem_51.png

 

 

We've seen a lot worse, that's for certain!  Ignoring the eye-sore that is the 970 Great Lakes low :lol: , it is indeed nice to see at least a fantasy -NAO and a huge high over Greenland late in the GFS run.

 

 

Even before that, Bob.  you can see how the +NAO breaks down to finally get some cooler air to filter in.  That part has been so hostile of late and through next week.  Each day has this starting around the same point in time which might be a sign that it sees a change in pattern.  Its not constantly getting pushed back

 

Yeah, I have to admit that the GFS the past couple of days has been showing glimmers of hope beyond about mid-month.  Nothing spectacular, mind you, but something that leads one to hope for better changes down the road rather than a wall-to-wall Pacific firehose.  It remains to be seen, of course, if there's any validity to this, but it will keep me looking at least.

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