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January 2021 Medium/Longterm Pattern Discussion.

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I think a lot of this has to do with the MJO being predicted to go phases 5/6 which are very warm vs the -NAO which is quite negative.  One thing I notice is the variations in the Pacific trough.  As Webber noted, there is super fine line between cold and total torch and nothing in between after d10.  If the ridge, like the EPS, sets up closer to the Pac Coast....the trough will extend eastward in a 95-96 fashion.  The GEFS is nearly a completely different solution with that eastern Pac ridge.  Again, I tend to support the EPS solution.   I feel the Euro stuff has superior physics when it comes to juggling multiple features:  SSW, conflicting Pac/Atl features, changing wavelengths, etc.  It is not infallible, and I definitely don't hug that model.  However, I think the idea that cold pushes eastward is legit.  

As a side note, take some time and go back through the winter run-up thread.  I think our ideas from that thread(dating back to summer and earlier) have been really good and have encompassed a lot of what has occurred this winter.   

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12z CMC has the same piece of energy but gets the hp out in front to the storm and creates a CAD situation east of the Apps.  Definitely something to be watched with that much higher pressured to our north.

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Minus the real cold, can't complain up here snowfall wise, "yet", lol.

    We have saw warm , -NAO linkage , MJO finally gaining Amp. out of COD, on  models more than once so far this Winter and it didn't happen.  So, even though I'm more Leary this time, especially with the Niña Aleutian ridge in place now. However, I'm still leaning somewhat in favor of a similar thing happening this go around. EPS ftw, 60/40 %.

     Main thing to watch I believe is the MJO . As Carvers aluded, is prob. what is causing the warm east progression. That and of course the Pac Ridge position , of which proximity of MJO would affect as well, along with Niña forcing. 

   

      

      

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Of note the 12z GFS is significantly colder than other modeling after 180.  Let's see if the Euro supports it at all.   The GFS has a tendency to spot cold shots first, but the CMC is not supporting it which makes me wonder if it's a red herring.

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12z ICON does lend some support to the GFS with the big 1044 high over the top late in its run.   IF that high is real, that is going to be factor and a nice improvement.  

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For NE TN folks, that little shot of precip over night is showing up as accumulating snow for portions of NE TN on the Euro and ice on the GFS.  The 12z RGEM also has wintry precip for portions of NE TN.  Something to keep an eye on....could make the morning commute interesting.

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For NE TN folks, that little shot of precip over night is showing up as accumulating snow for portions of NE TN on the Euro and ice on the GFS.  The 12z RGEM also has wintry precip for portions of NE TN.  Something to keep an eye on....could make the morning commute interesting.

Certainly another sneaky system that has the chance to over-perform for us. NAM isn’t as enthused.
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I seem to recall seeing models trying to cut storms straight towards big highs in the past like the Euro does around 192-198. I don't think it ever has actually worked that way when it came verification time. With a -NAO and a HP north of it I just don't see the storm running up through from the Gulf to Eastern Kentucky.

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1 hour ago, 1234snow said:


Certainly another sneaky system that has the chance to over-perform for us. NAM isn’t as enthused.

I’m not enthused! Winters aren’t what they used to be in East Tennessee!

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18 minutes ago, John1122 said:

I seem to recall seeing models trying to cut storms straight towards big highs in the past like the Euro does around 192-198. I don't think it ever has actually worked that way when it came verification time. With a -NAO and a HP north of it I just don't see the storm running up through from the Gulf to Eastern Kentucky.

Right with u on that buddy. I think it could be models are having a tough time balancing what a typical trough west ridge east solution with strong counter blocking. 

      I guess it could come up so far but, would then more than likely transfer eastward. Hopefully for us, if it does it'll do so b4 coming that far North.

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1 hour ago, 1234snow said:


Certainly another sneaky system that has the chance to over-perform for us. NAM isn’t as enthused.

They all except the last system overperformed here. I'm at 17.05" for the season. Probably be about half that if most models had been right , and that within 24 hrs of events. 

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The fickle MJO might exit its prolonged weak phase for phase 6. That isn't good, but several members forecast it heading toward the phases we like after that. I'm not sure what verdict that will have on our winter and how that might mitigate the Eastern Pacific being a bully, since I am so green at this.

 diagram_40days_forecast_GEFS_member.gif

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33 minutes ago, Blue Moon said:

The fickle MJO might exit its prolonged weak phase for phase 6. That isn't good, but several members forecast it heading toward the phases we like after that. I'm not sure what verdict that will have on our winter and how that might mitigate the Eastern Pacific being a bully, since I am so green at this.

 diagram_40days_forecast_GEFS_member.gif

Webb's saying that the RMMs are showing something other than a true MJO wave:

 

 

Now, is that good for us? I have no idea. I'm still not sure what the differences are between Equatorial Rossby Waves (ERs) (maybe that thingy I noted early this AM south of Baja?? which seems to have already dissipated), the "Low", or a Kelvin Wave, and the MJO. 

The MC region has a flare up again N. of the equator, though:

giphy.gif

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I mentioned this in banter earlier, but looks like we're going to ride in the SSW rodeo again:

giphy.gif

 

aapepfB.png

 

If the GFS is correct in its depiction of the MJO RMM plots/ convection/ whatever is going on, that would line up with a warming triggered over Siberia. Another High descending, another mountain torque, another jet extension, this time with a more La Ninaish N Hemisphere state (of course with a -NAO too):

giphy.gif

 

giphy.gif

 

Of course that is medium to long range, so it could change. 

Like Carver's said though, I am a more of a fan of how the EPS control bumps a ridge over the west coast as the Gulf of Alaska low rolls backwards over the Bering Sea

giphy.gif

 

 

 

 

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41 minutes ago, Holston_River_Rambler said:

I mentioned this in banter earlier, but looks like we're going to ride in the SSW rodeo again:

giphy.gif

 

aapepfB.png

 

If the GFS is correct in its depiction of the MJO RMM plots/ convection/ whatever is going on, that would line up with a warming triggered over Siberia. Another High descending, another mountain torque, another jet extension, this time with a more La Ninaish N Hemisphere state (of course with a -NAO too):

giphy.gif

 

giphy.gif

 

Of course that is medium to long range, so it could change. 

Like Carver's said though, I am a more of a fan of how the EPS control bumps a ridge over the west coast as the Gulf of Alaska low rolls backwards over the Bering Sea

giphy.gif

 

 

 

 

Saddle up.  Just remember these SE ridges that connect briefly to high latitude blocking do a number on the SPV.   Then modeling goes to crap, and we have to wait a few days for the dust to clear.  I “suspect” that recent trends towards more favorable outlooks past D10 on the EPS and GEPS are likely tied to this.  Would also likely mean the NAO is going nowhere.  Commerce model mayhem. 

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18 minutes ago, Carvers Gap said:

The 12z GEPS at 500 past d10 is a beauty.

Sounds a lot like last year. The cold was always 7-10 days away. :( Maybe it will finally happen.

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2 hours ago, Icy Hot said:

Sounds a lot like last year. The cold was always 7-10 days away. :( Maybe it will finally happen.

Nah.  Definitely is much different than last year.  We have had a lot more snow in our area.  We have a -NAO.  Pacific like last year is not cooperating.  Atlantic is nearly perfect.   I am not a fan of the SSW stuff.   I feel like that works for us sometimes.  This year, those SSWs fouled what was a good pattern.   Honestly, this year I didn't expect much.  Think my winter forecast is in the winter spec thread.  I normally don't bang my own drum, but was pretty clear that we would have long pauses between events.  Moderate Ninas are a pain.  Now, do I think we eventually get some more cold?  Sure.  I will try to link that forecast here.  Give me just a sec.... 

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I think you all need to dig back through the winter spec thread.  Lots of great thoughts there by many posters! I think most of us were super clear about the difficulties of moderate Nina winters.  I don't always get a seasonal forecast correct, but this has worked out pretty well so far regarding temp and pattern stuff.  Precip idea is too dry.  Those ideas were posted during June.  Here are some excerpts.  Can't say you weren't warned well in advance...

"Best chances for snow will occur late November into early January.  Expecting a big thaw in January this year, BUT I do think we see bouts of serious cold this winter despite my AN temps forecast.  I was really bullish at the end of last winter regarding the upcoming winter being a dud.  And it may well be.  Strong to moderate La Nina's are generally a non-starter IMBY.  The good news, as I have stated before, is that we really need the Pacific to cool down some, and it has been some time since we have seen a strong La Nina.  Winters that have followed strong La Ninas can be pretty good in MBY, so I will suffer through a strong Nina event if need be this winter..."

"....As for snow, everybody wants to know how much we are going to get.  The answer is that it is absolutely impossible to know.  I think our best chances will be early.  After that, one would think that January and February will provide some very long timeframes between chances.  That said, it just "seems" the weather pattern from the past two years right is switching up. We are out of shoulder season which fooled me into thinking the pattern had broken early last winter(the pattern being a little pocket trough forming ad nauseam over the Mountain West in the front range).  With some big heat already being felt in the Mountain West and a transient ridge reforming every few weeks there...makes me think we are seeing a transition.  So, I am less negative about the upcoming winter.  My gut says it will be better than I describe above, but my brain says to beware of moderate to strong Nina patterns - they are generally hostile to winter in the SE.  So, I will go with BN snowfall, but maybe closer to normal than many will forecast, but better than last winter.  Short and sweet with no graphics."

 

 

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Honestly, I have shared privately that we might have 2-3 legit windows this winter.  So far we have had one right around Christmas - maybe another minor window to begin January.  I suspect we get one more good one.  Wavelengths will shorten up during February.  I don't really sweat the "it's always at d10" stuff.  We all know how that works.   And again, when we are talking about the MJO, usually the pattern is not good.  

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