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John1122

December 2020 Medium/Long Term Pattern Discussion.

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Regarding the 12z suite....That is now the ICON, GFS, and now GEM with systems coming out of the GOM just after hour 84.  Again, cold source is lacking...but that track (SE to NE) can be snow in the NW quadrant at this time of year.  

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Also beginning to see the pattern breakdown late in week 3 on both the EPS and GEPS with the trough lifting towards Alaska and the SER waiting in the winds as the EPO retrogrades into the Aleutians.  Long way off and that could change, but is a very persistent signal on modeling and Weeklies runs.

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D14+...Just looking at the MJO, that is some weak sauce stuff.  Maybe it trends stronger like last year, but it can barely get out of the COD.  And it looks like modeling wants to get it into cooler phases quickly if it goes into the warmer phases at some point - which looks low amplitude at this point.  Might be tough to get this trough out of the East...maybe we get the pattern where the cold extends from western Canada and into the nation's mid-section with bouts of cold in the East.  Primary storm track is a cutter into the Ohio Valley with secondary up the coast?  Are we going to go with a "Dec 1989 Lite" look with a flip to warmth for the rest of winter or maybe a "95-95 Lite" look?  I have no idea.  The ensembles in the LR seem sort of split on the matter.  Those are cold maps around d10+ off the top of my head.  Been a long time since we have seen a full latitude trough...of course we could just go zonal.

Until then, we might have some more things to track for the next 2.5 - 3 weeks.

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37 minutes ago, Holston_River_Rambler said:

RGEM out to hour 84 verbatim would be a heart breaker, but I suspect, if this were to verify, there might be more fun after hour 84:

giphy.gif

 

giphy.gif 

Whole lot of energy running around on that map.   Looks like a phase just east of the area to quote a good friend.  That said, the trough over TN is about to go negative tilt.   As we learned with this last storm, phases are finesse deals.  Most modeling just "figured out" today that a storm was possible.  Have to think no solution is locked in...  That said, I would be feeling pretty good in the NE with that look.  We really need to be pulling for that energy to go neg tilt slightly earlier.  The 18z GFS was well west of the RGEM and is on the others side of the envelope.  Kind of like being in the middle of two solutions at this point.  LOL.  Great share.  Illustrates the complexity and coolness of following winter storms.  Bunch of 1s and 0s make a pretty neat map and solution.

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RGEM out to hour 84 verbatim would be a heart breaker, but I suspect, if this were to verify, there might be more fun after hour 84:
giphy.gif&key=ea2349d5df8386c7201e27d3eee0c84a03308167569c4be69d6c15825bc1cbb1
 
giphy.gif&key=342ea39f613e2a5831b1d06879236121782c8e3dae0745d5ca6de46135f03fcd 

You make great gifs. It really simplifies it for those who have less knowledge. Thanks


.
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It is fantasy land, but what a beauty at the end of that GFS run. It has been hinting at something around mid-December. It is at least a window to watch. It is also followed by some bone chilling cold.

image.thumb.png.958c4943a20ae716ba0822645cfcf300.png

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46 minutes ago, Wurbus said:

It is fantasy land, but what a beauty at the end of that GFS run. It has been hinting at something around mid-December. It is at least a window to watch. It is also followed by some bone chilling cold.

image.thumb.png.958c4943a20ae716ba0822645cfcf300.png

 

This comes about with a ridge on the West coast and the elusive -NAO working in combination. 

As long as we can keep the Pacific on board we have shots of getting cold and a suppressed storm track. 

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If you like bone chilling cold, this is the map for you. EPO blocking in Alaska and NAO blocking creates a -AO as well and the takes the cold from Siberia and dumps it through Alaska and into the Lower 48, aimed perfectly at our region.  

gfs_z500a_nhem_60.png

gfs_T2ma_nhem_60.png

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2 hours ago, John1122 said:

If you like bone chilling cold, this is the map for you. EPO blocking in Alaska and NAO blocking creates a -AO as well and the takes the cold from Siberia and dumps it through Alaska and into the Lower 48, aimed perfectly at our region.  

gfs_z500a_nhem_60.png

gfs_T2ma_nhem_60.png

We are overdue for a true arctic outbreak imo and it would fit well with some of the analog years I have seen like 1989

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So much flipping and flopping by models on the weekend system. Now the 6z NAM has gone to almost totally losing it by dumping more energy over N. Mexico. But now, even though the Euro still has some version of it, both the NAM and the Euro seem to be seeing a chance for the left over energy to interact with another (lol) piece of N. stream energy.

giphy.gif

As it stands on the 0z Euro it would be too positively tilted to do much for us, but as Carvers has noted there is soooo much energy flying around, it almost isn't worth looking at either this weekend's set up or the one I gifed above, more than 24 hours out, if that.  

 

Like Wurbus said, models really like the Dec 14 - 17 period for some sort of storm in the east. It fits one of the ways we get storms, as a pattern is shifting or reshuffling, or breaking down, a period ensembles are starting to see at the very ends of their runs. Storm-->arctic dump-->pattern shift.

EPS's vision for that window, as of 0z today:

 

giphy.gif

But as the EPS city charts hint at, there are cutters, miller As, and Miller Bs all mixed in there and even some where a cutter leads to a Miller A/B. Tis the season for hope though, until it isn't, lol.

giphy.gif 

 

 

 

 

 

 

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Just looking at today's MJO forecasts...beware.  The MJO has gone weak sauce(even more so than the last mention of it I had) - meaning it can barely get out of the COD.  The ensemble clusters are either more COD or very weak 4-5-6.  The hi-res models, which at one point propagated into warmer phases, are literally stuck in one place.  I think this is likely why we are seeing the look that John noted last night which is a trough stretching from AK to the SE.  Normally, one would think the SE would have a ridge blunt that cold intrusion.  IF(emphasis on IF) the MJO is correct, it may be muted if today's ECMWF and NCEP modeling is accurate on the CPC site.  That might ever so slightly open the door for a colder SE than once thought after Christmas.  Just spitballing, it might mean we get a normal cold configuration of La Nina, but the SER might be muted enough that cold could head SE.  In recent years, that cold has had trouble getting past the Plains, but that was with a very strong MJO which seemed camped out at high amplitude in the warm phases of 4-6.  

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The MJO was CRAZY strong last year, I remember. It was way over in the positive quadrants, stuck in phases 4,5, and 6, and what exacerbated our woes was that monster positive AO.

 

I've noticed how the graphical representation of it right now has it in the middle

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1 hour ago, Carvers Gap said:

Just looking at today's MJO forecasts...beware.  The MJO has gone weak sauce(even more so than the last mention of it I had) - meaning it can barely get out of the COD.  The ensemble clusters are either more COD or very weak 4-5-6.  The hi-res models, which at one point propagated into warmer phases, are literally stuck in one place.  I think this is likely why we are seeing the look that John noted last night which is a trough stretching from AK to the SE.  Normally, one would think the SE would have a ridge blunt that cold intrusion.  IF(emphasis on IF) the MJO is correct, it may be muted if today's ECMWF and NCEP modeling is accurate on the CPC site.  That might ever so slightly open the door for a colder SE than once thought after Christmas.  Just spitballing, it might mean we get a normal cold configuration of La Nina, but the SER might be muted enough that cold could head SE.  In recent years, that cold has had trouble getting past the Plains, but that was with a very strong MJO which seemed camped out at high amplitude in the warm phases of 4-6.  

There was a study done on one of the old forums several years ago centered around Atlanta regarding what phases/amplitudes they scored sig winter weather in...surprisingly the COD produced more than any other amplitude. I believe you hit the nail on the head...to score we have to rely on a weak version of the SER (more so for the eastern side of the state. Over amplify in cold phases and the cold overbears the Gulf...reverse for the warm phases..torch city.

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MJO looks to be going toward a position a bit more typical of La Nina as we head forward, and AAM looks like it's going to start tanking soon.  I would start keeping an eye on medium range guidance for one or more severe weather threats to start showing up between now and Christmas or so.  No real specifics other than that, but it may be time to start having our eyes open...

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12z GEFS and GEPS definitely showing a trough which slips back into Alaska after 300.  LR guidance has been bouncing around with how far that cold can intrude into the US.  Depending on where that boundary sets up (the AK trough potential nosing SE) will tell us a lot about things going forward after mid-month.  

As for severe, the "thunder in the mountains" saying (snow within 10-14 days) has been pretty sound in recent years....

If the MJO can make it out of the COD, will be interesting to see how long it stays in the warmer phases.  Some schools of though out there that it may just keep going which would be fine by me.   

After the system this weekend, there may be a few shots of cold/snow showers after that...we will see if that trough lifts out with the storm or digs in for a few more days.

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The 12z EPS is not a bad look in terms of cold.  Probably will be some cutters involved with that look as well which definitely could produce some rumbles of thunder in NE TN.  One interesting thing I noticed is the ridge backing into the Bering Strait.  Normally, I am not a huge fan of that, but there are some winters where that was prominent and are notable exceptions to that thought.  January of 1996 is one of those analogs.  In the Northern Hemisphere, the January 96 analog looks nearly identical to what the EPS is depicting at the very end of its run.  Yesterday, I thought aloud about whether this winter would be like 89-90 where winter started early and evaporated or if it would be like 95-96 where it continued - obviously any 95-96 reference is a "lite" version as extremes like that are exactly that - extremes.  If I get time later I will share the similarities, but one of those similarities is a ridge off the end of the Aleutians and extending into eastern Russia.  Rainshadows 59-60 comparison is a good one as well.  No idea where this pattern is heading after Christmas, but just kicking the can around a bit.

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1 hour ago, Fred Gossage said:

MJO looks to be going toward a position a bit more typical of La Nina as we head forward, and AAM looks like it's going to start tanking soon.  I would start keeping an eye on medium range guidance for one or more severe weather threats to start showing up between now and Christmas or so.  No real specifics other than that, but it may be time to start having our eyes open...

Same things were brought up back in '95-96 Fred as well as 2010-11 and a couple Factors warred against the full La Niña pattern takeover . Oh yes, it did try especially in 95-96 as short lived bouts of mild would come east only to be shunted by strong blocking in the NAO domain and other areas as Carver aluded to.

         Of course, Niña was weak that season so, odds are less favorable for that yo happen now and more in favor of more niña influence.  However, what about 2010-11 ? Strong Niña but, remained cold overall in the East. Blocking was one reason. What was the others ?

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9 minutes ago, Daniel Boone said:

Same things were brought up back in '95-96 Fred as well as 2010-11 and a couple Factors warred against the full La Niña pattern takeover . Oh yes, it did try especially in 95-96 as short lived bouts of mild would come east only to be shunted by strong blocking in the NAO domain and other areas as Carver aluded to.

         Of course, Niña was weak that season so, odds are less favorable for that yo happen now and more in favor of more niña influence.  However, what about 2010-11 ? Strong Niña but, remained cold overall in the East. Blocking was one reason. What was the others ?

I'm very much not talking about the full winter.  I am simply saying that, for the next few weeks, we are heading toward a pattern that would possibly favor one or more severe weather threats between now and Christmas.  I honestly expect us to flip back and forth between the current pattern and the coming pattern for the rest of the winter.  CFS in particular wants to take the MJO back to the Pacific during some point in January and into February.  I kinda expect it to do that given what we have seen thus far.  February 2011, the MJO didn't budge from the Pacific.  My post had nothing to do with expectations for the winter overall.  It was telling folks in this area to start paying attention to systems ejecting out of the Plains between now and Christmas.

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51 minutes ago, Fred Gossage said:

I'm very much not talking about the full winter.  I am simply saying that, for the next few weeks, we are heading toward a pattern that would possibly favor one or more severe weather threats between now and Christmas.  I honestly expect us to flip back and forth between the current pattern and the coming pattern for the rest of the winter.  CFS in particular wants to take the MJO back to the Pacific during some point in January and into February.  I kinda expect it to do that given what we have seen thus far.  February 2011, the MJO didn't budge from the Pacific.  My post had nothing to do with expectations for the winter overall.  It was telling folks in this area to start paying attention to systems ejecting out of the Plains between now and Christmas.

Gotcha ! Thanks for the clarification.  I expect back and forth as well. MJO does rule the roost many,( if not most, times ) tbh.  

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