Carvers Gap

LOL. He has been salty lately! I like it though. Jeff shoots straight. I can be just as salty at times. He and @Mr. Kevin are just making sure there is balance to the force. Staring at the big red blob over the Aleutians and eastern NA....Literally, I sit and look at operationals and ensembles and am like, "How long can that feature stay in one place?!" Heck, I am just glad to see it wobble just a bit!

Yep. No idea of it happens, but the scenario is a possibility. The 12z GFS shows high latitude blocking galore. The GEFS is well into 7 approaching 8 on the MJO plots of CPC. However, I do urge caution with those as Jeff makes a sound case for it not rotating into 8. That said, Atlantic blocking could offer some relief as it did last winter. Those guys in those tweets have forgotten more than I will ever know.

12z GFS...Kind of wonky after d10, but does manage to pop a massive east basted -NAO(loosely defined admittedly). Also, the much discussed ridge lasts about one week. Seems suspicious for it to break down that quickly, and the GFS is often too quick to roll over well established ridges. I use this term a bit to much. But certainly is a break from continuity. The evolution of that pattern is wonky enough to cast doubt upon it. However, it is not without some support from previous CFSv2 runs. Higher elevation snows still showing up for next weekend as well. If I hadn't been watching the big red blob over eastern North America for nearly a week straight in LR modeling, I would actually be ok with that run considering it is only December.

You are just preparing for basketball season. LOL. Hey, may be time to talk a little basketball in the banter thread.

Thanks for the humbling compliment. Truly, there are many on this sub-forum and other sub-forums who know much more than I do. I learned(and still learn daily) from those folks, and realize each day how little I know(the more that I do this). What makes AmWx so awesome is that it is a collection of people who enjoy the weathe/climater(enthusiasts is a great word), and generally keep it free of the clutter of the rest of this world. We just come here and talk weather which is awesome. We are also truly fortunate to have meteorologists who participate. Hopefully, we can find some cold weather this winter. My wife's family is from northern Ohio! So, nice connection there!!!

Thunder in the mountains!!! LOL.

John pretty well covered the first potential winter event next weekend which will likely precede an underdetermined period of warmth which follows. The EPS certainly looks like it would kick the trough eastward(if it continue?) late in its run as AN heights move into the GOA. Just to show that we aren't talking out of our minds. This is what the CFSv2 has this morning after a similar set-up (to the EPS) on it. Will be interesting to see which fork in the road modeling eventually takes. I do my best not to talk in absolutes but it can happen. So for now, just presenting two options. The warm option has been well documented. However, I do not think it is a given right now that things turn warm and stay warm through the core of winter. I certainly don't discount that, but certainly can see that the potential for other scenarios exist. Again, my overall winter forecast ideas are warm with January and February being the warmest month. My main contention is that cold(possibly severe at times) will be embedded within those warm means similar to 17-18. IF(stress IF) the AN heights in the Aleutians move into the GOA, this is the potential that exists if that happens. The control is a little later with this evolution, and I think it is certainly possible that the CFS breaks down the eastern ridge too quickly. And again, the CFS is not a model which I trust as it has a cool bias at times. However, with the Euro suite bouncing around about as much as the CFSv2...might as well give it a look.

Thanks, PSU, for the great posts. I eventually made a similar map just with a NH view. It is posted in TN Valley thread. I compared it to the 18z CFSv2. I also have added the analogs for the d8-14 CPC LR forecast. Some famous ones and some infamous ones. Been trying to make sense of the Scandinavian AN heights I am seeing showing up in modeling after d10. It is interesting to see a similar feature showing up(on analog maps) in the Scandinavia and/or Ural regions.

Notice the the three air masses(cold and warm). Actually the December analog package looks similar to our November which we just had. Also, notice the ridge near Scandanavia - as fickle an analog as it may be. Current differences would have nearly opposite 500 features over NA and Greenland. Either we have just left this configuration or we may be headed there. Below is the 18z CFSv2 for the last part of December and first part of January. Not exact but close to the analog maps above.

Here are the December composites of PSU's Nina maps. I haven't taken into account which were second year Ninas.

Here are the d10-14 analog packages. Some interesting ones in there. Beware, this graphic might change with each update. There are extreme winter analogs (warm and cold) in that package. The best and worst winters I have experience are found in that analog package.

I don't think the way to colder weather will be via an SSW though a perturbation of the TPV is probably likely at some point this winter season. Just pointing out that some similar features to those analogs are showing up on current modeling. Pretty cool I think. We will see in time where that leads. I asked in the MA thread if PSU knows how those Decembers looked. I just don't have time to enter those into reanalyses program. If you have time, go for it. Would be interesting to see what a composite of those previous Decembers looked like...

PSU, I wonder what those Decembers looked like?

Take a minute and look at the analog package graphic of the past 30 years of La Nina's. PSU notes there are two different clusters. There is a bit of a misconception the the trough is in the West. Now, also note the ridge just east of Scandinavia and the ridge in the central Pac. Those features are showing up in some variation in LR modeling.

I tend to agree with Jeff on the MJO, though I am less bearish for winter. Jeff pretty much holds court over the IO and western Pacific knowledge. When in doubt, follow his lead on that one. I think we are going to need help in the Atlantic as you note earlier. The CFSv2 is the way out of long term warmth. No idea if it is right. I don't share a foxhole with that model at any point! LOL. OR....in the really unusual circumstance it gets cold during warm phases. For me, just too early to tell. I definitely agree with base-warm for winter. I just think we see some extreme cold embedded. My question is do we get 1 or 2(with the second being after mid-winter) cold intrusions. I do think the ongoing BN precip is likely a more limiting factor for snow. Makes precip so much harder to connect with colder patterns if there is little precip in the pattern. The QBO cycle should produce cold. It is uncanny how well descending QBOs correlate to cold in E TN. So for now, we are looking for windows for potential snow prior to the potential warm-up. I like the idea of an eastern ridge from Dec 15-22 at least. We will see if that continues from that point on. I would lean that the warmth continues, but again, no slam dunk. I do think there is a chance for some cold around Christmas or slightly thereafter. Going to leave you guys to it for a bit. May check back later this evening. TN vs Purdue in the Music City Bowl in Nashville....will be fun to track the wx for that one.

That was never in question.

Euro monthlies are warm, but when aren't they for winter? Maybe a few examples, but wicked warm bias in general. As for Hugo, just thought his information was interesting. I generally buy into the idea that it is going to be difficult for the MJO to work into 8, but who knows. I generally try to look at both sides of the coin. The CFSv2, which I scorn regularly, is not base warm from Christmas week onward. Again, it is December 5th. Not unusual for winters to start warm and return to cold, especially after cold Novembers. It is not out of the realm of possibility that the winter will remain AN either. There are precedents for both. I am certainly not going to hang my hat on a wx model which has a know warm bias or a known cold bias. We will know soon enough. Winter forecasting can be humbling for us all...and if it hasn't been yet, it will be.

Actually that is not true IMHO. -3F for November. While that is not a winter month, fits Nina climatology to the T. Warm start to fall followed by a quick flip to cold late in fall. Textbook front loaded cold...problem for us is the front load came during a time when we really don't get a ton of snow historically.

I think Jeff summed-up Bam's track record of late. IMO, more of an SST problem where the cooler temps in areas where 8-2-1 reside won't allow impulses to propagate into favorable phases. That said, we are not really into longer wavelengths associated with winter yet - meaning wavelengths are still changing. Until those really set-up, not sure where those "standing waves" set-up over the US as well. SER is definitely favored at times but not guaranteed. Right now we are seeing three pools of BN heights and three pools of AN heights in the northern hemisphere. That is extremely stable. However, I suspect we move to four of each by mid-winter. See if you can dig up some articles about teleconnections of Scandinavian ridging and/or Ural ridging in relation to patterns over NA during winter. Might also see if that Scandinavian ridge is a prelude to high latitude blocking setting up(potentially due to an SSW). Also, some really good information is what John posted earlier about La Nina winters for this area. I trust his information above all other sources.

Interesting. Found this on the MA forum.

I can say this much, I am not losing a second of sleep about modeled warm weather patterns on December 5th. LONG way to go. Could it be a non-winter? Sure. But could it be a winter with a memorable cold snap? Sure. Saw where JB is worried about the late 90s non-winters as a possibility. Thing is, that is always a possibility but is about as unlikely as a severely cold winter. But one look at the CFSv2, and the long term continuation of a warm pattern is no slam dunk - reference MA forum discussion. We have just come off a November at TRI which was -3F. So, we already have had a front end cold snap of sorts - the weather doesn't adhere to manmade calendars. We aren't going to stay below normal forever. We are right on time for a switch in patterns. The positive is that we know there is a decent correlation between cold Novembers and winters which are BN. While there are a few clusters of analogs that produce warm, nearly snowless winters....most second year La Nina winters have some winter. Many of those winters have extreme cold. While last year was not a second year Nina, it did produce a memorable period of winter for those in western TN and Texas. That is the calling card of La Nina.

Interesting to see the 12z GEFS begin to allow the eastern ridge complex to decay/retrograde west. Don't think so? Switch your model over to surface temp anomalies and let it loop. Moves east, and then slips back into the West again. The deep trough which was forecast to go into the West is nothing more than a blip. Hate that for the ski slopes there as they are suffering now.

Yeah, I don't see cold locking in before Christmas for more than a day or two. Think our best chance for snow next weekend is for the cold to crash into the back of the system while a slp or wave buckles it, thus slowing it down. Long shot, but not impossible at all. Tough to know as modeling was nearly blind to the amplification.

Hurricane force winds and snow. Somebody's dream scenario somewhere. LOL - not mine. I definitely could enjoy a blizzard, but not touching 125mph winds!

Yeah, that was a good look, John. Looks like we have two timeframes to watch....Wednesday and next Sunday. Wednesday looks marginal, but it is there on modeling. Maybe a dusting for some areas? Next Sunday is one to watch. Long way to go, but this appears to be a low that cuts followed by a potential second low. Just how far that boundary gets south is going to be key. In the LR, the CFSv2(notable cold bias) seems to like some cold around the Christmas timeframe, another warm-up, and then much colder. I would not disagree. Base warm for the next few weeks as others have noted with cold interludes. However, I suspect that we see a more prolonged cold pattern(2-3 weeks) at some point this winter.