Carvers Gap

This is Part 3, and the final of my series of posts this morning. These posts focus on the medium and long range(those are my interests). ALL of this will likely change to some degree, but let's hope we keep the basis. (There is certainly PLENTY to talk about prior to the 11th, and I have not discussed it with these posts). Anyway, here are comparable hours of the three major ensembles. I have no idea if these verify. BUT, this is an example (not to be taken as gosple) of how a favorable Atlantic(Boone has discussed this) can save a crappy Pacific. The 6z GEFS has a perfectly placed NAO right over the Davis Straits. The 0z EPS is less optimal as it has a block, but it is debatable if that is a true NAO or displaced WAR (western Atlantic ridge). The 0z GEPS is pretty much what you want to see if you want lots of snow in the East. The conveyor belt from Alaska to the SE is on tap. Now, all of this gets kind of wild. Why? Well, there is an attempt at a zonal Pacific air mass. However, with the block, some cold should surge southward. So, we get this mix of zonal and polar/Arctice air which should equate to storminess. Two of those maps are essentially turning a Pacific firehose loose on a cold air mass centered over the Lower 48. Blend those three maps together, and you get a pretty good pattern. And this is what it looks like at the surface(I might be off 6-12 hours per map due to not paying attention to toggling and being too lazy to go back and fix it!) I have mentioned the MJO is driving the bus. But when I started digging this morning...maybe it is not??? And that is open for much debate. We may be seeing a winter where the Atlantic is driving the bus. That can happen. We certainly want the Pacific if we can get it, but blocking over Greenland provides confluence over our area(where we want phasing to occur). Right now, phasing is east of us. Let's see what happens if we see HL blocking develop over the Atlantic. Temps may be marginal, but January is our one month where temps don't have to be below normal for snow. We can actually get snow with normal temps to slightly above normal. Now, if these maps flip warmer, we know modeling is probably focusing on the IO/Indonesia area where warm MJO phases originate... For now, we had better hope the AO/NAO take hold. Of particular caution, the SSW has been occurring for some time. Credit goes to the sometimes maligned JB. He has been writing about this since mid December and predicted it months ago. I noticed that Amy Butler(nobody better at strat warm stuff) is now mentioning a true SSW might be at hand. Think about this....we are probably in the middle of an extended warming. That means that the actual tropospheric results might be impacting current wx and not just 2-3 weeks out. The caution I mention is this...we often see models erroneously send cold eastward w/ SSWs, and then trend West w/ the cold. That said, that was during the past three consecutive La Nina winters.....the trough wanted to go into the West anyway, especially w the past PDO signal. This winter is more of a signal for cold dropping into the West and sliding eastward quickly with less SER(no SER?) to stop it. Remember when the cold hit the Plateau and wouldn't come a mile further? All of us east of that do, and it was properly discussed yesterday. With the setup above, the cold would charge down the Plains and crash maybe all of the way to Florida. One might be concerned with a suppressed pattern, and that may well occur. But w/ the PNA being negative to neutral, we may well see a broader trough(mentioned in the MA forum) which allows systems to slide across instead of head to Cuba.

Here is the Dec 27 6x GEFS NAO plot. The AO looks almost identical. It just tanks. That is the counterbalance to a bad MJO. The Euro Weeklies turned out to be accurate after the aforementioned hiccup. Here are there Dec 26 0z AO, NAO, and EPO teleconnection plots. The green line is the mean, and blue is the control for those new to these. Unlike the GEFS run above which is 16 days, the Weeklies run to the second week of February. They are modeling an extended bout of -AO, -NAO, and then a -EPO(Jan 19th). I just realized that I cut the dates off...so use the EPO turning negative as a benchmark(Jan 19th). Now, what is striking(maybe disturbing) is the control is NOT in sync with the ensemble. Now, that isn't totally unexpected, but that does signal some conflict within the model itself.

I am going to place a series of posts (more for discussion as there are DEFINITELY two sides to this coin). Take a look at the NAO/AO couplet. Notice anything? When they were positive this month, it got really warm. When they were briefly negative to start the month, there was brief cold to follow. Now, there is a little bit of a lag, but in general....surface temps IMBY correlate to the NAO/AO phase. We have been a whopping +13.83 degrees above normal at TRI for Christmas for the time frame of Dec 24-26th. Ext LR modeling very accurately portrayed the warm-up, and its demise. From about 4-5 weeks out, they nailed the turn to seasonal/colder to within about 48 hours. They had Christmas week as the transition week w/ the exception of a 2-3 day hiccup where they lost continuity. That is impressive. But Merry Torchmas! Folks, these two graphs were about all that I used when I first started following wx modeling. Well, I followed those and the NOGAPS. Both were surprisingly accurate, and I am not sure that I am getting a much better today. The graphics are certainly better, but those graphs in tandem with the NOGAPS were decent. So, here is what I know when I see that couplet turn negative in tandem. It is about to get cold. It is about to get stormy. There is more potential for snow. That December peak in the positive domain would have meant near record warm temps.

The 0z GEPS and 6z GEFS are mercifully developing textbook -NAO signatures around mid-Jan. That could fight an upcoming potential bout of a VERY hostile Pacific. The MJO crawling through warm phases looks more and more likely. There is still an outside chance we could get a low amplitude pass through warm phases or a COD. Back to the NAO....during Nina winters that NAO has hooked into the SER every, single Nina winter(of the past three winters) I "think" at one point. With the SER missing right now, the NAO is less likely to make that connection....but make no mistake, if the SER is there, the likelihood of the SER connecting with the NAO goes way, way, up due to the MJO phase. If the NAO block does not take hold, a return to a more favorable pattern after the 10th could be anywhere between Jan 25th or even as late as the second week of Feb. The MJO is very close to a "winter ender" if there is no Atlantic help. If the MJO rotates (as slowly as prognosticated....it is a little faster today), it would leave maybe 2-3 weeks of winter on the table - maybe. So, we need what hasn't happened during the past three winters, we need the MJO to rotate through warm phases...and still stay cold in eastern NA... the mid-court bank shot so to speak. The great thing? Modeling has it. Fingers crossed.

We are AN for rainfall for December at TRI. This month has been super beneficial. We still have a ways to go in order to get things replenished, but that was a good start. Hope everyone else is able to cash-in on some precip. Rain shadows up here are no joke. With a Nina summer on deck, we need to get decent rainfall this winter. I think east of the TN river drainage in E TN is the best bet for normal rainfall.

Until it proves me wrong, the MJO is the Draw Four card in this UNO game....

Cosgrove thinks springs shows up during March (above normal?) mainly because the Nino collapses during the next 8 weeks. If the Nino holds on, that would mean a cooler spring. If Nina shows up, warm.... @jaxjagman, do you have the ENSO graph for the next few months? But to answer your question, I am not sure. I could see March being cold to start and end warm. That is just an educated guess. If winter goes severe during February, it would make sense for it to snap back to a warm pattern once the cold is spent.

I suspect modeling is waaaay under doing the warm-up. Ensembles are starting to see the MJO rotation now, but no slam dunk that it is warm. Where I would have said there is about a 90% chance of significant warm wx after the 10th, now I would say 70%. Then cold looms again after that - maybe 4 weeks of seasonal/BN and we make a break for spring. The NAO could completely erase the warm sig on modeling...but I just think the MJO wins.

If the MJO was driving the bus, this should park a trough out West.....that is a really cold pattern right there. Hints of an EPO ridge, NAO(slightly displaced), and a confluence over our latitude. Normally, I wouldn't show a 360 hour ensemble thumbnail, but go take a look at its past few runs.......this is a big change, and that started overnight.

The CMC has a winter storm just before 200h. That would bring the zr/sn line well south if that verified. Fun suite today.

Silas, I am beginning to think the Plateau might be a decent spot for this Friday deal. Keep an eye on the 2nd. I would read afternoon discos today.

And there it is at 171. That has been on modeling for several days on the GFS. The 12z GFS is no different. I would like to see the CMC get on board though with at least having some reflection of southern stream energy. Without that energy, it is just snow showers and flurries.

Basically, what we are trying to "cook-up" is a clipper partially phasing with southern stream energy on the 2nd.

Pretty crazy to see the differences between the GFS and CMC at a 132. The CMC is missing the southern stream energy completely. If it was there, that could have been a decent run. The GFS has energy lagging back a bit in the northern stream. That system around Jan 1 or 2 is one to watch as well.

Snow here in the 'hood lasted in the shade for about three days. It wasn't much, but crazy to see a dusting last that long in the shade. Ya'll are gonna have to get your act together on the Plateau! LOL. Yeah, it looks like modeling is consolidating on some energy sliding through middle TN. It wouldn't surprise me for this to have more precip(per Boone) and also for it to trend NE. But that is a fairly textbook track for that type of system. The storm track over the next 14 days should get pushed far, far to the south. I am actually kind of watching to see if Chattanooga can score in this pattern.

The 12z RGEM has a decent little mini-thump for middle TN and northern Alabama. I like the RGEM with systems like these.

Here is a quote from LC this morning. He actually posted shortly before I posted my previous post(but I hadn't read it yet). Here is what LC had to say. Hopefully, he won't mind me quoting him. If so, I will be glad to take it down.... But the 500MB level outlines show an impressive -AO/-NAO blocking signature emerging by January 11. This is very close to the analog projection, and would support a very cold western two-thirds of the USA vs. a warm East after the 15th of January. There most certainly will be a "Thaw", but probably only 7 to 10 days worth across the lower 48 states before winter comes back full force.

We are very likely going to have to get help from a -NAO as the MJO is about to go to crap after the 10th....crawl, and I mean potentially crawl through the warm phases. I am talking like 20 days just to get through two phases on one model plot. Then, there is also a group of model plots which slam into phase 3, can't advance, and then rotate through the COD. That said, I think modeling has a bias for being too low with amplitude this winter. I was honestly surprised to see the MJO plots this morning as global ensembles don't seem to be synced in comparison with what their (ext) weeklies yesterday were portraying. Those were some very BIG moves on ensembles last night re: 500 structure after the 10th. Both the 6z GEFS and 0z EPS broke from continuity, and had a much colder solution. The best I can tell is that the NAO/AO couplet may tray to take over as the main driver. The NAO is showing up quite nicely on LR global ensembles(not the Weeklies...but within 16 days type of stuff). As one friend noted, beware....modeling has showing that great look only to hook the NAO into an eastern ridge. So, proceed with caution. I still think we see a really window until maybe the 10th roughly. Then, we take a 10-25 day break(timeline dependent on the MJO progression), and then we hit a stretch where we see good MJO phases, blocking over the Davis Straits, and ample cold in Canada to draw from. But....I think there is now potential on the table(lower probability...but plausible) that the lull could evaporate. Like yesterday, I think we see an opening salvo, a lull(maybe extended), and then the hammer drops. Hoping school systems have plenty of time banked.

The 6z GEFS is very decent for most of the forum. And yeah, this weekend is wild on modeling. I would guess this would jog north a bit. But the Euro has a much different location. Fun to track.

Wait until the last minute to see where that low jogs. Modeling is all over the place right now. Then, maybe rent a VRBO in the area where it is supposed to be the worst. Roan Mountain is easy to get in and out of(the base...NOT the top). Gatlinburg would be an option, though GSMNP will close the road over the top at the slightest hint of snow nowadays. Ober has done really well of late on NW flow events. Townsend would be another. A good sleeper option is Beauty Spot near Newport, but make sure to turn around if you cannot get out of there. Also, have maps printed as cell service is iffy there. That said, there is a Methodist Camp near Beauty Spot...if you get stuck, go there.

Last year, the writing was on the wall by this time - the trough was retreating into the West and was done in the East. @Itryatgolf70saw if first, and was correct. This time around, I think we are looking at a legitimate winter pattern during the last half of winter. My only concern(and it is significant) is the MJO really crawls through the warm phases which surprises me. I did no foresee that. The MJO was a little more quick about its business this morning on the CPC site. But really, the MJO shouldn't be dawdling in the warm phases at all. Cosgrove thinks this is a natural reset after the early cold of Jan. He has been adamant that the last week of Jan and most of Feb could be a strong winter wx pattern for the Plains -> eastward. Looks like a classic set-up IMHO. What is crazy, it reminds me a lot of a combination of 95-96(weak Nina) and 14-15. Those are big winters, and I apologize to everyone for sensationalizing a bit much....but the pattern wear cold hits in early January, retreats, and then returns is a normal pattern progression for this forum area. Maybe since we are a little warmer this go around, it will be like 14-15(light). Later this month and/or early Feb....If the NAO combines with an MJO 7-8-1-2-3 progression along with the QBO descending, that is a great set-up. Now, it could miss. We do live where it wants to rain most of the time....but it certainly looks like a very cold set-up is building for North America.

I think what we are about to see is the opening salvo of winter, followed by an undetermined but warm pause, and then multiple repeats of Jan1-10 from roughly Jan22-end of Feb.

The 18z GEFS ensemble looks very good BTW for a large chunk of the state for the entire run. Decent signal on the operational and ensemble for this weekend in NE TN, but this is woefully tough for modeling to figure out....changes are not done yet - I feel confident in saying that only.

12z ensembles(CMC and GFS) are rolling currently, and many members do show chances for light accumulations later this week. There are a wide range of solutions ranging from west to middle to eastern forum areas or some combo thereof. Good luck to modeling as it tries to figure that one out. I do think the pattern after next weekend looks really good FWIW. edit: To clarify, modeling looks good through maybe the 12th before taking a 10-20 day break.