Carvers Gap

The 12z CMC pattern looks really good and so does the Euro out to 180.

I believe the CFSv2 is off its rocker wrong regarding the MJO. Go look at it on the CPC site. You can tell it is not going to correct to its forecast. I was hoping it would be right, but its MJO plot looks way off. JB had a post this morning which basically(if I read this correctly) stated that the MJO is not in phase 7 as it is likely being moved erroneously to 7 by the tropical activity in that MJO region. The OLR maps are a mess due to the cloud cover from the tropical systems. It is why we see the MJO push into 7 and then abruptly retreats back on all modeling not named the CFS - meaning the tropical system leaves the region and it corrects back. Once that system exits, the MJO returns to its normal transit as OLR data will be accurate. It is likely going to get to 8, but it is falsely being pushed along by tropical activity which truly doesn't represent convection for the MJO. In other words, the MJO is not in phase 7. More likely the MJO is actually in phase 6(the surface wx over the US reflects that look), and it will crawl from 6 to 8. This is likely why are seeing modeling jump to cold solutions too quickly. Models are jumping the gun as the input due to the MJO error is causing havoc. They likely get to phase 8, but much slower than projected right now - more like early January. So my advice, proceed with caution as at some point it is going to leave phase 6. We may not get a ton of lead time. Positives this AM, blocking is showing up. Now, is that blocking a result of a flawed MJO number? No idea. If the two are connected, all LR modeling is off right now. It may well be that if the blocking is independent of the MJO, the Atlantic is about to co-drive the bus. If that is the case the CFS may be on to something. For me however, the wonky MJO it has produced this morning is evidence that the model is likely partially wrong. ALL OF THAT SAID, the CFSv2 did nail the trough after the 20th where other modeling did not. So for now, we cannot completely toss. If you are an MJO expert, please free to add or subtract from these comments......

Well, the CFS seems to like your area! Hang on tight if it is correct....

18z CFSv2 doubles down on the duration of cold. The control of that run is extreme with temps during the coldest week of January(second into third week) nearly 30F below normal over western parts of the forum area. I highly doubt that occurs, but yikes. That is pipe buster city right there. Generally, IF the MJO eventually rolls slowly through phase 8-1-2 during the coldest part of winter, that would be something to behold. I am way ahead of myself. Could easily go wrong. We have seen cold model runs revert to warm patterns in reality. So, huge grains of salt. I refuse to share a foxhole with the CFS.

If I had to rate my favorite weather patterns, a weak La Nina is at the top. A weak El Nino(w a proper Pacific SST gradient) would be a close second. Neither are slam dunks, but they work IMBY. We are adding a -QBO to the mix this year. We are also seeing teleconnections, with the exception of the AO which is hit or miss, heading to favorable territory on LR modeling. The MJO could certainly still balk, but for now, looks headed for 8 and couple that with a slow progression. There are some good signals there. A word of caution to all....the best signals in the world don't make a wx pattern happen. Some years have great signals and go to crap. Seems like a recent winter had beautiful teleconnections and LR modeling looked nearly perfect during December. Then the SSW came and screwed it all to ....well, you know, "Grandma Got Run Over by the Stratosphere." For now I like the climatology of the La Nina for some periods of severe to seasonal cold. And seasonal cold will get the job done during late December and early January. Flies in the ointment are of course the MJO regions which don't favor convection due to BN SST temps - that is a problem. The PDO is not in phase for a cold eastern seaboard - that is a problem. So, again, just blend it....and we get a our shot. Biggest concern I have is one that doesn't get a lot of pub. We aren't getting a lot of precip. Lack of precip IMO is the single greatest cause of BN snow. Gotta see that pick-up.

I haven't read the post. I may have misread that as well. So Grit is not saying orbit across the COD from 7 to 2...but to actually go through 7-8-1-2. I would tend to agree that is a strong possibility. Those invests are going to cause havoc, and could even skew the MJO reading. Just an in general observation not meant for D-Boone...The 18z GEFS again has a pretty strong signal for a -NAO. I know there is some discussion about west based or east based. Get those AN heights(even if not the core) in the Davis Straits and good things begin to happen. One word of caution to the masses, if the -EPO ridge gets super tall...the trough can still tuck west underneath it. I saw it occur for nearly two years straight recently. That tucking of the trough under the EPO ridge could also just be a common error. Lots to sort through and that is what makes this fun.

Ditto.

For sure. The current NAO depiction is slightly east of where we need it. However, if we get that block into Alaska proper(not the GOA which is prime real estate) which is being showing in modeling...that likely dumps cold into the West which spreads eastward as it moderates. Ideally, yes, we want the motherland to dump into the East, but that just doesn't seem to be case. Even with phase 8 of the MJO, cold dumps into the Plains and spread eastward. I doubt we see a perfect block as those are rare, but blocking itself will likely send plentiful cold into the Lower 48. I will take the Euro operational and run with it. It isn't perfect, but it would provide some chances. The SER is going to be with us this winter. When is it not? LOL. That is not a bad thing if we can get cold into the mix. No SER and we lack the ridging needed to get systems to turn north. As Boone noted, Canada is cold this year so at least the source region for cold shots is good. Saw Jeff's post. Yeah, just going to have to let things work themselves out for now.

The 12z GEFS, GEPS, Euro, and CFSv2 have great looks. The 12z GFS and EPS not as much. Now which of those models missed the potential trough amplification around the 21st and was the last to see it? Honestly, I would take the 12z Euro and run with it if that look at higher latitudes verifies. Sure, we would have some bouts of warm wx, but that is a given during any southern winter for the most part. But that potential block(if real) is going to push cold air east at times. Super similar look to last winter. There is A LOT going on right now in terms of variables being unknown or fluid...Again, the winter pattern has very likely not shown itself yet. I stand by this...base warm pattern with cold intrusions. If the CFS is right, I am wrong with that last sentence. Remember all of the ensembles that were wall-to-wall warmth just a week ago. Not so much now. In general at this point with lots of variables undecided: Blend model solutions and go straight down the middle. Why? The solution is usually(not always) found between two extremes. That leaves us with a blended solutions which is base warm but leaves room for cold intrusions and winter weather. I a definitely glad to see modeling take a step back from the wall-to-wall warm solutions from 7-10 days ago. Welcome to winter - southern style.

I think I have laid out my thoughts on this pretty clearly with my earlier post this morning. I don’t have anything to add at this point. Not that we have a choice in the matter, I do think the MJO is going to crawl this winter. If we indeed make it to phase 8, modeling will at some point move to that colder look. It is also important to remember that the Carolinas generally get much different results from La Niñas so that impacts perspectives. Have a good Sunday!

Not a ton to add this morning. The 0z Euro is by the far the most aggressive model in moving to a look which would deliver cold in the Lower 48 with original from the Arctic. As John noted, models are bouncing around. I originally just took that to be them dialing in a cold shot. I tend to agree that we are probably seeing a pattern change of some sort and of a duration TBD. The CFSv2 is what I hope we transition to, but is by no means a certainty. The MJO certainly appears to be poised to take a trip through the cold phases. Will it happen? Time will tell. If this is true, modeling is going to switch to a pretty cold look. If it is not, it will stay warm. It is worth noting that ensembles now "see" the cold where before they had a suspiciously stagnant patter. Obviously, they smooth things out....but still. If the MJO is correct, I am suspicious of any model which reverts to the big ridge in the East ad nauseam. I would suggest the pattern will be bouts of severe cold followed by extreme warmth until the pattern switches the cold to out West after mid-winter. I could easily be wrong. Let's put it this way, if I saw a model which was cold in the LR but the MJO was rotating into warm phases, I would be suspicious. The opposite is also true. Plenty can still go wrong, but to me it looks like LR modeling does not reflect the outcome that their own MJOs are depicting. To close and beat a dead horse simultaneously, if the MJO is right...we get cold for longer than a week. If the MJO is wrong, the West gets very cold for many weeks.

For sure. An east based -NAO will often retrograde to the west, especially with the warming which just occurred at high latitude. Keep the fires burning. See you all in the morning.

That is mega block on the 0z. I will reference John's post above. I think models are sensing a relatively substantial change after the 20th. Probably tough to know exactly where the chips fall at this range. His posts perfectly states what is potentially going on with modeling. The 0z GFS run is a textbook block. I am not worried about the features at our latitude at this stage in the game. Get that kind of block into place...that is what we are looking for. That would likely deliver very cold air into much of the Lower 48. It is backing off the 21st as a start date. Maybe it is a bit too fast. Maybe it is up to the old trick of pushing cold air back. Key is the block. Get that and let everything else fall into place.

Thing is....IF the -NAO gets established, it is very stubborn in moving. Last winter, modeling erroneously tried breaking down that feature. So key features on maps today: 1. Double block: Some form of AK/Aleutians block couple with a block near Greenland. Aleutian highs are not uncommon during La Ninas. They are normally deal breakers, but for some reason they also show up in cold analogs even without Pac help. 2. PERSISTENT southeast ridge. 3. Periodic extreme bouts of cold and warmth. All of that fits very nicely into La Nina climatology. If it is real, we should have some chances.

The 18z GEFS ensembles have a whopper of a -NAO. So, now we are beginning to see ensembles "see" the possibility for colder solutions in the LR.

The official ale of the TN Valley sub-forum?

Been windy and rainy today. Much needed rain has fallen for most of the afternoon. Leaves are finally off the trees for the most part.

Well, we have been waiting for the ensembles to jump on board. The 12z GEFS....that is quite a change in the LR compared to just a couple of days ago. Big trough late in the run.

Again, well said and thanks!

Yeah, well said. Any guesses which way this heads?

That probably verified out at 30-35 mph stuff thankfully. I think the winds must have pulled-up just far enough off the ground, and that spared us. You could year it, just never made it to the ground.

Bought to drive into it! Thanks. Literally just finished running/biking.

If you really just need a lift this morning, take a look at the 6z CFSv2 control at 500. Enjoy those. You don't see that type of blocking every day on modeling.

First off, thoughts and prayers are with those affected by the severe storms and tornadoes last night in western areas of our forum and in other sub-forums. Secondly, great discussion by everyone both in the severe thread and in this one. Really hope the look in the 6z GFS continues, especially long term. That is how you exit the warm pattern and maintain a winter one for a couple of weeks. Not sure that happens, but the MJO would suggest the cold might hang on longer than expected. Ensembles finally have the trough around the 21st. That leads me to believe they are likely missing other amplifications. As for the snow, I like that look. No idea if it actually occurs, but both the Euro and GFS have something similar. If the cold front is strong, that possibility exists. As the trough enters the eastern US and leaves, that is the first window. Real question then becomes whether a second shot of cold pinwheels in. Some modeling drops it west, while others drop it into the nation's mid-section and scoot it eastward. The GFS, as it did early last season, has the hot hand right now until the Euro takes the throne as the winter pattern stabilizes. The CFSv2, though likely was a bit overdone, may score a bit of a coup if it gets cold prior to Christmas as it had the cold first. Again, not my favorite model, but worth noting it has a warm-up after Christmas at 6z, and then another cold shot during early January. So, I will keep it short for this morning.

I think the SSW has to be embedded in modeling somewhere as the high latitude blocking showing up seems indicative of that. But beware, I have seen SSW fails and then modeling flip back warm OR the cold just dumps somewhere entirely different than originally modeled(could be better or worse). We talked about volatility a week or so ago. Very few things more volatile than an SSW showing up in LR modeling. Literally nothing after the split is likely right. Cohen is smart. I haven't read any of his stuff this winter. I quite twittering about four years ago, so I don't see a lot of what is on social media. I probably should do that more, but just don't for whatever reason. I follow Cosgrove on FB and that is about it....and I do this. Feel free to share Judah's stuff though. I may go catch his blog this evening now that you mention it. I do like Webber and HM though. Strong Twitter game for them. Our mets in this region are the most accurate though. Snow in MBY can be from sliders, but our sliders have to turn the corner a bit in NE TN or Kingsport gets shafted. Flow has to back for the most part. Now JC and Bristol do just fine. Bit of a rain shadow in Kingsport. Our biggest snows are normally a trajectory from SW to NE for the snow axis. Our biggest snows often tap the GOM and/or Atlantic. I have found that big snows in DC usually involve lighter amounts here. Middle and western forum areas often require different ingredients though not always. Last year is a great example as middle and western forum areas got hammered...nada here. Best snows here occurs on Arctic boundaries which have an axis which runs the Apps or SLP through the Carolinas which run from roughly Mobile and inside Savannah. You all do better when the low cuts up the eastern valley - which sucks for us! LOL. Chattanooga folks have multiple rain shadows, get the warm nose, and deal with system trending north whenever the opportunity presents. Bama and Mississippi have done ok in recent years - I think. Ah, and the dreaded dry slot in eastern areas is a bear.