Carvers Gap

The GFS has been bad outside of day 5....really bad. Just look at the 500 vort map today. Crazy town. However, it is usable inside of d5. The agreement between the GFS, GEM, and ICON is a good thing. How that potential phase unfolds is important. Just look at the 500 vort maps and you can see the interaction. The good thing is that there may well be another window w/ the storm which follows the Jan15-16 storm.

Yes. I am still sifting through the entire suite. I don't see exceptional cold at this point, but seasonal looks likely during that time. The second window(second ridge retrogression) for cold looks like it could be winter's worst. This is why I am not overly sweating the MJO right now. The "storm window" where we see a deep eastern trough w/ lots of energy and cold diving into it between Jan 15-20th...want to guess the MJO phase? Six. The CPC MJO models loop the MJO into 8 by the end of the month. There is probably some lag(maybe a week) in that surface reflection here. But it makes sense that the MJO matches the next retrograding ridge cycle. If we can score in 6, roll a ridge east-to-west after that, and score phase 8 at the end of January or early Feb...that might be a really good rotation. See GaWx's comments about phase 6. Anyway, still plenty of uncertainty...but it the potential for an interesting few weeks of weather is increasing.

On the 12z GFS, that trough is negative tilt over Georgia. The surface just wasn't there quite yet. But give me that setup 10/10. Then the GFS loses it in the West. The GEM and ICON had very similar setups. The phase is not really a finesse deal. It is just timing. With that deep trough potentially in place, we are simply watching to see if the STJ can interact w/ the northern stream. Pretty wild look on voracity maps.

That trough has been on modeling around has been on modeling for a few days. In fact, it was the image golf noted was not from the correct model run(I fixed that and thanks for the heads up). Again, I used to just look at surface maps w/ pressure gradients on it. That looks is good. It may well not mature until it gets to the EC, but it is trying to go neutral over Alabama. If it does, look out.

Honestly, before the 12z GFS lost its stuff...the GFS has a similar solution at 500 to the GEM. The GEM wasn't far from the ICON. Big piece of energy rotating through around 189. The potential for a phase is increasing. How that unfolds is still TBD, but man.

The 12z GEM at 500 has a lot of energy in it. Never quite gets it together, but several small vortices rotate through. That said, models are flirting with something big between Jan 15-20. The GEM almost cuts off energy over the Gulf Coast during that time. In fact at 192, it does cutoff a low over southern Alabama.

The 12z GEM manages to keep its stuff together and that energy(which was headed from West Yellowstone to Hawaii on the 12z GFS) gets sent into the base of the trough south of Tenn. I can't see the surface, but the 500 anomaly looks nice.

The 12z GFS is off the rails....at 200 it managed to send a storm from West Yellowstone, Montana, to San Francisco, California. I kid you not. Just look at the surface maps, the 500 sort maps, or the 500 anomaly map. Insanity. I mean could it happen? I guess. Is it likely. Nope. Toss the entire run. But let's play "I'll take the ICON at 180 hours for $200"....it manages to phase the bottom three x's and was on its way to the fourth(northerly).

The 12z AIGFS is pretty much a Feb 2015 redux. Nickel and dimes lined up.

The 12z ICON was like watching 10 episodes of a show, finally getting to where you think you know what is gonna happen, and then you gotta wait 18 months for the answer. That baby was set to rock.... How many ways can a storm phase, three? That was like a quadruple phaser.

The 6z GFS. That'll work. So will the 0z.

The 18z AI EPS. Some big dogs in there. Two separate storms. Windows are 14-15th and the 20th.

The 18z GEFS and AI GEFS are AIFS Euro are COLD in the window that we need them to be. Keep the STJ cranked, and let's roll.

Basically, the 18z GFS traps a piece of the TPV under HL blocking. It just sits and spins while locked over central Canada. This is what ensembles might not be able to see. It kind of looks like LR ensembles w/ a SER. But...that SER is minor as it is getting lifted into place by the strong BN heights over Canada. The HUGE plus on this run....storm track is right over our forum area w/ repetitive winter events.

After 200, the juiced STJ is firing right into an inbound Arctic air mass.

We got JB talking about a d15 warmup. Meanwhile, this GFS run is going to have it snowing in Cuba.

An outlier the 18z GFS may be...it is about to send it.

Haha. That is just an insane HL blocking run by the 18z GFS. It is either the beginning of a trend(and I have seen more NAO recently on modeling in this time frame) or this is a toss. It is a beautiful pattern, but for sure an outlier.

The 18z GFS continues the trend of bringing light snow to the region around Jan 15. Miraculously, a huge NAO is in place.

Great discussion in here this afternoon. I enjoyed reading all of that - even if it isn't all snow!

The interesting thing about La Nina...there are a few analogs which aren't dry during winter. I think @John1122 has posted those thoughts prior. In fact, they can produce flooding rains at times. I don't think we are out of La Nina quite yet. That said...there was worry about Canada losing its cold. The 12z Euro(yes, it is at the end of its run, but has support from its ensemble and across some other models) had this at the end of its run. Let's see if the 12z CFSv2 can get on a run. If flipped cold for Jan 21-31. I probably is a blip, but the image below kind of fits where I think we are going. The coldest air is going to push into the Canadian Prairie and refuse to budge. I am sure the West will get its fair share...but one good cutter, and any warm-up would go poof! This also fits exactly what LC's analogs have shown for late winter. Can you imagine what the Lower 48 would look like w/ a strong amplification in either of the blocking areas would produce? The SER will fight, but w/ that air mass as a plausible option...we may need a little SER.

1). The 12z Euro appears to have some chances as well w/ multiple vortices and energy climbing the EC. That pattern is loaded w/ chances every few days. 2) If you watch the end of that run, the western ridge rotates rapidly west through the Aleutians. It moves so rapidly, it might well allow the EPO to rebuild. If you look at the end of the GFS run, it sticks a trough out West. But the ridge in the Aleutians moves so quickly that you can almost see the ridge sliding underneath the western trough, ie the eastern trough is already retrograding. 3) I don't lose a ton of sleep at this time of year. What I "think" is going to happen is part of the TPV is going to crash through central Canada and almost force a trough to stick in the center of the continent vs out West. The SER will fight it, but cold will push against it as it pinwheels around that trough IMHO. I think the 12z AI GFS is the extreme eastward version of that look. I think the Euro is about right...I might nudge it a bit west - speaking of 300hrs +. 4) Again, I remain optimistic that the Jan11-21st time frame is a good one for wintry weather. Then, we get a TBD break(could be quick). Then we repeat the same cycle. Again....One variation(instead of a western trough) I think has some merit is the 500 TPV rotates int0 central Canada on its throne, and makes everything work around it. Very blocky looking pattern.

The 12z GEM has a storm along the coast during the 14-15th and a northern vortex crashing in. Close miss but still some snow. Good overall pattern though. As for Bam, I generally have steered clear of that site most winters....flip-flop city but some really good content at times. Right now, the MJO seems decoupled from the NA weather pattern to some extent (certainly some influence). I think the window from the 11th-21st(maybe a little longer) is a good window. Then, it looks like another ridge will retrograde through the East. The positive from the GFS is that it RAPIDLY moves the Alaskan ridge through the Aleutians into Asia. The faster that goes, the faster that we see the ridge develop in the West again. February looks like it will have another deep trough develop between Feb1-10. Remember, I am big on finding windows for winter precip, and then watching details as that window draws closer. I do think there is a chance the ridge locks out West, but maybe a 40% chance on that.

Man, the 12z GFS is just barely missing on some decent chances. By 258 and just barely in fantasy land, the 12z GFS looks very similar to its AI counterpart. Jan 17 is kind of a timeframe I have circled when the base of the trough flattens out, and allows for storms to slide across.

The 12z ICON buckled the jet further west than the 12z GFS. I wouldn't be surprised to actually see a cutter in that time frame...that is how "off" that run was Jan14-15 on the 12z GFS.