Carvers Gap

Let's try this one more time...the 12z GFS has a second wave of frozen precip Monday for areas along the northern Tenn border, KY, and SW VA. The 0z CMC had this as well - waiting for its 12z run.

We are close to having to start a thread for this weekend. The 12z RGEM has ice over much of the eastern valley. The 12z GFS is less formidable, but has snow for SW VA and NE TN. The 12k(edit) NAM has snow over the Plateau and SW VA/E KY. Very close call, and getting dicier with each run.

And that CFSv2 at 6z sure looks a lot like the GEFS ext last night for December.

JB mentioned that all of the predicted stalls of the MJO have not occurred yet. He said modeling is having to adjust to the idea that the MJO is just continuing on around. Now, FTR I am not opposed to the Euro idea of a stalled MJO in 8-1! I really don't know honestly. I do think the MJO is going to reload though and rotate around once again. I found the CFSv2 seasonal this AM to be reasonable for DJF. This fits with a weak Nina. I have noticed multiple models w/ the NAO beginning to fire. To me this implies that cold drops into the Plains, very cold air at times. Then, the cold pushes south eastward. Basically this goes in sequence....cold -> thaw -> very cold.

No wonder models are all over the place....

The good thing that I see with regards to the mid-month ridge rolling through is that it is temporary on all ensembles this morning. It is always in the realm of possibility that the ridge is a pattern change, but for now it looks transient at best(3-4 days at the longest). That ridge, as long as it rolls through, could very well set the stage for the coldest air of the season(so far) to fill that trough behind it. There are pretty strong mechanisms in place to deliver cold air d10-15.

The 0z 3kNAM and 0z RGEM show frozen precip over NE TN and SW VA over the weekend. Just something to keep an eye on....

@John1122, these last two basketball games and football game....like watching it snow in New Orleans, man.

The 18z AIFS has 2-3 very strong cold fronts w/ the anafront ending the run.

The last four runs of the GFS for Dec 12-17th.

The 18z GFS shows one of two extremes which have been modeled in the past 36 hours. That is a crazy cold run. Real feels have ranged from the 70s to below zero with these swings - for the same hour!!!

Haha. If u want to see a wild swing, and it has been going on for a bit…look at 360 on the GFS at 18z and then flip back and look at 12z (temp anomalies). We are talking 40-60 degree swings! Good times.

The 18z RGEM has company…the 12z NAM. Both are at range so the usual caveats apply. The 18z GFS wasn’t too far off.

The 18z RGEM is worth a look if you live in E TN from Knoxville northeastward and also the Plateau as this likely trends northwest.

And there is more. This is where the 12z GEFS left things at the end of its run. That is a cold look with two mechanisms with which to send cold southward out of Canada - EPO ridge and blocking over Greenland. And to get great winters, we need some SER.

Then compare those to the very end of the 12z Euro. See that big ridge in Alaska? We know the Euro has a tendency to feedback in the West. If that trough corrects eastward(which it should) and it is actually real, that sets the stage for very cold air to rapidly flood into the NA mid-section. As Boone noted above, it is very common for extreme warmth to get pulled ahead of strong cold shots. You can see the warmth surging into New England. During old school winters, many great cold shots were preceded by storms and rain. There is also a path to very warm temps. But beware. We have noted that modeling feeds back in the Southwest. But...it also feeds back in the lee of the Rockies in Canada when extremely cold air enters into NA. IF the MJO rolls into 8 and doesn't do the GMON stall in phase 7, that cold will likely get kicked southeastward. That is why I am very interested in the next few days of MJO plots. If they get to 8, even in the COD, that likely means the trough is in the East.

And take what I just posted and compare it to the 12z CFSv2...

Typos should be fixed in that last post...at least you know it isn't chatGPT or Grok generated stuff from me! The typos tell the tale. Anyway, remember how I always say to look out when the control doesn't match the ensemble with the Euro Weeklies? The control has a habit(as does the GFS at range) at sniffing out bigger fronts. I think reality is closer to the control. I think ensembles are too washed out. What we are seeing is a strong presence of cold in the Canadian Prairies and Northern Plains in the LR. The pattern in our area is cold front -> warm up -> cold front...wash, rinse, repeat. The ensemble washes that out, but the control does not. I think the Lower 48 may see a pretty strong cold outbreak. Does it head to the West first? Likely. But.....if it comes down the Plains in the form of an anafront, it is gonna be freakin' cold howler. I am going to take a look at afternoon individual ensembles to see how many have that type of strong cold front.

Need to get him a handle and have him join the forum. He will fit right in with the rest of us!!! Haha!

The 12z Euro essentially has an anafront at the end of its run. The front isn't as north/south as we would want it, but it is good that is still showing. I think we see incredible return flow in front of it - likely record highs and severe. Then that baby pushes through and things freeze solid. Let's see if that hypothesis holds.

Both the 12z RGEM and Euro(see Boone commit above) have a system next weekend. By default the CMC has it as well. Looks like a time of day type of deal. Plenty of northern stream energy after that. I suspect modeling is too quick with exiting the cold eastern pattern. I do think a ridge rolls through though, and a stout one at that. I also think an anafront is still on the table.

I don't have any thunder in the mountains, but I am bringing this to the table... The Madden Julian Oscillation has an odd resemblance to the Death Star.

Well now, that is a proper 12z suite incoming.

Let's see if the GFS holds on to this ana front idea. It likely won't be there each time, but that is now 2 of the last 3 runs(18z and now 6z). If I remember correctly, it has a knack for that - I cold be wrong. I do think there will be some sort of warm-up embedded in all of this. It looks like mid-month is when it is most likely. Right now, I just think modeling is not recognizing the MJO very well at all. That is why I want to look at the plots this morning. Until the MJO moves to the right side...I have my doubts about any sustained warmup. Even the 0z Euro has an anafront of sorts at the end of its run w/ severe in front of it(not uncommon in my experience).