Carvers Gap

Big thing for the LR forecasts is to see that trough in the East moving forward in time mid mont. GEFS is definitely the better of the 3. It is worth mentioning that the GEFS did really well with the Feb '18 strat split. That said, if we steal a storm shortly after Jan1(before the warm-up), that would be big. Something to watch.

The 6z GFS and 0z CMC also have it to varying degrees.

Sneaky system on the Euro operational at 156. The GFS has had this off and on.

Yeah, I think the first two weeks of January just after the New year(barring a thread the needle situation) have flipped warm. That said(and I really even hate saying this, because if I had a nickel...) in about 14 days, the 18z GEFS is showing a workable pattern. Trends have been pretty good this afternoon. Need to see those moving forward in time and increasing in relevance as they get closer...I can't do the backend winter deal from the past two years where we waited, and waited, and waited. This could be a pattern change or just a relaxation of the pattern from December. I simply don't know. This morning I would have said pattern change...now maybe more like a pattern relaxation. Some great SSW posts this morning - that event will have a big say so going forward. Lots of uncertainty from mid-January onward. The MJO is going to fight anything good for the East. The -NAO should win from time-to-time. However, not having cold in Canada is a major problem. Like a broken record, I say this every year. Some truly great winters never got going until mid-January. However, Nina climatology will very likely make sure the Mountain West scores this winter.

Just spitballing....One thought I had this morning is that we are long overdue for a stretch of winters with -NAO/Atlantic blocking. If we could hit such a stretch, that gives us many more scenarios towards better winters and could offset MJO problems. The Pacific is defiantly a more consistent driver for cold when it is favorable. However, the Atlantic is saving our tails this winter. I fully believe this winter would have been very warm had the NAO not flipped negative unexpectedly. The NAO deal is likey tied to the AMO being in a warm phase for us...but maybe this(a stretch of NAO winters) is kind of a run-op or a cue that it is about to flip during the upcoming years.

Also, for TRI folks...I noticed that MRX is mentioning patching freezing drizzle in the AM. Just a heads up.

I think we are going to be fighting the MJO the rest of the way - very much agree. Hoping this strat split and high latitude blocking will provide some balance this year. I liked where the 18z GEFS went. Really hope that holds.

@Holston_River_Rambler, the 18z GEFS and GFS support your idea that we are going to see cold. The 18z CFSv2 does as well. The GEFS extended is meh, but it ran on an earlier run today I think. So, trends this afternoon have been quickly to a more favorable solution. Maybe those ensembles are "feeling" the strat split now? You may be on to something.

I wouldn't give up on your cold shot just yet. A little help from the PAC, and things would get interesting just after the 12z EPS run. The thing to watch now is how the EPS corrects now that it wants a trough in the East late in its run. Won't take much to take the d10-15 look on the EPS and make it better...and won't take much to make it worse. LOL. What is the phrase from last week? Living on the edge! This is your cold shot if it happens! Again, I like 09-10 and 18-19 as SSW events. 09-10 Turned out pretty well I think. Having that -NAO and -AO up there is to our benefit with the SSW.

Basically the NAO connects or extends into a ridge that stretches from lower latitudes into the Arctic. Normally, that is something one sees during the summer. As Boone noted, that is a fairly fair feature during winter. It is likely the mechanism that will split the TPV. When I see it during SSWs, I always think "torch." But you can almost take it to the bank the an SSW is under way (or about to be when you see the monster).

12z Euro - Western Atlantic Ridge City.

Cause you know like clockwork, the 12z GFS is going to go stone cold after I make a post about a warm-up - at least it is sort of in the time frame that was discussed. LOL. I actually don't mind unpredictability. I just don't like warm patterns which lock into place.

The 2019 split was right around the development of an El Nino. It seems that El Nino failed to couple immediately with the atmosphere IMO as evidenced by the Nina-eque conditions that would be had the following winter - which was last winter. IMHO, we finally had Nino conditions from that event just this past summer and those lasted into December of this year despite the Nina. So, that 2019 event might be a decent counterbalance to the Feb'10 event - those would be my two choices and they give a wide range of "good" and "bad" outcomes.

Here is the paper on the SSW for January 2019. Dig through it. I can barley understand about half of it. However, one can see the split in early January of at least one of the vortices into twin vortices. Have to go running. I have not read all of it. Will be chewing on that for a while. Seems to me there are similarities in both the Feb'10 and Jan'19 events. Looks like the 2019 did indeed split the 2019 SPV. http://s2sprediction.net/file/documents_publications/2019JD030826.pdf

January 2019 would be the other (glass half empty) SSW. I "think" both of those winters had some La Nina characteristics(both Feb10, and Jan19). 2019 did have an SSW event - debatable what it did to the TPV. I did go back and check this morning on the site below about 2019. That was the January that had a great look and went to pot due to the SSW(maybe partial or mostly unsuccessful split...think that split had small twin vortices at the TPV off the top of my head but the main vortex held) https://csl.noaa.gov/groups/csl8/sswcompendium/

Interesting stuff, Holston. January 1985 in terms of cold is what March 1993 is in terms of storms for NE TN. It is the Holy Grail of winter patterns. I think right now this is a very different era in terms of weather. Not sure the usual analogs apply - and that could be good or bad. We will see. Certainly not going to complain if the weather goes that direction. Will be tough to reverse the temps AN anomalies for the first two weeks of January I think. The one possible good scenario which I mentioned a few days ago(and this AM), is that if the cold were to dump into that trough forecast mid-month, that would be a well-timed strat split. SSWs in my experience are just terribly tough to predict. Truly hate that we are substituting what looked like a decent pattern for a flat unknown(leaning warm) pattern. "IF" this is going to be in our favor, we should begin to see that on modeling quite soon. The past couple of SSWs have resulted in cold dumping into the Rockies after a head fake eastward. Second half of the month of January would be our chance. My bigger concern is there is very little cold on this side of the hemisphere to even tap should the SSW behave favorably - takes some time to resupply Canada. I do think we are likely at least one more cold shot that would be a good winter storm window, even if the pattern flips to a western trough. Very much looks like the West is about to get winter after a quiet month in December which followed a great November there. @Holston_River_Rambler, see what you think about February 2010. If I was going with a glass half full attitude, that would be my choice in terms of similarities. Very similar in terms of set-up - even had a late December snow in NE TN.

A warm to very warm pattern is beginning to show up in the medium to long range ensembles, and beginning by midweek of this week. The 12z EPS has moved the eastern ridge flip to this Tuesday w one slp passing through it afterwards. The eastern ridge will likely get stronger during the next 7-10 days. This is the time of year when the EPS begins to rule the roost, but is not infallible either. It does provide some relief around d14 with a ridge redeveloping out West. We saw a similar look last year. As with this last year, the cold air supply will be likely lacking. My confidence is increasing that we are about to enter at least a two week time from from from say Dec30-Jan15 of AN to much AN temps w a seasonal day or two thrown in. After that, comes the game we have played for the last two winters....waiting for the pattern to come back. Is this trough out West a pattern relaxation or a new pattern. Don't know, but I do know that trough has been tough to move (during the past two winters) once in place regardless of EPO ridges(tucks under that ridge) and SSW events. The -NAO looks to be a consistent feature, but connects with the eastern ridge. There are signs this current pattern could return during the second half of January, but if I had a dime for every time I said that during the past two years, I would be a wealthy man. The MJO this morning is now forecast to go into phase three and likely four(with a warm tour likely), and I wouldn't be surprised to see it loop back through those phases once finished...the OLR maps show very little movement from the phase 3-4 regions. The MJO is now driving the bus, though the -NAO does sit in the passenger seat. I think the greater concern is that NA is going to be completely devoid of cold air for the foreseeable future. Now, it can still snow in a warm pattern, but is much more difficult. This year would be a possibility for exactly that with the -NAO in place and storms tracking south. The wild card which I hate to depend upon for cold weather is the strat warm. Yet again, it has fouled what looked like was a nice pattern on the horizon in modeling. Right now we are either looking at a potential pattern change to an eastern ridge/western trough or a long relaxation of the December pattern which was decent(not exceptional but decent). During the next 2-3 days, if we are still looking at the western ridge holding in the d14-16 range on the EPS, then we know the drill. So, hopefully (and I have low expectations for this)...we see the western ridge pop mid-month and the -NAO holds(there is some evidence in LR modeling that it may be leaving the playing field later in January according to the 6z CFSv2 run) - if so that is cold pattern IF cold air can be supplied to NA. (The once strongly forecast -NAO for the end of this month - it is positive today on the CPC site.). Maybe we can steal a storm in a warm pattern coming up. Last note, when the SSW hit in 2018, modeling flipped from warm to cold in one, single run for March. I am not holding my breath on that one, but that is on the table as an option. For now the SSW looks to impact East Asia and Western Europe. That could change. So January thaw or pattern change? That is the real question for me.

Another great resource from the NWS-MRX in regards to snow totals. I like this product.... https://noaa.maps.arcgis.com/apps/opsdashboard/index.html?fbclid=IwAR0QYePy3pyZYuuIS0jbRay_ZTOsakNgNxnZaAoB2TsaN0mHV2zxZ1c-btU#/4fe985838e464fb9bb980799443e01b6

Again, the 18z GEFS (or some variation) is a possibility for continued winter or a tough that extends from say Calgary to Kentucky. Those two set-ups have some prior precedent with a -NAO be a constant.

Would about have to be...I think.

The 18z CFSv2 Extended has flipped back to cooler for the last three weeks of January...but it has a much different MJO. Good point, @John1122. Yeah, this pattern would have been gold in Jan, @Daniel Boone. Let's hope this is one of these winters where the warm just never shows up in real time. It may well be that the pattern we move to would be that of 95-96(lite) where the cold stretches from MT to TN...models just aren't there yet. GEFS extended does hint at that after a couple of weeks of ridging in the East for weeks 2-3 of Jan.

Yeah, the GEFS extended has flipped warm with a ridge along the eastern seaboard after the first week of Jan. I would imagine there would be intrusions of cold west of the Apps...colder the further west one goes. Maybe a Montana to Tennessee special at times. Overall, warm look(after Jan 7th) w a maybe one trough rolling through after the 7th. Pretty big changes, but it does bounce around some.

See what you can find. Seems like opinions are split(pun intended) on whether this is good for eastern NA. Watching the GEFS extended run right now. Look like a very warm week 2 of Jan with some hope for week 3. Will update in a bit. Watching Liberty and Coastal Carolina. Thanks for your updates!

Areas of "blue" for the SPV don't necessarily imply cold at the surface - sometimes it is the opposite right? I was looking at the GFS with its split at 18z....looks like the cold in NA is under the warmer strat anomalies. . 50mb will tell us a little better where the split goes, but for now...we need to be hoping this doesn't couple with the TPV IMHO. Again, there can be great years with TPVs and modeling could flip cold at the last minute. IMHO(and it is only an opinion) is that this SSW would not be an improvement to the pattern which we are currently in. It might be time to get my seed order prepped ASAP if this SSW goes the way I think it could. I will still hold out hope that it goes the way of some great winters. Be a tough pill to swallow if this SSW ruins this pattern.

What we want to see is what the 18z GEFS did. The eastern ridge fires during week 2 of January, but a trough sneaks in underneath it. That allows a western ridge to fire. Once could imagine that allowing very cold air during the second half of January to slide into that trough. That said, I am not chasing cold into the second half of January this year. If it happens, it happens...but I won't be tracking that(not after last year's persistent fail on that). The worst case scenario is the 12z EPS and 12zCVSv2 extended....-NAO connects to an eastern ridge and never relents. Like Boone, runs counter-intuitive for a summer pattern to develop during winter, but I have seen it happen. However, La Nina climatology favors a trough in the West. Enough Grinch from me this evening. LOL. Needless to say, I don't like the trends after d10, but as we know...that can still change. This will flip quickly if it is going to change. That flip might not be seen for another week or two(speaking of cold if the split occurs).