Carvers Gap

The 18z GFS has found the -NAO again after d10. It is pronounced.

The invest is a thorn for sure!

I like the pro tips. Let’s keep those coming! LOL. Hate to hear about the ski trip. Dr No visited the UT three point line last night in NYC. Have never seen anything like it.

I think if I was in Alaska right now, I would be making sure I had things ultra winterized - more so than normal for there.

If you want a redux of last year's sever Arctic outbreak in the nation's midsection, that is it. -61F air(not departures, but 2m surface temps) are in NA for that run of the GFS. Basically, the cold in northern Russia rotates over the pole and is in a southerly trajectory over NA late in the run. Impressive.

Welp, looks like we have some folks on the board. I could see it on Bays and maybe could hear some rain with ice hitting the leaves, but no official logging of snow IMBY. Awesome for the other folks though!!! 12z GFS, as one very much expects, has another variation of a blocky pattern developing after the 21st. It actually manages to get one trough through around the 22. What is waiting in the wings on that run is very cold. The 12z GFS gets there differently, but manages a double block. This time the -NAO is forced by the AN heights exiting the mid-latitudes of eastern NA. It is less of retrogression of AN heights in northern Europe. That would imply the 12z feature would be transient. Retrograding NAOs tend to hold much longer than ones which are forced IMO. Oddly, the Pacific is in our favor after 300 on that run. Sur seems like an EPO ridge is going to hold once those AN heights in the GOA slide eastward. I guess the main message for that run(and the 6z and 18z run) is that the delivery system for a very cold air mass into the Lower 48 is showing up in the LR of the GFS operational. LONG way to go, but the big red blobs are less stationary and semi-in-the-right place late in that run. Edit: After 360 the trough dumps west bu the Alaskan block and NAO blocks are strongly in place. We take that. The trough would very likely kick eastward if those features are real. Truly, what we want in place is the block, and then let the chips fall.

The 6z GFS has pretty substantial blocking beginning to form around the 19th. You can see what it does from there. 0z was less impressive, but it is back(for now) on this run. At this range, doubt the look will be consistent, but at least want to see it showing up some.

Didn't mean it like that at all. I just needed to go back and read it. Had no problem at all with any wording. You always do a great job! My apologies if it sounded that way.

I need to go back and read your post again! Lots of similarities to last winter for sure, but just a bit earlier. Second year La Nina might push that just a hair eastward - anyway I am hoping so. LOL. And I know you know this, but BN temps in early January are COLD! We'll see. I may be out mowing the grass at this rate.

The GFS ooks like the 12z CFSv2 w/ a double block late in the run. Monster EPO ridge while the ridge over the eastern US retrogrades into southwest. Ridge to the east of Greenland. That would unlock the floodgates(meaning cold air masses) if real.

For kicks and giggles check out the Alaska AN heights late in the 18z run. You know we are sitting on a potentially long stretch of warm wx when we are looking that far out. Impressive nonetheless. That would deliver a big shot if cold.

Hard to tell. I think there is really a chance for cold after the 20th, and especially after the New Year. But that is preliminary guesswork at this point. For now, I am watching the operational GFS at LR as it will likely catch(even be a bit too quick) cold intrusions more quickly. The ensembles will change very slowly. I think the pattern itself is base warm. The trick is trying to nail down anomalously cold air masses embedded within a warm pattern. That is no easy feat. I don't think we will see wall-to-wall cold like the CFSv2, but it is not without precedent. Also, the warmth is not without precedent either. As you know -NAOs are notoriously tough to predict at range. Last year's -NAO does give me hope that we may be entering a cycle where it is more prevalent during winter, but we will see. Global ensembles go out to the 23rd, and they are solidly in the status quo camp. I really think operationals will see any amplification or reorientation of ridge/trough axis alignment...first. For now, we wait.

No problem. Man, sometimes I am in the school carline(or just in a hurry) and it looks good on the iPhone, and then looks like hot garbage on a bigger device! LOL.

The Atlantic if the CFSv2 is right. If that Atlantic ridge forms, it may force things to back-up in NA and buckle the jet. It is close enough to NAO land that it may well behave in the same manner. The 12z GFS operational was super close to this. Now, as you know, we are dabbling on the edge of the accuracy of computer modeling. So, this is pure speculation on my part.

I usually take about 5-10 minutes after each post and make sure it looks/says what I want it to say.

Give me a sec....still editing that post.

The CFSv2 at 12z reminds me of the 18z happy hour runs prior to the GFS getting its most recent update. Not saying this is going to happen. The possibility is there if the MJO manages to rotate into phase 8 which some members of the CPC MJO model group were flirting with. Maybe there is some strat stuff in play. Yes, I know it will be tough for the below scenario to occur, but it is not without precedent during La Ninas(nor is the warmth without precedent). However, high amplitude 7 even getting close to 8 could force a PNA/EPO ridge to pop. The NAO, fickle as it is to predict, is showing up in modeling now at times. Below is the CFSv2 for early January. Needless to say the departures under that are ridiculously cold. Some of those departures are twenty degrees below normal at the coldest time of the year. Now, the CFS will have a different solution at 18z. Just how that model works. This is a double block....EPO/PNA and an Atlantic block. This is not a forecast. This is spitballing for the upcoming pattern. I don't own a wx blog nor operate any social media for wx. I don't trade in futures nor do anything in the stock market. This forum is pretty much it for me. So, zero reason for me to hype. This is just discussion. This may work out and it may not. The Euro Weeklies...just flip all of the ridges to troughs and troughs to ridges. I should add that BN heights in the SE occur much earlier than this on this particular model. This is just where it goes a few weeks after things switch up. The CFS begins to move pieces around after December 20th by undercutting the ridge with BN heights in the SE.

Tagging onto my earlier post, the fronts generally pinwheel in the northern tier of the Midwest and Plains. The development of an EPO ridge, if true, is a significant adjustment by the GFS. The GFS, though often too quick with pattern evolution, will often catch adjustments more quickly than other models once the winter season settles in. One other not with that run, there is a low in the Aleutians instead of crazy AN heights. The CFSv2 could score a coup on this if it verifies.

Fairly interesting look on the 12z GFS as it pops an epo ridge around the 17th. A HB vortex then pinwheels cold fronts into the lower 48. Most of the fronts are not overly impressive, but that look can work.

Maybe snow tomorrow morning in some of the forum area, and a record high Saturday possible at TRI. Then, maybe "cold chasing rain" snow after the from passes Sunday. @Holston_River_Rambler, great posts.

I don't follow them on social media. I don't even Twitter. LOL. Most of the cool tweets I read are from AmWx or @tnweathernutwill keep me plugged-in. I get up in the morning and work through models, usually before I go to any sites just to have an unbiased perspective. May catch some of the Bills game as the weather their is windy and at times snowy.

Yeah, those cats are sharp! East based is kind of dry NW flow if we are lucky with a ridge trying to belly in from the southwest. My thinking on that is the east based NAO would hopefully retrograde westward.

You know they really aren't that far off right now. Just spitballing, but I think we have a cold shot coming later this month. They are possibly sniffing out a trough amplification(no idea if a pattern change) after the 21st. But yeah, I like 17-18 as my general rule for this winter...but I think we get a second shot of cold this time around due it being a second year Nina and the QBO in our favor. November being cold is a big card. I mean the Weeklies control is stone cold while the mean is warm - not sure I have ever seen the two that opposite. The control just unloads on the forum area with -20F departures at times(and a prolonged cold shot at that). JB made a good point this evening - he noted that the AO and EPO are negative in the means for the 12z EPS late in the run(think it was the EPS but you can check me on that) where they were not at 0z. The Weeklies are derived from the morning run. Would have been interesting to see the Weeklies run from the 12z run. Maybe some light at the end of the tunnel. Let's just hope it isn't a train! LOL.

Of course we knew the Weeklies (Euro) would be toasty. I wasn't expecting its control to be exactly (and I mean totally) the opposite for the entire run.

I mean is it too much to ask for the Pacific and Atlantic to both be in sync just once every twenty years or so?! LOL. I think the cold is there this year. Just need to get out of the eastern ridge and/or gradient pattern(where the cold is bottled up north of the lower 48). I tend to think the November pattern will repeat in a way that disrupts the overall base-warm pattern. I was reading a post on FB from some folks in western Montana. They are like, "Where is the snow?" It is brown up there when snow pack building should be well under way. I have a feeling that is about to change for them though.