Uncertainty

Aside from a short brush with a +NAO (blue) around Xmas, it’s looking more and more likely this early winter period is going to be a special one for coldies… Before Christmas we have a strong -NAO signal, here at week 3 Every chance of a very snowy outcome between day 10 and 15 as the trough to the sw pushes NE along the flank of the Greenland high, meeting the very cold air that has rotated half way across the hemisphere to meet it. A stellar, if rather precarious possibility. After Christmas the blocking returns. Just as the maestro Masiello has suggested. There’s even, whisper it, the first cluster of very weak members in the strat charts Good to see the steroid vortex signal from the last update weakening. Keep a watch on that cluster, every chance it could grow in the coming weeks. The 12z eps are synoptically quite incredible. All in all, an enthralling outlook. Like it or not, this Greenland high looks the real deal.

This really is something from the 12z eps And this, at the end of the run, is quite frankly astonishing. I have viewed extended eps charts for many years. I don’t want to be too hyperbolic. Nor am I saying it’s going to happen. But, as a chart at such a long range, it’s simply sensational.

GEM day 9 Serious cold, getting closer…

Greenland has fallen!

At 330 hours, The mean charts from the eps and geps Are hugely supportive of a north easterly flow even at this extended time frame. This means op runs that follow this theme, like the frankly preposterous gfs para, are both plausible and possible. Al aboard the Kamchatkan Express? As early as day 11, the JMA is preparing our air from Alaska! In the meantime, the UKMO continues to annoy and frustrate, planting seeds of doubt. Yes it might end well, but we never see that bit and it’s different from other output so that adds uncertainty. You can’t discount it, but the amount of times even in the last two weeks it’s been on its own and later found wanting is telling. There does however seem little chance of snow here during the retrogression phase, thanks to those se euro heights that have thwarted coldies so often in recent years. The low to the sw too influential to suggest anything white and flakey manifesting before day 11. It’s almost back to its ‘heat pump’ position it took so often this summer. It’s clear to see the SE flow it’s causing on the eps mean at day 9 Recent years have seen this low struggle to progress SE. It could trend further se, but equally it could trend stronger or even further NW. one eps cluster has it close enough to bring rain to many in England late next weekend. The GEM representative of this scenario This would bust many of the ‘settled weather returns’ forecasts that have understandably been made in recent days. It would be ironic if we end up with all this blocking and a low parked just to our sw throughout. There is so much to be resolved, even with the initial trough disruption early next week. It’s ever so interesting synoptically compared to most years - indeed it could be heading somewhere quite remarkable - but it still has all the same frustrations when following the models.

Our hopes and expectations Black holes and revelations! PS What kind of a jet profile is that? Azores to the Arctic! Big time retrogression occurring on the pub run These are truly incredible charts for early December.

Looks like last night’s run was an aberration!

Christmas looking interesting with a hint of low heights to the S… Would be cathartic after last year’s Christmas debacle! Looking further ahead, the New Year period looks primed for further amplification near Scandi/Svalbard I honestly think we have a 70% + chance of a midwinter SSW. The weakening Nina, high Eurasian snow cover, cold southern strat analogs and crucially, continued blocking to the NE combined with indications the mjo could cycle towards 4–>7 late Dec all back up such an assertion. Interesting times ahead, beyond the considerable mid term excitement For coldies.

EC46: Blocking, blocking and more blocking!

The key takeaway from the absolute smorgasbord of solutions for mid-next week —> week 2 is that we’re going somewhere interesting but we’ve got no idea how it is we’re getting there! Both gs op runs find blocking but make a faff of getting there. It might take 2 or 3 bites of the cherry. Also, no obvious route to snow in the forecast at present…

You’re doing a brilliant job pal. So many great articles on Google scholar I would recommend to you and anyone else interested. Have you read the research on the impact of East Pacific Ninas on the mid winter NAO? Google Scholar SCHOLAR.GOOGLE.COM This article, a tad beyond my pay grade, suggests that low sea ice concentration in the Barents-Kara region is a good predictor of a wintertime -NAO. Judah C signposted me into this research. Google Scholar SCHOLAR.GOOGLE.COM Regarding this winter. I’m fairly confident on the east based Nina classification I’d like to get the thoughts from the sea ice folk on the SIC in that crucial Barents - Kara region this Autumn, am I right in saying they are below average? If so, then both factors support continued interest for cold lovers beyond the upcoming amplification period…

A mean easterly on the eps at day 10 The trend today seems to be for the significant amplification to occur to our west behind next Tuesday’s low. But there are variations on the theme. The ECM is fairly representative tonight, taking the trough down the N sea into Europe with strong high pressure building over the top to the NW. The UKMO looks out of place with this now, surprise surprise. The GEM is yuck, but as others have pointed out still follows the general pattern it’s still blocked, just the trough gets stuck over the U.K. The para sends the low through France The point is, there are still a large spread of options for this time next week, even though the destination (blocking to the N and a euro trough) looks rather set. It’s after day 10 though that things could get really interesting… This morning’s EPS at day 12 Westerly mean flow This evening’s EPS day 12 Easterly mean flow It really is rare to see, in the canonical stormiest time of year, as pronounced an -NAO as that, especially modelled 12 days away. Plenty that can go wrong of course, but this signal has been signposted for months. Should it occur, it will be a victory for the teleconnection tea leaf readers. Of which, I am glad to be a member.

ECM takes three attempts to successfully get there, but support for the giant Azores-Scandi-Ural link up has grown this morning. The GEFS now has a mean easterly at 360(!) Anomaly Given the very strong strat forecast from the ec46, I would personally rather we ended up with a long lasting Ural /Scandi feature rather than an -NAO / Scandi trough. The latter would give us an early shot at cool/cold but the former might keep the SPV in check or even set it up for the knockout blow in late December. If the week 2 easterly sets up right we could get cold from the east but the orientation would have to be quite precise. GFS and ECM both have a euro trough but there is too much pressure from the Atlantic. @IDOhas highlighted why this could be the case. If, like me, you don’t want the high to retrogress away from the NE. That’s potentially a good thing, as long as the Atlantic energy is not so strong that it blows the whole lot away. The GEFS have really moved away from that latter option. As Marco has noted, the clear East-based rooting to La Niña correlates strongly with Jan/Feb -NAO. If we chuck in a New Year split, then the the game’s afoot for the mid-winter period. Here’s to the long game. If you were after a stonking Greenland block day 9-15 then you’re going to be disappointed this morning. If you want Anthony Masiello’s (the closest thing to a sage you will find on Twitter) winter prediction (late Dec split SPV) to come true, then join me and root for the Ural block.

Thanks BA I didn’t actually know that. I did know that the automated NOAA forecast forecast on a Sunday uses NAEFS hence the idea behind the ridge becoming a bigger player in the 8-14. I think the models underestimating of the Canadian segment strength is a major player in many of our failed cold spells. However, sooner or later, a forecast like this will verify. The tricky part for us is knowing when it’s just a fantasy and when it’s the real deal. For me, it’s about consistency and the forecast generally upgrading as we head closer to verification. This one (eg possible December blocking) has also been pretty well signposted for a few months now. The next week will be crucial in getting the building blocks in place.

ECM, anyone? Thats 4 runs in a row with the gigantic high to the NE dominating out weather! It’s there on the mean too, though a bit more Atlantic influence as you’d expect as this range. Still a chance the modelling being too quick on this high to influence us directly, but the chances of it’s existence manifesting have increased this morning. After that it’s blocked or blocked on the extended eps Mirrored by the GEFS (I talked about consistency yesterday) A bit messier on the GEPS, but still a clear blocking signal to the N NAEFS has it too Good agreement across the hemisphere there at over 300 hours. Expect more influence from those NEern heights on the 8-14 noaa tonight. We are getting close to being able to say something is stirring here…

Ecm would put continued pressure on the strat into December. A west based -NAO would allow it to strengthen unabated. I’m rooting for the ecm style solution, though that would of course be vulnerable to the dreaded ‘flattening’.

Wow. That about sums it up mate. ECM and JMA go big time on heights to the NE First settled end to a JMA run in quite some time, apropos of not very much.

That’s an encouraging anomaly from the GEFS. Need some consistency now and of course for that anomaly to get stronger. Until then, plenty of lows to get through…

Virtually impossible to know where we are headed beyond day 6 or so. Both gfs runs have gone off on one with a weak west based -NAO, a bit of a stall on a low exiting the states and things could get interesting quite quickly The GEM has flipped from a southerly tracking zonal pattern to stronger heights to the NE ending with a U.K. high. The UKMO looks really, really wet. I don’t think the ecm will repeat it’s over amplified antics from this morning but i wouldn’t be surprised if both the gfs and gem options are there on the ens, along most likely with a flatter pattern and something similar to this morning. There are lots of lobes of Arctic heights kicking about as well and I don’t trust them at this range. All in all a very tricky forecast. Best get the tea leaves out.

Absolutely right. There are so many options. The para goes for a big AR and the op goes for a big ridge to the NE. Still lots of flat and very blocked members in all 3 ens suites, even though theme of heights to the N/NE remains… As @Allseasons-si has posted, the eps has flipped back to a slight majority of members going for a big block to the NE compared to this morning. But you wouldn’t be surprised if it flipped again in the morning. If we are going to get a block to hold, not fall away in the 8-10 day range, we need consistent upgrades, not this two steps forward two steps backwards business we have now. It’s frustrating.

Perhaps, but 19/20 was an exceptional event. There is no analog, statistical or modelling based analysis I can see to support suggesting we likely to be in for a +++NAO winter. An ssw is more likely than normal this winter (c/o Tonga and the cold southern strat this year). There is no strong +IOD like that winter. The Nina is east-based (supports blocking). The +solar/Wqbo combo supports blocking. December continues to look blocked on the 46 and most seasonal forecasts. Unless you are able to share convincing evidence to support your assertion, then I will have to respectfully disagree my friend.

2019/20! What on earth is suggesting that Don? Unsettled weather in November? C’mon pal: Not one of the seasonals has that signal, and they all had it at this point that winter. I’d say a 16/17 winter is plausible, and of course the nightmare scenario winter is always possible, but there’s no evidence for that right now.

Was it not ever thus? Except perhaps in the zonaliest flat fest. The GEFS and eps look similar at the back end even though they don’t tell us much about what it’ll be like on the ground here. We could end up with blocking to the N but unable to shake the ridging to the S, CFS has that scenario…

EPS and GEFS remarkably similar at the back end of the runs. I’m not sure this is write off winter territory. Two people on the winter forecast thread have effectively done just that. IT’S MID NOVEMBER! I do share the concern that the SPV will quickly restrengthen and if the Ural blocking signal wanes over the next month or so then perhaps… but this has not occurred as yet. Indeed, the Atlantic is stalling on the latest iterations of the gfs and GFSp I’ll let you know when the towel’s ready for throwin. And it ain’t tonight.

Do I detect a rare bit of optimism sir? It is a very odd Scandi high that one later on the gfs, it looks as if it should be shoved aside as quite weak. Once again, it leaves us tantalisingly close… The GEM drops the +NAO signature, and then some, but leaves us in a sort of no man’s land. The para has another go at scandi heights So lots of blocking appearing in late Nov, it’s just very hard to know where it will manifest at present. I like the icon at 180 On it There looks a fair chance the high retrogressing to the NW could be reinforced by the trough stalling off the eastern seaboard, this in turn should force the low to the west into Europe… Not sure on that chart though as not really reflected in other output yet. I’m still not seeing a believable pathway to deep cold in the medium term, too many options. Nevertheless, the charts continue to be unusual and interesting heading into winter.