Uncertainty

The night is always darkest Just before the dawn! It took a pretty crazy storm to get there @Mike Poole - as you say s’about time we had some excitement. It’s been dismal in here recently - recriminations galore (the vast majority of it completely understandable!) after our 351st fail of this utter let down of a winter. The pub run shows that a) another potentially hyper stormy period is plauisble and b) Atlantic blocking is not off the table but is unlikely until over 12 days away. It does turn into a very cold and snowy run

@blizzard81 @Ali1977 Feels like we’re the last remaining contestants on some cruddy game show called winter 2023/2024… But the gem and UKMO say we live to fight another day!

To be Or not, to be

GEM promising too. We just need the wraparound of cold on the eastern flank of the high to deliver a cold pool. That’s not happened on tonight’s output but the Atlantic profile has improved considerably. Still time for this to flip back and forth a few times but you would think with the mjo stuck in 7 that some form of hp influenced weather is more likely than straight line swerlies at the very least. @joggs yeah mate you’re right. Hopefully we see a cluster have a go at that and we sneak a cold easterly in at the last. We’ve been robbed so many times lol.

Lukesluckybunch it certainly is. If we could sharpen the Atlantic jet another 5 or even 10 degrees polewards, we’d be in business. @blizzard81much better trends indeed… It feels like the first set of op runs in quite a while that have veered back to a more easterly medium term solution. We need much more momentum though over the coming days for that thing that rhymes with east and also comes from that way yonder…

The ICON isn’t as dreadful as recent gfs iterations and fits pretty well with recent ensemble runs. We do have a low over S Italy. I would have liked that run to progress further as to jet to the W of us looks to be sharpening. Regardless, a long way from cold advection on that chart. Though as @blizzard81 spotted the ec 6z control did have a go at a scandi with the jet rotating around the eastern flank. But we also need the Atlantic jet to play ball. Hopefully the gfs op can finally pull one from a colder cluster today. Looking upstairs a big shift towards a major ssw today with over 80% of GEFS members going full Tonto. This is going to make the output even more wild and unpredictable in the coming days and weeks.

The eps builds the high further to the NE, not so much a U.K. high anymore @IDO ? This high seems rooted over scandi. Last night’s eps was more a northerly Sceuro. Its not a BFTE yet, but it’s an improvement towards a cold fetch easterly…

A full on easterly on the gfs, and following the footsteps of the ensembles? Not to be dismissed. Is there a lot of model fatigue? Really surprised this spell (post low-gate) is not eliciting more interest. Some have quickly dismissed it. This feels like the start of a significant cold spell. Also if the low does stay on the ecm trajectory we’re looking at amber warnings for snow. Again surprised at lack of interest. The BFTE was weeks after our period of interest e.g end feb vs mid feb. And that had phenomenal interest on here.

There’s been a real sea-change in the output tonight in the 7-10 day range, regardless of what happens with the will it won’t it north / south Thursday low. The heights to the N of the U.K. seem more to just build spontaneously, rather than be reliant on WAA from a stalling Atlantic low. It’s apparent across the 3 main models. GEM 0z GEM 12z Notice the Azores low is now squashed. Heights are rising to the W and N of the U.K. - though the shortwave W of Iceland could be an (academic) nuisance. ECM 0z at day 10 On the 0z ec, we are reliant on the Atlantic low to build the ridge through the U.K. and on to the NE if we’re lucky… On the latest ec Completely different. The Atlantic is spilt into two jets, the sub tropical jet is sending multiple squashed lows towards Iberia whilst the northern arm builds the Icelandic high. A much rarer scenario than the above and one I’m more familiar with from archive charts than from my own forecasting experience. What does this mean? Are there models ‘seeing’ the road to northern blocking the ec46 has so consistently promised? I think they are. And there are other factors driving this transition to a colder paradigm: - modelling is picking up on a much weaker strat than anticipated a few days ago, though an ssw looks 50/50 and the strat has been weird this year and you wouldn’t want to call it yet. - the mjo is forecast to stick around somewhere in phase7 and(possibly) onto 8. A good sign for cold weather - the massive AAM surge and accompanying +EAMT favours blocking patterns, especially when the above factors are in play - The ec has been incredibly consistent. As consistent as I’ve ever seen it, even taking into account the daily runs It continues to advertise a marked cold and blocked spell. Indeed, the colder than average temps are back tonight too. When looking for significant pattern changes in My personal forecasting area - the 10 to 15 day range - I look for a mean high in an unusual place to persuade me that a signal is genuine. The geps has had this for a few days but now the other two have cottoned on: GEM: mean easterly with a Greenland block and S euro low GEFS: a highly anomalous North Sea high with a flow from the east in the S This retrogresses to a NEerly The eps is still pouring out. But @Mike Poole assures us the clusters are bankworthy and he knows his clusters. Unsurprisingly, he’s not wrong. They are sensational for cold with a eurolow of some description and varying degrees of blocks to the N. So is it a done deal? Ha. Of course it isn’t. We’ve been here before and further and still had everything bust. BUT… you can’t deny the incredible synergy between the telecons and the models - and particularly the consistency of the sub seasonal modelling. In conclusion. It might, just might, be time to… buy more grit! Original post: https://community.netweather.tv/topic/99814-model-output-discussion-22nd-jan-2024-onwards/?do=findComment&comment=5029050

Don’t think I’ve ever posted a single non-op perturbation before but… Eps control… Hopefully you’ll understand why I chose this one!

There’s been a real sea-change in the output tonight in the 7-10 day range, regardless of what happens with the will it won’t it north / south Thursday low. The heights to the N of the U.K. seem more to just build spontaneously, rather than be reliant on WAA from a stalling Atlantic low. It’s apparent across the 3 main models. GEM 0z GEM 12z Notice the Azores low is now squashed. Heights are rising to the W and N of the U.K. - though the shortwave W of Iceland could be an (academic) nuisance. ECM 0z at day 10 On the 0z ec, we are reliant on the Atlantic low to build the ridge through the U.K. and on to the NE if we’re lucky… On the latest ec Completely different. The Atlantic is spilt into two jets, the sub tropical jet is sending multiple squashed lows towards Iberia whilst the northern arm builds the Icelandic high. A much rarer scenario than the above and one I’m more familiar with from archive charts than from my own forecasting experience. What does this mean? Are there models ‘seeing’ the road to northern blocking the ec46 has so consistently promised? I think they are. And there are other factors driving this transition to a colder paradigm: - modelling is picking up on a much weaker strat than anticipated a few days ago, though an ssw looks 50/50 and the strat has been weird this year and you wouldn’t want to call it yet. - the mjo is forecast to stick around somewhere in phase7 and(possibly) onto 8. A good sign for cold weather - the massive AAM surge and accompanying +EAMT favours blocking patterns, especially when the above factors are in play - The ec has been incredibly consistent. As consistent as I’ve ever seen it, even taking into account the daily runs It continues to advertise a marked cold and blocked spell. Indeed, the colder than average temps are back tonight too. When looking for significant pattern changes in My personal forecasting area - the 10 to 15 day range - I look for a mean high in an unusual place to persuade me that a signal is genuine. The geps has had this for a few days but now the other two have cottoned on: GEM: mean easterly with a Greenland block and S euro low GEFS: a highly anomalous North Sea high with a flow from the east in the S This retrogresses to a NEerly The eps is still pouring out. But @Mike Poole assures us the clusters are bankworthy and he knows his clusters. Unsurprisingly, he’s not wrong. They are sensational for cold with a eurolow of some description and varying degrees of blocks to the N. So is it a done deal? Ha. Of course it isn’t. We’ve been here before and further and still had everything bust. BUT… you can’t deny the incredible synergy between the telecons and the models - and particularly the consistency of the sub seasonal modelling. In conclusion. It might, just might, be time to… buy more grit!

Lots of easterly eps members. The mean is very close to a mean easterly This is not a regular ‘slight anomaly’ - it’s a pretty strong signal. The clusters might not be available on the ec site but they’ve arrived on the Icelandic site and are worth a gander The GEM ensembles continue, as they have done over the last few days, to look spectacular As to the midweek low next week…. Experience tells me it’ll trend further North / deepen. However, that’s often towards the end of a cold spell (think feb 21) but this one is at the start so perhaps it will stay squashed and give central areas a good dumping. I’m yet to see one in my last 10 years of looking though so I’ll believe it when I see it. Lowland N Cumbria has seen snow in the last decade, obviously, but from weak systems moving south or showers in a cold flow. Not from an Atlantic system hitting cold air and pivoting. They’ve always gone too far N.

How about this for a mean chart - gem ens - huge signal for the Atlantic to get shut off later in W2… Meanwhile, the 18z is a mess - but the euro trough is the key here. Get that in place and once the MAR comes we’re in business. The 46 still so so consistent…

As @sebastiaan1973 has pointed out, the signal on the ec 46 is incredibly consistent. And only getting stronger… Enjoy the mild weather whilst it lasts!

The ecm and gfs ops are absolute best case scenario stuff. We’d need to see an awful lot more runs going for the wedge to have any confidence. Still the charts are stunning so here they are: More likely (and better represented on the ensembles) though is the gem solution, perhaps not quite as intense. However, what is starting to look more likely, is the long heralded blocking later in week 2. The target period is now just coming into the scope of the big 3 ensembles and the gem ensembles are really keen on this tonight. This would reflect the sub seasonal picture that the 46 has been consistent on for weeks. And it’s not alone, the normally hesitant cfs weeklies are on the same page too. We’re at the all or nothing time for this winter. February will define our perceptions: cold and snowy and the seasonals have the last laugh. Another bust and the told-you-so’s will be crowing forevermore (with good reason, to be fair).

@northwestsnow objectively, the evidence at face value suggests that we should. We’ve got to strike gold at some point nws. So many factors in our favour this time

GEFS looking interesting too…

Beyond the op fantasies, the best chart of the day for me is this one: Even as recently as Thursday, the 46 had been keen to stall the mjo in phase 6. Today it firmly pulls it into phase 7 and even mulls a further advance into 8. @feb1991blizzardhas posted the composite already but it’s worth looking at again to see what could be on the line here: Now how does that correlate with the anomalies later in feb on the 46? Rather nicely, one would have to say. On top of and related to all of this is the frankly ferocious +EAMT burst we’re presently seeing. Some of the +MT is from the rockies but even more of it is East Asian. Along with the tropical progression, It does all feel a bit 2018 but we’ve been burned before this winter and I’m still not fully convinced. The strat parking itself over the Barents is another factor to consider, quite possibly a favourable one too. Then there’s the matter of the downwelling waves from the teeny weeny ssw we had. Add in the IOD collapse, the sun, the moon and gravity waves and it’s all a bit much for my brain really. As ever, look out for the mean flow to shift away from the W directions on the sub 200hr ensembles before popping the corks. However, there has clearly been a positive shift for coldies in the outlook over the past few days and I think/hope some rather exciting charts are coming in the not too distant future…

Pub run contemplating the 2nd gfs Greenland push of the day?

@feb1991blizzardno one minded in 2018 did they. Apart from the mild folk that is. They probably minded

@blizzard81 here’s some certainty for you: the 0z runs will be rubbish haha! I was as sure as I’ve ever been about feb cold given the seasonals. It’s more of a nervous yes now. We’ve had 2 Greenland highs that have faded before we got the really good stuff this winter and a surprising amount of zonal mayhem in between (or not, given the strong Nino, solar and mjo p4…) I still think the signals (fading iod / late winter Nino, mjo to p7, consistent ec 46) etc are pointed to mid feb cold but - in this game - one can never be, ahem, certain!

@LRD I think the anomaly shows just how dire Februarys have become as a slight ridge to our w looks like major retrogression when it ain’t. I always look for a mean flow from a direction without a W in it to get really interested. At the moment the 12z eps are intriguing but still a mean westerly and thus a watching brief only. The positive from tonight’s runs is the drain of purples from the mean charts away from Greenland. There are lots of good ensembles, but again not enough to suggest a clear cold trend.

Most exciting d10 op chart for a while potential wise The actual chart is a bit more mundane, but you’ve gotta start somewhere, right? Monster scandi storm, not unsurprising give the SPV will be there too. The ensembles have been flirting with this idea, nothing other than a whimsical idea at present. Let’s see what the clusters say…

That’s a sobering last chart Seb. This is the framework within which we have to operate…

GEFS finding an AR, much like last night’s eps. GEPS offering moderate support The trop vortex over scandi reflects the SPV’s forecast position. Thus Atlantic height rises viable in the extended. Extent unknown.