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Catacol

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Catacol last won the day on January 2

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    Wellington, Somerset
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    History, Rugby, Cricket... and snow. World of Tanks ain't bad either.
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    Frost and snow. A quiet autumn day is also good.

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  1. What patterns do you see in this Stewart? To my eye it's a pretty inconclusive indicator of much... However I'm not liking the second graph of an indicator of parallel similar years. None of these had much cold within 2 years - apart from 2016 to the Beast....and that has to be seen as a somewhat freakish anomaly. If we get years like 88 or 99 next season I'll have to emigrate...
  2. More years than not - yes. The sub tropical high pressure belt is increasing in strength and it will be harder and harder to displace it. However that one year in 10 pattern where factors align to provide sufficient momentum to catapult a major blocking high north could therefore produce serious cold if everything aligns. In essence - all roads lead to more incidences of extremes? For the UK more warm than cold extremes, but the cold ones might catch the eye just a tad. Will be interesting to survey what happens over the next 30 years. Hope I live that long....
  3. Well - here we go perhaps. Not quite last chance saloon - but certainly if we don't get a pattern change of reasonable significance in the coming phase, then winter will be running out of time. Just one chart - tells a story. This chart shows very clearly the ongoing interference caused by the standing wave through the Indian Ocean at 60E and the failed effort through late Dec in the last passage of convection through the pacific. The hope last time around was that convection intiated into the maritime region in the last third of December would bring a coolish blocking pattern - but the indian ocean remained active, the signal was clouded, AAM rose but not enough and we ended up with a pretty grim warm SW feed. Worst of all solutions unless you like winter mild. As expected the next bout of convection is on the way - it has kicked off just to the west of the maritimes and this time is forecast perhaps to maintain a higher intensity while at least the indian ocean fades away. What this should do - in theory - is shift the wave pattern and inject momentum into the sub tropical jet to allow a wave break and a ridge to form. Given the gradually shortening wavelengths of the season now I would think to the west of the UK is more likely than to the NE though NWP is toying with both - but I'd guess we might see heights to the west rise and then hold their ground. 2 problems - first of all the forecasts of the decline of the Indian Ocean driver have proved wrong before. As of today it is still in place. And the passage of this MJO wave has to break through the relatively land dominated area around the maritimes where often it can fade. There is no guarantee. The second problem would be that, given above average vortex strength right now, the ridge might build and then, in any case, be outdone by high lat westerlies. I used the analogy of another web writer of a "buzzcut" a while ago. Tells it rather well. And then - given shortening wavelengths - might our mid atlantic high retrogress to the west and once again leave us on the warm side of a trough? I wouldn't rule that out - I would far rather see a Scandy ridge develop as the starter - but without a substantive shift through 7 - 8- 1 I don't think this will occur. A dying phase 7 signal as is currently being touted would favour the mid atlantic high. Confidence has been dented this winter. I'm hoping for a major ridge as the MJO breaks through at least to phase 8 and a drag of air in from the east under a high centred to our north. I fear a weaker version positioned a little further west with cool NW flow over the top the best we manage. Snow instead for the south of France? Very little margin for error on this now given where we are at present.
  4. Correct - and in the first place it assumes sufficient momentum in a jet angled NW to SE to force a significant wave break that can then hold its latitude. At 9th January we are still quite early in any attempt to interpret what may happen in the back end of the month when the Pacific signal may possibly come into solid territory for colder solutions, and seeing just how much disruption this might do to a strong trop vortex. We all know being brutally honest that we had hoped for a much less robust +AO pattern pushing through multiple layers of the polar atmosphere than we have now in the flatter phase of the cycle, and therefore the amount of well targeted momentum and upstream amplification needed to rock the boat as the crucial phase at the end of the month comes into play is higher than we would want. So I’m personally hanging tight for a bit yet and saying little. Reasons to be optimistic? GEFS may possibly be doing a better job of reading the MJO than EPS at present with signs of decent amplitude progress towards phase 7, and we rolled the dice in a pretty average context in 2018 and rolled double 6 for The Beast. Plenty of research now showing how an Atlantic system and relative pressure gradients in 2018 produced a disruption of extreme significance for vortex damage. What was rolled once can be rolled again.... (admittedly unlikely....)
  5. But it might create a context for temperatures that might challenge a January warm record or two. Signal for trough digging into the mid Atlantic opens the door to the possibility of a long draw SW stream for a day or two. Sigh. Hard work at the moment while we wait to see if late month evolutions can shake the tree.
  6. Would agree with all this, though the AO/NAO plunge in Feb was only the control run? However the timeline you out together here Malcolm I think is our only real hope this winter season now for some proper cold.
  7. Important we don’t try to run before we can walk on this. JMA weeklies pointed to a surge of heights towards Scandy a few days ago, but then flattened the ridge. Why? Because the Pacific signal is set to flatten out a bit after the lagged effects of the recent AAM spike work through. I’m not convinced this first sign of Scandy heights will make it. We lost too much of the blocking pattern over Xmas when heights failed to get particularly far north, and the vortex has coupled and powered up. But I’m hoping it is setting a precondition for the next round of convective wave creation to get a wave break up higher for early February. By this stage the vortex will be weakening, and the QBO will be more favourable. Close but no cigar for me in the period 17-24 January, but looking by that stage to see a more coherent Pacific signal working through again and another spike in GLAAM on the cards. Key will be the jet angle exiting the US in the second half of January and the extent to which the Euro/Scandy high can retain some latitude. If it sinks all the way back down then the wave break gets more difficult. Fine lines - but positive outcomes certainly remain possible. I just think we need to be a little patient. The first signs of a positive move would be NW/SE trough trajectory through the US on NWP products in the last 10 days of January. That would put in place the first piece of the jigsaw for a proper chance of a reverse flow in February. One good spell would help erase the disappointing 6/7 week run up! By the way - very much hope to be proved wrong on the blocking signal for just past mid month. If it gets cut off over Norway I’ll be grinning.... but my head is ruling my heart currently.
  8. Interesting from the US Navy... massive error bar to our north.
  9. I seem to be on a posting roll. 2 images. Hope springs eternal. ‘nuff said.
  10. North West. This is the wave 2 hope flagged by GP and hinging on a combination of momentum transfer from the current spike and expected renewed convection before month’s end. It assumes the maintenance of the North Pacific ridge which seems to be a near permanent feature these days. It has some legs. But gloom from multiple failures in recent years tends to lead to an assumption of failure and this forum is very glum today. Personally I will never forget Feb 18 and for that matter Feb 96....both events that came from pretty tame initial origins. There is always hope. Thank goodness for Skywalker...
  11. Hmmm - your gloom over this winter is colouring your judgement. I suspect you are correct when implying that the current winter will end up underwhelming and probably mild overall, but it is also the case that we have a changing Pacific context underway (probably) and another round of convection set to arrive in the next few weeks. While the background context is currently unfavourable it is incorrect to state that “nothing” can break the coupling. In addition there is currently a downwards propagation of reducing wind speeds underway from 1hpa probably the result of a long running significant wave 1 warming at the top of the vortex and when one considers the current spike in AAM that is helping deposit decent momentum into the sub tropical jet and thereby raising the possibility of a late Jan/ early Feb North Atlantic wave break I think to write things off is premature. None of the above disguises the disappointment of the current season, and the post facto analysis may hone in on an interpretation that sees the + IOD as the driver that has brought heat to Australia, floods to parts of Africa and a fixed forcing across the NH that has assisted in vortex domination, and perhaps we were over optimistic with regards to the switching of the QBO ( I’ve done a monthly analysis earlier in this thread demonstrating the significance of the December QBO signature) but I still think a nihilistic approach to up to 10 weeks of winter season future synoptics is off beam. 1 week with cold and snow in February would be enough to spread some honey on stale bread!
  12. Indeed - but those willing to put their neck on the block by coming forward with their thoughts on the future are due a modicum of respect for being willing to take a punt. Your decision to use a single op run at 16 days range to counter the arguments of another speaks (or probably shouts) volumes. Most I suspect appreciate the glass half full approach.
  13. Bottom up is troposphere led, not stratosphere. Back to the dance and who leads who. GP is referring to the signal for second half of January which sees equatorial convection return to the western Pacific and the GEFS punt for a Scandy/Euro block a bit like late November combined with a strong North Pacific ridge. I don’t have access to 14 day EPS so assume his data shows a similar wave 2 pinch. This is the best case scenario we have to hope grows wings. It has always been on the table as an option and the hope is that it could create a split flow in the Atlantic with the southerly arm helping enhance a block over Scandy with easterly flow underneath. The current spike in GLAAM provides a supportive momentum context in the medium term. Fingers crossed.
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