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  2. It may look better soon nws if it's later clusters mean anything.Day 10 at the moment maybe just to soon to pick up the hoped for change.
  3. Yes snow falling is a very different matter to it lying for any length of time. Surely it stands to reason that, given similar synoptics, that it is far more likely to lie when the sun is at its lowest, ie: December into January?
  4. DisruptiveGust

    North West Regional thread 01/09/18 Onwards......

    Can’t see much if any snow tbh, the 850 temps quickly going positive during Saturday before the main front activity reaches the region. Blizzards no, freezing rain maybe higher up where the freezing level sits. Wind maybe more of an issue but no mention of that in the warning. Aperge for 13:00 Saturday, 850 temps going up.
  5. Absolutely agreed Phil.. I want to see EC moving away from its 00z run ..
  6. Certainly more reasons for coldies to be positive than usual!..great update from exeter post crimbo and especially new year onwards..I'm a happy coldie and in the short term..some will see snow / snaw cover in the next few days..all in all..not your typical cr*p mild mush fest to endure!!
  7. cheeky_monkey

    Save our Christmas Songs

    you are all just miserable bar stewards
  8. Mostly clear and feeling cold with that SE breeze. Current Temp: 4.5c Today's High: 5.7c Overnight Low: 3.4c Wind: 6mph ESE High Wind Gust: 24mph
  9. oopsie didn't see this post my 12.10 Cheltenham is JARVEY'S PLATE (AM)
  10. News of the ec46 probably will be more revealing as to which way things may be going. Nothing really catching my eye yet Blue in the day 15 gef set with only weak anomalies plastered everywhere but the eps are at least hinting at something interesting by then. It seems many cold roads( indicators) are heading for around or just after Christmas.We should expect quite a weak Atlantic by then if these signposts are correct(zonal wind forecasts,tropical convection etc).Some reasoning to hope for heights to build further north as any sub-tropical ridging should become more pronounced in a weaker and buckling jet flow. Still at this range we have to say it still speculation.
  11. Bristle boy

    Met office 16 to 30 day outlook

    Taking into account Meto's usual understandable caution re wording, that last sentence smacks of a "smelling the coffee" situ.
  12. ""Predictability of downward propagation of major sudden stratospheric warmings Alexey Yu. Karpechko,et alMajor sudden stratospheric warmings (SSWs) are striking phenomena of wintertime stratospheric circulation usually defined as a reversal of zonal mean circulation fromwesterlies to easterlies. SSWs often have significant impact on tropospheric circulation and cause anomalies in surface climate lasting for up to 2 months. For this reason, dynamics and predictability of SSW receive considerable attention. It is however well-known that not all SSWs cause significant, long-lasting impact on the troposphere. In order to explain differences in tropospheric impacts following SSWs, several reasons have been previously proposed, including differences in type of SSW (split or displacement), persistence of stratospheric anomalies, preconditioning of the tropospheric circulation, and whether or not SSW was accompanied by a planetary wave reflection in the stratosphere. Here we address the predictability of tropospheric impacts by SSWs by seeking early precursors of the impacts. We separate midwinter SSWs into two groups: those which are followed by significant, long-lasting impacts on the tropospheric circulation (defined in terms of anomalous Northern Annular Mode) and those not followed by significant anomalies in the annular mode. We show that SSWs characterised by a more negative Northern Annular Mode index in the lower stratosphere around 150 hPa and enhanced wave activity propagation to the stratosphere during the first few days following the central date have a larger probability of being followed by tropospheric impact, both in reanalyses and in climate model runs. These anomalies play a more important role in the subsequent downward propagation of the signal to the troposphere than the type of SSW: whether it is a split or a displacement, or absorptive or reflective SSW. We propose that using these anomalies as precursors of tropospheric impacts of SSW can enhance climate predictability. https://rmets.onlinelibrary.wiley.com/doi/epdf/10.1002/qj.3017?purchase_referrer=scholar.google.nl&tracking_action=preview_click&r3_referer=wol&show_checkout=1
  13. But do any of them clusters fit in with Exeter for period around Christmas and shortly after they say northerly or northwesterly regime - cluster 1 wouldn't produce northerly northwesterly regime?
  14. Thanks for Karel for finding this research. https://pdfs.semanticscholar.org/12d5/f40389c3e38ca4be146450203a275d0ebd31.pdf Abstract Sudden stratospheric warmings (SSWs) contribute to intraseasonal tropospheric forecasting skill due to their surface impacts. Recent studies suggest these impacts depend upon whether the polar vortex splits or is displaced during the SSW. We analyze the annular mode signatures of SSWs in a 1000 year IPSL-CM5A-LR simulation. Although small differences in the mean surface Northern Annular Mode (NAM) index following splits and displacements are found, the sign is not consistent for two independent SSW algorithms, and over 50 events are required to distinguish the responses. We use the wintertime correlation between extratropical lower stratospheric wind anomalies and the surface NAM index as a metric for two-way stratosphere-troposphere coupling and find that the differences between splits and displacements, and between classification methodologies, can be simply understood in terms of their mean stratospheric wind anomalies. Predictability studies should therefore focus on understanding the factors that determine the persistence of these anomalies following SSWs. From the discussion part Recent studies using reanalysis data have suggested that the tropospheric response to SSWs depends upon the type of event, categorized as either a vortex split or displacement [Mitchell et al., 2013; Seviour et al., 2013] (M13 and S13, respectively). These studies found that the surface anomalies following splits project more strongly onto the Northern Annular Mode (NAM) than for displacement events. This is in contrast withCharlton and Polvani [2007] (CP07) and Cohen and Jones [2011] who did not find a consistent difference in the impact of splits and displacements using a different method for identifying SSWs.
  15. Summer Sun

    Premier League Discussion

    About time https://www.bbc.co.uk/sport/46550118
  16. Was just looking at those clusters and wondering which one fits Exeter’s latest musings .... possibly cluster 1 but I feel that the 00z suite doesn’t fit with the latest glosea run ....their musings becoming ever more indicative of a proper wintry spell in the new year .....10pm tonight we will be checking weeks 3 and 4 on the ec 46!
  17. Just scanning the outputs and there's little of any interest from a cold pov out to day 10 with the onset of the westerlies over the weekend. Something in the eps clusters caught my eye though beyond that with the main group showing a sharp ridging from Iberia north over t he UK an d by day 15 we see this. It could be the start of a move to a Scandi.block with those +ve ht anomalies up there- or it may be transient as the 2 smaller clusters show more of the jet pushing through. A pity we can't see the upstream flow and the polar field but just seeing that small area there are signs of some energy undercut from the Atlantic trough and as we can expect by that stage a slowing down of zonal winds it may develop into something.....
  18. The hunt for cold is about to bear fruit, some snow to come in the short term further n / e..especially at elevation and I have a very good feeling about the extended outlook at Christmas or soon after..I think coldies have plenty to smile about..cr*p mild mush looks in short supply and for a change..predominantly colder weather looks the form horse!!!!!..fingers crossed fellow coldies!
  19. Unusual to see GFS be the model keen on undercut and blocking while ECM rejecting it, a bit of role reversal there. We may not have to wait very long for this to be settled though. Both GFS 6z and GFSp 6z moved more toward ECM and the GFS ooz operational output had little to no backing from the ensemble suite so it is more likely its 12z output will do away with the undercut than ECM get on board. The one ray of hope is that 6z output tends to be rather progressive. It would be great to see GFS with a coup in modelling an unexpected cold spell so fingers crossed this evenings output shows just that.
  20. I wouldn’t be concerned about anything the CFSv2 shows ........it’s up and down like a tarts draws ......
  21. Much nicer now with blue skies but that winds certainly a cold one. 6.4°C
  22. I'll try to answer you D although my knowledge of just what goes in, now 25 years since I was professionally involved, is that data is basically the same regardless of the time, ie surface reports. Then it gets more complex with upper air data usually being simply, as with the surface data, just transposed by 12 hours, ie 00 and 12 z, less data at 06 and 18 z. Aircraft reports will also be more at certain data times. Then the models are simply set to go and carry on be it 00, 06, 12, 18 to their time end based on the same rules/laws etc. Thus I feel that 00 and 12 data sets are better, or were. Of course the usual myhs you quote re missing data over Xmas, and it is a myth, usually only brought out if the models do not show cold scenarios. The other point I was making is comparing like with like time outputs, is a valid one at time scales beyond 144 h perhaps 168h. Ftom 144h down then comparing successive runs is fine as the later data will over=ride data amounts. Hope this helps?
  23. In terms of days where snow falls the first half of dec and first half of apr have been fairly even where i am over the last 20 years.The days where snow actually settles is miles apart though, i've never seen snow settling and staying around for more than a few hours in April compared to lying snow for 24 hours + in at least half of the Decembers that i can remember.
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