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  1. 23 points
    The signal for a very distorted vortex is well in place for day 7 now - Ive annotated the map to show all the waves in the jet - when it reality for this time of year it should be 0 with a strongly positive AO The UK will get some of its first proper cold for Autumn - long may it continue..
  2. 21 points
    ECM 168> 192 says hello to a new pattern for the end if October - AO heading south - Huge PNA + Pattern - Deep Scandi Trough - Retrograding Atlantic high...
  3. 20 points
    ^^^ The JMA 4 weeklies has the negative trough anomalies over Mid / High lattitudes peaking this week only to all but evaporate from week 2 through week 4 being replaced by high pressure- Expect a negative AO & probable -NAO early November - perfect timing if you ask me....
  4. 20 points
    Love this time of year on the forum. The mod Thread really starts to get going again with all the craziness that I love so much. Looking forward to the many many laughs at the toy throwing incidents. The models are looking good for something cold at the end of the month. Cannot come soon enough, Hate this mild muck this time of year.
  5. 20 points
    It has been a while since my last posting about the stratosphere. I remember back in the days, I was trying to be a strat modelling pioneer, making graphics that people demanded but were rare to come by. I was among the first, if not the first in the world to produce fully public HD-3D/4D polar vortex animations. I am here again now because there is still something that people demand but it is hard to come by. It is seasonal stratospheric forecasts. Those are almost impossible to come by as far as I have searched, unless you have a fat wallet or you are full time professional. Thanks to the Copernicus project, I now have access to stratospheric grids of ECMWF and UKMO Glosea5 models. Configuration wise, those are the best two models in the world for seasonal stratospheric forecasting. The only one that could join them is the JMA-SEAS model. So I present you four graphics for now, monthly mean forecast. Considering it is just the October initiated forecast, so we have a long lead time, and its a monthly mean of 50 members, its actually impressive. The signal is visible. I will add more graphics with time and every month with new runs. I do plan to make a permanent home eventually for these graphics to be regularly updated on the Severe Weather Europe page where I am one of the admins. Will also add 500mb monthly anomalies there in the far future. The grids were in GRIB1 format with some non-conventional coding, so it took some trickery to produce it, but I have "cracked the code", so there is much more of this to come.
  6. 17 points
    Yes - they look very promising! -NAO, retrogressing high and strong heights around Greenland. Coldies could be getting their early season wishes come true very soon!
  7. 17 points
    What a pretty picture... A tri-pronged attack on the trop vortex and a tanking AO
  8. 15 points
    Evening All So my second main post in relation to Autumn / Winter 18. Thus far the initial forecast for this first half of Autumn has been really satisfactory with some notable successes- The Anomaly chart for Sept 1 to the 13th has shown that the jet has been forced off way to the North allowing perpetual Southerlies / SE winds to invade the UK & indeed western Europe- * We have seen notable heat - nearly 80F on 13/10 Oct - * There havent been many 'westerly days' & rainfall has accumulated for some over short sharp bursts as opposed to the usual steady build up. ( Again highlighted in the first post ) * Also whats been a key player & also has close similarities with Summer is the depth of the blocking around the mid lattitudes - Record breaking High Pressure in July over Europe , & September sees record breaking High pressure over Alaska- Sept 1-Sept 15 Global Anomaly This anomaly thats lingered up until the tail of September has been the main reason that W Canada has had the very cold start to the Autumn & also why Siberia has been a little slow to start with snowcover - The ice anomalies & low thermal gradient this year are really allowing for Higher than average pressure to exist in 'situ' even at Northerly Lattitudes - Examples of these powerful highs appearing at high lattitudes started appearing in 2010- Note The december to Remember- The second spell started with a 'super high' What these High pressures create is intense areas of WAA on the western flank & the same with cold on the eastern flank- they also allow for more Northward / southward penetration of the warm/cold So the conditions they bring are deemed 'extreme' for the localities on the recieving end of the advection- Backing up this theory of Low ice / warmer arctic seas > Higher Arctic Amplification > Intense WAA/CAA is the range of the metric of AO which in the past 10 years has gradually been stretched scalewise up & down - This Late Autumn / Winter - seems the perfect platform to deliver more of the same - Exceptional warmth interlinked with some potential for exceptional cold ! There are unlikely to be any over riding negative signals this winter- - Neutral El Nino Signature - Downwelling westerly QBO unlikely to be to adverse to the pattern- With more emphasis on positive links - Weak to possibly 'very' weak stratospheric vortex including a possible early warming event December to weaken the vortex further - Stronger disconnect in terms of tropospheric & stratospheric coupling - again the very shallow gradient weakening the 'westerlies' - Very low solar activity supporting the westerly weakness - 'Super high pressures' migrating Northwards towards the pole creating sharp transitions / modality changes in teleconnection metrics ( AO / NAO / PNA & POL ) these will also create big Stationary patterns of warmth & cold around the mid lattitudes For me the signals are overwhelming & give us a range of solutions for Winter that strongly suggest a below average DJF with a high probability of at least a 1 monthly rolling period ( not to be confused with a recorded CET month ) being below 2c. Higher incidence of Northerly & Easterly outbreaks. I dont rule this out exclusive to DJF - but also with the pattern expected to flip towards the end of October we could see some of this blocking in place throughout November. My eyes have turned to the stratosphere, which has seen a burst of activity lately bringing the zonal wind up above average of about 22 M/S - however the ensemble suite has shown that this may well be the peak for the moment as we drop back towards 20 M/S again in November ( the average being 30-40M/S as we head towards December ) So there we have it- some late Autumn / Early Winter insight - - Big Flips in the AO with some decent negative values arriving - Super High pressures retrograding up towards the arctic Circle generating significant CAA & stationary cold patterns - Possible early warming Late Nov / Early Dec to really take any Westerly sting out of the Jet CIAO for now....
  9. 14 points
    Updated Accu Forecast, just released. In all seriousness though, their attempts at this are a complete joke. We are either wet or stormy, the one time they opted for something different in 15/16 (cold spells) the winter was the 3rd warmest on record.
  10. 14 points
    The 06Z GFS is starting to come out (and it’s true that the ECMWF shows one), but: 0Z GFS (GEFS) Perturbation No. 16! Also, having had a little look at the 00Z GEFS postage stamps, Perturbation No. 1 shows quite a chilly Northerly around a similar sort of time (Tuesday 30th October). While it is far into the run with some varied solutions to be expected, a fair few do show some kind of High Pressure in the Atlantic (some amplified, too) with some keeping the High over the U.K. Not to be taken too seriously at that range, but cool to see.
  11. 14 points
    Anyone else think this looks like a torpedo? We have been waiting...
  12. 13 points
    People are getting too hung up again on the 10hPa zonal wind at this early stage - only a month ago it was looking weak and now it's strong. The 12z GFS shows how quickly things could change from above average to below throughout the depth of the atmosphere - Looking longer term strongest wind for October 20th in the MERRA2 dataset was 20/10/1981 - this was followed by the very early SSW on December 4th (and the bitter weather that ensued). And it just so happens, 20/10/1981 is the closest 30-day analogue to 18/10/2018 for 10hPa zonal wind - A couple of days later, the strongest zonal wind for 22nd October was 1998 and is the 3rd closest analogue to 18/10/18 - this year also had an early SSW on 15th December. Not necessarily a prediction for this year but an indication of what can happen.
  13. 13 points
    Its brilliant to see so many posters come out of their Summer Hiberanation, gearing up during this Autumn and to the coming winter! This place is buzzing tonight!!! But who can't get excited when your a coldie and the ECM teases you with this.... All fun and games of course just for now, cause we all know how fate likes to tease us and when it looks all too good to be true, its snatched away before our very eyes! But there is much to be optimistic about this year! Let the roller-coaster that is model watching, commence!
  14. 13 points
    In the land of repeating patterns, the modelling over the past few days continues to promise much for coldies ..............
  15. 13 points
    Half way through October. Time to stir.... Interesting reading RJS's comments in the seasonal forecast thread regarding extreme cold in central Canada and likely downstream trough from this event. If this can be given as a base state heading into the start of winter, then exact positioning of the long wave pattern becomes guessable. Note the MetO ENSO forecast As many forecasted several months ago we are heading into a weak Nino winter with consequent pressure applied to subvert sub tropical high pressure belts and therefore the possibility of a more southerly tracking or split jet. GLAAM is in a moderate to strong positive phase and the Nino imprint onto the atmosphere is clear from the GWO state which has been locked into the 5 - 8 orbit for weeks now For the foreseeable therefore a pattern that wont encourage flat westerlies, should instead see a good deal of jet wobble and curve, and an autumn that for now looks to remain fairly blocked. With an eastern US trough likely then the suggestions from a number of posters that a mid atlantic high may develop downstream looks about right to me in the context of the above. That might help to bring about a frosty and foggy passage into November.
  16. 12 points
    With winter approaching over the horizon, a lot of people's thoughts are turning to cold weather potential, but while that's fine, it's not everyone's cup of tea. So, we've started this thread for the cold hunting side of model discussion, with a general discussion thread also up and running for those who'd rather look at all other aspects of the model output. Despite the focus on cold weather potential in this thread, please do keep it to the model output. Want to view the model outputs? You can get all the major ones here on Netweather: GFS GEFS Ensembles ECMWF ECMWF EPS NetWx-SR NetWx-MR Met-Office Fax GEM GFS Hourly Model Comparison Global Jet Stream Stratosphere
  17. 12 points
    A glancing blow is better than no blow!!Great to see potential for our first Arctic cold snap towards the end of next week on the Gfs 6z operational..a bit more westward correction would put us in the bullseye for a wintry spell..fingers crossed!
  18. 12 points
    Yes there's some good news for coldies, the Ecm 00z ensemble mean longer term favours a cold shot.
  19. 12 points
    The one theme that remains consistent this morning is the dry theme. Which suits walkers like myself who love to enjoy the beautiful Autumn colours nature has afforded us .
  20. 11 points
    Morning all. This picture below taken in the village last season and news today is that the resort will open on 1st December to start the ski-ing season ( subject to decent snow cover of course ) Good news from our Portal Weather Service provider is encouraging for a early cold spell, starting next week ! After weeks of warmth , a abrupt change from Summer to Winter conditions in the mountains by the last week of October. A deep trough over the Arctic Region should eventually move towards Scandinavia early next week. Both the Atlantic ridge and North European trough likely to intensify and should result in the sharpening of the cold front. Cold air advection will follow into parts of Eastern /Central Europe for a time. The model used for snow depth forecasting indicates 30cm of fresh snowfall in our range of mountains by 31st October (40%) probability rate. Most global models in agreement at 144t but variations at 240t shown on ECM /GFS outcome. The view from over here and their own model indicates something more along the lines shown by GFS , but overall its going to get colder and that more than likely includes the UK . To early for the fine mesh model to give precise snow accumulations in resort but one we will be watching with anticipation next Monday/ Tuesday. C
  21. 11 points
    I went hunting for cold and found some on the Ecm 12z!
  22. 11 points
    The pattern is evolving pretty much as expected with the amplification upstream of the Aleutian low/Alaska ridge and vortex/ trough down the eastern side of N. America complex linking to the subsidiary vortex near northern Scandinavia, All neatly complimented by the burgeoning subtropical high in mid Atlantic. All of which portends a strong north westerly upper flow adjacent to the UK and generally a quieter and cooler spell of weather for same but there is still a lot of energy exiting upstream and the north could well experience more windy and changeable weather as systems swing around the high pressure. So to a tad more detail starting with the 500mb and surface analysis at midnight The front straddling the country will continue to struggle very slowly south east bhut weakening into a mainly cloudy feature with perhaps the odd patchy drizzle. Thus still pretty cloudy over much of England and Wales but not too bad in areas where this breaks with cooler and clearer air behind the front (note the different airmasses in the midnight Castor Bay and Nottingham soundings) with th high pressure ridging north east. Still a fresh breeze with some showers in the far north west. Overnight the front continues it's slow journey with the drier cooler air covering much of the country with a fair bit of frost around. So tomorrow, after the chilly start, will be dry and sunny, except perhaps early on in the south east Overnight Thursday through Friday the ridge generally stays in control but fronts associated with a low tracking north of Iceland do encroach and bring rain and freshening winds to the north west but remaining fine and relatively warm elsewhere By Saturday it's worth remembering the opening comment as another very deep low swings swings north east on the very strong jet with once again the associated fronts bringing strong winds and rain the north west, albeit temps a tad above average. The front(s) continue to move south east on Sunday accompanied by the rain and freshening wind so a rather N/S split temp wise with it remaining dry and warm in the latter before the rain arrives. And the NH profile at T120 which is not a million miles away from where we came in
  23. 10 points
    This is the model output looking for cold potential, if you want realism with what the models are showing you could always head over to the general model discussion thread instead?
  24. 10 points
    There's an index member in my research model with a period of about 6-7 years (it hits with relative precision at 13, 20, 33, and 46 years and needs a slight adjustment at the 6-7, 26-27 and 39-40 year intervals. Look how juicy this analogue set is (going back to start of CET) ... this is listed by the January of each case so years before these contain the Nov-Dec analogues ... and this includes only those cases needing adjustments of less than ten days ... because we're talking about retrograde index, the off-set pairs run earlier for first more recent, going back in time, and later for second of the pair, by about 10 days, e.g., the 6,7 set would include for example 2013 an earlier index by 8 days than 2019, and 2012 a later index by 7 days. It's similar for the 39,40 pairs. For example there, 1979 would be running later than 2019 by about 7 days. For the 26, 27 set, we are looking at the more recent of the pairs being 6 days earlier and the second less recent being 8 days later than 2019. (6,7) 2012,2013 ... 1966, 1967 ... 1920, 1921 ... 1874, 1875 ... 1828, 1829 ... 1782, 1783 ... 1736, 1737 ... 1690, 1691 (13) ...... 2006 .......... 1960 ............ 1914 ............... 1868 .............. 1822 ............. 1776 ........... 1730 ............. 1684 (20) ....... 1999 .......... 1953 ............ 1907 ............... 1861 .............. 1815 ............. 1769 ........... 1723 ............. 1677 (26,27) . 1992,1993 . 1946,1947 . 1900,1901 ... 1854, 1855 ... 1808, 1809 ... 1762, 1763 ... 1716, 1717 ... 1670, 1671 (33) ....... 1986 .......... 1940 ............ 1894 .............. 1848 ............... 1802 .............. 1756 ........... 1710 ............. 1664 (39,40) . 1979,1980 . 1933,1934 . 1887,1888 ... 1841, 1842 ... 1795, 1796 ... 1749, 1750 ... 1703, 1704 ... (before CET) (46) ........ 1973 .......... 1927 ............ 1881 ............... 1835 .............. 1789 ............. 1743 ........... 1697 ......... _______________________________________________________________ This slice of the past catches quite a few of the exceptionally cold winters, narrowly missing 1709 which only needs a 15 day adjustment towards earlier dates, but being out of phase entirely with a few like 1740 and 1963. However, the overall average of these winters when adjusted by the required number of days (where daily data available) produces a profile that reaches a minimum of 2.5 deg below the current average around mid to late January and runs generally below normal throughout the winter season. The notable cold winters in the set include 1684, 1716, 1763, 1795, 1829, 1855, 1881, 1947, 1979, 1986, This index value is rated as 10 to 15 per cent of total variability and is second most significant. It is related to inner solar system magnetic field flux changes associated with the planet Mercury. The one slightly larger index value components is related to Jupiter and the analogue set there is regarded as linked to progressive features so less associated with blocking, more to do with position of long-wave ridge and trough features. One other detail that I can report from the research is that retrograde episodes can be expected roughly every second month from this index value, and on a longer, slower time cycle, about every 7-8 months from a separate index member, and that one has analogues with winter 2010-2011 and also includes 1978-79 and 1962-63, also 1946-47. The episodes would be expected to occur 2-3 days later each eight years going back in time, and you start to lose well-timed analogues before about 1906-07, running into a different set timed for somewhat earlier running back from 1823-24, so that includes 1816, 1808, 1800, 1792, 1784 and 1776 as analogues for January. This does not look to be a dominant index value in the research, but it's good to see a reasonably low temperature index from that one combined with the principal retrograde member. If we can't build the cold blocking pattern out of these materials, then we seem to be losing our best chance but the long solar downturn may allow weaker analogue sets to succeed in the future. You have to wonder if we have a "big one" in our near future despite what we are allegedly doing to the boundary layer. It does concern me, but a signal of +1.0 C competing with all these others may be in over its head, we can only hope, right Fred?
  25. 10 points
    Late October fog = cold snowy winter. Simple as!
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