Jump to content
Problems logging in? ×
Snow?
Local
Radar
Cold?

Leaderboard

Popular Content

Showing content with the highest reputation on 23/12/15 in all areas

  1. A Worrying site to the end of the year with yet more storms for those area's that certainly don't need it! Still not eye candy for us to gt excited over in terms of SNOW! but let's see what January will bring is In the meantime seeing as I can't build a snowman ive built a "Mudman" with all the rain we've had!
    44 points
  2. Which equates to stable, high, +AAM signal, global wind oscillation phase 6 untainted by Indian Ocean convective anomaly. Quite good model agreement for a cyclonic phase to develop, and residual height anomalies centred over the Kara and Barents Seas will tend to force a more negative tilt to the jet. Still no imminent sign of anything unseasonably cold, yet, but this shift in global forcing to a more classical Nino will make life interesting from mid Jan, not least the stratosphere where we will see some more tangible developments from 11th onwards where a big wave 1 and 2 hit is being lined up. cfs hovmollers consistently persisting the tropical forcing just east of the dateline suggesting that this +AO / west qbo regime is beginning to relinquish its grip
    33 points
  3. Stratosphere forecasting is probably just as complicated as traditional weather forecasting and when you break things down there are both positive and negative factors which will affect whether a stratospheric warming will occur. Before I get into these factors lets just recap a few basics about stratospheric warmings. Warmings tend to come in three flavours. The first is a minor warming (wave 1) which tends to push the stratospheric vortex away from the pole and tend to be common. These warmings can often push the vortex towards the UK resulting in wet and windy weather while setting up blocked weather patterns elsewhere. This blocked pattern can often provide the conditions for a major warming to follow in two to three weeks time. A major warming (wave 2) will tend to split the vortex in two and tends to be a little less common than minor warmings. The result for the UK depends on where the two lobes of the vortex are at a particular point, but often you can expect a slowly moving blocked pattern giving a cold spell for the UK. Finally there is the final warming which indicates the break up of the stratospheric vortex and ultimately the polar vortex which can lead to a variable pattern and some cold out breaks over the UK. These warmings are caused by upward propagating planetary waves (Rossby Waves). OK so let me explain what I think these planetary waves are and how they work. Wave 1 represents a blocking pattern where there is a single major blocking high pressure in northern latitudes. Typically this blocking high is connected to the Siberian High or norther European high pressure in Winter. Wave 2 represents a blocking pattern where there are two major blocking high pressure areas in northern latitudes. Typically these might be North western Canada and Siberia. Wave 3 would represent three blocking highs in northern latitudes. Placement of the blocking high also seems to play a key role with a suggestion that Blocking Highs over the Euro-Atlantic sector tend to enhance the upward propagation of Planetary waves, whereas blocking highs over the western Pacific lead to a strengthening of the polar vortex. OK if you want to know more and see how these work follow the link below. http://www.sparc-climate.org/fileadmin/customer/5_Meetings/GA5_PDF/KazuakiNishii_SPARC_GeneralAssembly2014_14Jan.pdf So any old high pressure in winter will cause a stratospheric warming? No it is never quite that simple and there are precursor and conditions for these waves to propagate upwards into the stratosphere and affect the polar vortex. One source of precursors is possibly gravity waves in key areas with these smaller scale waves being able to penetrate above the stratosphere (mesosphere and ionosphere) to affect conditions there which will slow the winds slightly at the top levels of the stratosphere. These lowered winds then become susceptable to planetary waves disturbing them. Another link which sort of skirts around this. http://www.sparc-climate.org/fileadmin/customer/5_Meetings/GA5_PDF/PosterSessionB.pdf Now your head is probably totally confused about different waves I have better give a brief explanation of what gravity waves are as opposed to planetary waves. Gravity waves tend to result from either thunderstorms or low pressure systems crossing over mountain ranges. It turns out that particular mountain ranges and storms systems tend to have a large effect on whether planetary waves affect the stratospheric vortex. These gravity wave hot spots in the northern hemisphere winter include the mountains of Norway, Greenland and the UK. This might suggest that wet and windy weather in the UK and Norway might be a precursor to a stratospheric warming. Another link with some nice maps of where gravity wave hot spots occur. http://onlinelibrary.wiley.com/doi/10.1029/2012JD018658/full So we are starting to get a bit of a picture about how stratospheric warmings might come about. I have of course missed out on Kelvin Waves (particularly relevant to Tibetan plateau in winter) and solar tides. I am sure somebody here will go away and check up on these things to give an even clearer picture. Link explaining how all the different wave types combine together. http://arxiv.org/pdf/1412.0077.pdf Waves are part of the story but there is perhaps one more dimension that needs exploring a little and this is around ozone amounts over the pole. Ozone concentrations over the pole at high levels in the stratosphere alter the temperatures at those levels. Ozone depletion at the top of the stratosphere results in warming at this level and cooling through lower layers in the stratosphere. When temperatures go below -78 C Polar Stratospheric Clouds form which deplete the ozone further. This causes increased wind speeds in the stratospheric vortex which become ever harder to displace (i.e. No amount of planetary waves could shift it). One cause of ozone depletion in the top layer of the stratosphere is the pulling down of Nox from layers above due to Energetic Particles. What I think this means is that space weather or more particularly solar activity can play a part in whether stratospheric warmings occur (Note that EPP activity while related to the solar cycle can be slightly different). Gravity waves can off course play a part in excitation of the thermosphere and mesosphere changing ozone concentrations as well. A little bit of discussion about this at the following link. http://www.atmos-chem-phys-discuss.net/15/33283/2015/acpd-15-33283-2015.pdf Seems to me that Geomagnetic activity might play a part as well. http://www.swpc.noaa.gov/products/notifications-timeline So having said all that and knowing a little about the drivers are we any closer to understanding whether a stratospheric warming is likely this winter ? The answer I think is that there are some possibilities as energy is transferred from the troposphere into the stratosphere, but that we have a very strong stratospheric vortex which is going to take some shifting. After the current wave which we should not expect to shift the vortex much there is another wave forecast for around the 5th of January. I don't expect much from that one either but it might set up the conditions ready for a further wave. So I think we are looking at late January and into February as realistic windows of opportunity. Much will depend on ozone depletion due to cold stratospheric temperatures against ozone transport from lower latitudes.
    24 points
  4. Good!! They have had enough blizzards and freezes !! I have no sympathy for them whatsoever!
    18 points
  5. Sigh. Some of the prima donny, hissy fit posts in this thread (and others) are getting as tedious as this weather. Negative nellys everywhere. The output IS changing. As GP has alluded to, we may be at the pinnacle of this +AO spell right now. The FI of modelling has been hinting at a gradual degradation of the rampant tropospheric vortex for days now. Only the Greenland based segment remains with integrity into Jan. Not good for us in the short term BUT how long (given we'll only just be into Jan) do you think this Greenland based segment can realistically retain its integrity? Indeed, the past 2 GFS runs have hinted it may not remain intact into the second week of Jan.
    15 points
  6. Someone asked me the other day if I'd been away because I looked tanned. I replied, no. I live in the Lake District...it's rust" We need those 200mm of rain to push off somewhere else, it's getting silly now. Sorry off topic, but I think some communities are close to breaking point.
    14 points
  7. Hi Team Just a pop in and bear with me as I'll be editing too. I know Eva is coming, I know my middle cold didn't work out but something I did mention was a stormy New Year. Now this is a tad worrying as Eva is just a warm up if this happens, and there has been plenty of hinting in the models so we must watch it ruddy nora! This ain't cricket.....That is a massive double whammy folks....watch zone BFTP
    13 points
  8. Quite a few GEFS at day ten show a positive PNA developing. By day 11 this is even more pronounced with the Azores high displacement. Are we seeing the first signs of a MJO induced change? For newer members the PNA stands for Pacific North American pattern, in the charts below the one on the left show areas of higher pressure, orange/red and lower dark blues/purples. Normally with an eastern USA trough if you have enough amplification the Azores high displaces further west and low pressure sets up more to the east of the UK. This would be a marked change in pattern and would remove the Euro high from the south which has set up for the last month with the jet angled more se. If you get enough upstream amplification you can get a northerly toppler scenario or at least some decent PM shots. Much depends on the response to the MJO signal. Lets hope the ECM follows this trend and its still early days so we'll just have to hope that we can get some change to the relentless mild conditions.
    12 points
  9. The benchmark for cold air seems to be the 850 0C isotherm. I don't know if anyone summarises each month on here, but that chart is a pretty good summary of December 2015, which with a few annotations could represent practically any December day:
    9 points
  10. Even on the ECM day 9 chart you can see the cold being displaced slowly more and more into the mid latitudes. SE Europe going cold and that huge mild dome we've been sat in for much of December being eroded from both sides. All good signs going forward.
    9 points
  11. Well with regards to last year it was actually a substantial warming setting some daily temperature records at some levels, though it appeared the wave forcing may have just tailed off too soon. Looking at a couple of current analogues for this year shows how similar set ups can give different results but also the potential forecastability of the stratosphere. The two closest 30-day analogues to the GEOS 10mb 60°N wind forecast for 31/12/15 are 09/01/1981 and 12/01/2000 - this is as calculated by way of mean square difference over 30 days. This is shown in the graph below, dark blue = 2015, orange = 1981, yellow = 2000, cyan = analogue average. Both analogues show a reduction in wind speed starting within the next couple of weeks, with 2000 almost achieving SSW - windspeed 0.6 m/s after 27 days - this shows the fairly typical amount of time required to get to a wind reversal from the current level, so eg 27th Jan 2016. 1981 didn't reverse till later in the season but what is remarkable firstly is the similarity in profile of the variation in wind speed between the two years, the correlation over the next 60 days is 0.857. But why the difference in wind speed? Maybe the forcing was different, however then remarkably again, the 60°N 10mb wave 1 geopotential height for the two years was almost identical - Remember, this match in wave 1 profile was not selected directly but by similarity of the previous 30 day wind speed to this year. Ultimately 2015/6 might not follow either of these years, but analogues for the other variables tend to give similar results of possibly end of January or start of February though certainly not guaranteed.
    8 points
  12. Today the Astronomic winter has officially begun! Or well, winter… in the Netherlands we have yet reached another all-time record daily high. We have seen so many daily temperature records here that people barely notice them anymore. However, there is of course much more going on behind the scene! Most importantly, a significant pattern change is bound to take place the next couple of days. Will it bring significant winter weather? Or are we going to see a continuation of this extreme mildness? Of course much will change over the next few days regarding the outcome, but still we can definitely say some specific things about the weather to expect. Before doing that, I would like to take you through a tour showing just how unique the warmth is we are experiencing. Time to dive into the Spring month called December! A crushing month A record-warm December month is what this month will certainly be. But this December monthly record is not going to be broken, it is going to be literally crushed. And that is something we can say 9 days before the closure of the month. The previous December record high mean temperature stood at 7.3*C, set in 1974. Currently, December 2015 has a mean temperature of 9.6*C, a whopping 2.3*C above the previous record. And this is not going to change much, judging from the latest ECMWF ensemble: ECMWF temperature ensemble for De Bilt, the Netherlands from the 00Z run of 22-12. Source: Weerplaza. The blue line denotes the average temperature for December. The black line indicates the mean temperature that one can roughly expect averaging all the members. This temperature equals about 9*C. Applying a rough calculation, this would mean that the final temperature will reach 9.4*C, which is more than 2 (!) degrees above the previous all-time mean temperature high for December. South-westerlies “ohne ende” It has been windy during most of December, but most impressive is the prevailing wind direction. The image below shows this: Wind direction and -strength for De Bilt, the Netherlands for December 2015. Source: KNMI. It will not get much more south-westerly-dominating than this. About 90% of the time the wind has had a southerly component. Roughly speaking, the source location of the air has been’ tropical’ most of the time, originating from the seas near the Azores. These locations aren’t standing out for their cold winters weather to say the least. Given all this, it seems clear that lots will be written in the media about the unpreceded warmth in the coming days. I’ll provide a short update once this record-breaking December has come to a close. Polar vortex on the move From looking to the past we are now going to turn our eyes to the future. As Nick alluded to in the previous post, one of the most significant changes taking place is the position of the (lower stratospheric) polar vortex. 100 hPa heights for today 00 UTC as analysed by ECMWF. Roughly, the center of the low pressure area indicates the location of the polar vortex.. Source: FU Berlin. For now, the Stratospheric polar vortex looks to be rather circular. However, things are going to change a lot, as we can see 8 days later: 100 hPa heights for T+192 (8 days out) as forecasted by ECMWF 00Z run of 22-12. Source: FU Berlin. The first thing that shows up is that the polar vortex will be by far not as circular as it is now. In fact, its main centre has moved southwestward towards Greenland. It needs to be stressed that this is all is not caused by a SSW. From zonal to blocked? Often, such pattern changes in the stratosphere result in amplification of the flow near the surface as well. This means that the flow starts to be more north-south or south-north oriented instead of east-west. In other words, the Jetstream starts to meander a lot. This is also what we are going to see happening as well. For us, the most important ‘consequence’ of this all is that ahead of the polar vortex, high heights start to build at this level giving credits to believe that this will also lead to a significant blockade at the surface in the proximity of Scandinavia. So far, December has represented high pressure over Central Europe. So what are the differences compared to what we have seen during the first parts of December? 1) Low pressure activity is more active near Greenland and to the south. 2) High pressure activity over central Europe is anchored slightly more to the north (though the exact location remains to be seen). A setup to winter weather? With such a setup forecast, a high pressure area at the surface near Scandinavia is a distinct possibility. Does that also mean that winter weather is on the way? The answer is most likely not. But why? For the reason why it is useful to look at the ECMWF and GFS for 10 days out: ECMWF (left) and GFS (right) 500 hPa heights (colours) and surface pressure (black contours) 12Z T+240. Source: Wetterzentrale. The plots given above are for 2.5 days further out than the stratospheric charts of the ECMWF presented above. In both cases we see the polar vortex nicely represented at 500 hPa as well by the purple colours (very low heights, so intense troughing). Both charts also show something of a Scandinavian/European high pressure area. But both charts are definitely not suggesting anything wintry. These charts would result in a continuation of south-westerlies instead. Why is that the case? The ‘block’ is in both the ECMWF and GFS located too far to the east to be of much influence on the weather in Western Europe. It only tends to hold up approaching low pressure systems from entering Europe, instead sending them northward towards Iceland. The troughing over the Central Atlantic, on the other hand, is able to exert its influence over Western Europe. As we are going to be located in the upper branch of the troughing, the consequence is again mild southwesterlies. Back to where we started: southwesterlies “ohne ende” What we can conclude is that, despite the pattern change occurring in the upper levels of the atmosphere, the result is only a continuation of the same theme. With blocking in the upper atmosphere to be set firmly in place, the southwesterlies could last for quite some time, making after a record warm end of December also a very mild start of January a very distinct possibility. The best evidence for this can be found in the ensemble forecast for the wind direction. ECMWF ensemble of wind direction for De Bilt, the Netherlands from the 00Z run of 22-12. Source: Weerplaza. 180 degrees indicate southerlies whereas 225 degrees denote south-westerlies. The black line is drawn to emphasize the ‘location’ of south-westerlies. Even past the start of January, most ensemble members show a domination of south-westerlies. For example, at January 5, the chances on a southerly to south-westerly wind direction still seems to be about 80%. This, in combination with the ‘stuck’ upper pattern and the very mild ensemble temperature forecasts given at the very start of this post, lead me to believe that for the next 2 weeks or so, the weather will be most likely on the mild side. The question is only by how much. Concluding note I hope with this post I have shown just how extraordinary this December has been. And that even when the ultimate weather near the surface does not change, the developments taking place aloft can still be very interesting to follow! If you have any questions, do not hesitate to ask! And finally, a nice Christmas and best wishes to 2016 to all. Hoping for an interesting 2016 weather-wise! Other sources For the daily records, the following sources were used as well: Weergegevens MSCHA
    8 points
  13. Never mind the hunt for cold for now, a further risk of some serious flooding to come over the next 7-10 days in the north. EC is showing 200mm easily for parts of Cumbria during the next week. That storm on 29th/30th needs closely watching as well.
    7 points
  14. That's a helluva stormy approach to New Years on tonight's 12z ! Then, this extreme evolution Unsurprisingly the clustering highlights the uncertainty in evolution. Fingers crossed this one bombs in the atlantic and gets stuck there.
    6 points
  15. Certainly a chance of snow within the systems as it pulls cooler air in at times from the N/W especially with elevation. Some proper Winter storms on the way if the GFS materialises. Quite an eye opener, And not good news for the already flooded areas with yet more heavy rain associated within these deep systems.
    6 points
  16. What's new? Don't we already have 14/15c almost 60F. It couldn't really get worse for coldies in the UK could it?..To me, the only way is up and the best Christmas present netweather has had is Glacier Point post regularly, that guy's meteorological knowledge is amazing and I hope he's right about mid Jan onwards!
    6 points
  17. You have to remember that BOMM run is nearly a week out of date - with the exception of UKMO (7 days), on that date, the rest were returning to neutral/near neutral in the early stages phase 6. It is only in the last few days that the signal for amplification and progression has become stronger.
    6 points
  18. Still nothing for us to get excited over this winter, lets see what January throws at us In the meantime
    6 points
  19. 5 points
  20. Serious question - why on earth would you go with BOMM as an indicator of potential MJO development? That wild array of squiggles from its members is exactly why I wouldnt give it the time of day. Much more significantly the ECM is more solid of a transition through into phase 7 and towards phase 8 with much less disarray
    5 points
  21. Reasons to be positive as a cold lover :- 1. We have just about lived through one of the mildest December's on record, so we prob wont see one as mild for some time (We Hope!!!) 2. Its only December 3.We are currently heading into a deep solar minimum, so we could see some coldish winters coming up over the next few years, even if this winter does turn out to be a mild wash out. 4.For those who haven't seen snow since 2013 the law of averages suggests you will, and a for all those who think we wont see snow again at low levels we heard all this during some of those dire winters in the late 80s and 90s, as we have seen since then we can still get snow at low levels!! 5. Remember for every 1988/89 ,2013/14 1997/98 and November/December 2015 extreme mild winter we can also talk about 1947,1963,1987,1991,2009,2010,2013 cold spells, so in our climate we can get both extreme mild and cold in winter. If we are in a mild period at the moment then so be it, but there is a good chance that a some point we will enter another cold period. 6. Dont get to hung up on the models as they can and do change. 7. Its only the weather. 8.Its Christmas, who knows next one we may have a screaming easterly setting up and we wont be talking about dafs coming out ! Am sure you could draw a list of negatives up as well, but that's not the point, as I have said before this type of weather kills the mod thread as most peoples are looking for a cold and snow fix in winter. I miss the buzz and expectation of the build up to a cold spell as much as any cold weather lover, but am old enough to realise it isn't always goanna happen. So don't get to hung up try and follow the more knowledgeable posters and if someone's posts upset or anger you hit the ignor button. Merry Christmas to you all and your families.
    5 points
  22. Brilliant hope Eva doesn't wash him away! Some hope from GP looking at mid-Jan onwards we do need something to remove that warm bulge that has resided over us for weeks now, heart goes out to those flood victims in the NW
    5 points
  23. All of us as well if that comes off Tiny BFTP
    4 points
  24. Heres another version of the MJO , its been smoothed out to reduce interference. I don't normally link to anything with CFS in the title but I liked this forecast! lol MacRitchie explains below the reasoning behind this MJO version. This is modeled after the Wheeler and Hendon (2004) RMM phase space and is most similar to a similar approach that I’ve written about in MacRitchie and Roundy (2012). This approach uses the CFS MJO projections, as used in other figures on this website, to track the MJO. This results in a smoother signal than the WH04 index with less interference from other modes. I've just put up the abstract of the study. Previous works have shown that most of the rainfall embedded within the Madden–Julian oscillation (MJO) occurs in large eastward-moving envelopes of enhanced convection known as super cloud clusters. Many of these superclusters have been identified as convectively coupled Kelvin waves. In this work, a simple composite-averaging technique diagnoses the linear and nonlinear contributions to MJO potential vorticity (PV) structure by convection collocated with Kelvin waves. Results demonstrate that PV is generated coincident with active convection in Kelvin waves, but that this PV remains in the environment after Kelvin wave passage and becomes part of the structure of the MJO. Analysis of the Tropical Rainfall Measuring Mission (TRMM) rainfall suggests that 62% of the total rainfall within the MJO occurs within the active convective phases of the Kelvin waves (88% higher than the rain rate that occurs outside of the Kelvin waves), supporting the hypothesis that diabatic heating in cloud clusters embedded within the Kelvin waves generates this PV. I'm not sure if you followed some of the debate re the MJO versus Kelvin waves, the above might go some way to explaining some of the interplay between the MJO and Kelvin waves.
    4 points
  25. Well the one good thing is that January will surely not be as mild as December has been......
    4 points
  26. Not really much to add this morning, it does seem for a time that January will start where December finished. ECM ens GEFs A cyclonic south westerly flow likely with mild and fairly unsettled conditions prevailing. There are weak signs that we could see something nearer normal develop further ahead, the GEfs hinting that the main core of higher heights may return to a more normal position near the Azores, resulting in more normal temperatures with polar maritime incursions at times. This could change as we approach the turn of the month, in particular to see whether we see low heights develop in a more favourable place as apart from that Azores ridge, there is a lot of detail left to define. ^haha nice LSF
    4 points
  27. Can I be cheeky and ask your confidence level on this please? !!
    4 points
  28. Only if model output can be trusted out to T+936. Also, it's surely far too early to dismiss the Net-Weather Winter Forecast?
    3 points
  29. How can you say that it won't at some point? A positive PNA if it came with an amplified eastern USA trough would change the pattern as it would draw the Azores high further west. I think we should keep an open mind to see what plays out re the MJO. At this point I'd just be happy to see the removal of that Euro high.
    3 points
  30. Good question. I think for the timebeing we're going to have to sit tight and see what the NWP response will be. So far the MJO composites have fitted well with each phase. If the positive PNA sets up then the amplitude of that eastern USA troughing will determine the movement of the Azores high. Do you remember the time when we used to see northerly topplers? I say that because a true Arctic northerly toppler hasn't been since I could fit into a 34w pair of jeans! lol I think trying to dislodge that PV for a lengthy period of time is going to be difficult however if the MJO can help us then we would have a chance of some nw/n flow. The response to the MJO isn't an exact science, we can just keep our fingers crossed. I just want rid of that Euro high which is seriously getting on my wick now.
    3 points
  31. evening just checked the latest and seen the output for here on Boxing day. Can't quite believe it. What's causing the front to stall? or is it another one of those horrible lined up with the isobars long fetch rain forever systems from hell again? Would really like to get a feel for the reliability of this, given the significant change from the prior run as I might be building heavy walls tommorow as a result!
    3 points
  32. Would not be surprised if Cumbria is under a red warning again by Boxing Day. What a hateful season this is.
    3 points
  33. That high pressure (or at least the factors creating it) is a complete waste of space. Firstly, it forms to the north of the UK and deflects the Arctic flow that was heading in our direction away to the east. Secondly, it drifts to our east and blocks off the eastward progression of any Atlantic lows, meaning they track south to north over the UK then up towards the pole bringing ridiculously mild air over here. A high pressure over Europe is only any use for UK cold if it is anchored to the pole and the Jet stream is forcing low pressure systems down through Iberia and across the Alps.
    3 points
  34. Absolutely no support from it's members and is typical of GEM, late with correcting a false signal. Mean and Control at T216: The models all went crazy when the wave was introduced, a well known tendency entrenched in all the models. The actual effect from this local amplification is as we probably expected in the current +AO and ENSO for the HP/Ridge to be mobile and move away as quickly as it arrived. Due to the current long wave pattern its introduction gives us another plume of mild uppers and unfortunately the prospect of further rain to the NW. After that mild push (till 30th) we have a more zonal setup and depending on where the polar jet sits certainly more PM air than of late. Only one of the GEFS offers a blocked pattern at D16 and we can pretty much dismiss any cold setup before the first week of Jan at least. Week 3 & 4 of the CFS offers further bouts of SW'lys, but I am not buying that at the moment: The BOMM, which was one of the first LR MJO models to pick up the amplified Phase 6 and 7 are now moving away from that. So it is difficult to know how any MJO signal will manifest with the ENSO background noise. Seen some composites and there is little guidance at the moment so not too sure what to expect in that respect. Hopefully a change to the long wave pattern in early Jan? The PNA pattern looks like returning to positive in a week or so and this should tie in with the w2&3 CFS anomalies: So nothing too promising there though temps wise, again more of a PM flow. The ECM mean does show that drop in temps with time, though scatter after D8 and the op looks an outlier (again) by D10: Nothing brewing in the strat at the moment: A case of grin and bear it and hope that mid-Jan onwards there is a pattern change.
    3 points
  35. I can't unfortunately find the original post but so far this Winter is proceeding more or less in line with Roger Smith's Forecast. From memory, his forecasts are usually pretty good and free from hyberbole and he's going for a decent cold spell end of January into February. To be honest, that'll do me fine for Winter. One decent fall of snow, that hangs around for four or five days, topped up with a few showers.
    3 points
  36. I like the look of the GFS 06z so far. Great negative tilt to the atlantic trough by 180 hrs. This is something GP pointed out last night. Negative tilt due to increasing heights towards Kara Sea.
    3 points
  37. How do you know that? It could even be not as cold as March 2013 but far snowier.
    3 points
  38. A least we can't say the pub run was boring. It had more floods A fierce storm more floods widespread snow New Years day More floods Another brutal storm More floods
    3 points
  39. Normally this wouldn't be worth posting but since it's Xmas and we have had nothing to cheer this winter.
    3 points
  40. I suppose it's always down to location wether it be too far south or north,in your case you was too far north,ironically,this was the scene here that month albeit i went up a couple of hundred feet to witness this,this is a road would you believe
    3 points
  41. LOL this winter is an absolute joke, daffodils everywhere, blossom on the trees and the models, don't get me started on the models..But at least it's Christmas!!
    3 points
  42. Cor blimey - it is depressing in here today. But I think some meat on the bones above is due - and also strat junkies need to get their radar right. Firstly - all 13 of the MJO models available over at the CPC are today forecasting move into a decent phase 6 in the next few days. Firs thing to note there is that this has taken the models by surprise - if you check the verification stats for the MJO GFS you will see that the last 2 weeks has seen a constant undermodelling of the strength of the convective pattern out in the Pacific, and I would hazard a guess that the models may continue to do this. And yet - the ECM MJO forecast today is much more vigorous than it was yesterday... and the forecast today from our own MoGreps model - highly regarded I believe - shows a clear signal for continued strong MJO activity heading towards phase 7: It is a pity Mogreps does not go much further out... but both ECM and GFS today are singing to the same tune. If we get to phase 7 - and to be clear this is still obviously an if - then the January composite is much better viewing for those who like their winter cold: Secondly I think people need to start viewing the Strat with a sense of perspective. A full vortex breakdown is obviously the holy grail for cold lovers.... but in reality total breakdowns do not occur every year... and many cold spells from the past have not materialised from total breakdown scenarios. A weakening of the vortex combined with a favourable pacific MJO may well be all we need to get blocking in the right place, and so it irritates me to see tweets from those like Ventrice used as though they are proof of the end of winter. That is total nonsense. Our current setup has a little way to go yet, and then as GP stated the other day it looks odd on that the pattern will shift to the east and the trough drop over the UK. Temps back down to somewhere near normal with the chance of height rises in mid atlantic as well as in western Russia. What happens after that will be hugely dependent on correct MJO modelling as well as trop led disturbance to the vortex - both of which many of us are pleased to see aligning in the right direction. Just how well the convection will hold together in the pacific, and just how great an impact wave breaking is going to have on the vortex is up for grabs. Both may fail. Both may succeed. We may get partial joy from one or both. BUT for sure the pattern is at the peak of its dreadfulness, and statistically we all know that front loaded El Nino winters get less zonal and more blocked as time passes. So let's keep a bit of perspective. We need to ride out 2015 and see what occurs in the first week or so of January. If the MJO begins to camp in the COD and wave breaking simply bounces off the vortex then by mid January perhaps we can start to worry. But not yet.
    3 points
  43. And a classic bombing is being suggested.With so much cold air flowing south,this is not unusual however it can be overlooked by many.These eyes will be paying close attention to developments likes.
    2 points
  44. Well finally the MJO expert at NCEP has downloaded the correct PDF file! His conclusions are that the MJO could force a pattern change over the USA and Canada. More ridging over the NW and the AO trending neutral. In terms of the GFS 18hrs run personally I hope this is the right trend because it finally removes that Euro slug high and has high pressure to the ne. At this stage I'd rather see high pressure to the ne coming out of Russia to help deflect the jet into Europe and finally bring some snow to the European ski resorts. Whilst that possible upstream change doesn't guarantee snow nirvana it might at least bring some cooler PM shots and could develop a bit more interest later depending on the response to the MJO. In terms of the GFS and its possible storms it does have a known bias for overdoing these. So lets hope for a change to something more seasonal but with any low pressure toned down nearer the time.
    2 points
  45. Could you get any more cliches in that post?
    2 points
  46. And it will be in March bring it on the 18z going for cool pm,lets get rid of this sceuro high and MOVE ON.
    2 points
  47. This would fit into the interesting category if not downright scary.
    2 points
  48. Well this is as painful modelling as....oh last winter. Is it me or have the models provided virtually nothing but pure frustration for most of 2015 - in all seasons? Obviously it's only the first day of winter officially today - but if there's no change at some point in the next 2 and a half months or so, the last 2-3 winters will have provided literally 2 attempts at snow in low lying England - utterly pathetic for those of us wanting seasonal and proper weather for each quarter of the year. For those that counter that with 'its rarely hot in summer either' - at least it's sunny and dry some of the time - us winter folk can't even get a bloody frost. Obviously there are factors against this part of the earth getting cold spells for prolonged or frequent periods, but to me, it just feels like the entire swathe of charts, the analysis, the strat, 5 different models etc that we have available these days are taking away the 'over night' flip ability, or the 'catch you by surprise element' of the models away and affecting/dampening the mood of the thread. It certainly feels like everytime someone has a positive comment to make, they have a chart, or a link, or a piece of writing thrown back in their face. For sure, everything we have these days are brillant for educational purposes and they do definetely enhance the technical ability of our forecasts - which can only be a plus, however, for me, it takes away some of the fun. I liken it to the good old days of being a wrestling fan as a child... no internet, no spoilers...everything that happened felt 'real' - these days we are bombarded by taped programming, spoilers and the internet...taking away the fun, even though you can't help but 'see' the spoilers you know will ruin your fun? (Or would have 15 years ago). Reading this thread tonight, you could/would effectively as a novice, come in and go away with the notion that you can effectively write off the next 2-3 weeks for cold weather and then come back to see if things changed. That wouldn't have happened a decade ago...AND YET..we are no further ahead now than we were 10 years ago in producing a 2 week forecast..says it all really.. Still, plenty of turkey, alcohol and family to enjoy in the next week or so folks. Enjoy - and have a good one.
    2 points
  49. As I mentioned in the strat thread earlier this month, some previous strat warming events saw the tropospheric pattern change (i.e. blocking) before the official stratospheric vortex split or displacement. The 1986-87 winter featured a strong El Nino, the strat vortex displacement didn't officially occur until Jan 25th '87' but the infamous brutal cold easterly started early on in the month. Check out this strat loop here: http://www.meteo.mcgill.ca/~pmartineau/updated_graphs/svw_anim/all_gif/1987_01_25 However, we are long way off seeing any major pattern change for now. The tease of the Scandinavian high with deep cold air developing over NW Russia looks to become increasingly out of reach as very low heights/deep cold over Nern Canada and Greenland drives a strong and flat jet up against the +height anomaly trying to build north to the east. The NWP ops and ens are more weighted to pushing the +height anomaly east out of reach of the UK unfortunately. Though one positive, albeit still verging in unreliable timeframe, is that as the low heights spread east again, we gain a colder Pm westerly flow, with increasing chance of northern snow as we enter the new year. However, that's if the models aren't understimating the block to the east! Even though no pattern change looks likely for the foreseeable, thanks to the unhindered and strong polar vortex, the ridging to our east does, at least, seem to be punching the Polar Vortex around a bit, as recent ECM lower strat charts have highlighted next week in the geopotential height field. But are the current waves bouncing against the Polar Vortex more like ping-pong balls rather than canon balls? As Mike Ventrice mentions on twitter, time is running out to weaken the behemoth that is the Polar Vortex this winter. Lets hope a SSW occurs in late Jan, as per Judah Cohen's latest update, to bring a cold end to winter. We may even have a trop pattern change before any SSW, as my example above shows. The MJO looks favourable, but there is a great deal of uncertainty whether the wave will be coherent enough once it reaches phase 7 to really make much effect to change the northern hemisphere teleconnections ... certainly the models aren't picking up on it for now. It's a long waiting game this winter for uncertain reward if any reward.
    2 points
×
×
  • Create New...