Jump to content

damianslaw

Model Forum Host
  • Content Count

    7,838
  • Joined

  • Last visited

  • Days Won

    6

Everything posted by damianslaw

  1. Thanks for clarification, certainly in recent years, the PV seems to have taken until early December before it has started to get its act together, so I can see some logic in what you are saying. Lets see where we are in a couple of weeks time, if by then we are still seeing a fragmented disorganised PV in the longer term output, then mmm perhaps it isn't ever going to get its act together this winter..
  2. It was number one in Dec 1994, which was a very mild month overall..
  3. Think you will associate these songs with the cold snowy February of 1983, both were number one round that time.
  4. I'm no expert and find backing up my seasonal thoughts on evidence very difficult. I tend to think the base state for the season doesn't tend to set in until nearly a third into the new season, and at 3 weeks or so ahead of where you are when making the call, too far out to have any ideas how things might happen from using the model output at the time. Not explaining it well, I'm saying winter base state for rest of winter including well into March often sets in around christmas, likewise summer, around June solstice - i.e. northern hemispheric state develops into a groove around then. The opening to each season has a lag effect, and consequently often feels like the season just gone. When it comes to winter in particular, I often write off the first fortnight of December in terms of expectations for cold an snow and begin to look for clues around middle of the month as to what the season might hold overall. One thing I look out for is the behaviour of the jet through November and into December as this can offer insights into what it might do through winter proper.. I'll give some general thoughts for what its worth at the end of the month.
  5. Lots of uncertainty how things may pan out as we end November.. pehaps signs of a bit more mobility longer term as heights to the NE ebb a little further to the east allowing the trough to anchor a bit further east than has been the case recently, this would as you say allow possibly for some colder polar air to feed down from the N or NW as being hinted at by some of the models longer term - only hints. There are also signs the azores high might ridge further NW which would also help to steer frontal features more towards S Scandi - the other option might be for heights to build more strongly to our south, sending the jet further to the north. I agree though the most notable feature is no sign the jet is going to stir into high speed anytime soon, and it looks very sluggish, and prime territory for trough disruption and splitting, with every chance heights will have an easy time to develop and become strong blocking features for the foreseeable - where these heights decide to move to is the hard question to answer.
  6. When you think of winter songs your first thought is often christmas music, as it dominates the start of the winter at least, so my memories of winter songs tend to be more associated with those that were in the charts in January and February. Jan/Feb 91 - 3 AM Eternal by KLF and Seal - Crazy spring to mind Jan/Feb 96 - Babylon Zoo - Spaceman Dec 96 - Robert Miles - One and One, Toni Braxton - Un-break my heart Dec 09/Jan 10 - Lady Gaga - Bad Romance, Jan/Feb 10 - Owl City - Fireflies March 13 - Bastille (forget name of song) These were songs that seemed to be everywhere at the time.
  7. The lower heights to the north are very weak and not uniform which is the interesting aspect allowing for wedge / ridge of heights to sit underneath to the south of greenland - over to Iceland and Scandi pushing the jet on a more southerly track. Shallow stretched elongated low pressure systems, primed to slide and split in situ, with cold uppers to the north, a recipe for borderline rain/snow events, indeed what happened on Wednesday for some.
  8. Only very weak positive, possibly neutral even a bit below, azores high way to the south, and higher pressure towards Iceland and Greenland with low pressure further south - preety much same we have had past few days which has been negative.
  9. Another post from me, yes echos of November 2009 this month so far, in terms of the trough becoming unstuck over the UK, delivering copious rain, coming unstuck against heights to our east, and it was a weak atlantic as well.. difference this month so far, has been the position of the jet much more southerly, and hence it has been much chillier so far than Nov 2009, but agree very very strong similarities.. we had serious flooding in Nov 2009, with a more southerly jet, this has happened about 150 miles further south and east this month.
  10. I think it depends on how the cold has come about in November. This November has been chilly but nothing especially cold, and the recent colder weather with snow for some has come from cyclonic low pressure system, not deep rooted northerly or easterly airstreams as occurred in 1985 and 2010, which is interesting in itself. I do agree I am always a bit nervous when we have cold spells in November on the back of cold northerly or easterly airstreams, or indeed just cold anticyclonic conditions as has happened in some recent Novembers, short spells around third week 2015 and 2016 for example, 1988 being another classic example. However, I'm not at all concerned when it comes about due to cyclonic conditions.. Nov 96 a good case study in this respect, yes the cold vanished second week January, but we had a preety cold 6 weeks late Nov to early Jan becoming very cold around christmas. I'm taking alot of optimism from the synoptics this November so far, more so than any November probably since 2010, and to an extent 2012.
  11. Yes interesting in that a change to something milder isn't coming via the normal route i.e. a strong powered up westerly/southwesterly, instead low pressure anchoring down and south of UK.. winds from a SE source, coming off what is still a relatively warm continent, similiar synoptics in a few weeks time, when the continent has cooled more markedly would be offering a different affair. Not saying the current pressure pattern will hold right through the winter season, but if it did, it would be a cold one, and possible very snowy, not bitter cold, but cold all the same.
  12. I agree, eyes need to be on developments to our NE, and the transfer of energy in the PV towards Siberia which would create the scandi trough and consequent cold air advection on the east side of Greenland, conversely warm air advection on the west side - the classic evolution to a Greenland high.
  13. Thanks for that. Dalwhinnie has a preety unique situation, set within a wide bowl of high mountains, not deep within a valley as such. There is a plateau of sorts and I suspect it is due to its location as a meeting point of other valleys that are set within high mountains and the cold air collecting within them that creates a frost hollow, Normally the coldest spots are those places set deep within high enclosed valleys, at lower elevations, though I guess Braemar is similiarly located so not always the case. I was up in the Cairngorms end of October and it was notable how quickly temperatures fall once dusk sets in, in Aviemore the temp was already freezing point at 6pm in not especially cold uppers.. something to do with the cold air from off the mountains quickly draining into the valleys I suspect. Here in the Lake District we can achieve similiar effects, but we usually need a deep cold pool overhead and very light winds or no wind to stir the air. Many of the central lakeland valleys are deeply enclosed but conditions need to be just right, with deep snow cover helping.
  14. Models in good agreement at present into the semi-reliable even, which you often can't say. Changes are afoot which hopefully will result in some drier conditions for a time at least for all compared to the very wet weather recently, but still overall staying unsettled with further bouts of rain, and as we move towards end of next week, unfortunately these could become quite slow moving and heavy affairs again, and yet again targeting central parts, as we see low pressure anchored down over the UK not able to go any where due to rising pressure to our NE and north. Gradually becoming milder as we the week wears on as well, as we import some milder air from off the near continent, nothing exceptional, but feeling less cold than recently. With it becoming quite cloudy and overcast as well, as we lose any polar air influence. Longer term - models suggesting heights staying strong to the NE and trying to edge NW towards Greenland, and a southerly tracking jet will be maintained, signs also of possible cold air advection down the eastern flank which would allow for a more concerted transfer of heights to Greenland enabling a colder pattern to develop - but possibly still staying unsettled with low pressure never that far away to our SW, slider low territory which could make for some significant wintry precipitation. Alas this is just one option, the other is that we maintain the status quo with low pressure continuing to park itself directly over the UK but in a position that doesn't enable any cold air to infiltrate. The other scenario is for high pressure to anchor down from the north and we end up with dry stable conditions, and depending on its position either a cold frosty spell, or a dank chilly spell as hinted at by the Met Office. All conjecture, lots of options as we enter winter.
  15. Sorry again - what is the current running minimum figure so far this season then..
  16. Mmm had expected perhaps the CET to be around 6.5 degrees, given we have had some very suppressed maxima in recent days over much of the CET zone and nights haven't been especially mild - mmm expect downward adjustments at month's end I think - possibly quite significant.. Looking ahead, CET values looks like returning close to normal in the days ahead, a little below at first, but then probably slightly above as we move through next week, helped by quite a bit of cloud cover at night rather than maxima, so we may on about the same value as today this time next week. Latter part of the month hard to call at this stage, a finish in the 6's still the best bet at mid-month point.
  17. Ground above about 600 metres has retained a snow cover since Sunday now, not bad going given we've had quite a bit of sunshine, proof the uppers since have been cold enough to maintain such cover. In some recent winter months, to get 5 days on the trot of such cover has been hard to achieve, so not bad at all at this early stage in the season. We've had a preety decent week overall since last Thursday deluge, a bit of rain, and a few showers but nothing on a par with regions further south. Again evidence of the southerly tracking jet which has meant we have been on the north side of any frontal systems and they haven't managed to pivot our way. Much of Scotland away from the east has also had such weather. Expecting some further light snow for the tops overnight, and don't expect the snow cover to go away in a hurry even though uppers do look like creeping up a bit later tomorrow and into Saturday.
  18. A long remembered winter, probably one I will bang on about when I'm 90.. (I hope!). The christmas freeze and snowfall of 5/6 February being two of the most memorable winter events of my lifetime so far. It was an episodic winter though, which kept it very interesting, started off mild but quickly turned cold on the 5 December, rest of the month saw cold dominating in the main, and it was good to see the mild trying to oust it away in the run up to christmas, winning for a day, but then forced to retreat. We had a 7 day run of ice days from 25-31s Dec. The first three weeks of January though were preety miserable, mild cloudy dank affair. The period from the 21st Jan until the 9 Feb was exceptionally snowy here, a very cold easterly blast that eventually produced a good few inches on the 26th/27th, the following few days became a bit milder, but still cold, then bang we had the battleground snow event on the 5/6th Feb which left 18 inches here. The snow stuck around until the 9th, the rest of Feb was preety cold, further snow on the 18-20th, and ended cold. March brought more very cold weather and snowfall, further snow in April and a notably chilly frosty May.. the winter that didn't want to go away. I group winters 95/96 and 09/10 in the same category, and to an extent the following two that followed were very similiar as well 96/97 and 10/11, the latter more extreme but both saw very cold starts ebbing away by second week of Jan and the rest of those winters were very mild and wet.
  19. December 2001 was quite an unusual month, it was a very dry one, and often cold with lots of frost, and had a very cold snowy last week or so. It began on a very normal footing, with the atlantic in ascendance, with wind and rain and mild temperatures, the siberian high lurked far to the east, and heights were strong to the south. On the 6th /7th we saw the unusual occurance of the euro high suddenly moving north and linking with heights to the NE, to become a major blocking player, shutting out the atlantic on its westerly trajectory for the rest of the month. From the 7th right through until around the 20th, the UK sat under an anticyclone producing cold frosty night and days and lots and lots of sunshine but no snow to speak of. Things changed around the 21st, the high then began to retrogress west into the atlantic as a scandi trough formed producing a cold northerly flow and widespread snow. The rest of the month was characterised by cold northerly airstream and further snow at times, with heights eventually migrating over Greenland, allowing a proper high to form there for a few days, meaning the year ended on a bitterly cold note. Its a month that is often not really discussed, but for wintry weather, it was a decent December, pales against the likes of 2009 and 2010, and even 2008 and the events of late Dec 2000, being more akin to 2005 in some respects, but it was good to see such synoptics. Looking back at Decembers between 1995 and 2010, we did quite a bit of anticyclonic cold weather on occasion, in 1995, 1996, 2002, 2005, 2006, 2007 and 2008. More recently only 2012 and to a degree 2017 produced such weather, most have just seen the atlantic dominating as in 2011, 2013, 2014, 2015, 2016 and 2018.
  20. Don't normally comment on charts way out in future, but its not a bad chart in the essence it would bring a good drying out to places that need it. Also at the surface it would be quite cold in the south at least and with light winds any frost and fog would be slow to clear. Looking at other features, there is a deep scandi trough to the NE about to pull down very cold uppers into scandi, and also some warm air advection through east atlantic towards Greenland, no sign of azores high - not sure whether it would happen, but that cold to the NE could come in the back door through its eastern flank and inflate the high northwards through the UK, with consequent atlantic trough undercutting.. all conjecture, but it seems a fluid pattern rather than a holding one.. Conversely the cold air might not make it down the eastern flank, but instead the atlantic trough allows some form of height push towards southern scandi at least.. Or as you say it could just all hold in situ and a SW airstream strikes through mid atlantic and we sit underneath the high.. Anyhow, not worth speculating really..
  21. Weatherwise, I find September the most trying month.. yes we can have lovely spells of dry warm sunny weather, but with the ever weakening sunshine, extreme heat chances quickly ebb away, and a day with sunshine in September and temps in the 20s never has the same feel as one in May-August. It is a month characterised by 'benignness', the first autumnal storms can happen, but increasingly we have had to wait until October. Also there is always the chance of first frost, but again usually not until October. Its a month that doesn't know if its summer, or autumn.. In general feel though, I must admit November for some people is a very miserable month, the low light levels, the ever increasingly damp dank atmosphere, and promise of many more weeks of darkness. Often too early for any meaningful snow or cold if you like that sort of thing, more usually just grey and wet. January can be equally depressing, but far higher chance of cold crisp frosty snowy days.. If it wasn't for christmas, overall I would rank December as most depressing month though.
  22. Wasn't aware of that, preety good going for Ireland given its more westerly position, under what are not very cold uppers.. proof you don't need cold uppers to deliver snow at this time of year. Must be the evaporative cooling effect, and the fact there is a slack airstream. Where was the picture taken ? height above sea level. Indeed last Saturday saw similar conditions in parts of lowland Wales.
  23. Yes best sticking to the reliable timeframe roughly 144 hrs, the trajectory and shape of recent low pressure systems has been on a NW-SE path and much shallower stretched affairs.. so every reason why UKMO might be right, rather than the closed large low pressure system being shown by GFS which has a propensity to blow such features up. ECM is showing a different position/track in the longer term, but I'm not sure on this, a feature sat to our south. Its all very messy, and unfortunately it looks like remaining very wet indeed, with slow moving frontal features, slack pressure gradients so no wind to shift the rain on.. Lots more cold November rain.
  24. There are hallmarks of November 2009 in the pattern so far this month and set to continue. Nov 2009 was dominated by a trough, which sat further to the NW, meaning NW parts received most of the heaviest rain, and heights sat strong to the NE and east which locked it in place, earlier in the month it dived south, around mid month it dragged in a very mild SW flow, by the end of the month it sank down through the UK again and brought a northerly.. interesting parallels.. the difference in the position of the trough this month is meaning it is turning into a much colder month than Nov 2009 which heaviest falls of rain in more central locations. The azores high also sat far to the SW in 2009 - it never got a foot in, it tried to ridge NE just after mid month allowing for a return to mild SW winds, but was forced to retreat back SW again later in the month, when it resurged again in early part of December it migrated to join with heights to the east, and well was never to be seen again for the rest of that winter..
×
×
  • Create New...