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Catacol last won the day on February 6

Catacol had the most liked content!

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

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  1. Sharp rise in GLAAM that kicked off around 4th July now impacting on the atlantic pattern, with a much more meridional feel on the horizon. This is the path for the next 10 days Beyond this all to play for. From a personal note I'm interested to see if AAM increases and the current MJO wave move the atmosphere into more of a Nino pattern longer term, or whether enough residual Nina remains to hold off a global shift. It looks like fine margins to me. Pacific temperature profile is neutral but forecast steadily to rise. MJO wave is the biggest in a while, but may not make progress into the pacific as quickly as expected using norms. Ventrice notes, using NOAA data, progress of the kelvin wave through the atlantic and towards Africa through late July - will this help reduce the azores high and give the atlantic trough more legs via westerly wind bursts and undermining of any azores influence? In conclusion - short/medium term looks like a Nino style pattern giving heat, instability and thunder storms. Longer term into August? Uncertain. If GLAAM flattens then so too will the pattern.
  2. Transition from a prolonged period of low AAM to one where we have a slow moving pacific wave gathering some strength and adding positive momentum to our part of the world was always going to create some NWP uncertainty. I wouldnt bank on any more meridional style pattern necessarily remaining for long - forecasts are continuing to water down the extent of the AAM spike, and I wouldnt be surprised to see a reset into an azores dominated situation by month's end. Having said that I have come to the conclusion that forecasting the pacific profile is far from simple and trends are a long way from specific outcomes - so we could still maybe get a dramatic spike and then a second half of summer with a lot more north/south influence to things than we have seen of late. It was said before that developments in the first half of July would define the rest of summer, and we still have a few days to go before we get to the 15th!! All still up for grabs.
  3. Interesting to see the GFS forecast of pacific activity get ever more vague. The relatively tight clustering of GLAAM forecasts a week ago have descended to apparent confusion Models struggling to pick up pacific trends with any certainty, so NWP output beyond 10 days is definite fantasy at present. Given lag times we could possibly see a very different atlantic profile if Nino imprints on the atmosphere at that point. Looking at longer range trends it can only be a matter of time before it does....so if not mid August then certainly in September I think. More continental instability and thunder storms would represent a welcome change.
  4. NWP will be struggling with mixed macro signals right now - GLAAM is spiking, but variance in forecast output in the last few days makes in unclear just how much energy will be pumped into the atlantic. Also the MJO is growing, but forecasts are confused as to speed of progression and NOAA reports talk of a fairly static and slow signal over the next 2 weeks. The pacific profile is unexciting at the moment - no dominant signal at the equator. End product is a trend that should really be promoting a more amplified pattern according to GSDM expectations, but the atmosphere is not ready quite yet to lose its Nina state. End result I suspect will be a pattern that will bring more unsettled weather to the north, but an azores ridge that will remain strong enough in situ to give the south some good extended conditions. Agree with a few posters that heavy thundery showers may come into the mix on top for the south, with the spike in GLAAM helping the Euro ridge to border on a scandy one... with lower pressure over central Europe. With the right alignment here plume activity as we move closer to the end of the month is a possibility.
  5. Yes - I really like this bit. I am lining up some reading over the summer once I get a break from work to be stronger in my grasp of these macroscale events. Interesting to see the 365 day progression of GLAAM The very obvious oceanic Nina imprint on the atmosphere is clear throughout, with GLAAM sitting mostly below 0 and often tipping towards -2SD. Note the small peak in November that gave us early winter ridging, a bigger peak in December that got a few of us excited (including me) but was then countered by the very steep drop off after Xmas - and then note the massive spike from -2SD up towards +2SD in the space of a couple of weeks in early Feb that gave a total increase of 4SD, smashing the vortex to shreds and giving us that memorable March. Note we now sit in a very low period of GLAAM when looked at across a full year. I guess the question is - are we about to see another major spike that will serve to disrupt the base Nina state? With the ITCZ sitting further north in summer than it is in winter currently we have a very benevolent low AAM pattern promoting the azores ridge as sub tropical high pressure belts are dominant. If westerly momentum is inserted at the tropics via the next developing wave, then we can expect a more meridional pattern to emerge and our current ridge to push further north. As ever the big question, should this occur, will be: will the expanding ridge trough pattern place the uk on the warm dry side, or the cooler/wetter side? Will be interesting to watch things unfold. Of far greater interest to me though is the potential end of a long phase of Nina. With the pacific definitely warming up the end of Nina is nigh. The timing of this will again be very interesting to watch, and for those with an interest in the autumn/winter this is a very important development too.
  6. A great post as ever Tamara - as I come out of hibernation long enough to blow my nose for the zillionth time this last month, search for a cool patch anywhere in the house, and pray that rain might come to save the garden. Ugh. I make no secret of my utter loathing of hot summer weather. In my book, if you want it hot go to Greece. Anyway - why my first post in a long while? Well - aside from the fatigue of a long winter season on NW crowned with the excitement of March I have also been watching the pacific on and off through Spring, wondering just how the engine room of the planetary weather systems might view summer 2018 with knock on effects into the winter. MetO forecast now is fairly bullish as to a move towards El, Nino Region 3.4 emerging round about now from neutral to slight positive, with a gentle gathering up towards +1 by the time we hit mid autumn. As Tamara states - if we are to get a coupling of the ocean base state with the atmosphere which has retained a Nina blueprint for a long time now then we absolutely must see a significant rise in GLAAM. It cant happen any other way. ECM MJO forecasts clearly show the spaghetti heading towards a phase 5 orbit as the MJO hits the pacific and JMA's July MJO composites clearly show the strong atlantic ridge supported by this evolution through phases 5 and 6, assuming this MJO gets out of the COD So - will we get a Nino orbit as potentially suggested above? Knife edge. I am uncertain that a very neutral ENSO appearance through most of July is going to bring that ocean/atmosphere coupling into a Nino phase quite yet - Schraldi plots with their well known low AAM bias are unexciting and unless the Nino grows in strength faster than either the Met or the CPC are expecting then any impact looks to me to be towards the end of summer and into autumn. If that is the case then one would expect the pacific to reamplify via an unimpressive MJO phase with the likely result of the UK ridge replaced with some kind of UK trough. However the water in the equatorial pacific is warm from west into centre (Nino 4 through to Nino 3) suggesting the MJO could possibly grow through phases 5/6/7/8... and it is not beyond the bounds of possibility therefore that July sees a tropical surge with consequent impacts in the sub tropics, namely suppression of the pacific ridge with consequent downstream impacts that might see the Euro warm spell continue. After all... look what happened in February. No polar vortex to worry about in these summer situations. Less complex.... but still complex enough to ensure that long range weather forecasting is fraught with difficulty. Where Tamara is spot on in my opinion is that the evolution of conditions in the pacific through the first fortnight in July is likely to dictate the course of the rest of the summer. Meanwhile my T shirt is now sticking to my back and the only solution to this misery is another cold shower. Hooray.....
  7. Hehe - go on presenting! I wasnt having a dig... just dont understand the wringing of hands over perceptions of an event that has barely started. Stuff the models and the radar now - enjoy what's through the window everybody. If staring at radar and high res model runs is your cup of tea while flakes are in the air outside, then this whole snow hunt thing has become rather warped. March 18 is delivering some snow.... could be 5cm, 10cm or 15cm. Could be more... nobody will really know until tea time tomorrow and that's the fun of watching it fall.
  8. Cumulative snow charts arent worth the pixels they are shown on. That chart generally shows the warnings are in the right place - the rest is down to luck. How on earth can people be getting jumpy now?!! Good grief - this has only just started....
  9. I'm no great sage on short term nowcasting... but my favourite tool is the Euro4 model which gives more detail I think than Arpege and is generally pretty accurate. It has maintained its position on the SW being hit by the sweet spot for several runs now... and as such for Devon and Somerset I feel quite optimistic. Main action will be tomorrow morning. https://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=euro4&MODELLTYP=1&BASE=-&VAR=prty&HH=24&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=
  10. Evening Chio - good luck tonight and tomorrow. 2 snow events in one season for the south... whatever is going on??!! Happy days. All we need is a dramatic SSW like the one just past - but in early December next time..... :-)
  11. Yep - been quiet since "Emma" - didnt really think we'd see much more action this season even given a late Spring... but this little blast is going to be noteworthy I think. Just goes to show how much impact an SSW can have on our weather, way above and beyond the impact of pacific forcing if we are honest. The fact that there was a Canadian Warming in Dec 1962 helps explain the starting pistol on that famous year. Anyway - let the flakes fall and the fun commence. 2 snow days in one season for Somerset... and we have only just reached the beginning of the interest in terms of the falling solar cycle. Exciting stuff.
  12. Hehe - its early days.... I love the start of an event like this. The end is far enough way (sometime later tomorrow afternoon) that we can just enjoy it to the full. Like the first present from under the tree.... :-)
  13. Well well.. who'd have thought we would have such a blast of Spring snow. Falling moderately now in Wellington and starting to stick. How much can we get by midday tomorrow? Anyone care to hazard a guess?
  14. It's a very bizarre forecast. Such a massive increase in pacific forcing is not "normal" - assuming we know what "normal" is. I have a lot of reading to do this coming warm season... but we seem to be experiencing climate extremes that challenge the record books on a far too frequent basis. I notice that water temperatures in the Gulf of Mexico are extremely high at the moment too. In terms of NWP output I would agree - what we learned a few weeks ago about algorithms and their construction via approximations made would suggest that a pacific spike of the magnitude forecast by GFS via WSI will create some peculiar runs and increased inaccuracy. We are too late in the winter season now I think for any major impacts - but less arctic ice = ever greater energy release in years to come during refreeze = ???? in terms of global patterns? Thanks for the links by the way - plenty to get stuck into...
  15. I agree whole heartedly with this. I sound cavalier (because extreme weather excites me) but I think we are starting to see regularly now the impact of modern climate trends. I am most concerned/interested by the situation in the arctic though all is interconnected in some respect, and the big MJO cycles this season on top of strange QBO behaviour last season on top of a monster Nino the year before is all rather significant in my mind. I think as we move into a low solar cycle - possibly a big minimum (though I wouldnt suggest I have any great knowledge of solar trends) we could see more of these severe winter episodes - on top of the potential for flooding and also significant heat waves. Where the apparent slow down in the gulf stream fits I dont know... but it all suggests more extremes more often. We may simply have to accept that "average" weather will be less the norm, and learn to deal with it. Frankly there is very little we can do to change anything in the short term, and I dont see a medium term solution either. Our children and grandchildren have already had their hand dealt. Political and economic arguments are for another thread another day... but more extreme episodes of winter weather, whatever the context, will at least keep life interesting!! In the meantime I have decided to spend the sticky warm season of summer (yuck) reading up on two areas specifically: arctic ice loss and solar influences on the jet stream. I know you are a bit of an ice expert and enthusiast - anything you could draw my attention to regarding the arctic would be appreciated.