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supernova

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Posts posted by supernova

    Model output discussion - cold proper on the way?

    in Forecast Model Discussion

    Posted

    5 minutes ago, in the vale said:

    This is a key post. The SSW commenced with a reversal at 10hpa around Xmas if I recall, with discussion at the time that, on average, it takes around 2 weeks for that to make it's way down a long, long way to be felt at the surface. This downwelling seems to have been quite a bit slower than expected. Sorry ITV edited for brevity.. 

    Agreed. DL’s original point well made. Good point on the other side from DPower too, that not only may the downwelling be slower but also weaker than anticipated. Both likely, I think. 

    Model output discussion - 7th January onwards

    in Forecast Model Discussion

    Posted

    2 minutes ago, kold weather said:

    GP, I'm watching closely because we could ge the holy grail, a successful East/North/east transition without any mild sectors. Its very rare and does need everything in balance, a few ensemble members do manage it.

    Of course there is also the real threat as you suggest of a breakdown from the west, which probably would get repelled back the way it came.

    Supernova, the GFS para has a lot of snow on its run, its a fair bit snowier than the GFS 06z op!

    That's not something you get to say very often about a run like that! Exciting times.

    • Like 1

    Model output discussion - 7th January onwards

    in Forecast Model Discussion

    Posted · Edited by supernova

    6 minutes ago, feb1991blizzard said:

    Looks like a NE flow to me - expect the Greenland heights to be maintained - take back what i said - possibly migrating scandi at the end, its the NW where we have below average PPN on there, the blue colourss are in the NE, you wont get massively above average PPN charts with those charts with blocked signals - don't forget, you only need average, even slightly below average - weekly averages for this time of year are around 20-25mm of PPN, so even if you get half of that - you are looking at 10-12cm of snow!!

    Sorry Feb I misread those anomalies. Good spot from you and @karlos1983. Yes, of course, average would be fine if the cold finally prevails. And though not comparing winters, we do love a NE flow on the east coast (unforecast Polar Low came bounding in 2010 and buried us)! Here's hoping. Anyway, much to cheer within the ECM outlook tonight - let's hoping the Euro's have the edge currently.

    • Like 3

    Model output discussion - 7th January onwards

    in Forecast Model Discussion

    Posted

    19 minutes ago, northwestsnow said:

    LOL 18Z is  SNOWMEGEDDON  DRUNK.

    Dont even know how to spell it lol..

    Fixed that spelling for you @northwestsnow  Honestly GFS is on one this week. Not that any of us have a crystal ball but seriously the swings from run to run make even the Brexit negotiations look stable. Let’s see what rhe Para has to  offer...little change up to 96... potentially slightly less progressive?

    • Like 2

    Model output discussion - 7th January onwards

    in Forecast Model Discussion

    Posted · Edited by supernova

    GFS Para FV3 better wedge alignment and heights up to Iceland compared to 18z GFS at 144 onwards although @Mucka‘s point about the slider well made.

    AE388C64-8B61-41DF-878E-5F4450AD8B43.thumb.png.8ac5c14fa63f1331a524aab15f604aba.pngFF14C10B-B9F9-40C6-92A9-2CFB6AAB6122.thumb.png.4eb6ca2ceb1c12407b8d5ddab75bc3b6.png

    Then by next Friday, Para advecting continental cold Eastwards whilst GFS has us in significantly warmer uppers (although unsure quite how cold the Para gets as it’s stalled on Meteociel again).

    7B8BF360-E1E9-4674-A4F4-88A89343F968.thumb.png.6386b584b67210db43722ebda7343174.pngFB005D9E-4A95-4922-94FD-0EF83302188B.thumb.png.f7ebbd54130378114eb643a30e9fdee2.png

     

     

     

    • Thanks 1

    The Hunt for Cold continues 02/01/19

    in Spring Weather Discussion

    Posted

    Hard to find much cheer for coldies in the models tonight, as evidenced by the downcast tone in so many of today's posts. As Ventrice pointed out earlier today, we're talking a different gravy to the SSW in Feb.

    320067695_ScreenShot2019-01-06at19_21_41.thumb.png.d3012b966561c1b85d200fc5db6724e4.png

    Matt Hugo also quick to reference widespread surprise at lack of amplitude compared to predictions.

    714233126_ScreenShot2019-01-06at19_21_12.thumb.png.07de00f986186efd381144f7dc8c8257.png

    Thank goodness we have the potential effects of an ongoing SSW to provide a sliver of hope for late Jan onwards. Might come to nothing, of course, but imagine the mood in here if we didn't even have that? So it seems forecasting the UK's weather is, ultimately, pretty straight forward...whatever you think might happen, or most want to happen, is almost certainly not going to occur in the way anybody expects! Models might be better than they were, but the glimmer of light they shine into the future remains dimmed by nature's dominant unpredictability. Another reason to hope we might see some of the white stuff before winter's done with us, perhaps.

    The Hunt for Cold continues 02/01/19

    in Spring Weather Discussion

    Posted

    Don't think these have been posted yet today. ECM Op 850's sitting on or above the mean initially then tracking toward the colder end of the suite after Jan 8th. Be interesting to see whether tonight's ensemble trend colder still as indicated by GFS/ICON so far today. Cool, cold, or winter proper? Still much to be decided I feel.

    Screen Shot 2019-01-03 at 15.19.52.png

    Hunt For Cold: Model Discussion - Heading Into Christmas

    in Spring Weather Discussion

    Posted · Edited by supernova

    7 minutes ago, feb1991blizzard said:

    Not sure i agree with this, yes its the GFS but it keeps on putting the PV back together after the split, unless we see the wide split modelled in the next few days, i would say anything unlikely until last third Jan, i would'nt rule out the trop doing what it wants but to me there is just no sign that without a favourable SSW, that the trop is likely to do anything other than transient fog and frost episodes, not saying we can't get there but we need to see something soon in the extended modelling.

    This might help a bit Feb. Admittedly only one (Op) run in deep FI but it does at least show the potential as we enter the New Year and the trop begins to respond to the SSW. Let's hope GFS has finally started to smell the Christmas coffee - certainly a classic Northerly evolution as you follow the suite beyond the initial high. Be interesting to see if other models follow over the next few days.

    gfsnh-10-384.png

    gfsnh-0-372.png

    Edit: Guilty of simultaneous posting but point still valid I think. Beyond the dross, there is hope, is my summary.

    • Like 2

    Stratosphere and Polar Vortex Watch

    in Spring Weather Discussion

    Posted

    39 minutes ago, Mike Poole said:

    This chart illustrates what has been bothering me if I'm reading the ensembles right as from all models not just GEFS.  It's like the different models are modelling different systems.  Why?  Something very different about this SSW, maybe?  Previous ones I've viewed, and there haven't been that many since I started model watching, the models were all consistent re the strat at the 10 day out timeframe, if I recall correctly. 

    Interesting observation Mike. Seems there’s speculation GFS is inaccurately forecasting and/or missing essential obs re the Ural high. Interesting paper supporting your point re early predictability of major SSW’s here, highlighting subsequent importance of Ural blocking accuracy (if I’ve interpreted correctly). Thx to Dr Butler for sharing (Twitter). ://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081091?af=R&

    • Like 1
    • Thanks 1

    Model output discussion - The Hunt For Cold

    in Forecast Model Discussion

    Posted · Edited by supernova

    *Pops in for new season Hunt for Cold. Pops out again.* GFS Op a warm outlier post day five (London GEFS posted earlier) but today's predicted synoptics still mighty interesting compared to the dross we're normally trying to shake the upsides from - albeit not as evocative as some of yesterday's eye candy. Good to be back, despite some of the naysayers already posting! Blocky and coldish? I'd say.

    • Like 5

    Model output discussion - after the beast, what next?

    in Forecast Model Discussion

    Posted

    Surprisingly quiet in here all things considered. No doubt everyone's heading to the regionals. Meanwhile, can any of our more experienced members help me understand the potential consequences of a convergence zone being as we seeing them drawn on UKMO faxes over the next couple of days? Two air flows converging in the same area? Constant showers? Couldn't find a useful explanation anywhere.

     BRAEU_24.thumb.gif.f3138da023c124855b3fa5678ce760f6.gifBRAEU_36.thumb.gif.4f8d208c8de257cd6eb560aad532c930.gif

    • Thanks 1
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