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blizzard81

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Posts posted by blizzard81

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    Still quite a few different solutions from the ECM ensembles at T120hrs:

     

    Theres some much better solutions than the operational run but also a few stinkers aswell:

     

    attachicon.gif120.gif

     

    You can see on the short De Bilt ensembles that the operational run especially in the middle is right at the top end, a lot more colder options:

     

    http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

    Crucially supported by the control run so the chances are it is on the money.

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    And yet, amidst all the uncertainty, we have the higher res ops at day 9/10 (ec/gem/gfsp)  all taking a depression se without there being obvious resistance to it heading ne. as i said yesterday, it wouldnt surprise me if this depression ends up a bit further west by the time it tends se into europe. it could be an interesting european visitor. watch this space.

    You and your big mouth. Unless ECM is an outlier of course.

    • Like 1

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    The best analogy that can be used to describe the current output is England trying to do a penalty shoot out at the World Cup, just one miss after another!

     

    A serious of opportunities where one slips on wet grass, the other blazes over the bar and the other hits the post!

     

    The catalogue of misses one can correlate with the output, the shortwave that hangs around for too long, the ECM now has a less developed low over the USA and not enough interaction with the PV chunk etc etc.

     

    The last vestige of hope is something alluded to by CS, which I will call the GOH Gap of Hope!

     

    attachicon.gifECH1-144.gif

     

    Either something develops here to add some forcing on the trough or its a one way ticket to mild especially as the more favourable upstream pattern shown by the ECM 00hrs hit the buffers.

    Yes Nick, very well put again. The ECM tonight is an absolute shocker for coldies. At least it is not in it's usual teasing mood with promising charts far out.

     

    The ECM is fast becoming the GFS which I used to deride frequently and is fast becoming King only upto T144hrs but a complete chump after that point.

     

    So my fellow coldies its either the GOH or I fear my helpline will need a big influx of new telephone operatives!

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    Not much of huge interest to take from a day that's thrown out 'holding pattern' runs. However, I am very interested that the highest resolution model ( ignoring the para ) wants to take the most energy se and disrupt when it could easily take it ne. It wasn't too many winters ago that the diving trough was the signature of the cold season.

    Absolutely. I remember Nov 2009 very well and apart from getting soaking wet every day, I remember looking at the output and thinking how unusual it was to see the negative nw to se tilt of the systems coming in off the atlantic. Very different from the usual south west to north east track. This Nov is looking very similar.

    • Like 2

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    I know I keep banging on about this but tonight's ECM 12z is a perfect opportunity to test this out. If you go from 144 to 168, you will see pressure rise suddenly up towards the Iceland/east Greenland area. None of the other 12z runs go with this. Lets see if it verifies over the next few days.

    just going back to my post last night - see above. The ECM run this morning goes a long way to proving my point about it's over amplification issues. And this was at T144 to T168.

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    what ive noticed steve is the 12zs seem to be bring the heights and amplification back into play but as soon as the 00zs come out next day then everything falla flat again and we start the process all over again!!we just not getting anywhere with this and also ecm was way further west with the pattern over europe over the past few days and now has gone east again! !! The ecm had such a strong area of high pressure across scandinavia and well into the uk just 24 hours ago for the end of this week but seems to have pushed slightly East like always!!

    Yes, and the Meto had no doubt whatsoever about this in their extended forecasts. A big early season win for them and it now looks much less hopeful for a cold spell in the first half of Dec.

    • Like 1
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    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    GFS 18z parallel shows at classic battle post 240 hrs between Scandi high and the atlantic, something we haven't seen for many years.

    A classic 80's winter scenario and one I remember quite a lot as a child. BBC forecaster, be it McAskill, Giles, Fish saying a front moving

    in from the west, making it to the east coast, only for it to be shunted back west by the massive block to the east - oh happy days  :closedeyes:

    • Like 13

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    Seems to me that nothing much has changed today really. It really doesn't matter what the detail is at day 10 or more. All that matters at that range is that there seems a consensus that high pressure will probably be sat over Scandinavia. The detail can be filled in later.

    Yes, today's output screams Scandi High at day 10. How cold ? That will certainly take a few more days to resolve.

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    It all unravels because it blows up the shortwave and this phases with upstream energy. As soon as you get this phasing you lose the dig south of the trough which helps to build the ridge towards Greenland, the UKMO is pretty similar with a blown up shortwave.

     

    Because the models don't want to send that shortwave se then its crucial that it remains shallow, both the ECM and GFS do that, the GFS love child  P and the UKMO don't, sum total not great.

     

    I would still urge some caution regarding all the outputs good or bad for cold, there are some uncertainties with events in the eastern USA which do effect how the jet exits the eastern USA past T120hrs.

    Exactly Nick, that's what worries me about todays output, especially the UKMO agreeing with tonight's GFS parallel. Tomorrows runs

    should resolve the questions over the shortwave - nervous Monday coming up!

    • Like 2

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted · Edited by blizzard81

    With Thanks to the MET office for the reverse Psychology today

     

    This posted at 4pm

    UK Outlook for Monday 1 Dec 2014 to Monday 15 Dec 2014:

    At the start of the period the most likely scenario is for a continuation of unsettled weather to affect western parts of the UK. Spells of rain are likely further east at times too but the best of the dry weather is expected here. As we head through the first week of December there are signs that rainfall amounts should become nearer normal. There is currently no signal for temperatures to become lower than average but instead stay around normal for many, perhaps slightly above, especially across southern Britain. Of course, a few rather colder spells are likely during any quieter periods of weather, with a chance of overnight mist and fog in places, and patchy frost - this may be more likely across northern areas.

    Issued at: 1600 on Sun 16 Nov 2014

     

    just 6 hours later

     

    http://modeles.meteociel.fr/modeles/gfs/runs/2014111618/gfsnh-0-174.png?18

     

    vertical advection over Greenland -

     

    Cheers guys :clap:

     

    :rolleyes:  Nice one Steve. The only thing that worries me is that this is not the parallel run   :cc_confused:

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    Hi Ian, just years of seeing over amplification from ECM - Especially in Iceland and southern Greenland area. Many other posters on here have noticed this too. I may sound thick here but what do mean by ENDGAME ?

    I know I keep banging on about this but tonight's ECM 12z is a perfect opportunity to test this out. If you go from 144 to 168, you will see pressure rise suddenly up towards the Iceland/east Greenland area. None of the other 12z runs go with this. Lets see if it verifies over the next few days.

    • Like 2

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted · Edited by blizzard81

    Sorry, but where exactly has this supposed ECMWF bias of over-amplification been cited? UKMO colleagues say no such bias known to them. Moreover, citing NOAA:

    "Compared to the other 2 operational models described above (GFS & UKMO-GM), the ECMWF does the best in predicting mid/upper tropospheric heights during the colder part of the year(such as October through April). The ECMWF tends to perform quite well in predicting amplitudes of planetary-scale regimes such as the Pacific/North American teleconnection (PNA). This model can also perform outstandingly during low to high planetary-scale wavenumber transition events, and northern hemispheric-scale regime transition

    .Outperforms the other medium-range forecast models during shallow cold air situations."

    (NB: The citation re UKMO-GM was written prior to operational introduction of ENDGAME).

    Hi Ian, just years of seeing over amplification from ECM - Especially in Iceland and southern Greenland area. Many other posters on here have noticed this too. I may sound thick here but what do mean by ENDGAME ?
    • Like 6

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    Dont recall but the difference here is blocking in our vicinity which we didn't see last winter - modelled or actual! The point I'm making is low heights to our south raise the chances of western advection of any cold that drops into the block over to our east. At the moment, there is no deep cold in any blocking although late November under a continental flow will feel decidedly chilly.

    I suspect there are many clusters at the moment in week 2 and we need to wait a few days for the primary one to cone to the fore.

    Thanks BA. Well, after viewing the GFS 06z parallel, I am as confused as the models right now! Hope this jet streak from GFS at day 10 that nick f alludes to is a red herring.

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted

    the ECM ens are again happy to send low anomalys into europe to our south beyond next weekend. this means there is an average chance of advecting some low uppers from the east into the mix of any blocking. Thereafter, we have signs on both gefs and extended ECM ens that there is a decent chance of heights rises Iceland/Greenland (not Northern Greenland). without having spreads available on extended ECM, it's tricky to work out any direction of travel but I would end this post by saying that the ens no longer preclude winter arriving by months end.

    Hi BA, am I correct in saying that it was the ECM that teased us with the promise of lower heights into Europe last winter, only for it never to come to fruition ?

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