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phil nw.

Model Output Discussion 4th Dec.2013-12z onwards.

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Well it certainly looks like the zonal train is on its way but at least it will be "weather" not the god awful boring nothingness we have had for much of the last few weeks. As for cold well i think lets see where we stand after xmas.

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Well it certainly looks like the zonal train is on its way but at least it will be "weather" not the god awful boring nothingness we have had for much of the last few weeks. As for cold well i think lets see where we stand after xmas.

 

You'll probably get slated for writing off the majority of December but I think its a fair assessment. GFS T+72 to 384 is virtually identical, pattern wise frame by frame as is ECM to +240. Deep PV to the NW, High to the SW = Mild wet and windy for UK...desperately need some sort of upstream change to disrupt the pattern.

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Why am I not at all surprised by the ECM this morning. Pretty much a mobile west/south west pattern with alternating mild periods and cooler periods with wintry showers over northern hills. Nothing like the blocking it was touting the past couple of runs.

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Well gfs this morning is awful heavy rain and gales for the entire run. Don't like the noises been made from the professionals at the met either at the moment. Think I'm already considering writing off this winter. Because looking at the models and long term signals it's not looking or sounding good. Anyway will come back after Xmas and see if any signs have changed. So happy Xmas to you all and happy new year. Hope everyone has a great Xmas.

Think it's a bit extreme to write off a whole winter when we're a mere 11 days into it. Face it. We can't tell exactly what's going to happen in 10-15 days time, let alone in 80 or 90 days time. Maybe these Lows are what we need to break the current stagnant set up. I'd rather take gales and rain, along with cooler temperatures, rather than the overcast nothingness and above average temperature..

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Despite the present models and the approaching winter solstice we should take comfort from the fact that the ground continues to lose heat way into January and the sea does not begin to warm until March - I am far less qualified to comment than most of the regular posters here but our best chance of real cold or even severe winter weather will surely always be in mid to late January and February. This has usually been the case in past years and it is far too early to tell from present models what will happen that far out, so there is still every chance we could all be building snowmen in 2014. There is even now the vague hint of an outside chance of real cold reaching us in the far FI reaches of the GFS - and It would not surprise me to find snow on the ground in many parts of the UK by January 1st.

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Odd Temp extreme for Mid December... 14 deg early morning in Scotland, and -4 Deg in the South East ... Id take the High pressure if that could become more widespread. As for the Models there could be quite a few Storms this morning and some of that Rain looks intense, Plus there's the fact theres a wall of High pressure to our East , so flooding could become the main Christmas headlines this year. 

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Lots of cold zonality for the north of the BI on the Gfs 00z op run with ppn turning wintry at times with snow on higher ground from time to time along with shortlived milder interludes. The 00z is a very unsettled run with low after low, most of them vigorous and bringing gales / severe gales at times with periods of heavy rain interspersed by colder showery weather as active cold fronts clear through with a backwash of polar maritime air, scotland and especially the ski resorts has a good chance of snow at times with this type of set up..at least it's not mild, mild, mild..there is colder air at times and IMO it's far better than the current stagnant nothingness, good riddance to that by the end of this week.Posted Image

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Well gfs this morning is awful heavy rain and gales for the entire run. Don't like the noises been made from the professionals at the met either at the moment. Think I'm already considering writing off this winter. Because looking at the models and long term signals it's not looking or sounding good. Anyway will come back after Xmas and see if any signs have changed. So happy Xmas to you all and happy new year. Hope everyone has a great Xmas.

All the signals are pointing to a scandi high dominated second half of winter , so really don't know where you get that from , Ian and any other forecaster will only ever say with confidence the next 5 days at most, maybe giving hints to the longer 10-15 day trends , but anything after that is nothing more than computer modeling , and we know how much they change , it's easy to get frustrated when things look bleak but putting dec 10 aside we very rarely have snow and cold in December , it's normally dominated by zonal weather as the vortex reaches its strongest point later this month. Last winter when we had everything going for us on the face of it , especially December with an 80% chance of a Greenland high according to Stewarts winter forecast , we all know what happened , it was a flop ,with too much energy left toward Greenland which actually remained in situ all winter even in jan , giving us a slightly +NAO all winter , so trends really can be meaningless for our tiny island .So just sit tight and our time will come, my first snowfall last winter came on the 18th jan , but because we had a snowy second half of winter everybody forgets the first half .

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Crucial timeframe & areas to watch tomorrow- T 126-144  -

 

ENERGY SEPERATION. -  GFS likeleyhood @ resolving this - LOW.

EUROS probability - Higher.

 

This is the GFS pushing the energy through the block-

http://modeles.meteociel.fr/modeles/gfs/runs/2013121018/gfs-0-144.png?18

 

Notice the area west of Ireland- trying to break away from the main core of the jet-

 

Remember the GFS Bias- 1 single stream of energy - not resolving split energy.

 

End result- energy / associated system moves East through the block.

http://modeles.meteociel.fr/modeles/gfs/runs/2013121018/gfs-0-168.png?18

 

 

Now pick a run where the GFS sees a split jet like the UKMO @ 144 - ( PTB2)

http://modeles.meteociel.fr/modeles/gens/run/gens-2-1-156.png?18

 

All of a sudden the split energy is providing more amplification of the jet & a cut off low

http://modeles.meteociel.fr/modeles/gens/run/gens-2-1-180.png?18

 

What you are seeing from the ENS means tonight ( GFS 12z, ECM 12z & more than likely the ECM DET32) is the poor resolution of how to model a split flow past 144 hours-

 

Where the UKMO & ECM OP are just developing it. Once the models get a grip on it they usually expand on the idea of splitting the energy away which will result in a swift move by the ENS means to a more amplified pattern.

 

The CFS presented earlier showed the end result of the split flow perfectly.

 

By what I have seens of the 18z - expect CHANGE tomorrow. especially the ECM- split flow FTW

 

 

S

Morning Steve - serious question have you seen anything this morning to support the above? I cant really to be honest, however I'm keen to learn where you were coming from last night and what we should be looking for to support the above this morning.

 

Many thanks

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Hope GEM isn't right , or we will have another huge Storm to worry about next week ....... South would be in right trouble with that ...

 

Posted Image

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Good morning folks. Here's how I see the 12 midnight outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Wednesday December 11th 2013.

 

All models show a slack Southerly flow with a continental influence in the SE making for a foggy start for many with a touch of frost under clear skies for others. Elsewhere the air will be maritime and milder with a lot of cloud and some rain in the far NW. Through tonight cloud will extend East to many areas and troughs will begin to make headway across the British isles from tomorrow changing the weather to more changeable with rain at times, principally on Friday and Sunday with a colder and drier interlude lasting through Saturday as a ridge crosses by from the West.

 

GFS then shows all of next week with Low pressure out to the NW and troughs rushing NE across the UK in a strong to gale force SW flow. rain at times would occur everywhere and it could be very wet in the NW with copious totals through the period over hills and mountains. There will be less rain in the SE at first though even here towards the end of the run it will become very wet and potentially stormy at times as we move towards Christmas. A white Christmas looks unlikely away from Scottish mountains due to temperatures being near to or above average throughout.

 

UKMO closes it's run today showing a Low pressure trough swinging East across the UK next Tuesday with some rain and wind for all before clearer and colder conditions temporarily spreads in from the West through the day.

 

GEM is similar on Tuesday before an intense Atlantic depression spawns some powerful Low pressure areas which zip NE across the heart of the UK later with rain and storm force winds at times followed by squally showers on a strong Westerly breeze. Though technically quite mild in would feel cold in the strength of the wind and rain which in itself could be copious at times.

 

NAVGEM this morning shows Low pressure well to the NW in a week's time but with a strong SW flow over the UK ahead of a squally trough moving it's way slowly SE across the UK through next Wednesday. It would remain mild for many through the day.

 

ECM offers very changeable conditions next week with spells of strong and mild SW winds alternating with brighter and drier interludes when it would be briefly less mild. Overall the heaviest rain would be to the NW with the longest dry spells towards the SE.

 

The GFS Ensembles today show complete support for a relatively mild and unsettled spell to commence this weekend and last until Christmas at least. With winds often strong and from the SW the wettest weather will be in the North and West but even the SE will see some heavy rain at times if this run is to verify.

 

The Jet Stream remains very strong throughout the run and maintaining it's NE orientation firstly located NW of Britain but moving further SE over the UK and on towards Scandinavia next week keeping the UK under the influence of mild and string Atlantic winds throughout.

 

In Summary today there is an unsettled spell on the way. As the High to the SE migrates further away several hundred miles the UK is able to tap into more in the way of Atlantic mobility and aided by a powerful Jet Stream there is the potential for some powerful storm systems to develop over the North Atlantic and the North of Britain over the period. Details differ between the output but the general message is plenty of wet and windy weather to come with the usual caveats that the heaviest rain will be in the North and West while the SE sees the best of any drier interludes while all areas are at risk of gales, severe at times. It will remain generally mild though a few days of colder weather may be thrown in at times behind cold fronts when temperatures return to average briefly.

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There is a mobile set up coming but I think we'll see that it won't be as straight forward as the ECM.  I think in about a week there'll be quite a complicated set up developing/developed with a possible attempt of more amplification in the Atlantic.  Not thinking dramatic change to northern blocking but certainly not a sustained SW'ly run as per ECM.

 

BFTP

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As for the overrnight suites, the zonal train still looks set to arrive in the near future and then press on to an unknown destination deep into Russia during next week.

 

As BFTP (glad to hear things have improved for you personally Blast) said the ECM is current worst case senario as far as amplification is concerned, with system after system blasting in on almost wholly mild SW'erly winds. UKMO and GFS do suggest a little more amplification at times, meaning a few 'colder' shots are possible, but once again this morning any thing cold looks at long way off...almost certainly post Xmas.

Edited by Paul
MODEL discussion, not yet more point scoring

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Whilst the 00z's look a bit flat, the trend to troughing into w Europe in week 2 is notable. Question is if it becomes cut off and shallow way to our south as the Azores ridges back in behind or not? 'Not ' being the result that will lead to a pattern change.

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Rinse and repeat this morning with the mobile zonal pattern locked in for some considerable time.

All main models confirm this so very consistent and no indicators at all of any wintry weather apart from the highest mountains & hills of the north & then nothing sustained.

Sometimes very mild, mostly mild or if lucky average temps and becoming more unsettled.

Very zonal ENS with effectively no cold runs at all this morning.

 

Posted Image

 

Should be quite pleasant in any sunshine when it occurs and no travel problems likey at least. Posted Image

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Odd Temp extreme for Mid December... 14 deg early morning in Scotland, and -4 Deg in the South East ... Id take the High pressure if that could become more widespread. As for the Models there could be quite a few Storms this morning and some of that Rain looks intense, Plus there's the fact theres a wall of High pressure to our East , so flooding could become the main Christmas headlines this year. 

Fairly typical in this kind of pattern though Chris, with the Foehn effect created by the Scottish mountains warming the air considerably as it descends into places such as the Moray Firth. Looking at the flow on all 3 models for the remainder of the day 16c looks distinctly possible up there, whilst parts of the SE that hold onto fog until this afternoon could struggle in the low single digits. 

Edited by shedhead

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The pattern I've seen over the last couple of runs is that the 12z's are much more amplified.

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As for the overrnight suites, the zonal train still looks set to arrive in the near future and then press on to an unknown destination deep into Russia during next week.

 

As BFTP (glad to hear things have improved for you personally Blast) said the ECM is current worst case senario as far as amplification is concerned, with system after system blasting in on almost wholly mild SW'erly winds. UKMO and GFS do suggest a little more amplification at times, meaning a few 'colder' shots are possible, but once again this morning any thing cold looks at long way off...almost certainly post Xmas.

Thank you Shed and appreciated

 

I agree re prolonged cold but not in offing [i would sticking to my 'overall thoughts]but I'm in the camp of rPM or PM airmasses affecting the UK.

 

GEM most interesting run of day....t144

 

Posted Image

 

 

And look at UKMO at same time

 

Posted Image

 

GEM at t162

 

Posted Image

 

Slight negative tilt with another sub low developing west of Azores.  Leads to this.

 

Posted Image

 

Plausible?  and interesting weather

 

BFTP

Edited by BLAST FROM THE PAST

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the upper air pattern below is what is almost certainly going to be that we see in the lead up to Christmas

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

So becoming increasingly unsettled for all areas as the changeable pattern at the surface in the NW extends south to all parts over the next week or so. The UK Fax charts show this development nicely. Quite mild at times, somewhat colder behind each low with perhaps a temporary ridge before another weather system moves in. A chance of some transient snow showers on the highest parts of Scotland but that is probably all in the way of wintryness for most parts. Windy at times as well particularly in exposed NW and some western areas.

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Rinse and repeat this morning with the mobile zonal pattern locked in for some considerable time.

All main models confirm this so very consistent and no indicators at all of any wintry weather apart from the highest mountains & hills of the north & then nothing sustained.

Sometimes very mild, mostly mild or if lucky average temps and becoming more unsettled.

Very zonal ENS with effectively no cold runs at all this morning.

 

Posted Image

 

Should be quite pleasant in any sunshine when it occurs and no travel problems likey at least. Posted Image

Really? No travel problems? Do the models not show some quite high rain totals? Wouldnt be surprised to see bad flooding in the coming weeks....and i think the wind could be an issue for travel too.

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