Model Output Discussion 1st Nov.2013

[Captain Shortwave]

That's a little more like it

Still a long way off, though it's nice to see it

[Ian Brown]

HI Phil - I disagree with the assumptions you are making in this post- almost Ian Brown esque-

 

 

What you are intimating is that due to the fact that the stratosphere is cooling that vis a vee there cannot be any cold or any polar blocking, & because the models aren't modelling any warming or any abate of the zonal wind there cannot be any cold either-

 

Well, that is why annoyed me with the stratosphere thread from last year - Everyone has gone stratosphere mad, sure is part of the system, however it doesn't have total control of the weather-

 

For example take the stratospheric profile for November 2010

http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/archive/50mb9065_2010.gif

 

Below the norm getting close to getting to the bottom of the range-

 

but what chart do we see in that month?

http://modeles.meteociel.fr/modeles/reana/2010/archivesnh-2010-11-25-0-0.png

 

 

The stratosphere will indeed continue to have its periods of cooling & hopefully as we head into Winter we will see a warming like last year where the temp anomaly goes off the scale-  we can of course then take some confidence into a cold -AO forecast.

 

There is however nothing to assert though that because there is no blocking now there can be no blocking in say 10-15 days time.

 

We should be keeping the options open looking at how things develop- & no one can say with confidence that there will be no blocking in 10 days, just because the stratosphere doesn't seem to be playing ball or because we currently have a period of zonal conditions....

 

I notice Ian piped up- his zonal forecast for more than 10 days of zonal conditions have finally come to fruition- hes only been forecasting them since 2008-

 

S

 

I will take the jibes on the chin as usual - but if i had had the time last night I was going to respond to Phil before Steve put it well - I find it astonishing that  blocking could be ruled out simply because of how the Strat is looking. Has this factor really taken on such eminence that it must be the tool that we use solely to determine whether blocking can occur ? I'm not having it.

[Barry12]

GFS 00z ends with another Greenland high

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=384&code=code&mode=0&mode3h=0&runpara=0&carte=1

I asked night if the ECM could show the block at 240 hour and it has!

Edited November 7, 2013 by Barry95

[mountain shadow]

That's not a Greenland High Barry, just an Atlantic ridge which would topple.

Still better than nought.

[Barry12]

Still looks nice to see though

[phil nw.]

I will take the jibes on the chin as usual - but if i had had the time last night I was going to respond to Phil before Steve put it well - I find it astonishing that  blocking could be ruled out simply because of how the Strat is looking. Has this factor really taken on such eminence that it must be the tool that we use solely to determine whether blocking can occur ? I'm not having it.

Just to clarify guys in OP i simply gave my view of the 12's as they looked to me out to the end of the runs.

I do think in Winter the Stratosphere is the big player and i simply underlined the fact that up to then the Srtao.profile showed no sign of weakening at the core.ie zw reversal at any level in order to sustain Arctic blocking-this may change and i said that.

Latest ECM outputs-which frustratingly are a day behind- continue to show wave 1 activity entering the top and filtrting down to mid-levels.

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

 and promisingly that Atlantic ridging is showing in the far output again this morning.

It may come to something later but as i said last night that PV is still pretty centralised over the pole with a lot of energy running over the top.

 

That may change at some point later on with a displacement or split but it ain,t showing yet-that.s all i was saying really.

It,s certainly better for some cold shots with a more buckling jet and if nothing else a mid-Atlantic block will help the jet to a more NW-SE split.

[Frosty.]

Yep the whole atlantic profile will change markedly as the SST's continue to fall and fall from their initially above average levels..the clock is ticking down to winter...now it's T- 3 weeks...it can't come soon enough for me.

Edited November 7, 2013 by Frosty.

[lorenzo]

The type of blocking over the nh can take on many shapes and forms, we can get a scandi block in a predominently zonal flow we can a GH in a cold stratosphere - Remember we can get cold with a neutral AO as well..I homestly think people put to much faith into the strat thread, its great to use as a guide and even more exciting when there is some explosive warming however that usually spans just a short period of our winter time-The strat is only just beginning to be discovered, we are only at the tip of the iceberg in terms of its interactions, what we do know is the larger the +ve anomalies do in terms of polar heights, but we would would be better off reanalising what the height profiles were like in the 'normal' periods not just the execptions.Im sure the strat thread will be busy this winter - however the bottom line is though because the models will model any such warmings they will be onto it before any forecaster on here as we simply dont have the full picture to beat them to it....S

 

Steve,

 

I get what you are trying to say, the strat thread is popular and people take what they want from it in a linear fashion. i.e Raging Vortex - no Cold.  Broken Vortex - Easterlies galore.  In reality it is trickier than that and not a guaranteed route to cold. You are right to say it is a guide, but I don't think we rely on the strat alone. This winter the GWO and ENSO are arguably more interesting as trying to understand and  fill the void in information left since GP departed.

 

Some images below that confirm the research being done regarding loading patterns for SSW events, which means we can look for these patterns in the model output and look ahead to attempt to predict the evolution of the strat, of course reliant on model information.

 

 

Meanwhile, the CFS view of the blocking for week 3 and week 4, teasing output into December.

[shotski]

That's not a Greenland High Barry, just an Atlantic ridge which would topple.Still better than nought.

Yes, but to say there is not high pressure over greenland is false. certainly not a raging pv over that area, 1035 mb

in fact.

[mountain shadow]

Chiono has always said from day 1 that a warm stratosphere merely increases the probability of HLB, no more, no less.

In the same way a colder stratosphere decreases the probability of HLB but it ain't impossible.

Getting way off topic..

[Chess01]

Why is there no activity in here . The models are showing an Atlantic ridge pushing Into Greenland which could promote blocking

[Summer Sun]

GFS over the next 8 days shows just above all the UK staying below average the only exception is the south west (Devon and Cornwall) and some western coastal parts, most of europe is showing now signs of cooling down some places remain 6c above average. Less cold air is also starting to move into Sweden and Norway

 

Why is there no activity in here . The models are showing an Atlantic ridge pushing Into Greenland which could promote blocking

 

Probably because the only hints of this are way out in FI

[Chess01]

GFS over the next 8 days shows just above all the UK staying below average the only exception is the south west (Devon and Cornwall) and some western coastal parts, most of europe is showing now signs of cooling down some places remain 6c above average. Less cold air is also starting to move into Sweden and Norway

Probably because the only hints of this are way out in FI

but there has be a trend for this in the last few days so we should bin the idea of already

[shedhead]

Why is there no activity in here . The models are showing an Atlantic ridge pushing Into Greenland which could promote blocking

The reality is ECM is showing that kind of POSSIBLE set up at T+240hrs...

 

 

...GFS on the other hand most certainly isn't.

 

 

 

So until both are showing similar at T+120hrs I wouldn't suggest anyone should get overly exited about the ECM.

Edited November 7, 2013 by shedhead

[SMU]

I will have a look at your post later lorenzo-

 

can I just ask where stuart has gone-  I dont really even look any many posts on here for time constraints these days..

who is doing the NW winter forecast- Crazy snowfanman?

 

Steve

[Summer Sun]

Latest from Gibby

 

All models show a somewhat showery Westerly flow across the UK now that the trough across the SE this morning continues to move away SE. This showery pattern lasts through until Saturday when a trough swings East and winds turn NW briefly with a ridge crossing East on Saturday night perhaps permitting a frost in inland locations as winds fall light. On Sunday a warm front crosses NE over Britain with dull and misty weather with drizzly rain for a time. Sunday night and Monday morning are then shown to be very mild and dull with another band of light rain pulling SE through the day on a weakening cold front to re-introduce colder and fresher conditions from the NW with scattered showers over the North.

 

GFS then shows quite benign conditions with Westerly winds over the UK around High pressure just to the South. Temperatures would recover to average or perhaps above in sheltered Eastern areas though the North could be subject to thicker cloud and occasional rain at times while the South might see patchy fog at night should skies clear and winds fall light. Then the pattern remains locked for a good portion of the later run with mostly dry and rather cloudy conditions predominating in the South while the North sees occasional spells of wind and rain. Temperatures would remain close to or above average until the end of the run when pressure building North over the Atlantic brings the threat of much colder air flooding South over all areas with rain and wintry showers and frosts at night right at the end of the run.

 

UKMO shows next Wednesday as quite quiet with High pressure close to the SW with an Atlantic feed of winds ushering in a lot of cloud from the West with some occasional rain to the NW while the South sees dry weather. Temperatures would not be far from average at this point.

 

GEM today shows a cool NW feed across Britain next Wednesday with milder air soon rounding the Northern flank of the High pressure to the South and bringing a period of mostly cloudy but dry weather in the South but occasional light rain over the North at times. Right at the end of the run winds freshen markedly especially in the North with gales and rain rushing East across these areas. Further South a cold front would bring a period of rain and wind followed by a sunshine and shower mix for all after Day 10.

 

NAVGEM brings another brief injection of milder air from the West towards midweek quickly followed by unsettled and wet weather spreading across all areas from the NW later as Low pressure sinks ESE over Northern areas. By next Thursday colder air is filtering South across Scotland as winds swing NE and as High pressure builds North through the Atlantic this looks destined to flood South over all areas late next week with wintry showers and frosts at night looking likely after the term of the run.

 

ECM shows a fast alternating pattern of milder and cloudy weather mixed with spells of colder and brighter weather with a NW breeze and showers, wintry over the North at times. It too shows a chance of colder air sinking South over the second weekend as high pressure builds North through the Atlantic with wintry showers developing from the North behind a spell of wind and rain for all.

 

The GFS Ensembles show a changeable pattern with rain at times for all areas with the heaviest rainfall to the North. Temperatures will be largely normal or somewhat above as uppers remain above average in the South for much of the run. Very late in the output there is an embryonic trend towards a pressure build North through the Atlantic which is supported by other output too and this could open the floodgates to the North for a big dip in temperatures between Day 10 and 15 depending on which model you view.

 

The Jet Stream continues to undulate over and around the vicinity of the British Isles over the coming week or so. Later on although reliability and accuracy falls away there is a tendency for the flow to want to shift further South and if this was to verify in a large way things could look rather different synoptically in a couple of weeks time.

 

In Summary this morning while this coming week remains as it has looked for some days now with High pressure building up towards the South with rain and wind becoming more infrequent the further South in the UK you go. The longer term output is looking a little more interesting this morning. It appears that High pressure may build North across the Atlantic later next week and beyond, perhaps towards Greenland. Should this verify, and it is still a very embryonic sign this morning the weather in 10-14 days time would shift towards much colder weather than we have sees so far this Autumn with the risk of sharp frosts greatly increased and the incidence of sleet or snow, in the form of showers also greatly enhanced over Northern Britain. We just need the following days outputs to grow this trend and maintain it's support throughout the various models and their ensembles.

 

http://www.norton-ra...is(2859336).htm

I will have a look at your post later lorenzo-

 

can I just ask where stuart has gone-  I dont really even look any many posts on here for time constraints these days..

who is doing the NW winter forecast- Crazy snowfanman?

 

Steve

 

Stewart left earlier in the year his new job prevents him from posting here anymore

 

http://forum.netweather.tv/topic/76241-this-is-the-end/

[cobbett]

Blimey Gibby mentioning snow - winter prospects must be looking up

[bobbydog]

The reality is ECM is showing that kind of POSSIBLE set up at T+240hrs...

 

 

...GFS on the other hand most certainly isn't.

 

 

 

So until both are showing similar at T+120hrs I wouldn't suggest anyone should get overly exited about the ECM.

 

the GFS is however showing it at T+384hrs

 

 

yes i know this is "FI" but +240hrs (as per the ECM) is still considered FI.

 

however unlikely these scenarios are due to their range, they are still realistic possibilities, or they wouldn't be there at all

[bluearmy]

the period post the 20th becoming more and more interesting for coldies. naefs spreads having a few days ago picked up a developing block west of the uk in week 2 (may happen/may not happen) is now showing a greeny/iceland high signal at the end of its 00z run.

 

add to that the ever increasing likelihood of an arctic ridge the other side of the pole (looks more kamkatchkan than aleutian now) and we have plenty of potential to keep the nwp interesting at the very least.

 

EDIT: apologies to some posters yesterday afternoon - the gfs 12z did indeed develop a 'sausage' at T384 - on the NH plot and short of time to look more closely, it wasnt so obvious.

Edited November 7, 2013 by bluearmy

[MPG]

6z shows further ridging in the atlantic with he PV smashed in deep FI.....becoming a trend.

[legritter]

Well gang things are looking good with plenty of options starting to arrive for us in the modells .we are all aware how things can change with the further outlook looking cold one minute mild the next so plenty for mild lovers and some for coldies .im pretty confident today that by the end of next week high pressure will be a dominant feature somewhere near our shores but location as usual will be critical .tonights ECM could start to show more tantalising charts in its later output ,is the zonal train on its way out or is it just stopping at the station .

[Frosty.]

is the zonal train on its way out or is it just stopping at the station .

All aboard the polar express..choo choo 

Edited November 7, 2013 by Frosty.

[shedhead]

the GFS is however showing it at T+384hrs

 

 

yes i know this is "FI" but +240hrs (as per the ECM) is still considered FI.

 

however unlikely these scenarios are due to their range, they are still realistic possibilities, or they wouldn't be there at all

On that basis everything is a realistic possibly as long as there is a chart for it.

 

For example the latest 384hr is just as much a 'realistic possibility', but that is only heading in one direction by T+408hrs!

 

 

As BA has suggested there may well be a route to something colder developing for the last 3rd of Nov, but posting charts at 384hr

or even 240hrs and calling them 'a realistic possibility' is still complete folly imo.  You normally only need to wait 6hrs and the

previously 'interesting' chart become anything but.....and visa versa of course. 

Edited November 7, 2013 by shedhead

[Summer Sun]

The only thing that would happen after the chart below is for the high to move across the UK until any cold makes it into the 7 day range and below extreme caution is needed as nothing is set in stone

 

 

So although it may turn colder it would be shorted lived

 

 

Very deep low pressure system over eastern USA in deep FI which would head across to Greenland

 

Edited November 7, 2013 by Summer Sun

[Snowmadsam]

 

 

Very deep low pressure system over eastern USA in deep FI which would head across to Greenland

 

 

But look at the Atlantic, its in a blocked state in that chart. What could happen is that high could move in to bring a milder spell of weather or we get some kind of change from mainland Europe....