Model Output Discussion 26/10 2012 >

[SMU]

http://modeles.meteociel.fr/modeles/gens/run/gensnh-21-1-162.png?18

18Z mean at 162- pretty good amplitude, a good 10N more than the first Scandi block-

expect some good charts appearing around 240 ISH

S

[weathergeek]

Ghost town...... Cue tumbleweed! Oh well, hope for some better updates in the morning!x

[Eskimo]

Ghost town...... Cue tumbleweed! Oh well, hope for some better updates in the morning!x

Huh? Seems pretty good at the moment!

[Mark Neal.]

18z much better than recent output. Be interesting to see what the models have in store for us on Weds. As we draw closer to winter, still a while yet-mind.. Trends and Output should at least start to become a little clearer.. Interesting times once again

[Robbie Garrett]

Hello,

Not sure if anyone saw me post, but the 2010 snow fest coldest didn't really start showing on the models for end of November till around about a few days from now. If anything is going to happen as we approach early winter, it will likely show in FI as we approach next week.

Was just having a look at the trends from the 18z for this evening, and remarkably it's very similar to 2010 for Europe. Maybe slightly better on this run for the 6th November 2012 than in 2010. The jetstream on both 2010 and 2012 charts undercuts the block instead of going above it, a jet stream movement south.

Strangely enough, there is 5hPA difference in the high pressure. over europe... remarkably there are only minor differences around the world from the two.

384 hours - 6th November 2010

384 hours - 6th November 2012

I could be wrong, but I am pretty sure that this mid-month November was a neutral NAO. Which is what has been trending recently on the GFS.

NAO looking to trend neutral, then looks likely to go back where it came from.... eerily similar to 2010??

GFS back in 2010 was very ups and downsy in terms of forecasting the cold that was about to come.

On the 11th of November 2010 it teased us with this..

Just have a look at what it did for November 12th 2010.

It got to the 15th November 2010, before it was 100% certain we was going into something very cold, and absolute snow fest.

I suspect models to start to firm up soon, if there is going to be a cold spell at the end of November. Interestingly the MetOffice is also going for something below average, maybe a hint of something to come??

In FI, but nice to see nonetheless:

Height rises over Svalbard on Fi 18z...

http://modeles.meteo...0-276.png?18?18

oooof!

http://modeles.meteo...0-360.png?18?18

Edited November 7, 2012 by Robbie Garrett

[shotski]

so here we go again chasing the cold in fi which probably will never happen or it just gets pushed further back in time.and then when it does arrive its nothing like the models show.why not try and get the shorter term forecast more accurate first then once you have good data for that it will make the longer range forecast more accurate.bet this time next week there still no real change to the pattern.just typical late autumn weather.

I see what your saying but you should really look a bit deeper than just each individual model run and then folks reactions to it. anything beyond about t-180

is just for trends and the exact details should be binned. There are some very good posters on here and you soon pick up who's posts are worth their salt.

[IDO]

The 18z, last night was a typical pub run, best forgotten.

This morning the GFS 0z shows a continuation of the cool zonal flow. This run has a more amplified trough (in FI) over the UK that pushes any Scandi blocking east. However I suspect this is an outlier and the pattern will be flatter, with another transient ridge breaking up the amplification:

http://cdn.nwstatic....erdeenshire.png

http://cdn.nwstatic....erdeenshire.png

The ensembles hint at this (pressure rise amongst majority members). The mean on the T850s have for many runs been rigid around the 0c, suggesting a continuation of this zonal pattern.

That "potential" remains with the weak PV:

http://cdn.nwstatic....384/npsh500.png

So it is reasonable to expect the possibility of a flip to colder runs, but that was the case last year, and it never happened. This current pattern is entrenched, like last year, the difference only in cool zonal rather than mild zonal. With ECM's horrible 12z last night hopefully not developed further today, we continue to await clear signs of change.

Edited November 7, 2012 by i'm dreaming of...

[Severe Siberian icy blast]

The 18z, last night was a typical pub run, best forgotten.

This morning the GFS 0z shows a continuation of the cool zonal flow. This run has a more amplified trough (in FI) over the UK that pushes any Scandi blocking east. However I suspect this is an outlier and the pattern will be flatter, with another transient ridge breaking up the amplification:

http://cdn.nwstatic....erdeenshire.png

http://cdn.nwstatic....erdeenshire.png

The ensembles hint at this (pressure rise amongst majority members). The mean on the T850s have for many runs been rigid around the 0c, suggesting a continuation of this zonal pattern.

That "potential" remains with the weak PV:

http://cdn.nwstatic....384/npsh500.png

So it is reasonable to expect the possibility of a flip to colder runs, but that was the case last year, and it never happened. This current pattern is entrenched, like last year, the difference only in cool zonal rather than mild zonal. With ECM's horrible 18z last night hopefully not developed further today, we continue to await clear signs of change.

Disagree .this year is completely different to last year, the PV this year is disorganised , weak, with the jet stram on a permenant southerly track, last year we had a raging PV, raging jet stream with it smashing into the uk full on , in fact we had a recordbreakingly high NAO , we are very very different this year,and regarding the 18z ECM last night. . There isn't one, I think you mean the 12z , unless you mean the 18z gfs was muck , which means you hate the cold as we had a good scandi high with raging bitter easterlies heading over the uk.

Just another note to those that has read gp in his vid expects an average if not mild dec, I suggest you watch the vid again, you will see that every single signal is pointing toward a very blocked winter pattern , the ONLY one against it in dec was the cfs , he did not say he agreed with it, infact if you look in the strat thread yesterday you will see he expects a cold dec, with signs of northerly blocking with wave activity 2 weakening the vortex and smashing or displacing it with other things in the pipe line already as we head toward jan. All in all a very very good sign this winter for a fantastic year this winter , certainly expect a snowier winter than last year, infact there hasn't been so signals in favour of a cold blocked winter for a long long time.

[Gibby]

Good morning. Here is todays morning look at the 00zs from the big models this morning Wednesday 7th November 2012.

All models show a moist Westerly airflow over the UK currently with a lot of cloud and hill mist and drizzle in the North and West. Some brighter spells may occur in the lee of high ground. Tomorrow looks very similar though with a weak cold front having crossed through the day a better chance of some dry and brighter conditions may show up later behind a band of light and intermittent rain. On Friday a more active cold front moves SE over the UK with rain and a fresh SW breeze transferring across all areas through the day. Later winds veer NW and Saturday is a colder and brighter day with showers in the North and West falling as snow on Northern high ground. This weather will last into Sunday before a ridge dries things up later in the day with the East seeing the better conditions last. By Monday the ridge has crossed by and a milder SW flow returns behind a warm front through the day bringing rain across the UK later.

GFS then shows a cyclonic period of weather with fronts crossing NE frequently under the influence of Low pressure either to the NW or West of the UK. Early in the week the flow will be relatively mild but it may become less mild through the week as the showery wrap around from the depressions drags some slightly colder air across at times, particularly to the West. FI today shows a continuation of the Westerly biased weather type under the effects of Low pressure to the North and NW. Fronts and areas of rain will continue to move into the UK and slow down and weaken in the vicinity of the UK. Some cooler and showery interludes are likely in between the Low pressure areas. It will be windy at times with overall temperatures never far from normal.

The GFS Ensembles show a continued period of normal value uppers. Most members support a sine wave type pattern as milder rainy weather intersperses with somewhat colder and more showery conditions. Rainfall is scattered about throughout the run indicative of Low pressure to the North and NW with some higher totals in the South at times as fronts get hung up by High pressure over Europe.

The Jet Stream shows a continuing of ridging over the Atlantic with a SE moving jet West of the UK as a consequence. Later the flow develops a trough near the UK and over the British Isles in a week's time before the flow turns North over Europe over the Northern periphery of the High pressure there..

UKMO shows deep Low pressure stretching from Northern Norway to West of the Hebrides at midnight next Tuesday with a broad and relatively mild SW flow covering the UK. Troughs embedded in the flow would bring spells of rain and strong winds quickly NE at times through the day.

GEM shows a very disturbed pattern too with Low pressure over or just to the West of Britain delivering a cyclonic airflow and copious rainfall at times, especially to Western areas in near average temperatures.

ECM shows unsettled and often wet weather too in it's later stages as Low pressure to the North and NW pile trough after trough into the UK where they weaken and disrupt as their progress East is thwarted by a High pressure block over Europe. So rain will be the key weather with rather less wind than is shown on the other models.

In Summary a very unsettled look is the order of the output today with Low pressure to the North, NW or West being the driving forces of the UK weather. With high pressure over Europe the passage of fronts and Low pressure is blocked leaving an almost semi permanent trough over the UK delivering potentially heavy and persistent spells of rain in places. The UK lies on the mild side of the depressions throughout though some rather chillier polar maritime air could bring some intervals of sunshine and showers at times, especially in the West. Frost and fog problems would be very scarce in this rather breezy and cloudy setup over the period of the output.

[IDO]

Disagree .this year is completely different to last year, the PV this year is disorganised , weak, with the jet stram on a permenant southerly track, last year we had a raging PV, raging jet stream with it smashing into the uk full on , in fact we had a recordbreakingly high NAO , we are very very different this year,and regarding the 18z ECM last night. . There isn't one, I think you mean the 12z , unless you mean the 18z gfs was muck , which means you hate the cold as we had a good scandi high with raging bitter easterlies heading over the uk.

Just another note to those that has read gp in his vid expects an average if not mild dec, I suggest you watch the vid again, you will see that every single signal is pointing toward a very blocked winter pattern , the ONLY one against it in dec was the cfs , he did not say he agreed with it, infact if you look in the strat thread yesterday you will see he expects a cold dec, with signs of northerly blocking with wave activity 2 weakening the vortex and smashing or displacing it with other things in the pipe line already as we head toward jan. All in all a very very good sign this winter for a fantastic year this winter , certainly expect a snowier winter than last year, infact there hasn't been so signals in favour of a cold blocked winter for a long long time.

Sorry ECMWF 12z was a stinker, the GFS 18z was nice but has no current support. I am not writing off winter, just suggesting that there is nothing trending for cold in November. The Synoptics are clearly different compared to last year, but my comment was that the UK tends to be held in 4-6 week patterns and we are currently locked into one of these. The forces keeping us in this zonal flow appear to be stronger than the forces needed to change the pattern and have been for a while. Is there a reason you believe that within the next 15 days there will be a flip to a colder scenario?

[khodds]

Mods delete this if you feel necessary, but weren't we to expect the models to flip from run to run over the next few days? I thought we were warned about this.

[Severe Siberian icy blast]

Sorry ECMWF 12z was a stinker, the GFS 18z was nice but has no current support. I am not writing off winter, just suggesting that there is nothing trending for cold in November. The Synoptics are clearly different compared to last year, but my comment was that the UK tends to be held in 4-6 week patterns and we are currently locked into one of these. The forces keeping us in this zonal flow appear to be stronger than the forces needed to change the pattern and have been for a while. Is there a reason you believe that within the next 15 days there will be a flip to a colder scenario?

No nothing in the next 15days , like you said maybe cold zonal, but it's the last 3rd of the month I feel we can look to, maybe the last 10days or so.

[johnholmes]

Mods delete this if you feel necessary, but weren't we to expect the models to flip from run to run over the next few days? I thought we were warned about this.

the models, that is the synoptic type, flip from run to run period-nothing new in that

[khodds]

No I realise that John, and I understand that - thank you. I just dislike people over analysing each run and *bining* things.. I thought it was trends we looked for. Its very disconcerting when amateurs like me read threads that are throwing runs out because they don't show what they expect them too.

[latitude]

No I realise that John, and I understand that - thank you. I just dislike people over analysing each run and *bining* things.. I thought it was trends we looked for. Its very disconcerting when amateurs like me read threads that are throwing runs out because they don't show what they expect them too.

There can be a lot of model bias in this thread. Stick to the more experienced posters, makes understanding a lot easier. I find the mild people here won't except any change to cold until it is actually snowing on their house.

Edited November 7, 2012 by latitude

[phil nw.]

No I realise that John, and I understand that - thank you. I just dislike people over analysing each run and *bining* things.. I thought it was trends we looked for. Its very disconcerting when amateurs like me read threads that are throwing runs out because they don't show what they expect them too.

Yes it can get confusing for newer members-as it does sometimes for many of us.

Looking at all the overnight data the continuing picture for the next couple of weeks is this current pattern with the UK under the influence of the Atlantic.

A look at the mean heights from GFS/ECM op runs out to days 8-10 show good agreement on this upper trough close to the UK.

http://www.meteo.psu...WF_0z/test8.gif

We can see the Russian heights further east but looking at the ens means for further on and insdeed the GEFs there`s no indication yet of those heights moving this way.

[Thundery wintry showers]

A good summary by Gibby there- I may add that there is a chance of the frontal system on Friday/Saturday hanging around for a while over East Anglia and the SE, possibly giving a grey damp day on Saturday in those regions, but otherwise the weekend is looking bright, with some showers in the west. There is strong cross-model agreement on the tropical maritime-dominated regime for next week, reflecting a slide into a progressively milder zonal pattern.

I can understand the focus on FI as the upcoming week's weather looks about as ordinary as it gets, although with Atlantic-driven westerlies in charge there will be more 'weather' than if we were sat under a cloudy anticyclone. The Russian/Siberian high, although a potential source of easterly incursions for much later in the month, may well help to keep us in a mild south-westerly pattern at the 7-12 day range as it will prevent low pressure systems from getting east of the Greenwich Meridian.

Edited November 7, 2012 by Thundery wintry showers

[phil nw.]

A good summary by Gibby there- I may add that there is a chance of the frontal system on Friday/Saturday hanging around for a while over East Anglia and the SE, possibly giving a grey damp day on Saturday in those regions, but otherwise the weekend is looking bright, with some showers in the west. There is strong cross-model agreement on the tropical maritime-dominated regime for next week, reflecting a slide into a progressively milder zonal pattern.

I can understand the focus on FI as the upcoming week's weather looks about as ordinary as it gets, although with Atlantic-driven westerlies in charge there will be more 'weather' than if we were sat under a cloudy anticyclone. The Russian/Siberian high, although a potential source of easterly incursions for much later in the month, may well help to keep us in a mild south-westerly pattern at the 7-12 day range as it will prevent low pressure systems from getting east of the Greenwich Meridian.

That last sentence in TWS`s post is a good point.

A block to the east can give us comparativley milder conditions such as the 00z ECM is modelling here

the lows can`t get get to our east and deliver a consistent colder flow from north of west- such as happened at the end of October and at times in recent days.

We either need the pattern to kick east for this or for any eastern block to regress this way pushing the vortex west of Greenland.

Remember this?

The trough over the UK became split and cutoff from the main vortex to our north as pressure built back from the east.

Some of the low heights then located to our south as the high built across and along came the easterly.

which led us into the remarkable cold spell of Nov/Dec 2010 with heights locating over Greenland for a while.

Edited November 7, 2012 by phil n.warks.

[Frosty.]

Still no realistic end in sight as far as the current unsettled pattern is concerned, yet another very disturbed gfs and ecm ens mean today, a trough generally just to the northwest of the uk for many, many days feeding rather cool air from the north atlantic across all areas and occasionally polar maritime sourced air as the trough changes shape and position, high pressure continuing well to the east and later, to the south and perhaps a more settled interlude for the south and southeast not long after mid month but then unsettled again, also a little milder at times in the south but mostly the temps either near average or just below with wet and windy spells alternating with clearer, cooler and showery intervals. I would say that possibly the weather could be set to settle down during the last 7-10 days of november with increasing risk of fog and frost as the anticyclonic conditions to the south and east merge and engulf the uk but that's only my interpritation.

[johnholmes]

There is strong cross-model agreement on the tropical maritime-dominated regime for next week, reflecting a slide into a progressively milder zonal pattern.

Which model suggests this to you Ian?

I have not been able to look at the 00z but the 06z played through the Net Wx Extra msl-Td facility shows Tm air for about 48-60 hours for some areas and less than that further north. Other than that short spells then the overll impression that run gives me is two fold both next week and beyond (however reliable that may or may not be).

Fairly windy at times especially for the north and west and also feeling on the chilly side in the breeze with Td mostly below about 6C and at times well below that value?

[Frosty.]

I would say that fine and dry days will be at a premium during the next few weeks, tomorrow looks nice as a brief ridge pushes east and then sunday could also be an improving day after overnight showers clear but apart from that, with persistent low pressure drifting down from iceland next week, windy and rainy days look frequent and only seperated by sunshine and blustery showers, so tomorrow is probably the pick of the week as it will be a dry day with good spells of sunshine.

[phil nw.]

Heads up-will be locking this thread in 5 mins. and opening a new one in time for the 12z outputs.