Model Output Discussion 26/10 2012 >

[Panayiotis]

Some of the other Models have that low running down the North Sea instead , but 15 days out so who knows. CFS seems worse at predicting short term than long term but maybe thats how its designed. Looking at a few of the Models it could get rather Frosty in the South by the middle of next week with NW flow but High pressure Nudging across from the SW. I'm right on the coast so Frost is rare but inland Southern England could record there first negative temps of the Season .

Its one month and 15 days away..

[BLAST FROM THE PAST]

Forgive me if im wrong, but isnt that a surface high on that chart you posted, not the Greenie High that usually causes cold to feed into the UK. If it is a surface high, it wouldnt be in the wrong place because it wouldnt make any difference to achieving a cold shot or not.

Yes but its developing into it if you run the sequence from say t324. its jsut an example but that HP developing won't disappear overnight but I take your point.

BFTP

[Vertical Limit]

I would just like to say that from my perspective as a novice trying to get to grips with understanding the models, that the recent posts from BFTP, AWD, Gibby, Frosty039 and others, showing charts and explaining what you are actually seeing, without bias toward any particular weather type, is enormously helpful for people like me. Please may these in depth posts continue - thank you.

Regards

VL

[Mark Neal.]

I would just like to say that from my perspective as a novice trying to get to grips with understanding the models, that the recent posts from BFTP, AWD, Gibby, Frosty039 and others, showing charts and explaining what you are actually seeing, without bias toward any particular weather type, is enormously helpful for people like me. Please may these in depth posts continue - thank you.

Regards

VL

+1. Some excellent analysis offered by some of the more experienced members. The models are interesting to say the least at the moment. I am looking forward to hopefully a few days of settled and chilly conditions next week, albeit will probably be brief if it does arrive. Thereafter there seems like we could see a few solutions.. Will be watching the 12z runs unravel with great anticipation...

[johnholmes]

As a supplement to the first class inputs from several folk going out to T+144 and at times beyond using the synoptic outputs I will start a new idea tomorrow.

Using various charts I will do a pdf post each Friday, sometimes more often if time allows, largely ignoring the 'near time frames' and looking at how the weather might turn out from about 6 days out to about 2 weeks perhaps getting on for 3 weeks. The charts being MJO, 30mb, AO, NAO,500mb anomaly, NAEFs outputs, and any other that seem to give some indication.

Edited November 1, 2012 by johnholmes

[Adam lufc]

Very quiet again. Guessing not very encouraging, exciting data on offer tonight so far.....

[gottolovethisweather]

Very quiet again. Guessing not very encouraging, exciting data on offer tonight so far.....

Have a read through the more recent posts please, much as many other lurkers will have done.

If you are looking for raging Blizzards or a late Heatwave then I guess you would be correct but it is only early November afterall.

Best get back to lurking myself and as others have commented, we owe thanks to those who are providing us with all the informative posts.

Edited November 1, 2012 by gottolovethisweather

[Methuselah]

Well...if something anything like this were to develop, in reality, I think that many folks would be walking about, with a smile?

http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20121101;time=12;ext=384;file=h850t850eu;sess=41195aafce2688f87e28f262e1f78d1a;

[Mark Bayley]

Very quiet again. Guessing not very encouraging, exciting data on offer tonight so far.....

The charts are encouraging in that PV continues to remain disorganised and not particularly strong, right out into the middle of November. Its looks like it will remain cool and showery for the most part, with any snow mostly confined to the higher ground. Although an interesting northerly at the end of the GFS run.

Edited November 1, 2012 by Mark Bayley

[Mark Neal.]

A teasing end to the GFS 12Z. Showing a northerly... What a tease! Right out in Fi, so big pinch of salt. Be interesting if this will be trend that will continue in future output.

Good point Mark B! I have also been looking and it does seem to be that the PVreally is disorganised and no sign of real strengthening, this time last year a complete different ball game was unfolding!

[chionomaniac]

No comment on the ECM yet?

I will. Look at this for a disturbed vortex at T+192

Fantastic.

I have to say, we are just waiting for the right wave break / deflection over Greenland and bingo.

Edited November 1, 2012 by chionomaniac

[Mark Bayley]

No comment on the ECM yet?

I will. Look at this for a disturbed vortex at T+192

Fantastic.

Or better still, this one, with no purple to be seen! And a quite good -AO developing

Edited November 1, 2012 by Mark Bayley

[chionomaniac]

Or better still, this one, with no purple anywhere! And a quite good -AO developing

Yes - I can't quite believe how the restrengthened polar vortex gets smashed to smithrereens!

[Met4Cast]

ECM 216 = Yuck.

Sure, Greenland High and blocked Atlantic, but its West Based, we end up in mild Southerly winds whilst cold air digs down into the Atlantic

[phil nw.]

Yes - I can't quite believe how the restrengthened polar vortex gets smashed to smithrereens!

Very unusual C.-to say the least.What do attribute this too?some sort of zonal wind reversal at the lower levels putting the brakes on?.

[Gibby]

Good evening. Here is the evening rundown on the 12zs from GFS, UKMO and ECM tonight.

All models continue to show a complex Low pressure near or over the British Isles between now and Monday with showers or longer spells of rain and snow on Northern high ground. The showers will be heavy and squally over Southern Britain in blustery and cold West winds. early next week sees the Low moving away East taking a legacy of showers away from eastern Britain on Tuesday.

GFS then shows a weak ridge later Tuesday with a drier spell for most before a front brings fresh to stron winds and rain SE over Britain midweek. A further ridge moving West to East on Thursday is followed by a backing of wind towards the SW with fronts bringing rain to the NW by Friday. Through this period it will become less cold generally. The South may see 48 hours of dry weather before all areas become unsettled and rather cold again through the early part of FI as Low pressure moves SE over Britain with rain, showers and hill snow all likely through early FI. this continuing feed of systems from the NW with brief ridges of high pressure continues for the remainder of FI with temperatures held at rather cold levels over Britain.

The GFS Ensembles shows a continuation of rather cold conditions across the South through the run. Rain at times shown throughout the run indicates a Atlantic low pressure influence with brief spells of near normal temperatures as weak ridges pass through. There is nothing 'very' wintry shown on any of the members runs tonight.

The Jet Flow continues to blow across Southern Britain and Northern France for the next 72 hours or so. It later ridges North through the Atlantic and back down SE over Britain next week.

UKMO for noon on wednesday shows a broad and milder Westerly flow with a lot of cloud but little rainfall away from the far North.

ECM too shows a rather more vigourous WNW flow with strong winds and some rain for many Northern areas through the midweek period before a drier spell returns on Thursday. Late in the output there is a change tonight as the trough progged to move down over the UK on the earlier run backs West with a Southerly feed over the Uk with rain for these parts but drier in the East and certainly not as chilly as recently everywhere. The Low eventually winds up down to the SW with Western regions bearing the brunt of the rain in near average temperatures.

In Summary tonight the weather is still very interesting synoptically. The current cold pattern looked like it could be replicated in a week or so but tonight the European output has backed the trough West keeping the UK on the milder side of Low pressure later next week, eventiually creating a cut-off Low down to the SW. Nevertheless, with High pressure still maintained in the Greenland area a trough will always be situated to the near West, over or East of Britain in the outlook period so it's unlikely that any sustained settled weather will develop over the UK anytime soon.

[phil nw.]

ECM 216 = Yuck.

Sure, Greenland High and blocked Atlantic, but its West Based, we end up in mild Southerly winds whilst cold air digs down into the Atlantic

This could well change on future runs though Daniel.The fact that the vortex is fragmented gives plenty of openings for HLB(high latitude blocking). That`s the positive for cold seekers.

Edited November 1, 2012 by phil n.warks.

[Frosty.]

Yes - I can't quite believe how the restrengthened polar vortex gets smashed to smithrereens!

Yes chio it looks like he's going to be busy again

I'm not surprised the models are hinting at a Northerly in FI since the ens mean today is indicating a nw/se angled jet throughout most of FI with a good chance of an arctic outbreak or two further down the line. As for this weekend, it looks rather cold and cyclonic with clusters of heavy showers with local flooding possible but also a good deal of sunshine and cold enough at night for slights frosts where skies clear.

[Met4Cast]

This could well change on future runs though Daniel.The fact that the vortex is fragmented gives plenty of openings for HLB(high latitude blocking). That`s the positive for cold seekers.

Oh agreed, I was just pointing out that a disrupted Votex, -NAO and -AO could still result in mild weather for the UK should the -NAO be West based

[chionomaniac]

This could well change on future runs though Daniel.The fact that the vortex is fragmented gives plenty of openings for HLB(high latitude blocking). That`s the positive for cold seekers.

Yes, Phil, - one definitely needs to look at the bigger picture!

Don't just look at the Europe based charts or you could end up disappointed. At T+216 we never see true verification but we do see great trends!

Also that far out I don't look at the 850's (or not seriously) - the pattern is far more important.

Edited November 1, 2012 by chionomaniac

[andymusic]

Yes chio it looks like he's going to be busy again

I'm not surprised the models are hinting at a Northerly in FI since the ens mean today is indicating a nw/se angled jet throughout most of FI with a good chance of an arctic outbreak or two further down the line. As for this weekend, it looks rather cold and cyclonic with clusters of heavy showers with local flooding possible but also a good deal of sunshine and cold enough at night for slights frosts where skies clear.

cold enough right now for snow here in Wales! - just like the nae said!

[phil nw.]

Yes, Phil, - one definitely needs to look at the bigger picture!

Don't just look at the Europe based charts or you could end up disappointed. At T+216 we never see true verification but we do see great trends!

Also that far out I don't look at the 850's (or not seriously) - the pattern is far more important.

Indeed C.To some members this may look as if it`s come out of the blue and it`s worth them revisiting the Strato.thread to understand some background to this.

I wont add anymore here as i will be drifting off topic.

[snowking]

Also that far out I don't look at the 850's (or not seriously) - the pattern is far more important.

Just to back that point:

SLP

Day 8: http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX_00Z.png

Day 10: http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX_00Z.png

850's

Day 8: http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_T_P850_G2NHX_00Z.png

Day 10: http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_T_P850_G2NHX_00Z.png

SK

[johnholmes]

I find it quite amusing how one run tips the sanity scales so to speak for some on here who really should know better.

Okay so the T+240 ECMWF 12z would bring milder air into the SE but not really the NW.

However, for newcomers try the link below and see how different models including ECMWF change in the 12 hour timeframe.

Which is right? The 00z or the 12Z ECMWF or the GFS 00z or 12Z for that matter.

And yes do look beyond the European area for trends. Do read what the more reliable and less knee jerk reactive posters post. You will soon find out who generally gives reasonably objective assessments.

It will get worse as winter approaches you I promise. Tell me at the end of February if this was one forecast that was well over 90% correct!

link below

http://www.weatheron...200&WMO=&ZOOM=0

go to weather maps-expert and then click on whichever model you want to look at and down the left hand side of the chart you are able to click on the last few runs to compare. Clever bit is that the software automatically changes the time scale so you are always looking at the same forecast time.

Edited November 1, 2012 by johnholmes

[Zakos]

yes, if looking for future cold potential, it is essential to look at the hemispheric pattern, rather than the conditions the UK is in.

you may look at this chart and say this is terrible for cold lovers as their is warm air is being pumped up from the south over the UK.

This is completely irrelevant if your looking for future cold

a look at the H500+SLP shows an area of high pressure in the Atlantic and low pressure to the south of the UK. yes there is a euro high which is causing the UK to be under the influence a mild airflow, but there is good potential for cold down the line.

And finally, a look at the hemispheric pattern is very encouraging. The polar vortex is incredibly week and fragmented,there is clear potential for the UK to experience a cold spell later on.

Of course this chart is 240 hours away, and subject to change,but I am just using it to illustrate a point

I do not see solid evidence of a cold spell anytime soon, but I also cannot see much sign of a strong Polar vortex being sustained, it is going to gain in strength soon but already there are hints it may become weak again. Stratospheric temperatures did take a dive earlier but subsequent warmings have bought it back to average levels.

There is certainly very little sign of the Atlantic having much of an effect on the UK, or a strong jet stream.

I think there is a good chance of a cold spell fairly soon, for now though, all eyes to the pole to see how strong the PV gets and if it can be sustained.