Winter Model Discussion 12Z 22/1/13 onwards.

[lord stratus]

The update cover the first 3 weeks of February (till the 21st) so no sign of cold, according to the Meto, for much of February!

Karyo

We'll be heading into spring then so here's to a good if not great cold spell just had. Looking forward to next winter!

[chapmanslade]

The irony however is that having said all of that they're still unable to forecast with any great degree of accuracy beyond 4 days at best. In the 1950's the accuracy was at 2 days.

The question is, if you take away the computer model can a forecaster forecast. If they are presented with a chart at 12z today and asked to provide a forecast for 1,2,3 days ahead without the use of a computer can they do it. Half the people in here can interpret the models to provide a forecast and how many of those are expert mathematicians, physicists etc.

All the lay person wants to know is will it be wet, warm, dry or cold, not be baffled with b******t. It's about the end product - an accurate weather forecast; from what I can see, all these advancements in technology, the sciences etc and for what...........to extend the forecasting accuracy by 2 days!

2 days is double 4 days which is a huge increase when you consider the logarithmic effect of very minor changes at day 1. The forecasting has been very good of late but the significance of minor differences with snow are much greater than with rain. So what if we get 5mm of rain or 25mm - it's just wet. 5cm or 25cm of snow is a whole different ball game. There are few things more irritating to a professional than an amateur expert, whatever the field. Watching Casualty doesn't make anybody a doctor ! If the b*******t is baffling then all you are ever going to get is wet, warm, cold and windy and be prepared for disappointment - there are no simple terms with the weather - it is extremely complex. Hopefully in 50 years time we may be at 6 or 8 days for a forecast - but even that is simplistic as certain weather patterns are more predictable than others such as the big summer anticyclone.

[howmuchsnow]

The twenty first century meteorologist relies too heavily on computer modelling. This lazy controlling mindset filters through to joe public, blinding everyone into chaotic confusion. Scrap the computers, bring back pencil, paper, common sense and develop those excellent FAX charts.

My forecast for the next few days is uncertain. There is a greater uncertainty for next week. Into February and the risk of rain and snowfall is at odds with each other, it will probably be dry across much of the country and wet around the edges.

[bradymk]

We can dream

There have been a few stunning members in far FI for the last several suites, unfortunately for the time being, they are outnumbered but quite a few show a mid atlantic ridge. Im being optimistic here though and the outlook is pretty poor for next 10 days but hopefully we can get a mild and dry spell rather than wet and mild. Looks like the further SE you are, drier it will be.

[Summer Sun]

And bringing this tread back on topic it looks like its going to be a very windy weekend for some it all starts on Saturday in the far north west

Before the winds ease during the morning

For the bulk of England and wales we should have a decent day on Saturday with light winds and no rain, temperatures will be low however away from the south west, you can see below whats heading our way

Into Sunday and a deep depression crosses the UK everywhere is likely to see strong gusts at times

Heavy squally showers (snow on the high ground) are likely to follow after a very wet night on Saturday and early on Sunday in the west with the east last to see it clear

Temperatures will remain low for most but to the south its starting to turn milder

Monday is likely to be a mostly dry day as well with just the odd isolated shower

Again for the bulk of the UK it remains cold but milder conditions continue in the south

Wind speeds start to pick up in the west

By Tuesday the milder air sweeps across the UK

At the same time the wind picks up

And heavy squally showers follow after another area of rain clears through during the day

[BurntFishTrousers]

Into Sunday and a deep depression crosses the UK everywhere is likely to see strong gusts at times

I'm not seeing a deep depression crossing the UK on Sunday??

Edited January 23, 2013 by BurntFishTrousers

[lord stratus]

Did I say it should be cold??

No I said blocking is historically more frequent during Feb than Dec. You will also find the frequency of E,lys is greatest during March, April. Lastly gales and deep Atlantic LP systems are also more frequent during late Autumn, early winter. This all ties in with the fact that during late winter the PV weakens and so does the PFJ because the thermal gradient becomes less in late winter.

I know you meant a blocking pattern but the point I am making is that the expected or desired weather type doesn't always play out, this is why the weather makes an ass of us on this forum and the professionals on many occasions!

[Snow phall]

The irony however is that having said all of that they're still unable to forecast with any great degree of accuracy beyond 4 days at best. In the 1950's the accuracy was at 2 days.

The question is, if you take away the computer model can a forecaster forecast. If they are presented with a chart at 12z today and asked to provide a forecast for 1,2,3 days ahead without the use of a computer can they do it. Half the people in here can interpret the models to provide a forecast and how many of those are expert mathematicians, physicists etc.

All the lay person wants to know is will it be wet, warm, dry or cold, not be baffled with b******t. It's about the end product - an accurate weather forecast; from what I can see, all these advancements in technology, the sciences etc and for what...........to extend the forecasting accuracy by 2 days!

Can anyone tell me,how accurate were the models concerning the big 2009/10 freeze?How far away from the start of the event did the models see what was coming and how did they handle the breakdown?

Edited January 23, 2013 by Snow phall

[Summer Sun]

ECM is showing a zonal pattern once more tonight for the start of next week

[Moisty]

Is it wrong to say I am looking forward to milder temps and hopefully a few drier-ish days in the south next week as seems likely now looking at the models.

I cant come close to understanding the models as well as others on here but I have learnt to always ignore the MetO LRF, there is never any reliability of any forecast past 10 days or so.

I do hope cold returns but I am happy to see a milder interlude.

[mcweather]

http://www.wetterzen..._London_ens.png

Looks like ensemble number 5 has read GP'S forecast.

Nice trend leader and not the only one featuring a Greenland high later in the run either.

Edited January 23, 2013 by mcweather

[shotski]

The 500mb Anomoly charts are of interest as we head into early Feb.

Showing higher than average pressure over the Greenland area that may suggest

that lobe of the polar vortex could be on the move.

[cold snap]

straw clutching but isnt the ecm at 168 .a slighty better profile.?

[chris55]

I'm actually quite liking the ECM 144,

Will feel very different out, and that will be quite a change! Overall though that chart looks....well...odd, and going from gut instinct, doesn't scream weeks of Zonality to me.

[SMU]

If you are looking for cold this is about the most inverse chart you could get -

http://www.meteociel.fr/modeles/ecmwf/runs/2013012312/ECH1-144.GIF?23-0

Upper low over iceland & heights stretched all the way from Spain through europe out to russia- no troughs digging through that-

Perhaps some misplaced optimism today- the ECM day 10-15 ensembles have moved to a Mean along the average line & the spread fairly consistent either side, no clear signal for cold to return. Average joe at best.

The mild weather will greet us into feb with a very low probability of change before then- possibly lower than 5%.-

So that will usher in an above average Dec & with Jan aiming at high 3's to low 4s at best an average month within 0.5 degree either side.

8 weeks down, & this winter has average written all over it. It will take something exceptional to pull it out of the bag- & theres nothing within ANY indicator that shows that something big on the cold front is coming, however that doesnt negate the fact that something could crop up as we go through Feb to sway the overall averageness of Winter- all be it with Jan showing a fair chunk of weather at either ends of the spectrum- including 10-12 days of very cold air for the UK.

S

[chris55]

192 is "interesting", not showing cold in any sense, but I get a feeling this milder spell may well be short lived,

[Summer Sun]

straw clutching but isnt the ecm at 168 .a slighty better profile.?

The overall pattern though looks zonal to me

Once we get into these patterns they can take an age to leave

t192 has a huge low forming in the Atlantic

[Cheese Rice]

The ECM has a decent trend going with a threat of northern height rises in the latter parts of the output.

Edited January 23, 2013 by Cheese Rice

[shotski]

The overall pattern though looks zonal to me

Once we get into these patterns they can take an age to leave

t192 has a huge low forming in the Atlantic

But Gavin, Where is that Low in the Atlantic pushing warmer air to ? and the end result ?

[Summer Sun]

t216 see's the low moving closer to the UK

With milder air coming with it there is likely to be some heavy rain around

[nick sussex]

Upstream in the USA that low heading east at 168hrs could well do us a favour. If it engages that PV lobe this could help pull those low heights away from Greenland.

[cold snap]

possible height rise across greenland at 240,looks possible

[chris55]

Hints at a cold start to Feb in the making. Southerly tracking Low pressure and heights attempting to build in from the north and the Azores high backing West..

Edited January 23, 2013 by chris55

[SMU]

http://www.meteociel.fr/modeles/ecmwf/runs/2013012312/ECH1-240.GIF?23-0

A slight glimour at Day 10 - 2nd feb - sees energy breaking away across the UK & a SLIGHT increase in pressure over greenland adjacent to a half decent arctic high-

Thats where to 'hope' for in the coming days

S

[cold snap]

overall i dont think we can have to much complaints with that ecm run yes it isnt great.but by 240 we are making some progress to another cold blast.

overall i dont think we can have to much complaints with that ecm run yes it isnt great.but by 240 we are making some progress to another cold blast.