Winter Model Discussion - Cold Hunting - 20th Dec

[tesaro]

Have to say the medium range is looking rather disappointing to me.

http://modeles.meteo...-21-1-240.png?0

http://www.meteociel...1-240.GIF?21-12

So it seems we shall have to wait until we are into January before any significant cold spell could affect all of the UK. However despite all the promising teleconnections/stratosphere predictions I would advise members to be cautious until this actually appears on the model output. Another reason why im saying this is the Met O predicted the 2009, 2010 cold spells from some distance away and yet their 16-30 day forecasts continue to suggest more of the same i.e zonal. So whatever positive signs some are detecting on here the Met O don't agree.

Dave. Remember back in March this year. We were in a drought situation. I remember well the meto 30 day comments regarding a continuation of the dry conditions as i had plans to do some major home improvements. So i gave them the benefit of the doubt after there "BBQ Summer" washout and preceded to remove the roof from my garage.

Met Office 3-month Outlook

Period: April – June 2012 Issue date: 23.03.12

SUMMARY – PRECIPITATION:

The forecast for average UK rainfall slightly favours drier than average conditions for April-May-June as a whole, and also slightly favours April being the driest of the 3 months.

A few regrets a month later as im sure you remember.

This month is the UK’s wettest April in records dating back more than 100 years to 1910, the Met Office said on Monday.

They don't know whats going to be happening in 30 days time. They may have a computer the size of my flooded garage but its only as good as the human data thats fed into it.

[Methuselah]

I would say quite simply that the error is caused by erm!!, wait for it........... THE WEATHER BEING THE WEATHER

The weather will always be one step ahead of the models and that will never change no matter how much science evolves.

Just what I was thinking...Plus, all us 'pundits' made a pig's ear out of forecasting it?

[UV-RAY]

Just what I was thinking...Plus, all us 'pundits' made a pig's ear out of forecasting it?

Do we add the caveat that when the models show cold they are also wrong?

[BLAST FROM THE PAST]

Hi Luke, I am hoping to do some analysis of this and look into it a bit more and see whether we can prove/disprove any Null hypothesis. Before i begin, my opinion is that yes the sudden increase in solar activity did have an influence on the "failed" easterly. Not sure whether it was an overriding factor but imo it certainly influenced it. But i will now and try and find out more and see whether there is enough evidence to back this up.

It is thought by some of us that it affects the movement/placement of the Jetstream and where we are is one of the locales likely to be affected by it being on the edge of an ocean.

BFTP

[Frosty.]

There are some cold wintry charts for next week across the models, it's not as bad as some are painting it. I would think the further north you go in the uk next week, the more chance of catching some snow and increased frost and ice risk, the ecm is the worst with the jet tilting sw/ne due to european pressure rises and deep lows to the northwest and north but some of the latest models have at least got a seasonal wintry flavour compared to the hair dryer treatment we got last christmas when temps hit 15c in places on christmas day, some parts of the north will struggle to get above freezing this christmas, and boxing day looks even colder.

[EML Network]

Hi,

Havent posted on here for a while but I have been keeping an eye on proceedings in this place and I was particually fascinated by the failed Easterly episode and the fact that it seemed to be scuppered at the last minute and it even had a good level of teleconnection and other backround factor support.

I am just wondering from this do you think a sudden increase in solar activity could be to blame for the faliure of the Easterly and the rather Atlantic controlled pattern since? I do know that a sudden increase in solar activity can ramp up the jetstream. GP hinted at this in one of his posts implying that an increase in solar activity was recorded at the end of November and that could been at least partly to blame for his december forecast not going totally to plan.

So do you think solar activity could have been the "wild card" this month in the fact that it could have overridden the backround signals (including the strat etc.) resulting in a milder more Atlantic dominated month that expected?

Luke

What sudden increase in solar activity ? there was a little rise for a few days, but it's not anything that was noteworthy and there were no CME's during that time that were note worthy.

If anything solar activity has decreased somewhat in recent weeks.

I do agree that there is a slight correlation between solar Maximum and Solar Minimum winters, being warmer / cooler accordingly.

I think we will get a decent shot at cold this Winter, but I think it will be very short lived (maybe one week in early -mid Feb) ??

January's outputs aren't looking good at least for the first week, and if we do get a SSW event sometime around 7-10th Jan, then the lag time (3-5 weeks) put's us either in early Feb or Mid Feb before we feel the effects here in the UK.

That being said... Perhaps we will have a late winter this time around ...we've not had a cold March for A LONG time and are overdue one if you ask me !

Edited December 21, 2012 by EML Network

[Luke McDonnell]

What sudden increase in solar activity ? there was a little rise for a few days, but it's not anything that was noteworthy and there were no CME's during that time that were note worthy.

If anything solar activity has decreased somewhat in recent weeks.

I do agree that there is a slight correlation between solar Maximum and Solar Minimum winters, being warmer / cooler accordingly.

I think we will get a decent shot at cold this Winter, but I think it will be very short lived (maybe one week in early -mid Feb) ??

January's outputs aren't looking good at least for the first week, and if we do get a SSW event sometime around 7-10th Jan, then the lag time (3-5 weeks) put's us either in early Feb or Mid Feb before we feel the effects here in the UK.

That being said... Perhaps we will have a late winter this time around ...we've not had a cold March for A LONG time and are overdue one if you ask me !

I was just looking at what was responsible for the failed Easterly and the reason why after the failed Easterly we got quite a mediocre pattern for much of the rest of the month, and what could have influanced the jet to be stronger around our locale - the shortwave has been mentioned but that is just a mesoscale feature as opposed to a macroscale one like the teleconnections etc.

I have just been thinking - I was thinking of a good example to demonstrate that nothing is nailed on even when we appear to be in a protracted wet zonal spell and it seems that December 2000 was a good example of this. Apparently the cold spell of December 2000 came after a very wet and mild period - and the proceeding November was very wet with a lot of flooding just like now - and the first part of December 2000 was milder than even this month so far and then between Christmas and New Year we got the best cold spell for a while at least in this part of the world - here in Liverpool we got at least 10cm of snow and I remember the airport being closed due to snow and the snow remained on the ground for a few days - does anyone know why the outlook suddenly changed then and do you think something like it could happen in late december/early January especially considering the predicted strat warmings etc. - December 2000 seems to be a good example to show to those writing off the rest of December and January as it shows how quickly things can change from a very protected wet, mild and zonal period into a decent cold spell.

Luke

[High Altitude]

It would be good to have a chart drawn up like tick box with a list of all the background signals, their effects and how long any changes take to filter down. This way when we have the next cold spell modelled we can tick off the background signals and see whats in our favour. The list could start with the most influencing factor for the UK receiving cold and down to the least and highlighting any overiding factors. The example below is not exhaustive or in any particular order - i'm just trying to demonstrate an idea. What does everyone think? I'm not up to speed with all the factor and there effects so it may take me some time to complete but any suggestions or pointers would be appreciated?

Cold weather Signal Time lag effect on weather downstream Favoured for cold

1. Jet Stream Southerly track months/weeks/days/hours Yes/No/Neutral

2. AO

3. NAO

4. Stratosphere

5. MJO

6. PDO

7. Solar Activity

Edited December 21, 2012 by High Altitude

[Frosty.]

As for today, at least some temporary respite from the torrential rain and flooding, although the world didn't end, it must feel like it for those who are being continually hit by fresh flooding misery but today the models show a window of fine weather but wet and windy in the far northeast. Tonight it turns nasty again with more heavy and persistent torrential rain pushing northwards and eastwards across the uk through tonight and more especially tomorrow, the main zone of torrential rain eventually ending up across the far north and northeast of the uk tomorrow night and through sunday, even a risk of blizzards for shetland with easterly severe gales but the most disruptive snow looks like being across norway and south into the low countries, then brighter, colder and more showery weather spreading southeastwards by christmas day and boxing day with some parts of northern britain sub zero for a few days next week and also a risk of disruptive snow as low pressure moves east into the cold air after the middle of next week for the northern half of scotland at least.

[bluearmy]

Here are the ensembles for London, they are not that bad considering we are not in a blocked pattern. http://modeles.meteo...35832&runpara=0

ignorance would say post new year thats a 50/50 chance of a cold scenario

[Panayiotis]

ignorance would say post new year thats a 50/50 chance of a cold scenario

You would expect that as the models are not that good at predicting the weather 11 days away.

[BOMBHEADS]

on the 06z GFS there appears to be a trend through most of the run for cold air to try and push in from the north, i think it will just take an atlantic low pressure to take a more southerly / south easterly track pushed by a greeny high and we could be in for a decent cold spell from the north.

[Summer Sun]

By Sunday evening the south west is likely to see another 30mm to 40mm of rain accumulating parts of Scotland look like taking the brunt this time around with around 75mm accumulating in some spots

[bluearmy]

exter finally taking the upcoming warming into account on the 30 dayer. that must mean ecm and their own strat model seeing something similar to ncep.

[LomondSnowstorm]

By Sunday evening the south west is likely to see another 30mm to 40mm of rain accumulating parts of Scotland look like taking the brunt this time around with around 75mm accumulating in some spots

That's very concerning as the worst hit areas of Scotland around Fife, Tayside and Stirlingshire have already seen around 50-80mm of rain in the last 48 hours and still falling.

[bobbydog]

the GFS predicted the end of the world in F.I. - it was never going to happen....

[johnholmes]

I was just looking at what was responsible for the failed Easterly and the reason why after the failed Easterly we got quite a mediocre pattern for much of the rest of the month, and what could have influanced the jet to be stronger around our locale - the shortwave has been mentioned but that is just a mesoscale feature as opposed to a macroscale one like the teleconnections etc.

I have just been thinking - I was thinking of a good example to demonstrate that nothing is nailed on even when we appear to be in a protracted wet zonal spell and it seems that December 2000 was a good example of this. Apparently the cold spell of December 2000 came after a very wet and mild period - and the proceeding November was very wet with a lot of flooding just like now - and the first part of December 2000 was milder than even this month so far and then between Christmas and New Year we got the best cold spell for a while at least in this part of the world - here in Liverpool we got at least 10cm of snow and I remember the airport being closed due to snow and the snow remained on the ground for a few days - does anyone know why the outlook suddenly changed then and do you think something like it could happen in late december/early January especially considering the predicted strat warmings etc. - December 2000 seems to be a good example to show to those writing off the rest of December and January as it shows how quickly things can change from a very protected wet, mild and zonal period into a decent cold spell.

Luke

the first 14 days of this month were not mild

in this area the mean temperature was 2.2C the average is 4.6C

[Luke McDonnell]

the first 14 days of this month were not mild

in this area the mean temperature was 2.2C the average is 4.6C

You mean this month not December of 2000? Just had an interest in that month as it just goes to show how quickly things can change from a zonal mobile setup to a cold northerly set up which resulted in a significant snowfall for our location and I know how difficult it is to get a decent snowfall here in Liverpool. Does anyone know what resulted in the sudden change from a mild zonal setup to a colder one in December 2000 - was there a stratospheric warming then? And was it a cold zonal setup or a blocked setup - was the blocking already in situ prior to the cold spell.

As I said I certainly would not mind a repeat of December 2000 or even 2004 - and considering the setup I think we would be more likely to get a repeat of those decembers than December 2010.

[swilliam]

the first 14 days of this month were not mild

in this area the mean temperature was 2.2C the average is 4.6C

Hi John,

It seems, in this thread at least, anything that is not cold (enough for snow) is called mild or even very mild. I got told off for pointing this out a couple of days ago when someone said Christmas was going to be very mild when in fact the model predicition was for near or slightly below normal.

Stewart

Edited December 21, 2012 by swilliam

[kumquat]

I think the prime suspect for 'error', would be where an algorithm is given 'intelligent data' which artificially influences what it would otherwise mathematically wish to do. But you do need this, otherwise chaos theory would - by definition - ruin all of your hard work. So, it is a necessary evil.

That, and the fact that each set of equations is being performed on limited data confined within large finite elements. What is the resolution of our best models? 2km or something? So we are only ever talking approximations and not, of course, the complete data set down to infinite boundaries (i.e. reality).

And of course with each iteration, the errors become larger.

Edited December 21, 2012 by kumquat

[J10]

The Latest Ski Blog is out

http://forum.netweat...-december-2012/

Here is the Synoptic pattern extracted from it .

Synoptic Analysis

Starting with today's chart for a base point.

Sat 22 December -

The seemingly omnipresent Russian High is still in place (1044mb), this gives very cold weather for Russia Scandinavia and Eastern Europe, not quite so cold as you move further west. there is low pressure over Svalbard (988mb), with a surface High Pressure over Greenland (1036mb). There is High pressure over the western half of the Atlantic. Over the main part of the Atlantic there is a deep area of Low Pressure (980mb). Finally the Azores High is over Iberia and much of Southern Europe. This means a very mild flow into much of Western Europe, Due to the very mild air, this gives further very heavy rainfall for the UK. The Alps not for the first time in-between the weather systems, mild for western areas, cold further east but turning milder across the Alps.

Sun 23 December -

Since Saturday the whole pattern moves further east by around by several hundred miles. The Russian High Pressure a bit further east (1036mb) so still very cold over Russia and Scandinavia, deepening low pressure over Svalbard, with High Pressure building further over Greenland, the High Pressure block slight further east than yesterday. Still low pressure over the Atlantic, 980mb over Northern Scotland another centre 984mb over the Mid Atlantic. Not quite as unsettled over the UK, W/SW winds over the UK and Northern Mainland Europe. generally mild over the UK, very mild over much of Northern and Western Europe, including the Western Alps, while mild over Eastern Alps and generally much of Eastern Europe. The Azores High ridges into Iberia and gives some warm air here (+10 850Hpa)

Mon 24 December - The Russian High continuing to edge east, with the very cold air continuing to edge Northwards and Eastwards. Low Pressure over the UK (980mb), cool/mild here, with extremely cold Northerly winds to the North west of the UK with High Pressure over Greenland. To The South East of the UK, South West winds over much of Europe, with very mild or mild winds for most of mainland Europe including the Alps.

Tue 25 December - A continuation of the South eastward movement of the pattern. Surface High Pressure (1052mb) over Greenland, Deep low pressure over Svalbard through the UK and Scandinavia, pushes down some extremely cold air southwards. North West winds over the UK and North West Europe, cold over Northern UK, cool for much of the UK, mild over of Northern Europe. the very mild air in the far South East of the UK.

Wed 26 December - The Russian High for the first time in ages, largely out of picture. again very cold over Svalbard, but with more a zonal west to east flow further south, so the very cold air never reaching the UK. A generally flat pattern over much of Europe as well, with the Azores high in place. Very cold over Scandinavia, cold over Northern Europe, cool over much of Europe.

Towards Weekend - A bit of uncertainty at the moment, a Greenland High seems likely as does very cold unsettled air over the Svalbard areas, possibly again it looks as if the coldest air remains trapped over High latitudes.

The Current guidance is for. Low pressure over the Atlantic, with the UK on the South Eastern edge, as for much of Europe so mild SW winds with a Bartlettesque High Generally the further east you go, the colder it is, especially into Scandinavia and NW Russia

Edited December 21, 2012 by Jackone

[Bonjangle]

Just thought i would share this with you if you have not seen it yet... now this is cold Brrrrrrr

http://www.bbc.co.uk.../feeds/20771143 (Mods delete if this off topic) but i did want to share

http://www.bbc.co.uk...europe-20807587

http://www.bbc.co.uk/news/world-europe-20758885

Edited December 21, 2012 by Aquastarmist

[Summer Sun]

Signs finally today the that huge Russian high which is stretching into parts of Western Europe is coming to an end and not before time this should at least help the low pressure systems that come our way move through quicker instead of just getting blocked like they are now

Not much change on Sunday

By Christmas day its slowly heading east

By Thursday the high is well away from most of Europe

Into the New Year and theirs not much of the high left

Until we can get an area of High pressure building in the Atlantic further low pressure systems heading into the south west are inevitable

[SnowBallz]

I would say quite simply that the error is caused by erm!!, wait for it........... THE WEATHER BEING THE WEATHER

The weather will always be one step ahead of the models and that will never change no matter how much science evolves.

Blimey, that really is quite a statement

With greater understanding of the physics involved - notwithstanding the ever-increasing power of super-computing - the 5-day forecast today, is as accurate as the 1-day forecast, 20 years ago.

That's with the same 'weather' - it's not some new, easier-to-read weather.

So science has evolved; our understanding has evolved, and as has the technology at our disposal. There are some processes and phenomena which are still in the infancy of understanding, and as this improves further with more research, it's these advances which correlate through to greater accuracy.

Personally, I think some people expect too much; viewing these charts out in the 5-10 day range, wonder why they hardly ever verify, then bash the models. Laughably, some even look beyond 10 days. The verification scatter plots for all models post 5/6 days are hilarious. The goal for this decade, will be to extend that confidence out to the 7 to 10-day range - at least.

Look at the Japanese. This year they on-boarded the worlds' most powerful meteorological super-computer: 847 TFlops! That'll deliver to the JMA capability for higher-res, more layers, increased range and greater scope to calculate new variables - all resulting in more accurate, detailed forecasting. That power doesn't come cheap though: $1Bn investment by JMA, hence the respect Exeter has for them. I've actually heard that UKMO and JMA will be working together to develop a brand new experimental platform by 2014, with a view to roll-out onto the UKMO's newest super-computer in 2017. I think it's going to be something along the lines of a massively scaled-up, continental UKV, with multi-member ensemble support. That's what I've heard anyway.

The demand and importance for accurate weather and climate forecasts has never been higher; not merely to provide a good public service, but because so much of business - the success and failure - rests on solid accuracy. The Met Office make a tidy sum from licensing their UKMO base platform to meteorological agencies worldwide, and they also supply bespoke services to private companies and institutions. Beyond that though, or more - beyond borders - there's been a suggestion that worldwide meteorological super-computing could be harnessed, therefore delivering a game-changing array of forecasting suites. I very much doubt that will happen any time soon though, for a number of reasons - even though the benefits are admittedly exciting.

A lot of people knock The Met Office, but the proof is in the pudding: in this tough financial climate, 'the Brits' are the preeminent world leaders in meteorology. Other meteorological agencies procure their services, and - if you read as many papers as I do - you'll see that they're frequently referenced, when it comes to peer review and due respect. They're one government agency that the British people can be thoroughly proud of, and I can't imagine how many thousands of lives their work must've saved across the world.

[No Balls Like Snow Balls]

Blimey, that really is quite a statement

With greater understanding of the physics involved - notwithstanding the ever-increasing power of super-computing - the 5-day forecast today, is as accurate as the 1-day forecast, 20 years ago.

That's with the same 'weather' - it's not some new, easier-to-read weather.

So science has evolved; our understanding has evolved, and as has the technology at our disposal. There are some processes and phenomena which are still in the infancy of understanding, and as this improves further with more research, it's these advances which correlate through to greater accuracy.

Personally, I think some people expect too much; viewing these charts out in the 5-10 day range, wonder why they hardly ever verify, then bash the models. Laughably, some even look beyond 10 days. The verification scatter plots for all models post 5/6 days are hilarious. The goal for this decade, will be to extend that confidence out to the 7 to 10-day range - at least.

Look at the Japanese. This year they on-boarded the worlds' most powerful meteorological super-computer: 847 TFlops! That'll deliver to the JMA capability for higher-res, more layers, increased range and greater scope to calculate new variables - all resulting in more accurate, detailed forecasting. That power doesn't come cheap though: $1Bn investment by JMA, hence the respect Exeter has for them. I've actually heard that UKMO and JMA will be working together to develop a brand new experimental platform by 2014, with a view to roll-out onto the UKMO's newest super-computer in 2017. I think it's going to be something along the lines of a massively scaled-up, continental UKV, with multi-member ensemble support. That's what I've heard anyway.

The demand and importance for accurate weather and climate forecasts has never been higher; not merely to provide a good public service, but because so much of business - the success and failure - rests on solid accuracy. The Met Office make a tidy sum from licensing their UKMO base platform to meteorological agencies worldwide, and they also supply bespoke services to private companies and institutions. Beyond that though, or more - beyond borders - there's been a suggestion that worldwide meteorological super-computing could be harnessed, therefore delivering a game-changing array of forecasting suites. I very much doubt that will happen any time soon though, for a number of reasons - even though the benefits are admittedly exciting.

A lot of people knock The Met Office, but the proof is in the pudding: in this tough financial climate, 'the Brits' are the preeminent world leaders in meteorology. Other meteorological agencies procure their services, and - if you read as many papers as I do - you'll see that they're frequently referenced, when it comes to peer review and due respect. They're one government agency that the British people can be thoroughly proud of, and I can't imagine how many thousands of lives their work must've saved across the world.

The weather has and always will do something unexpected and go against all the rules, a computer model will never be able to expect the un-expected, there is nothing greater than mother nature. There has been numerous occasions where a forecast 24 hours prior to an event has been wrong, the weather "owns the models" not the other way round so to speak. I stand by my statement.

Edited December 21, 2012 by No balls like Snow Balls