Model Output Discussion - 19th - 25th December

[Frosty.]

come on guys it's obvious that ian brown is going to be right most of the time as uk winters are normally mild with prevailing swly winds as we have now, and hes right about how mild it has become and will continue to be right until the 500 mb anomoly charts change. The best we can hope for is a bit of upstream amplification with shortlived mid atlantic ridging with the jet becoming more west to east or nw/se if we are really lucky. It's much harder to predict cold and snow and be right, james madden is a good example of a cold ramper living in his own little fantasy world where it snows all the time.

[legritter]

we all know the high pressure to our south and s/w could be around for a long time ,BUT 10 DAYS from now it might just pack up its bags and equally disappear . the models are starting to show us possible outcomes , i cant see mild temp plaquing N/W europe for much longer ,as i said months ago , im sure this winter will be a quick change artist , just look at the potential weather over northern uk this week ,theres plenty of action taking place , so mild dross at the moment because mother nature SAYS SO ,but mother nature is full of surprises ,for you new ones , dont take to much notice of changing end charts as these are so hard even for a super computer ,but take notice of a run of consistant charts ,singing of the same hymn sheet , dont listen to anyone who tells you that the nights are getting longer and snow wont lay , have a good look at historical charts , this is a brilliant forum , gfs about to finish run soon , wonder what change there is on last 3 days of run cheers legritter .

[NorthYorksWeather]

Merry Christmas all!

Well at first glance the models don't look too promising for cold lovers in the short term, a quick scan through the ensembles in the latter stages (FI) give me a glimmer of hope. People may say its FI it will change bla bla but its christmas and this cheered me up here we go

Control Run 348 hours:

A nice northerly toppler!

P1 216

Cold North Westerly with snow in Northern areas

Another cold shot towards the end

P2 372

High ridging up to Greenland sending us a cold northerly

P3 384

Pressure rising over Greenland with a possibly link up to the Azores high.

P5 372

1055MB over Greenland, not sure what would happen from here but looks better than what we are seeing at the moment.

P6 348

Cold North Westerly as the Azores high tries to ridge to Greenland but fails.

P7 372

Textbook Northerly

P8 372

High linking up into West Greenland, if the block holds this would be good.

P9 288

Brief Northerly Toppler

P10 384

Another good looking end to the run yet again a block forming in the Atlantic and up into Greenland.

P12 372

Not sure about cold with this one but certainly looks interesting!

P13 276

Brief Toppler!

P14 384

Another Northerly shot.

P15 360

Same again!

P16 276

Nice Northerly!

P17 264

Brief Northerly/ Nor Easterly as a ridge topples.

P19 348

Promising looking chart!

P20 348

Cold North Westerly

This may change on the 18z and i admit there's no sign of any major sustained cold spell in the models but this shows there is certainly a pattern change coming soon for the better. hope everyone's had a nice Christmas and heres to a snowy 2012

[Grimsby Snow Lover]

A really feastive post there Vizzy, thanks for looking through the different ensemble charts and illustrates perfectly how our current weather pattern could change in a week or twos time.

Edited December 25, 2011 by Grimsby Snow Lover

[lukemc]

Hello again,

I haven't posted on this forum for a while but I am just making the point Ian that the "christmas pudding" does not exist - that was proven wrong by the last two winters - I remember you saying a few years ago that you said that "another winter like 1995-96 would not be possible anymore" - and how proven wrong were you on that - as we had the coldest winter since 1978-79 (1962-63 in Scotland) in 2009-10 and the coldest December for over 100 years last December - so if they can happen in a so called "christmas pudding" - surely they can happen again. Climate varies naturally - and we have been putting CO2 into the atmosphere for over 100 years so if that was true the effects would have been noticeable a long long time ago. I know many on hear find Ian Brown's posts annoying but there was a poster on another forum (TWO) who believes that the last two winters were just a fluke and winters are going to get milder and milder - and he also quoted that "if there is another 1962-63 in his lifetime, he will run naked down Oxford Street" - IMO and this is my personal opinion only, that is a whole load of nonsense - guys - and I am directing this at the cold lovers on here especially - many of you "coldies" on here find Ian Brown's post annoying but compared to that poster is is pretty benign - not saying that I agree with Ian's posts in any way but IMO we will have a good shot at cold and snow in the new year and I think the models will firm up on it soon. Merry Xmas to you everyone aswell!

Luke

[bluearmy]

Vizzy - most of those ens shots are brief northerlys which will probably be flattened a fair bit by the time they get below T144 as shortwaves appear which the models fail to pick up at two weeks timescale.

We need to see proper blocking in high lattitudes which will change the pattern from it's current zonal state. There are clues out there. ECM at T240 has a mean ridge into se Alaska and also just east of svaalbard. They may well be brief and caught up in the zonal flow but they do present chances of WAA which would help to change the pattern.

Also, we have recently seen the northern arm splitting some energy south as exits the eastern seaboard at the end of the naefs runs. What is also noticeable is the same thing happening in the pacific. I guess the fact a strongish ridge is shown in the west of north America in a couple of weeks ties in with a general drop off in the strength of the jet upstream.

[Jason M]

Dave, I think the stats show that the theory was not cobblers. Of course, you are right that the pattern is nothing new, but like yourself my experience is drawn from the late 70s onwards, so I use the era we know so well as the example.

Don't get me wrong - I believe we will see changes in the flat pattern but not necessarily ones that are going to benefit the UK cold wise, we could see these changes in 'FI' in the coming days.

Hi

For what its worth my money is on the Azores high ridging north but settling over us (after possibly a brief 'toppler') with the jet riding over the top. From that point its 2 weeks until it sinks south again and the status quo returns. Is that what your driving at Ian?

Its not unusual for us to get periods of zonality, but this situation is a bit more extreme as its a full on entrenched Bartlett set up along 88/89 lines. The outcome may be different, but from where we are currently it would be a brave person who bets against a winter in the 'very mild' category.

At this point i'm hoping GP or someone similarly learned is going to correct me. I draw my conclusion from years of interest rather than expert knowledge, it just seems to me the logical way forward. This does mean of course that the near continent would see some very cold weather next month, but this can lead to the holland ECM ensemble suite giving a very misleading picture as far as were concerned.

My son got a sled for Xmas today, so i'm really hoping i'm wrong on this! I also stress that this post isn't a dig at anyone as i do recognise others here see opportunities arising from the strat warming forecast or more generally from looking at the top down NH view and i respect these views (and hope they are right!).

Jason

[legritter]

HEAR HEAR , some good posts ,everything to play for , whats lurking around the next corner ,looking foreward to tomorrows runs perhaps a bit of firming up on the way cheers ps happy christmas ,let it snow , let it snow ,let it snow ,

[Grimsby Snow Lover]

I might be wrong but towards the end of the GFS run does this not show a much weaker PV?

http://hw.nwstatic.co.uk/gfsimages/gfs.20111225/18/372/npsh500.png

[phil nw.]

Happy Xmas to you all on Netweather. Sorry for my absence of late I've been really busy but to be honest the models have not been awe inspiring lately. As for tonight's output the ECM does present a crumb of comfort at day 10 but until that 1040mb high pressure belt out to the SW loses it's influence it's curtains for meaningful cold for the UK.

I have to agree with this.

All the midlatitude blocking modelled is as a result of the persistent low heights particularly over Greenland and our side of the Pole.

I think it`s perhaps the Xmas spirit that has affected model viewing today.

There is no evidence of high latitude blocking on the models --including FI.

What you see is the Vortex repositioning and and reorganising itself over the Pole.

In time we look like getting the flow more North of West occasionaly but apart from transient ridging there`s no real cold setup in the pipeline in current modelling.

.

[Snowstorm1]

Now FI or not this has firmly caught my attention thats is now 4 or 5 runs in a row by the GFS which has produced some decent cold hitting the UK surely this now has to be classed as a trend things are indeed looking up for us cold lovers but a hell of a rollercoaster is just beginning so strap in for the ride!

[NorthYorksWeather]

Vizzy - most of those ens shots are brief northerlys which will probably be flattened a fair bit by the time they get below T144 as shortwaves appear which the models fail to pick up at two weeks timescale.

We need to see proper blocking in high lattitudes which will change the pattern from it's current zonal state. There are clues out there. ECM at T240 has a mean ridge into se Alaska and also just east of svaalbard. They may well be brief and caught up in the zonal flow but they do present chances of WAA which would help to change the pattern.

Also, we have recently seen the northern arm splitting some energy south as exits the eastern seaboard at the end of the naefs runs. What is also noticeable is the same thing happening in the pacific. I guess the fact a strongish ridge is shown in the west of north America in a couple of weeks ties in with a general drop off in the strength of the jet upstream.

Yes i agree most of them are quick topplers but il happily take them after the winter so far. Like most not a snowflake so far this winter. Was just trying to add some Christmas cheer into the MOD thread.

I see 18z is also hinting at a Northerly in FI. Plenty of mild mush and some brief Pm colder incursions in northern areas to enjoy first

[lukemc]

Hi

For what its worth my money is on the Azores high ridging north but settling over us (after possibly a brief 'toppler') with the jet riding over the top. From that point its 2 weeks until it sinks south again and the status quo returns. Is that what your driving at Ian?

Its not unusual for us to get periods of zonality, but this situation is a bit more extreme as its a full on entrenched Bartlett set up along 88/89 lines. The outcome may be different, but from where we are currently it would be a brave person who bets against a winter in the 'very mild' category.

At this point i'm hoping GP or someone similarly learned is going to correct me. I draw my conclusion from years of interest rather than expert knowledge, it just seems to me the logical way forward. This does mean of course that the near continent would see some very cold weather next month, but this can lead to the holland ECM ensemble suite giving a very misleading picture as far as were concerned.

My son got a sled for Xmas today, so i'm really hoping i'm wrong on this! I also stress that this post isn't a dig at anyone as i do recognise others here see opportunities arising from the strat warming forecast or more generally from looking at the top down NH view and i respect these views (and hope they are right!).

Jason

But last year when we had the very cold December you could also say at the time it would be a brave person to bet against a winter in the "very cold category" - e.g. a winter riveling 1962/63 or 1946/47 but look what happened - we ended up with a mild second half of the winter rather than a cold one cumulating in one of the mildest Februaries for a while - I would say that just like last winter turned mild in the second half you cannot discount the possibility of this winter turning colder in the second half - what you have got to realise is that 1988/89 is to mild winters like 1962/63 is to cold - it is extreme and is a rare occurance in or climate - we are talking extremes here - the former mild, the latter cold. Just my logic coming into play here as I am a logical person.

Luke

[feb1991blizzard]

Not a bad GFS FI, and i dont mean from a PM / toppler IMBY perspective, rising heights over the polar regions and over a wider area this time, following on from bluearmy's post though, the best way to view the GEFS from a cold perspective is to not just look at the spread on the graph, we really need to see as many individual members as we can getting close to the -10c 850hpa line or even below for a considerable time and not just for one day, this would imply potential strong blocking to the east or the North and not just brief affairs.

[bluearmy]

Whilst I keep going on about positive events in deep fi over the high latitudes, I would caution expecting too much from the amplification shown beyond T240 by many recent gfs op runs. Experience tells us that these are usually flattened somewhat as the days tick by unless the overall strong flow is checked upstream somewhat.

[Jason M]

But last year when we had the very cold December you could also say at the time it would be a brave person to bet against a winter in the "very cold category" - e.g. a winter riveling 1962/63 or 1946/47 but look what happened - we ended up with a mild second half of the winter rather than a cold one cumulating in one of the mildest Februaries for a while - I would say that just like last winter turned mild in the second half you cannot discount the possibility of this winter turning colder in the second half - what you have got to realise is that 1988/89 is to mild winters like 1962/63 is to cold - it is extreme and is a rare occurance in or climate - we are talking extremes here - the former mild, the latter cold. Just my logic coming into play here as I am a logical person.

Luke

Hi

Time will tell

88/89 was extreme, and this winter may or may not surpass that! but its far more common for the UK to have largely snowless Winters than it is for us to get a 62 type winter. Whilst I understand your analogy with last December i dont think its valid in this case. Had we just had a 'mild' December i would agree that it cant be seen as a guide to what will happen (and frankly a mild Dec is the norm anyway). The reason I think this is different is the pattern were in. People on these forums react in horror to the 'B' word being used and rightly so in my view as a Bartlett set up is an absolute nightmare for those of us who want cold weather, simply because in the words of the old Ariston adverts it goes on and on and on and.................. .

Jason

[Zakos]

FI or not, the GFS has been consistent with the idea of a northerly in mid jan. Some of the FI charts over the last couple days have shown powerful northern blocking. This was (correct me if I am wrong) never shown earlier in december or november, even in the deepest of FI. The northern blocking is by no means certain, but it is looking much more likely than earlier on in the month IMO.

[Grimsby Snow Lover]

FI or not, the GFS has been consistent with the idea of a northerly in mid jan. Some of the FI charts over the last couple days have shown powerful northern blocking. This was (correct me if I am wrong) never shown earlier in december or november, even in the deepest of FI. The northern blocking is by no means certain, but it is looking much more likely than earlier on in the month IMO.

I would agree that the charts in FI are looking more favorable if cold weather is your thing,but I wouldn't use the term 'northern blocking' just yet as the pattern is not really blocked and is still mobile, if with a more southerly tracking jet. However, like we have seem in previous years GFS especially likes to bulldoze through any blocking shown in deepest FI. A new trend looks to be starting in about 10 days times, lets hope it only improves as time progresses.

[SMU]

Evening All -

I see nothing ever changes on here.......

Anyway a Couple of changes on Meteociel today- Thanks Sylvian!!!

Ensembles in NH form

http://www.meteociel...&mode=0&carte=1

now when we get those exciting FI runs we can see the full picture!

Also the NH Stratospheric temps as well

http://www.meteociel...0&ech=6&carte=1

Looking as things stand- its not very exciting-

The Approximate propergation time of a stratospheric warming event to downwell is around 16 or so days-

Im putting a Marker on around the second week of Jan for things to start to change & get some breaking of the vortex to the north....

Finally theres no such thing as a even larger teapot- it tarnishes the forums with utter nonsense-

As keeps being said- where was the even larger teapot on this day-

http://176.31.229.22...18-0-132.png?18 this winter just gone

http://91.121.94.83/...318-0-36.png?18 or the winter before-

The current pattern is poor, however it will break...

S

and finally - A even larger teapot special last year-

http://176.31.229.228/modeles/gfs/archives/gfsnh-2010121418-0-48.png?18

Edited December 25, 2011 by Steve Murr

[bluearmy]

Just to finish off the day - the ens mean T384 on GEFS has Scotland in uppers below -4c. The upstream jet looks to be taking a battering with a bit more energy headed south off the eastern seaboard. Looking at n America overall, I might suggest that the northern arm could be weakening to the extent that it drops out completely come mid jan. That maybe rather premature but given where we are at the moment, it's quite a shift within a couple of weeks.

[Bobby]

The pattern looks a fair bit less flat than we've seen recently in FI on the ensemble mean, the atlantic freight-train starting to run out of steam perhaps.

Edited December 25, 2011 by Barb-

[TEITS]

Dave, I think the stats show that the theory was not cobblers. Of course, you are right that the pattern is nothing new, but like yourself my experience is drawn from the late 70s onwards, so I use the era we know so well as the example.

Surely though Ian the cold spells in 09/10 prove it was cobblers. When I joined this forum I was told that N blocking was a thing of the past and that Dec 2010 type cold spells would never be seen again. Obviously this was proved incorrect and infact I would say synoptically the cold spells in Nov/Dec 2010 were probably the most impressive ever seen, for the months of Nov/Dec I hasten to add.

The Max temp on the chart below in Peterborough was an incredible -8C!

http://www.wetterzen...00120101220.gif

Edited December 26, 2011 by THE EYE IN THE SKY

[cooling climate]

Surely though Ian the cold spells in 09/10 prove it was cobblers. When I joined this forum I was told that N blocking was a thing of the past and that Dec 2010 type cold spells would never be seen again. Obviously this was proved incorrect and infact I would say synoptically the cold spells in Nov/Dec 2010 were probably the most impressive ever seen, for the months of Nov/Dec I hasten to add.

The Max temp on the chart below in Peterborough was an incredible -8C!

http://www.wetterzen...00120101220.gif

You should have asked someone for a new thermometer for

christmas. Your one is obviously broken lol.

[Mark Neal.]

Hi Guys, Hope you all had a great christmas, it seems for a few runs now, we are seeing signs of a potential change on the horizon. Definately makes for more pleasureable viewing for snow/cold lovers like myself. This mild weather will soon be gone and snowstorms will batter the country. One good way to confirm that a cold spell is on the way is when Daily Express start saying spring is coming earlier..

[Nick L]

You should have asked someone for a new thermometer for

christmas. Your one is obviously broken lol.

It WAS that cold though.