Winter Model Discussion - Cold Hunting -23/12/12

[IDO]

You can't assume that the 'pending SSW' will reverse the situation. It is not a guarantee that even if it develops as suggested that it will see cold air displaced to the mid-latitudes. The starting point will be from the worst possible position, with a deep PV over Greenland and established stagnant HP over Europe.

Agree totally. But a long wave pattern change will happen, however that does not preclude us from still being on the wrong side of the block for cold, in the aftermath.

Edited December 29, 2012 by i'm dreaming of...

[-uksnow-]

What i like about the GEFS today is that the trend from yesterdday to bring in cooler uppers is still there, if not more prominent. This is also showing up ont the ensembles with it dropping away during the latter stages of the run.

Could someone please link to the MJO forecasts?

[lorenzo]

Hard to be positive this morning, the PV over Greenland is as large and as intense as anything seen for some of the mildest winters over the last 25 years, and the NAO/AO strongly positive, despite suggestions that the reverse should be happening.

It will take a seismic shift to see a change in fortunes.

Good job we have seismic just around the corner then ...

EP flux really picking up this morning, more importantly poleward and reshuffling the NH Deck. Both charts here stratosphere then trop, the strat. chart looking more like the trop charts from earlier this month usually EP vectors are quite timid on these charts.

Time series for EP Flux shows the spike similar to earlier in the season, whilst boding well for the North, this time round looks more favourable for all with greater amplitude.

GFS languishing with MJO plots at present, out of sync with other models so looking at UKMO and ECM run, UKMO still most bullish and introduces phase 7 earlier. GFS remains in phase 3 hence the continued massive edge to zonal.

No denying the fact the PV has set up camp exactly where we do not wish it to be for the conveyer belt of LP systems, sting jets to boot another rotating round the Iceland trough and inbound overnight for us up here after a blustery night Friday.

S4 Lancia posted 2 charts from meteo GFS run in FI and the remnant PV is dispatched inside 5-6 days with temps of -80 at 10 hpa usurped by another warming phase within 120 hours, so another re-shuffle of the deck.

It has been a slow grind getting through this heavily positive NAO phase and the fortnight of model watching combining with the festive period I think has extended the frustrations of many. As we approach New Year we have the Atlantic blowing itself out hopefully the Vortex being obliterated, MJO tilting to more favourable OLR for Rossby wave set ups and perhaps just perhaps some notable cold mid month onwards.

Without these other factors I think the cause for despondency would be even higher and there would be no box of straws to go clutching in, still there are other teleconnections that point to a different outlook, just some final patience required until we see the patterns change.

Edited December 29, 2012 by lorenzo

[Jason M]

I tend to agree with the sentiments this morning. Watching the latest GFS roll out in its full horror, its going to take something astonishing to get out of this hole.

It's one of those situations where we are looking at 15 days min and I suspect this time next week people will still be talking about the strat and the we will still be looking 15 days ahead only with a new target date of around 20th Jan and on we go.

In the interests of balance there are a couple of straws late on in the ensembles but other than that its very difficult to find any evidence of height rises at high latitudes. Plenty of Iberian highs in the output and a good few mid lat euro highs which would sink anyway.

Jason

[BLAST FROM THE PAST]

Its only dire if one believes the model output into deep FI, what's to say they are right and that there isn't a change afoot? 06z maybe already showing subtle differences leading to bigger changes? I watched a programme the other day re the Feb 2009 event....quote MetO had to change update their LRF as a SSW lead to a hemispheric pattern shift at fairly short notice leading to arctic air spilling from NE Model output can change swiftly and we don't have to look back beyong 25 years to see that occurring either! Just to add that this disturbed pattern has been anticipated by some way back so its actually nice to see.

BFTP

Edited December 29, 2012 by BLAST FROM THE PAST

[TEITS]

As +384 now takes us to mid Jan i've been hoping for some potential to be shown on the GFS runs.

Unfortunately that isn't the case on the 06Z with more of the same i.e No N blocking, Strongly positive NAO

[Weathizard]

So frustrating looking at the end of this run because that strong high south of Greenland just wants with all its might to ridge north but the polar vortex is just too mighty and strong. Very zonal runs but cool zonality towards the end. Anyway this is all FI I'm just looking for trends, at least the AH is weak/not there.

+ the strat warming is a lot better of Greenland on this run so if its going to help us then it could do it that way.

[Bobby]

As +384 now takes us to mid Jan i've been hoping for some potential to be shown on the GFS runs.

http://modeles.meteo...snh-0-384.png?6

Unfortunately that isn't the case on the 06Z with more of the same i.e No N blocking, Strongly positive NAO

That vortex around Greenland is just pumping cold air into the Atlantic fuelling the Atlantic freight train, look how cold the uppers are over the N. Atlantic.

I can't see much end in sight until it clears off, hopefully the SSW will do it but that's a big if at the moment.

[mulzy]

Despite the "seismic" SSW event, the NWP not showing anything remotely cold/snowy. If anything the PV over Greenland and Azores/Euro High pressure scenario is being further re-enforced.

I guess we need patience...

Edit: This morning's ECM London Ensembles are significantly worse than last night's.

Edited December 29, 2012 by mulzy

[cooling climate]

Hard to be positive this morning, the PV over Greenland is as large and as intense as anything seen for some of the mildest winters over the last 25 years, and the NAO/AO strongly positive, despite suggestions that the reverse should be happening.

It will take a seismic shift to see a change in fortunes.

No one said the reverse should should be happening yet. It is six days still until we get any strong warming over the pole at the 10mb level another 3 days after that until we see this showing up

at the 30mb level. That is 9 days and then it has to propagate down into the troposphere and onto the H5 models hopefully.

Allowing several more days for this and you are looking at the middle of the month at the earliest

with the strongest effects felt during the latter part of January and through February.

Whether we are in the right local for the blocking remains to be seen but the blocking will be there.

Edited December 29, 2012 by cooling climate

[swfc]

Its only dire if one believes the model output into deep FI, what's to say they are right and that there isn't a change afoot? 06z maybe already showing subtle differences leading to bigger changes? I watched a programme the other day re the Feb 2009 event....quote MetO had to change update their LRF as a SSW lead to a hemispheric pattern shift at fairly short notice leading to arctic air spilling from NE Model output can change swiftly and we don't have to look back beyong 25 years to see that occurring either! Just to add that this disturbed pattern has been anticipated by some way back so its actually nice to see.

BFTP

hi bftp.Im guessing fi in anybodys eyes is just that.Would you be of the same opinion if it by some monumental change showed a major cold outbreak this evening on the 18 z or tom oz????.Thanks

[Ian Brown]

No one said the reverse should should be happening yet. It is six days still until we get any strong warming over the pole at the 10mb level another 3 days after that until we see this showing up

at the 30mb level. That is 9 days and then it has to propagate down into the troposphere and onto the H5 models hopefully.

Allowing several more days for this and you are looking at the middle of the month at the earliest

with the strongest effects felt during the latter part of January and through February.

Whether we are in the right local for the blocking remains to be seen but the blocking will be there.

I agree that allowing for time lag then any changes would not be necessarily apparent in the outer reached of the NWP at this stage. However, the starting point for any changes will be from the worst possible position, I would think that should we begin to see erosion of the PV over Greenland, by the time the set-up has switched to perhaps a more neutral NAO position, we would then be open to further (possibly unfavourable) developments further down the line.

[Jason M]

Watching the ensembles roll out to 192 and a subtle difference this time. The push of warm air is going a lot further north beyond Iceland on a fair few of them. Day 10 onwards might be more interesting this time as this should logically support heights over scandi.

Jason

Edited December 29, 2012 by Jason M

[bryan629]

Its only dire if one believes the model output into deep FI, what's to say they are right and that there isn't a change afoot? 06z maybe already showing subtle differences leading to bigger changes? I watched a programme the other day re the Feb 2009 event....quote MetO had to change update their LRF as a SSW lead to a hemispheric pattern shift at fairly short notice leading to arctic air spilling from NE Model output can change swiftly and we don't have to look back beyong 25 years to see that occurring either! Just to add that this disturbed pattern has been anticipated by some way back so its actually nice to see.

BFTP

HI BFTP

just a quick note....that programmes is on MORE4 at 6.50 again tonight, gave a good illustration of how quickly a SSW changed the weather pattern. Incidently the programmes followed by an hour long `` is our weather getting worse`` documentary.....i suppose you could ask the same thing about the models of late

[Frosty.]

Anyone thinking of going mountain climbing or skiing in scotland tomorrow should think again, it looks like blizzards for the higher routes tonight and tomorrow with gale force westerly winds and heavy snow, the higher levels will probably become impassable due to drifting snow. The models show a change from the middle of next week with the weather settling down, but in the meantime, be careful if you are going skiing in the scottish mountains as conditions will be dangerous.

[Cloud 10]

I've read a lot this morning about the strongly positive AO/NAO phase we are in at the moment

but i am struggling to find it?

AO.. NAO..

Have we somehow jumped back in time to the 90's?

AO.. NAO..

[Polar Maritime]

Yes Frosty some horrendous weather Scotland/N England over the next 48 hours, Storm force winds and blizzards down to 500m in the Scottish mountains, giving white-out conditions. V dangerous life threatening conditions.

A 60yr walker is still missing on the Cuillin Ridge (isle of Skye) since last night... i hope they find him before this front moves in...

[Frosty.]

Yes Frosty some horrendous weather Scotland/N England over the next 48 hours, Storm force winds and blizzards down to 500m in the Scottish mountains, giving white-out conditions. V dangerous life threatening conditions.

A 60yr walker is still missing on the Cuillin Ridge (isle of Skye) since last night... i hope they find him before this front moves in...

Fingers crossed they find him safe PM.

This change from mild to cold and snowy in the scottish highlands could catch some people out, so be safe everyone.

[That ECM]

As +384 now takes us to mid Jan i've been hoping for some potential to be shown on the GFS runs.

Unfortunately that isn't the case on the 06Z with more of the same i.e No N blocking, Strongly positive NAO

Good afternoon. Not the most popular first post me thinks but I believe patience is required before we see changes in the daily model output. The SSW is still 7/8 days away. The output will change if the SSW does prog and if it does the output will reflect this. Will it be somewhere in main land Europe or over us? Again this will take time to see.

So, as I said at the beginning, patience needed which is very difficult when we are watching run after run showing little of interest for those wanting winter.

Regards.

That ECM.

[mountain shadow]

The 0z GEFS had two cold runs in FI, the 6z has 3/4.

A good sign and hopefully an Op run picks one up soon.

[bluearmy]

The 0z GEFS had two cold runs in FI, the 6z has 3/4.

A good sign and hopefully an Op run picks one up soon.

Sypnotically, I liked the 00z gefs better. The control is one of the colder solutions on each run. Still to early to be taking anything from this tool but I it's better than seeing no cold members at all!!

[thesnowman]

As +384 now takes us to mid Jan i've been hoping for some potential to be shown on the GFS runs.

http://modeles.meteo...snh-0-384.png?6

Unfortunately that isn't the case on the 06Z with more of the same i.e No N blocking, Strongly positive NAO

You evaluation is spot on TEITS, we are definitely now looking out beyond Mid January for anything remotely cold,

My concern is that with lengthening daylight hours, and the total LACK of cold in WESTERN EUROPE, the continent will not now hold onto deep cold if it arrives, the outlook is extremely bleak for anything cold in the winter 2012/2013

[Froze were the Days]

Still very poor outputs in terms of cold, the only straw which can be clutched is the heights close to the UK at the end of next week and the possibility of growing heights near Scandanavia but this will probably only be a temporary blip before the Atlantic rolls in and a stronger jet stream to our north west again becomes established.

[snowking]

I agree that allowing for time lag then any changes would not be necessarily apparent in the outer reached of the NWP at this stage. However, the starting point for any changes will be from the worst possible position, I would think that should we begin to see erosion of the PV over Greenland, by the time the set-up has switched to perhaps a more neutral NAO position, we would then be open to further (possibly unfavourable) developments further down the line.

Ian I hear what you're saying, and in the never to be mentioned period in the 90's, we would expect such a pattern to continue rolling.

However, to suggest a strong PV over Greenland means that is unlikely to change within a matter of weeks....well lets test that theory against some of the coldest winter periods.

Cold Spell 1. December 2010.

Heres how things looked a few weeks before:

and:

Strong PV lobe over Greenland and into the Atlantic, yet just a few weeks later:

I'd settle for that.

-----------------------------------------

December 2009/Jan 2010

A pretty extended cold spell, so lets take a look back to November 2009:

Not as strong as we are looking at now, but still PV in a central location and into Greenland.

The results:

--------------------------------------------

February 2009 - a shorter cold spell yes, but a very good example of a PV turnaround.

Mid Jan:

Ominous to say the least, that then turned into this:

As previously said, not the most potent cold spell, but the most notable easterly for some years up to that point, and from an even worse looking PV situation than we have presently.

--------------------------------

Feb 2005 - not the best cold spell, it was more of a 'nearly' type cold spell. But from memory, we had snow fall here every day for 17 days, with some slight accumulations (the lateness in February didn't aid accumulation, but did aid convection)

It all came from this:

And became this:

-------------------------------

Feb 1991 - a very good example of what I will coin Rubbish Situation Reversal (RSR)

Heres Jan 1991:

Yuk. Had the internet have been as widely accessible as now in 1991, Nick's Prozac hotline would have been frantically mixing in some caffeine and sugar.

That became this:

------------

Jan 1987 - considered one of the most severe cold spells across Southern England of all time.

Here was the pretty dire picture before hand:

And then:

-----------------------

Jan/Feb 1979 - a pretty cold winter throughout, but some notable periods of RSR, for example, going from this:

To this:

The most notable thing here is the continued cold despite a strong PV over the arctic.

-----------------------

1978

Went from this:

To This:

(It should be noted, there was plenty of Cyclonic cold in between these dates too, but this is the best illustration of the RSR)

----------------

And then of course, the two big ones.

1963

From this:

To this:

And this:

----------

1947

To this:

--------------

So, we see that during ALL of the winters with major cold outbreaks, we have a period of intense vortex activity centred close to or over Greenland around 2-4 weeks before the onset of cold. Now this isnt saying that every time we have an intense vortex over Greenland we will get a cold spell, but it certain dispels the myth that we cannot turn around a terrible situation and a very strong +NAO.

The dates for which we have readily available stratospheric data, with RSR following, are as follows:

14 Nov 2010

27 Nov 2009

12 Jan 2009

16 Jan 2005

08 Jan 1991

07 Dec 1986

Of those dates, the following had Stratospheric Warming (not necessarily an SSW) just starting to take shape:

27 Nov 2009

12 Jan 2009

16 Jan 2005 (VERY slight)

08 Jan 1991

07 Dec 1986 (VERY slight)

So some weak correlation from a limited data set between vortex intensification and Stratospheric Warming too.

Hope thats useful

SK

[bluearmy]

You evaluation is spot on TEITS, we are definitely now looking out beyond Mid January for anything remotely cold,

My concern is that with lengthening daylight hours, and the total LACK of cold in WESTERN EUROPE, the continent will not now hold onto deep cold if it arrives, the outlook is extremely bleak for anything cold in the winter 2012/2013

in all the years I have been on this forum, I have never put anyone on 'ignore'. I need to congratulate you on being the first. I note you don't have a location in your avatar. You don't live in Dawlish by any chance?

Your posts are so negative with no evidence to support vague nonsensical statements. Last jan was similarly mild in eastern Europe and last feb was the coldest period for decades. Many parts of France saw a well below zero mean temp for the first tow thirds of feb. At least I won't have to read your rubbish any longer.

we may well see a mild winter overall. No one knows, least of all you. Why not put some evidence down like Ian does. I have no opinion on what the second half of jan and feb have in store.