Winter Model Discussion - The Hunt For Cold -18z 17/12/12

[Panayiotis]

At T120 the GH is strong no?, stronger than than the UKMO and ECM, this can only be a good thing.

I don't understand how this is not considered blocking?????

Its not considered to be blocking as the high has come from the Arctic and not the Azores. If we have the Azores ridging into Greenland this acts as a wall to stop ant incoming lows. If this high say linked up with the Azores (very unlikely however in this case) you would see a blocked pattern.

It's a surface high; Greenland is so cold that whenever there is not a low pressure system moving across, pressure builds rapidly at the surface due to the dense cold air. Any low pressure apporaching that high will break through easily. You need to see more green and orange on that chart which would indicate a high pressure with more depth which would be able to withstand the approach of a low pressure.

Very good knowledge but i think he was referring to the 'yellow' just west of Greenland? Edited December 20, 2012 by Panayiotis

[Southender]

As a learner this is the way I see things.

The Atlantic will keep throwing LP systems at us as there is next to no blocking.

The Russian HP will move and East and West over the next couple of weeks (At least).

This will allow some of the Atlantic systems to pass through, but others not.

The PV is pretty much doing the same. It is trying to transfer East and does make it at times. Before being sent packing back to the GIN corridor again, mainly due to the Russian HP.

This basically prevents any proper ridging building in the Atlantic and up to Greenland.

Add to that the Iberian HP which seems to be a stubborn wotsit as well, Is preventing any Atlantic systems taking a dive SE.

All in all its a pretty bleak outlook until the New Year. With any cold blasts being temporary from the N/NW. We just seem to be stuck in a horrible rut and the boundary line between cold and mild/average conditions.

As I said I am still learning. But that is what I see. Apologies if I am reading things incorrectly. Let's hope for something to change as we enter the new year. As unfortunately until then, this horrid pattern looks locked in.

[mcweather]

Although this is the model discussion thread, I must admit I can't see the point of over analysing every run especially the GFS when its start data is only six hours older than the previous set.

For my part I,m quite happy to go along with GP'S winter forecast. His latest post in that regard was that he thought things could start to get interesting from around 10th January. Which means that any really interesting charts with regard to that will probably not show until a weeks time at the very earliest.

Probably best to just sit back and let Christmas wash over you ( which with all this rain is all its going to do anyway) and come back between Christmas and new year when we might just might start to see some interesting elements being picked up in FI.

Speaking as someone the wrong side of 50, experience has taught me that the one thing you need in most British winters is patience, often that patience will be rewarded at some point.

Edited December 20, 2012 by mcweather

[latitude]

As a learner this is the way I see things.

The Atlantic will keep throwing LP systems at us as there is next to no blocking.

The Russian HP will move and East and West over the next couple of weeks (At least).

This will allow some of the Atlantic systems to pass through, but others not.

The PV is pretty much doing the same. It is trying to transfer East and does make it at times. Before being sent packing back to the GIN corridor again, mainly due to the Russian HP.

This basically prevents any proper ridging building in the Atlantic and up to Greenland.

Add to that the Iberian HP which seems to be a stubborn wotsit as well, Is preventing any Atlantic systems taking a dive SE.

All in all its a pretty bleak outlook until the New Year. With any cold blasts being temporary from the N/NW. We just seem to be stuck in a horrible rut and the boundary line between cold and mild/average conditions.

As I said I am still learning. But that is what I see. Apologies if I am reading things incorrectly. Let's hope for something to change as we enter the new year. As unfortunately until then, this horrid pattern looks locked in.

Good post. In effect we need Greenland High Pressure so we can get a decent chance of a sustained cold spell. Without Greenland High pressure we are just stuck in the rut as you pointed out very well. Anything else will just be transient.

[Matty M]

well there ye have it, we lose the Russian High and things would appear to look muck for the next fortnight+

Never wish away a Russian block.

[Mark Bayley]

There definitely seems a signal to ramp the MJO round to phase 7/8 as we enter January

And from some of the other models

http://www.cpc.ncep....clivar_wh.shtml

Which gives the following two composites

A signal for the NAO to return negative as we progress through the first weeks of January, and the AO

With developments in the stratosphere i think the first 1/3 January is one to watch for something a little colder (and more sustained) to develop. In the near term we have an awful lot of rain to get through, which will no doubt lead to flooding in some areas

I would also look NW for anything colder during the xmas and new year period, as advertised by recent GFS runs (i.e. brief n/nw'rly spells)

Edited December 20, 2012 by Mark Bayley

[nick sussex]

Not much change from the GFS 06hrs run, just a variation on the same theme with lows moving east and a chance of a few colder shots of PM air especially for more northern areas.

The energy spilling east is relentless and with the Azores high lurking a bog standard typical set up for the UK in winter.

The ECM ensembles for De Bilt however show a small opportunity around days 9/10 for something a bit more wintry:

There is a colder cluster there and this is probably in relation to troughing digging further se, this is likely to be a response to more amplification upstream caused by a developing low running ne out of the southern states, this could develop a temporary ridge to the nw.

Looking at the temps indicated for De Bilt, I think you can knock off a few degrees for northern areas of the UK given the set up.

I'd suggest we all start praying for that deep low to develop upstream!

For newer members heres what to look for:

Red arrow, low develops running ne towards the western side of Greenland

Black arrow, this sends some warm air north towards Greenland WAA warm air advection there helps develop a ridge

Orange arrow, the ridge places some forcing on troughing near the UK to sink further south and east.

This really is the only way to slow down the low train coming out of the USA and help pull the Azores high further west with the current set up.

Of course the ECM operational run may drop the idea tonight but its about the only thing I can find to talk about today thats remotely interesting!

I should add that NOAA suggest an active weather pattern but differences between the models in terms of the surface features:

A QUICK LOOK AT THE LATER 00 UTC

MODELS SHOWS CONTINUED VARIABILITY WITH TIMING/SPACING OF EMBEDDED

INDIVIDUAL FEATURES BUT CONTINUED SUPPORT FOR THE OVERALL ACTIVE

WINTER PATTERN.

The GFS and ECM differ in their handling upstream and that will make a difference to Europe, the ECM although not as good early compared to the earlier GFS 00hrs is far better at 240hrs in terms of overall pattern.

Edited December 20, 2012 by nick sussex

[EML Network]

Looking through the runs up until + 192, there's some very interesting developments on more than one of them ...in fact I am seeing a 2 way split, with half the members going for something like this (control run at +180)

and the other half going for something more akin to this (again at +180)

I suspect the truth lay's somewhere in between , at least we have something a bit more tangiable now to look forward to other than chasing an Easterly what was never really going to deliver

[Robbie Garrett]

I made a comparison yesterday, check my past few posts!

How do the current synoptics and model outputs compare with those of December 1978? As i remember, a very wet month that turned snowy after Christmas.

[Matty M]

if we are trying to squeeze a weak wnw out of the output it shows how bad things have got. i hope this strat stuff is all its cracked up to be. because we are heading in to an awful awful pattern.

[bluearmy]

mark, that MJO forecast looks very low amplitude which will be unlikely to have any global consequences (IMO). NOAA cpc did remark yesterday that there were signs of the MJO 'coming back to life' so maybe we might begin to see some forecasts of the amplitude increasing . until a strat warming occurs, it seems to me that the main player continues to be a strong atlantic jet and without something substantial happening upstream to it, we are looking at a mobile fortnight ahead with some upland northern snowfall and a possible runner bringing a surprise dump the only bright spots if you are looking for something festive.

[ronan]

if we are trying to squeeze a weak wnw out of the output it shows how bad things have got. i hope this strat stuff is all its cracked up to be. because we are heading in to an awful awful pattern.

Awful for the East or the UK as a whole? Some of my best snowfalls have been from the N/NW so if there's a chance of the odd blast from this direction them I'm happy!

[bradymk]

if we are trying to squeeze a weak wnw out of the output it shows how bad things have got. i hope this strat stuff is all its cracked up to be. because we are heading in to an awful awful pattern.

I disagree that it is an awful pattern Matty. It isnt the good patterns we have seen through first part of the December (although it didnt work out for us) however there is still plenty of potential for PM and northerly shots although these may be transient. After new year, mjo moving into phase 7/8 and also the strat warming. Also, GP said yesterday januarys potenial isnt totally relying on the strat.

[Matty M]

Awful for the East or the UK as a whole? Some of my best snowfalls have been from the N/NW so if there's a chance of the odd blast from this direction them I'm happy!

The whole. This type of set up may provide you a brief 24 hour period of snow showers but it cannot sustain for any length of time with that pattern.

[Matty M]

I disagree that it is an awful pattern Matty. It isnt the good patterns we have seen through first part of the December (although it didnt work out for us) however there is still plenty of potential for PM and northerly shots although these may be transient. After new year, mjo moving into phase 7/8 and also the strat warming. Also, GP said yesterday januarys potenial isnt totally relying on the strat.

Unfortunately no man is a messiah, you speak of GPs forecast as if it is tangible. It is just a mildly educated guess, with a little bit but not much more merit than any other poster on here.

[ronan]

The whole. This type of set up may provide you a brief 24 hour period of snow showers but it cannot sustain for any length of time with that pattern.

To be honest Matty after the let downs that we have had so far I'd take anything! Lol

[Robbie Garrett]

Well so far we are heading in similar tracks, most members don't realise that January/February are our best winter months. The saying white Easter is more than likely than a white Christmas bodes well with this fact.

I pretty much can see either a cold post Xmas blast, then most of January being transient but cool till the onset of the SSW and other conditions make way for a cols end to January and a super cold February.

Following on from that I'm not sure, wet windy and cool!

Ah, yes, sorry Robbie, I missed that due to 'crimbo stuff'. ;-)

I remember it being incredibly wet over the Christmas period in 1978. Similar?

I seem to remember fronts piling up over the country, and then being pushed back south again with cold easterlies just after Christmas (28th/29th?).

Any chance this could happen again?

Here's the chart for 31st December 1978. Extraordinary!

Edited December 20, 2012 by Robbie Garrett

[Mark Bayley]

mark, that MJO forecast looks very low amplitude which will be unlikely to have any global consequences (IMO). NOAA cpc did remark yesterday that there were signs of the MJO 'coming back to life' so maybe we might begin to see some forecasts of the amplitude increasing . until a strat warming occurs, it seems to me that the main player continues to be a strong atlantic jet and without something substantial happening upstream to it, we are looking at a mobile fortnight ahead with some upland northern snowfall and a possible runner bringing a surprise dump the only bright spots if you are looking for something festive.

Yes, most of the forecasts do indicate it remaining in rather low amplitude, with the UKMO perhaps more keen on something eventually a little higher, e.g. the operational

That was my thinking that given the update on the MJO 'coming back to life' we may see some increase. I think GP was expecting something like this to occur.

http://www.cpc.ncep....O/mjoupdate.pdf

http://forum.netweat...80#entry2451745

Edited December 20, 2012 by Mark Bayley

[UV-RAY]

Unfortunately no man is a messiah, you speak of GPs forecast as if it is tangible. It is just a mildly educated guess, with a little bit but not much more merit than any other poster on here.

Indeed, some seem to think of GP as a weather god.

The outlook remains gloomy for anyone wanting a lengthy cold spell, a 24-48 hour NW looks on the cards after xmas thereafter December 2011 all over again if the models are right that is.

[EML Network]

To be honest Matty after the let downs that we have had so far I'd take anything! Lol

I'll 2nd that, all I had IMBY throughout the entire 2011/2012 Winter was a few hours of snow, which turned to rain, and the year before that we had one epic snowfall event which dumped a whole 12 inches over night and was completely gone 24 hours later !

I think we are in a better position than we were a week ago, looking ahead, but as always everything is in FI territory (post +180) and as such exists solely in a computer model ..something we all tend to forget when looking at the various charts.

I feel more positive about what might come to pass in a weeks time than I have done for the past 3 weeks, even if is just a brief North westerly, northerly, north easterly, it sure beats countless days of westerly, south westerly's and 36 hours of non stop rain !

[The Northern Ramper]

I would rather have a poor spell that delivers a couple of days of transcient snow and cold than have all the building blocks in place and delivers nothing.

[Paul]

Can we keep it to the models in this thread please, if you want to talk about the sort of weather you want the models to deliver, or in fact moan about what the models are showing then please use this thread:

[Methuselah]

Unfortunately no man is a messiah, you speak of GPs forecast as if it is tangible. It is just a mildly educated guess, with a little bit but not much more merit than any other poster on here.

No Matty,we're not doing that at all: we are merely assessing its feasibility; you can only do that by observation. I'm not even sure whether the models take stratospheric anomalies into account?

[DR(S)NO]

Unfortunately no man is a messiah, you speak of GPs forecast as if it is tangible. It is just a mildly educated guess, with a little bit but not much more merit than any other poster on here.

Mildly educated guess Matty? I think there is more to GPs posts than just guesswork .I find them very helpful and educational.

[Buriedundersnow]

well i dont see many good prospects for the rest of winter just now but we will wait and see what develops with the models over the next week.

i'm not feeling to good about the strat today either having read a couple of posts in there today but hopefully it can all come good for some serious cold.