Winter Model Discussion - The Hunt For Cold - 10th Dec

[bluearmy]

So a little support there for low pressure anchored to the west and sw, lower heights over the northern Med and higher pressure to the nw.

I

nick, the area to the nw is probably not higher pressure. it more likely where the troughing is centred with the spreads to the south being shortwave energy running along the jet. of course that does raise the possibilities of some colder transient noreaster flows as the shortwaves pass to our se.

[MP-R]

One thing that seems apparent from the models is that, despite the zonal nature of the weather coming up, it doesn't look overly mild, maybe for very brief periods but I would say average at best. The GFS showing 975mb and blues over the whole country for Friday doesn't spell mild for me and FI does give some scope for marginal snow events in favoured areas towards Christmas.

Having said that, it still looks pretty grim for 'cold' cold. The only cold thing in the reliable will be the ferocious wind of the Atlantic!

[stainesbloke]

I know about weather in much detail but I can't get my head around what has gone so terribly wrong with the models...??? Why does this seem to always happen with us? It can't just be the Atlantic. Could anyone help to explain. It's extremely frustrating to see the models waste/ruin half the season.

Just bad luck this time more than anything else. The blocked trend was correct although we were just too far away to really benefit. As always the details in these scenarios are difficult to forecast and subject to massive changes. I disagree that this always happens though, it works out in our favour sometimes too, plus we are in week 2 of winter so half of winter is certainly not ruined just yet. Small changes in future outputs will result in big changes for us so one to keep an eye on.

By the way its currently -3 at midday where I am with freezing fog, if thats not winter, dunno what is!

[nick sussex]

nick, the area to the nw is probably not higher pressure. it more likely where the troughing is centred with the spreads to the south being shortwave energy running along the jet. of course that does raise the possibilities of some colder transient noreaster flows as the shortwaves pass to our se.

Are you sure?

Given the spreads further east and ne, block to the east, some residual energy to the ne between the Russian block and a higher pressure cell to the nw, low pressure west and southwest of the UK with lower heights in the Med. Further to the ne a lobe of the PV near Svalbard which has been suggested in some outputs as the PV begins to move again.

Edited December 12, 2012 by nick sussex

[Troubleatmill]

I know about weather in much detail but I can't get my head around what has gone so terribly wrong with the models...??? Why does this seem to always happen with us? It can't just be the Atlantic. Could anyone help to explain. It's extremely frustrating to see the models waste/ruin half the season.

Dont think its models Adam, its the weather and because we live in that temperate zone between cold and warm we are always going to be like this, its just part of living here and what makes us interested and 'wanting' extremes. Prob why ive not come across a weather forum in Egypt :s. i often think trying to get cold and snowy conditions in the country is like putting a rubber duck in a hot bath (atlantic) and trying to freeze it from the side...hard but not impossible

[Summer Sun]

GFS ensembles

Still all to play for IMO for Christmas week, there are plenty of member trending cold still, after this mild spell things should start to return to average certainly for the midlands north

[Cecil Hogmanay Melchett]

Those ensembles are shocking,zonal all the way im afraid!

Going to keep an eye on the strat thread for a week or two and hope chino etc have some hopeful signs for later in Dec and beyond.

[Weathizard]

6z ensembles are rubbish compared to the 00z ones which looked 50/50 for cold around 21'st. Let's hope Steve Murr's policy of binning the 06z is correct..

[Paul T]

From my perspective I’m not too 'upset' at the charts; yes they are appalling in general, but one should manage ones expectations.

When everyone was getting hugely excited, I said there was little chance of a classic easterly and also noted that a SW'rly was clearly going to raging until at least the 20th a few days ago. Now, I’m honestly not saying this to champion myself, I’m saying it in relation to my own expectations. I just look at what is most likely, not what I would most like to see.

Anyhow, onto my thoughts for the next potential chilly weather;

In my view, only one realistic force for change is apparent. Without this I will say that a colder spell is looking hugely unlikely in the medium term, and a distinctly average Christmas day would be on the cards.

The one force of change will be driven by a low shooting into Europe, or up the channel (into the North sea) and therefore bringing a chilly NE flow. If this occurs, then it could herald the start of a cold spell.

Personally I like the chances of this; I actually think a low will 'undercut' somewhat around 20/21st, but what I also think is that, unless Canada stops feeding the Jet with some stupidly cold airflow (=Strong lows being churned our way) then another low will just bash its way through, hot on the heels of our 'undercutter' therefore resetting the boredom of zonality.

I have attached an image, detailing the potential shortwave (at this stage) that could do the business.

Chances of this having a go = 50/50. Chances of this happening and then being a blip in zonality = 50/50

Edited December 12, 2012 by Paul T

[latitude]

GFS ensembles

Still all to play for IMO for Christmas week, there are plenty of member trending cold still, after this mild spell things should start to return to average certainly for the midlands north

I like your posts here, nobody would ever think your from NE England.

Personally dont see anything colder on the horizan in those ensembles.

[BLAST FROM THE PAST]

Fred, anybody who regularly issues LRFs is going to be wrong at some point and Roger and yourself also fall into this category.

I’ve been pointing out that the failed easterly episode at least occurred very early in the winter and there is plenty of time..however the other side of that is like saying well it’s OK about these missed chances, we will score in the second half. We know that things don’t always work out like that. At least the December CET is running below average – an above average Dec CET has invariably boded very badly for cold in Jan/Feb over the last 25 years.

Back to the 06z, not sure of it’s evolution in the mid-range that puts us on the cold side of the PFJ for a time. Later on it gets worse and another run that brings the PV back with a vengeance, admittedly this is deep FI and it may just be the model bias to default to zonality at the back end, but if anyone thinks the charts are poor today, then let me tell you the set-up shown at day 15 or so is much much worse.

More often than not for me Ian, I fell at the first and didn't even reach Bechers.....and came out with that admisson a week ago ....but tend to agree with most of the post and actually it is cold right now and not a bad start to winter indeed. However, I'm not in the camp that a mild Dec is bad for cold Jan or Feb.

Edited December 12, 2012 by BLAST FROM THE PAST

[Tom Montalbano]

At work, havnt got time for detailed post. Here's something I posted yesterday in another thread. Taking a step back from all the drama of model discussion, hopefully it puts a little realism into what we can expect on average in the UK, in December.

"Interesting discussion on this thread on where we go from here. Just want to make a couple of observations regarding Decembers in the UK in general. I really do feel that some members perception of what we can expect during the last month of the year has been greatly skewed by the very exceptional cold and snowy December of 2010. In my lifetime there have been only 3 Decs. with a CET of less than 2.0c., 1962 (1.8c), 1981 (0.3c), 2010 (-0.7). That figure rises to 8 Decembers when looking at CETs of less than 3.0c.

Looking at my own region, cold, snowy weather is not a common visitor during the first half of the month and indeed more likely to show its hand post-Xmas than before Xmas.

Certainly I feel there's nothing to be disheartened by at this stage of the winter, in any of the output from various model predictions and I really do feel by this time next week the outlook for the end of the month and on into January, will begin to look a lot more encouraging from a colder and hopefully, snowier perspective."

Regards,

Tom.

[Frosty.]

GavinPartridge

Brazilian midel also suggests zonal for Dec-Feb; http://t.co/PympjSUa

12/12/2012 10:54

GavinPartridge

UK Met Office seasonal model suggests a zonal set up is likely for Jan-Mar. #Mild http://t.co/23xbF27v

12/12/2012 10:47

The ECM also suggests Azores High with zonal to our north.

Not calling it yet but I think this Winter is not looking optimistic from a trend point of view.

Good! that means it will get cold then

Edited December 12, 2012 by Frosty039

[matty40s]

the Met are now looking at a spell of more persistent and widespread unwanted rain in the middle of next week, Where does this appear in the model guidance? I can only see the progression to the low this Friday.

[Iceaxecrampon]

Nailed on for Boxing Day

The other side of Winter.....

http://www.wmrt.org....-10th-dec-2012/

Ian

[Steve Cooper]

It's looking so bad for us ' coldies' that the METO yellow weather warning for friday is shaped like a phallus, just to rub it in. Lol.

[Frosty.]

Nailed on for Boxing Day

The other side of Winter.....

http://www.wmrt.org....-10th-dec-2012/

Ian

This is turning into the straw clutch thread, the models have sunk to new depths in the last few weeks but I believe they now have a better handle on the upcoming prolonged milder pattern, how ironic.

Edited December 12, 2012 by Frosty039

[bluearmy]

Are you sure?

Given the spreads further east and ne, block to the east, some residual energy to the ne between the Russian block and a higher pressure cell to the nw, low pressure west and southwest of the UK with lower heights in the Med. Further to the ne a lobe of the PV near Svalbard which has been suggested in some outputs as the PV begins to move again.

looking at the 850 spreads, i cant see such a strong clustering of heights to our nw nick. it may be a combination of a small cluster with weak height rises as per the op and a larger cluster with the trough there.

[Kentish Snowman in Yorks]

Could these next ten days or so

Not be what gp was alluding to

As a false dawn by models

Just a thought

I think this might be the post your referring to snowbob?

Posted by Glacier Point on 06 December 2012 - 08:47 in Model Forum Archive

As if NWP didn't have enough on its plate with the disturbance to the PV, MJO forecasts consolidating on a phase 2 projection. That will expose the GFS in particular (it has a large bias to tropical convection in the longer range) to greater pressure to turn the jet northward over Iberia. This will be a false bias given that the GWO is in phase 8/1 - and this is the superior measure. That lobe of the pv cut off over NE Siberia also rolling around like the preverbial loose cannon.

GEFS H5 day 10 a reasonable depiction however (huge snow potential btw):

Substantive ridge between Greenland / Iceland / Svalbard. Tonight's CPC 8-14 dayer will pretty much look like this. That will keep the jet well to the south and only when the ridge pulls fsr enough west will it be able to come up from the south. Always the risk however of shortwaves, but these likely to maintain our cold pool in situ by advecting the cold air westwards.

Stick with your ensemble means!!

[Frosty.]

Stick with your ensemble means!!

Yes, they are showing a milder outlook now with the russian high slowly disappearing back where it came from, that is what you will see when you stick with the ensemble mean. I have been watching this deterioration in the mean and it's quite alarming, in the build up to this phantom freeze the mean looked better and better but now it's looking worse and worse, certainly the gefs 00z was anyway, apart from a brief cold blip immediately prior to xmas, the russian high vanishes.

[latitude]

[quote name=Kentish Snowman' timestamp='1355320625' post='2444859'

Stick with your ensemble means!!

Edited December 12, 2012 by latitude

[snow drift]

So what your saying is, that when GP said stick to your ensemble means it was supposed to show 'cold' but instead now its showing 'mild'.

Now is not the time for an autopsy. We have lost IF within the thread. Treat people how you would like to be treated.

Edited December 12, 2012 by snow drift

[nick sussex]

looking at the 850 spreads, i cant see such a strong clustering of heights to our nw nick. it may be a combination of a small cluster with weak height rises as per the op and a larger cluster with the trough there.

Looking at the ECM ensembles wind direction there is at least some clustering there switching the wind direction to the southeast east or ne.

That would suggest the two solutions, weak pressure rise to the nw or troughing angled se'wards into Europe.

[Iceaxecrampon]

This is turning into the straw clutch thread, the models have sunk to new depths in the last few weeks but I believe they now have a better handle on the upcoming prolonged milder pattern, how ironic.

Yes - default UK murk - easy.

(my original message had a sizeable portion of sarcasm..... )

......but you never know.

Ian

[Frosty.]

So what your saying is, that when GP said stick to your ensemble means it was supposed to show 'cold' but instead now its showing 'mild'.

Not exactly, when GP said that it was really looking good but not long after he said it, the mean started to look worse. I'm saying that now things are looking pretty bad for a return to cold weather after tomorrow and we look like going into a prolonged milder unsettled phase with the russian high disappearing off our charts pretty soon.

Edited December 12, 2012 by Frosty039