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

[Buriedundersnow]

great to see upgrades early in the run and it continue through hope it keeps coming

[cold snap]

So don't worry everyone according to gfs tonight we will have a white Christmas

[chris55]

The sort of evolution we see on the 18z is not surprising really, whether we can get it to verify in another matter.

[swfc]

Don't want to be rude but of course many of us are frankly pi&*ed off. The models up until last Friday were showing a massive lottery win , then they decided the numbers were wrong. The thought of another wet mild Christmas fills me with gloom. Its perfectly understanable that some of us are down we had it all to look forward to. You'll see how exciting the nuances of rain and wind are when you see the current 602 user level seen below drop like a stone. It is bad and although you might mean well, telling me it isn't bad is even more irritating. Sorry mods but I had to say it . So let me wallow in self pity.

Move me to the suicide thread as I'm busy slashing my wrist at the moment and please don't call the samaritans or an ambulance.

Stick with"sorryTREND"

[Panayiotis]

And the topic comes alive! FI has shown another trend over the last runs, and thats the small Artic High,one worth noting? Looking at the NH chart most of the PV has moved to Russia/Asia a good starting point for cold..(yes its Fi but trends are looking good)

Edited December 10, 2012 by panayiotis

[swfc]

So don't worry everyone according to gfs tonight we will have a white Christmas

HAHAHA

[snowmadchrisuk]

were close to a full link up of heights on this run from Canada to Siberia at a very early time frame , any further southward movement of them shortwaves and mark my words a Cold spell will come out of nowhere , probably between +72 - +96 type of time frame , it looks very possible to me ..

[Skeggy Winter Storm]

OK, if the extreme FI came off for Xmas, Id be happy lol. Night all.

Its nice to see FI eye candy again am off to sleep bit easier

[Snowly does it]

Rather than the Atlantic pushing through in hope of amplification upstream bringing a Nerly shot, if the Russian High continues to hold position it looks like we may just have to wait for the Atlantic trough to the west to weaken then implode on itself to allow the Russian high to back west eventually.

Just hope we are not still sitting here come late December to rid of the trough to the west though!

I'm increasingly of the opinion that the 19/20 December is the key date for transition to favourable.

[-uksnow-]

Anybody still awake, is it not a noticable feature of the GFS over the last 3-4 days to keep re introducing the easterly or northerly topplers between 22nd onwards, GFS is meant to be the one to pick trends up and drop them again, isn't it? Now im not silly enough to think that these will come off, but surely we need to start looking for trends on this?

[karlos1983]

if this comes off I'll eat yellow snow

And on that note I'm off for around T+144 hours

[bluearmy]

Anyone notice a trend, the 18z giveth and he 00z taketh away.

Its got to be right in the end. The broad gfs fi trend of trough disrupts and sinks south continues. (Ish)

[nick sussex]

Rather than the Atlantic pushing through in hope of amplification upstream bringing a Nerly shot, if the Russian High continues to hold position it looks like we may just have to wait for the Atlantic trough to the west to weaken then implode on itself to allow the Russian high to back west eventually.

Just hope we are not still sitting here come late December to rid of the trough to the west though!

How long do you give this Nick F before you lose patience?

I'm giving the Russian high two days to show it means business otherwise I want shot of it as its beginning to grate on me! It's a shame we didn't have more amplification in the GFS 18hrs run upstream, things could then have progressed much quicker with that shortwave heading se rather than phasing and being dragged nw.

Can we find a bit more amplification tomorrow and see the Azores high retrogress further? I really hope so, and we need the ECM/UKMO to bring the trough east without that blasted shortwave in tow.

[Snowly does it]

Ok, I'm off until tomorrow night. Keep an eye on Greenland and the Azores from T156 out ;-)

[cold snap]

Just had a browse round the models all way out t240 +

BOM ECM GFS NOGAPS all show some potential

Possibility of another cold outbreak before months end

[Panayiotis]

Overall a good run, with some slight improvements in the shorter term (again!) in the longer term (+144hrs) looks better, and for me the low to the east of North America at 204hrs (shown in the 12z too) starts everything off in terms of cold, this low ridges the Azores high into Greenland which causes the low in front of the ridge to move SE giving us the easterly, that we are looking for. (As always Fi and subject to change).

[Buriedundersnow]

do we think we are on to the pattern now cos the ECMand the GFS aint that different from each other there quite close

both have a blocking ridge of high pressure on canadas eastern sea board stopping energy coming in from there

both have less shortwave energy going up the east of greenland past iceland

they both bring the high into scandanavia

Edited December 10, 2012 by Buriedundersnow

[bluearmy]

The thing is, before the 18z low res appeared, it was so miserable in here. A few fi frames of fun and the mood lightens. Nothing has changed. Tomorrows output will probably be very similar to todays. why not view it with a glass half full outlook and you'll enjoy he thread so mch more ??

[AGAL]

Anyone notice a trend, the 18z giveth and he 00z taketh away.

Its got to be right in the end. The broad gfs fi trend of trough disrupts and sinks south continues. (Ish)

They (the models ) do this until right at the last moment. A bit like a bullfighter waving the red cape and then yanking it away at the last moment. Yes we are that dozy bull. Mind you FI looks tasty snort........

[TEITS]

Only just viewed the 18Z but at last the GFS has come round my way of thinking.

Someone said earlier that the block will be blasted away but that has never been the case and all model output between +0 to +144 actually shows the reverse. Now the 18Z makes perfect synoptic sense because the Atlantic trough cannot move E due to the stubborn Siberia HP and without the PV over Greenland this trough will eventually weaken.

The +168 shows this perfectly.

http://www.wetterzen...s/Rtavn1681.png

What could spoil the chance of an E,ly is this LP that I have highlighted.

Ideally we need this LP to be held out W to allow the Siberian HP to back W.

Obviously what the 18Z shows might not be right but you don't need to be Bill Giles to spot the potential as i've been highlighting today. Infact I would suggest we still have a chance of this developing even sooner.

[Panayiotis]

Just to reiterate my point from my last point, 3 runs showing the ridge at around 192hrs and the low to the east of America...

First is the 00z, 2nd is the 18z and the 3rd is the 12z they are at different times and a day either side, but its a trend IMO, which i will be looking out for.

Edit:Looking at yesterdays runs, they all show similar trends around these timeframes..

Edited December 10, 2012 by panayiotis

[Timmytour]

Can't give up the ghost now while I have the FI of the pub run to look at.

I also amuse myself by playing the precipitation charts backwards from T+99 and imagine that's still how this week was set to pan out

[AGAL]

Only just viewed the 18Z but at last the GFS has come round my way of thinking.

Someone said earlier that the block will be blasted away but that has never been the case and all model output between +0 to +144 actually shows the reverse. Now the 18Z makes perfect synoptic sense because the Atlantic trough cannot move E due to the stubborn Siberia HP and without the PV over Greenland this trough will eventually weaken.

The +168 shows this perfectly.

http://www.wetterzen...s/Rtavn1681.png

What could spoil the chance of an E,ly is this LP that I have highlighted.

Ideally we need this LP to be held out W to allow the Siberian HP to back W.

Obviously what the 18Z shows might not be right but you don't need to be Bill Giles to spot the potential as i've been highlighting today. Infact I would suggest we still have a chance of this developing even sooner.

Nah that low uses blockbusters

[snowking]

Well here we go, its (just past) 11 o clock on Monday, and its time again for the ECM 32 control update:

Nothing particuarly promising up until around 500 hours it has to be said, with just the mean trough stuck to our west and the stubborn russian HP....what changes around +500 is heights also rise to the N of the UK, cuts off the mean trough and finally begins to force it to undercut. We then pull in a cool, cyclonic SEly flow until just into the new year, when blocking becomes more substantial and bases itself over Scandinavia. Towards the end of the run (around 8-11th Jan) We see the heights sink SEwards, with renewed heights to the NW out of Greenland, and a trough drops down through Scandinavia.

In summary, the pattern becomes more amplified the further we move towards January

SK

[damianslaw]

Not surprised to see GFS 18Z evolution, which continues to show what I believe is likely to happen in the run up to christmas i.e. the trough dropping SE thanks to heights building in the mid atlantic and the russian high putting the brakes on troughing moving across into scandi. Its a trend which I expect the models will struggle to get to grips with in the coming 2-3 days but by the end of the week once the trough is upon us they will react much better to the change in upstream signals associated with the movement of the polar vortex away from Canada and out to north russia. If we saw what happened so many occasions this summer in similiar set ups with the longwave trough anchored over the country it was always forced to either move SE or simply squeeze itself/wring itself out over the country with heights staying very low to the SW and much higher to the NW and N with the jet on a southerly course - the northern hemisphere is still in a very similiar state.