Hunt For Cold: Model Discussion - Heading Into Christmas

[seabreeze86]

GFS looking more amplified on our side of the pond,  much deeper low exiting the US could push the second ridge further north. We will see

[Optimus Prime]

1 hour ago, carinthian said:

No hunt for cold in Sweden. Their coldest day of the winter so far. Pictures from my daughters family place about 1 hours drive north of Stockholm.

C

The temperatures look quite low, but hardly a winter wonderland for northern  Europe towards the end of December.

1 hour ago, carinthian said:

No hunt for cold in Sweden. Their coldest day of the winter so far. Pictures from my daughters family place about 1 hours drive north of Stockholm.

C

Cold but i would be dissapointed if I was living in Sweden, and at the end of December all that had settled is a couple of inches! Good god this winters been a long and unpleasant drag so far .

[ItNeverSnowsInWindsor]

Much better in the shorter term on the gfs 12z run looking more amplified in the Atlantic. Hope it’s the start of more upgrades.

[Guest]

Short Update - More Changes in the Right Direction and Looking Great for a Cold Spell

I just posted this on a US forum and thought that you might like some Christmas cheer.  Expect some dramatic changes in the model output over Christmas for the New Year period and into January..

Our AAM (atmospheric angular momentum) and torque specialists (and myself) have been consistently pointing towards a huge spike in MT (mountain torque) following the recent fall to -ve levels. It's a bit like an elastic band being pulled back and stretched to the limit and then released and the lower it goes then the bigger the bounce back as mother nature must restore the balance.  Well this is already underway:

 

GLMT (global mountain torque - the black line) having nose dived is now rising again.  We can expect something similar to what we saw at the beginning of December.  Remember that these charts are always 2 days behind.  I would expect that values are already going +ve right now.  Note that NAMT (North American mountain torque - the blue line) and EAMT (East Asian mountain torque - the red line) are climbing too. EAMT is so important and the ups and downs can be seen clearly in the upper part of the chart. That blue blob at 30N to 45N is the -ve EAMT over the Himalayas, Tibetan Plateau and Mongolian Mountains.  We can expect that to turn to deep red (again) during the next  3 or 4 days as it goes strongly +ve and this will be bang on schedule. This is likely to send yet more planetary waves up into the upper stratosphere and may help to apply the final blow to trigger the major SSW several days later (perhaps around New Years Eve/Day).  That's if downward propagation is still struggling by then. Surface impacts may well follow more quickly than forecast.  In any event, the poleward shift in +ve momentum is very timely for favouring high latitude blocking as well as making the lower troposphere highly conducive and receptive to any SSW impacts. 

The relative AAM tendency anomaly and FT (frictional torque) are also rising again and the GWO (global wind oscillation) is steady in phase 8 and set to rush back to phase 5 with the rising AAM and torques - no time to include those charts now.

. 

Then we have this - have GEFS been on the Christmas drinks   We expected an adjustment to increasing amp but this is going off the chart and it would be even higher than the record breaking phases 6/7 that we saw during the February SSW event.  This is the bias corrected version!

 

Let's not get carried away (perhaps I should be!) - ECM still maintaining a change to low amp after Xmas but also progressing through the key phases favouring HLB.  Still time for the amp to increase.  We may not need all these teleconnections to fall into place but something very special seems to be brewing with some extreme events coming together..

Once again, I wish everyone a very Merry Christmas.  I'll try and produce several updates later this week after Christmas as what's on the cards as we move into January looks incredibly exciting for cold hunters in the eastern CONUS, eastern Canada, Europe and the UK.  This is dramatic stuff and absolutely fascinating for all those studying the background signals.  David  

Edited December 24, 2018 by Guest
check charts and correct typos

[feb1991blizzard]

7 minutes ago, nick sussex said:

Good  improvement on the GFS12 hrs run.

Note the low west of Newfoundland at day 7 , this will help pivot the PV lobe away less energy spilling east .

Yes, could be a stonker this, that trough on the East coast of Canada, i spumping WAA up nicely, whilst its round, its very stationary and doesnt look like it will ruin things by spilling energy out into the Atlantic.

[nick sussex]

Huge differences between this GFS run and the 06 hrs towards the north past day 7.

Also the UKMO is still playing Scrooge at day 6 . 

[Ali1977]

Up she goes at day 9.

Anyone having trouble with this website?

Edited December 24, 2018 by Ali1977

[ICE COLD]

Looking better

[carinthian]

3 minutes ago, Optimus Prime said:

The temperatures look quite low, but hardly a winter wonderland for northern  Europe towards the end of December.

Cold but i would be dissapointed if I was living in Sweden, and at the end of December all that had settled is a couple of inches! Good god this winters been a long and unpleasant drag so far .

I was there this time last year and the temp was above freezing with rain. Looks like plenty of cold for them over the coming weeks Arctic air  pushing into Sweden and Finland , thanks to the UK block. Blighty missing out for most of the next week or so , apart from Northern Scotland which may get some colder pulses. Yes, another miserable mild Christmas for many in Europe apart from the NE of Europe and Russia. Not been a bad day in Sussex but do hate the dampness and boring weather in the UK ( for the most part ) 

[feb1991blizzard]

3 minutes ago, Ali1977 said:

Up she goes at day 9.

Anyone having trouble with this website?

Seems ok nnow, its been crap lately with slowness.

[karlos1983]

5 minutes ago, Ali1977 said:

Up she goes at day 9.

Anyone having trouble with this website?

Yes getting error loading again. I had it yesterday too. On safari.

@Paul it’s happening again  it’s all I could do just to post this

Edited December 24, 2018 by karlos1983

[karyo]

At long last, the GFS is giving us a stratospheric split!  

Edited December 24, 2018 by karyo

[IDO]

GEM is very half-hearted with any Pacific amplification, just the wave pushing east and not much help for downstream:

D10 GEM: 

I have noted the 06z from GFS is more progressive with a Pacific Ridge, the 12z recently has no interest including today:

D9 GFS 12z & D9 06z: 

So with the lack of Pacific ridging on the 12z more energy pumping up the UK high. However the High is just oscillating over the UK and any push north is met by the wall of lower heights, and little indication any wave will be prolonged enough to break through that ceiling.

Another run, different upstream, but nothing interesting coming from the trop at the moment whatever is played out, so it is a matter of waiting for the bigger picture as at the moment the models are not showing the trop wanting to give the UK anything cold and wintry!

[The Eagle]

Shame we haven't been able to build on some positive medium term changes on the 00z runs today so far.

Last thing we need is everything flattening again in to January.

 

 

Edited December 24, 2018 by The Eagle

[feb1991blizzard]

Its having another go at the vortex in FI

[Mike Poole]

29 minutes ago, feb1991blizzard said:

Its having another go at the vortex in FI

Yes it is, but that's presumably because it didn't finish it off the first time unlike ECM. Really think GFS and it's ensembles have handled this strat event poorly so far.  

Back to the here and now.  I don't think I've looked at a single model run today that hasn't had high pressure in charge from Christmas through to New Year.  Some frost, some fog, some anticyclonic gloom no doubt, maybe some sunshine....but we await the game changer, the SSW, well we hope so.  It does seem unlucky that with a weak trop vortex so far this winter, we haven't managed to land anything. Maybe it's all coming at once in the New Year .

Edited December 24, 2018 by Mike Poole

[Singularity]

Hmm. Interesting GFS 12z; seeing more of the tropical contribution in the 6-10 day range, albeit the GEFS solutions all of a sudden look a little on the crazy side for the MJO amplitude. A halfway house between those and EPS seems a reasonable bet.

 

The split is also the best it's been in a long time GFS run-wise at 30 hPa on D10 and there's a hint of quick response to the AO - something the models will struggle to resolve properly that far in advance. The model then decides that because the vortex by N. Scandinavia and Siberia is the strongest, a vigorous transfer of low heights over to there should take place down in the troposphere that pays no regard to the tropical forcing... can't say I'm buying that, GFS! Smaller 'parcels' of low heights nipping across and merging with a lobe across W. Asia is more fitting based on historical cases.

Anyway, good to see the more northward reach of the ridge gaining ground for the 7-9 day range especially. Ironic how the sheer intensity of the high is what brings us such a brisk maritime flow before then; a weaker one would have allowed the air arriving via Tue-Weds weak continental drift to stick around more at the surface levels - meaning high fog potential carrying on.

I look forward to finally escaping the grasp of the unusually balmy maritime regime for an extended period. Until then it still looks difficult to achieve even a slight frost. Winter 2018-19 may, like summer 2018, be a preview of our 'normal' climate to come in future decades; milder and wetter except for when the beefed-up stratospheric warming events manage to turn things around.

[The Eagle]

A little surprised no one has mentioned NAVGEM. It's out on it's own but some height rises in the GIN corridor by 180 hrs on the 6z anyhow. 

 

At this stage we need all the straws we can get  

 

[Methuselah]

4 minutes ago, The Eagle said:

A little surprised no one has mentioned NAVGEM. It's out on it's own but some height rises in the GIN corridor by 180 hrs on the 6z anyhow. 

 

At this stage we need all the straws we can get  

 

And another straw - one that might wearing a little thin: at T+384, we might be on the cusp of something special?

 Oops!

[I remember Atlantic 252]

Another run like this in FI, early predictions but I reckon parts of Scotland are in for absolute snowfest, starting around January 6th metres of the stuff, few Parallel runs also shown it, 

[Skyraker]

https://earth.nullschool.net/#current/wind/isobaric/10hPa/overlay=temp/orthographic=10.99,74.26,360/loc=104.526,69.642

Worth bookmarking as its's a nice graphic to look at at any time.

 

+12C @ 10hpa

 

 

 

Edited December 24, 2018 by Skyraker

[northwestsnow]

36 minutes ago, karyo said:

At long last, the GFS is giving us a stratospheric split!  

Didn't see that K?

[jy]

Xmas can be a stressful time,made more so on here with missing plane and balloon data.Being the season of goodwill I have taken the following action.Earlier today,i purchased 500 balloons from Asda,using 25 per bunch,tied with festive string,gave me 20 sets,6 have been weighted just to float,7 have  a B AND Q Orange bucket attached,the last seven having an Aldi thermometer on board.My report will go as follows....if the 6 balloons are never seen again,its ruddy windy,if the buckets bring the balloons down  full of water its been hissing down with rain,finally if the rumour is true that cold air or water can make things shrink,its really cold,if the balloons explode its because very hot air has expanded them,as for planes,short supply,most are at Gatwick,anyone suggesting drones can get knotted SO ive done my bit to ease tension on here.................Happy Xmas one and all.

[feb1991blizzard]

9 minutes ago, northwestsnow said:

Didn't see that K?

https://www.instantweathermaps.com/GFS-php/strat.php?run=2018122412&var=HGT&lev=30mb&hour=237

[Duane S.]

We MUST see this, we MUST see that, the xxx update is so important this time or we will have to wait until February etc etc. Sorry, what?

Everything will look look different in a week and it still won’t even be January yet.

A stratospheric warming (nailed on and underway)  will hold in store many surprises to follow, things that the models haven’t come close to fathoming out.

Chill, be happy and stop lurching from one extreme to the other over specific aspects of stratospheric chart outputs, the greater picture is still in sight from what I can see. And even if the GFS has got this 100% right, it still will be a decent strat event with likely repercussions for the mid latitudes in terms of a cold spell for many.

Far too much 2 + 2 = 4 on here at the moment. We all should know by now that it doesn’t work like that at times like this. 

Worth reminding ourselves of what happened in late Feb/early March this year. As mad as that late winter ‘18 spell was, once underway it could have been so much better. It really was a case of the forcings being being too extreme and everything being thrown into high speed reverse. The HL blocking would normally have stopped over Greenland and given an extension to the cold but it just carried on accelerating away west all the way to Canada. This left us open to the Atlantic and the rest is history. Bigger isn’t always better!

.