The hunt for cold - Model discussion (late November)

[Mike Poole]

Well it is certainly interesting isn't it:

What strikes me is that even at T96 the models are in no agreement with the track of this low.  So any comments on later >T144 parts of any of the  runs aren't worth the pixels they are displayed on, first up.  

Seondly, the Narnia charts on the GFS last week are gone for good for the moment, but thirdly, we just don't know what the form output will be once the uncertainty is resolved.  Fourthly, if the ops are all over the place at this range, the ensembles - at lower resolution - could show anything and tell us nothing. 

Here's the situation at T96 on all main models:

My intuition is that the bowling ball ones are overblown.  Interesting also to look at the jet stream for those models that have the same plot:

Key issues, how strong is it and which direction is it blowing, and whether it looks a bit like a crab or not.

Should be resolved this time tomorrow and we can all move on!

 

Edited November 22, 2018 by Mike Poole

[Stuie]

@mike I thought yesterday regarding the JS was an upgrade and now it has sunk even further, the models are even struggling with that!

[Methuselah]

15 minutes ago, Nick123 said:

Getting ready for a very blocky Xmas period one hopes

We wish you a blocky Christmas and a snowy New Year!

[Stuie]

And the EC finishes in FI with almost a deja vu winter scenario, a monster russian HP/ridge. No doubt this will be 1050 tomorrow.

[tinybill]

certainly interesting  the  models  are   looking  into fantasy  world  any thing could  happen with the block  the models  are def  struggling  at  the  moment

[Duane S.]

Clearly we're going to have to endure some south westerlies, let's just hope as much energy as possible passes under the block.

The Atlantic lows are going to merge circa D5, that is clearly going to occur, and energy will subsequently track NE. However, there is a window of opportunity here.

If we then want a super quick return to cold we need a combination the longwave Atlantic trough and low EU heights (which goes back to getting as much energy s possible under in the next few days) to help draw up a column of WAA to reinforce our block as it drifts back east over Scandinavia. That would likely tip the balance in the blocks favour.

Even if not, I really don't think we will have to wait too long before the rollercoaster is off again. Not long at all.

[Summer Sun]

UKMO extended could lead to some colder air from the north for a time as the low pulls away?

 

[syed2878]

Yet again we have no agreement regarding next week with any of the models, Well I'm going to throw this in the mix.  This is the JMA WINTER 2018-2019 Update folks see what u guys make of it. Now this model is odd as we head into Jan and Feb. From gavs weather vids. 

 

[mulzy]

Ext EPS showing hints of blocking to the north with low heights over eastern Europe.  At the moment high heights are shown over the UK and into Iberia but signs look promising in the medium range.

Edited November 22, 2018 by mulzy

[The Eagle]

 

[bluearmy]

34 minutes ago, mulzy said:

Ext EPS showing hints of blocking to the north with low heights over eastern Europe.  At the moment high heights are shown over the UK and into Iberia but signs look promising in the medium range.

Looking very retrogressive to me longer term..... Euro blocking then n scandi blocking allowing cold and low heights to advect west into e Europe .......

[northwestsnow]

4 minutes ago, bluearmy said:

Looking very retrogressive to me longer term..... Euro blocking then n scandi blocking allowing cold and low heights to advect west into e Europe .......

Lets hope this is maintained and strengthened over the coming 2  or  3 days Blue

[Mike Poole]

I would like to use the most recent ICON run in the early stages to illustrate why the possible low from the Atlantic that may be forthcoming is NOT the result of a return to standard zonal winter conditions. ICON T3-60:

Look at what causes it, the jet is in a meridional flow, with north and south arms at T0, but the north arm partially seems to fold back on itself and reinvigorate the incoming energy,thus leaving the remaining  north energy floating in no mans land and the southern  arm given sufficient oomph to barrel up the low that's caused us so many problems to resolve.

Edited November 22, 2018 by Mike Poole

[ANYWEATHER]

Evening !  The Atlantic is trying to come back ,Gfs and Ecm  show it coming with stormy weather.... But how long for??? 

[markw2680]

2 hours ago, Mike Poole said:

Well it is certainly interesting isn't it:

What strikes me is that even at T96 the models are in no agreement with the track of this low.  So any comments on later >T144 parts of any of the  runs aren't worth the pixels they are displayed on, first up.  

Seondly, the Narnia charts on the GFS last week are gone for good for the moment, but thirdly, we just don't know what the form output will be once the uncertainty is resolved.  Fourthly, if the ops are all over the place at this range, the ensembles - at lower resolution - could show anything and tell us nothing. 

Here's the situation at T96 on all main models:

My intuition is that the bowling ball ones are overblown.  Interesting also to look at the jet stream for those models that have the same plot:

Key issues, how strong is it and which direction is it blowing, and whether it looks a bit like a crab or not.

Should be resolved this time tomorrow and we can all move on!

 

I’m a complete novice so may be well off but looking at them to me the low will elongate and follow the jet to the south? Or is that just me hoping 

[tight isobar]

The weatward advection of the cold russian arm..

Is very feasible..

Given current and progressive- plots/dynamics.

After the 18z (gfs)  will be worth a look around outs/synops...

Mjo/spaghetti's/ens etc...

The momentum-angular...and otherwise painting, an amicable picture for winter...2 say the least!

'Partialy stale data'..

But with insight correct'...

Madden julian oscilation(mjo)phasing into juicey-boxes.......gaining!!!

@wrap around

Chucking the PNA-index/forecast..

As ive mentioned-pre-posts!!..

Will be the lighter of the firework wick...(imo)....

Edited November 22, 2018 by tight isobar

[damianslaw]

41 minutes ago, northwestsnow said:

Lets hope this is maintained and strengthened over the coming 2  or  3 days Blue

I won't be viewing the models for 10 days from tomorrow, and fully expect this to be the pattern emerging as we move through early December, a temporary weak atlantic attack, heights building to the NE, and into UK and ridging NW. In many ways I'm pleased I won't be around next week as I suspect the models won't settle on this evolution until first week of December.

[bluearmy]

Amazed that the gfs op has stuck with the less defined Atlantic troughing day 4

[Mike Poole]

GFS18z may look like the lows going under T102, but it's that bit that gets invigorated by the jet and pulls it all back T120: 

It will now be a test of the power of that low re the remaining block...

T144 holding the low back a bit compared to recent runs

 

Edited November 22, 2018 by Mike Poole

[bluearmy]

Initial scan of the Icelandic charts ec46 reveal nothing of great note ....

[lorenzo]

1 minute ago, bluearmy said:

Initial scan of the Icelandic charts ec46 reveal nothing of great note ....

Think is is genuinely beyond super-computing at present Nick, at day 0 the peak of a Wave 2 split playing through, then immediately a Wave 1 attack on the strat to resolve also. Add in trop variables to the mix around MJO speed of phase / amplitude ( ECM vs GFS) plus additional momentum via the Pacific Jet. I would suspect that throws 'entropy' to the maximum levels in either regime products derived from the NWP suites..

[blizzard81]

Two consecutive nightmare mild winters 88/89 and 89/90 - end of November northern hemisphere. Compare to the end of November this year. Difference? I'll give you a clue. It starts with P and ends with V. 

[bluearmy]

3 minutes ago, lorenzo said:

Think is is genuinely beyond super-computing at present Nick, at day 0 the peak of a Wave 2 split playing through, then immediately a Wave 1 attack on the strat to resolve also. Add in trop variables to the mix around MJO speed of phase / amplitude ( ECM vs GFS) plus additional momentum via the Pacific Jet. I would suspect that throws 'entropy' to the maximum levels in either regime products derived from the NWP suites..

Just housekeeping tony ..........

[blizzard81]

6 minutes ago, bluearmy said:

Initial scan of the Icelandic charts ec46 reveal nothing of great note ....

They have been incredibly inaccurate before. Let's hope this is the case now. Must be a divergence between this model and glosea judging by the consistency of the meto updates. 

[bluearmy]

6 minutes ago, blizzard81 said:

They have been incredibly inaccurate before. Let's hope this is the case now. Must be a divergence between this model and glosea judging by the consistency of the meto updates. 

You need to note that the Icelandic ec 46 charts are less informative than the paywall version - not out yet.  And that clusters on ec46 aren’t available to us mere mortals .....