Model output discussion 25th Jan - The final third of winter beckons..

[chris55]

This cold pool looks excessive!! GFS probably overdoing things, but all part of the models finding the correct pattern, and if the GFS 12z has it right ill eat my hat!

[Snowman.]

Probably one of the best charts this winter in terms of HLB. UKMO is a beauty but the deep low is a little too deep very hard to raging westerlies from it but may be a little while before any cold moves in.

[Seasonality]

12 minutes ago, IDO said:

I was just pointing out the UK perspective, and of course your location the Europe picture is more interesting, as it really does not have much interest if Poland is snowed in and the UK is in a westerly flow; the same for the US going into the freezer when  the forecast was much milder! For my location the block being more persuasive has made little difference as to surface conditions, that being my point. I have no interest in that block bringing a continental flow for the last remnants of the winter as I want snow rather than cold.

The GEM moving from one cluster to another:

0z  12z

Which is my point re the models clueless at the moment. Expect changes run to run, cross and inter model.

And again you're completely missing the point of my post as you did with TEITS post. You deliberately misinterpreted his post and you are deliberately misinterpreting mine, I made no reference to interest in my location or your location or the US. I'm not sure what your point is other than being deliberately contrary, The fact is that TEITS was correct in pointing out Atlantic low pressure is not going as far into Europe as forecast and that this pattern has happened before this winter. I'm not sure why you keep trying to go off on tangents. TEITS made a valid point, you didn't understand what he said. Simples, as the Meerkat says. 

And if you have a look at the current run it even shows a little snow for you!

[MattTarrant]

A little chilly next Saturday....

 

[MR EXTREMES]

13 minutes ago, winterof79 said:

GFS

UKMO Colder in Europe

Ukmo is much quicker than gfs to I like it alot.

But still skeptical until the ecm is on board at 144 hrs

[bluearmy]

I find the gem solution more plausible than the gfs 

don't expect to get too many likes for it but that's where the modelling is currently headed - fi ops will lead us a merry dance. 

Unless the ecm has a flip in 90mins then I don't expect my stance to change 

[Ali1977]

1 minute ago, bluearmy said:

I find the gem solution more plausible than the gfs 

don't expect to get too many likes for it but that's where the modelling is currently headed - fi ops will lead us a merry dance. 

Unless the ecm has a flip in 90mins then I don't expect my stance to change 

The GFS op is a little isolated within its ENS so this is probably not a good thing. Over to the ECM 

[chris55]

3 minutes ago, MR EXTREMES said:

Ukmo is much quicker than gfs to I like it alot.

But still skeptical until the ecm is on board at 144 hrs

Im thinking we have quite a few ships we could possibly board, so to speak, and as yet no model has a clear direction with regards to this Arctic/Scandi high and where things will ultimately end up.

Just look at the differences in how the three models handle the high out east at 144

GFS

UKMO

GEM

 

[Gowon]

2 minutes ago, bluearmy said:

I find the gem solution more plausible than the gfs 

don't expect to get too many likes for it but that's where the modelling is currently headed - fi ops will lead us a merry dance. 

Unless the ecm has a flip in 90mins then I don't expect my stance to change 

What about the UKMO, blue.. I've been very impressed by it of late and it's pattern at 144hr matches closer to the GFS than the GEM?

[feb1991blizzard]

6 minutes ago, bluearmy said:

I find the gem solution more plausible than the gfs 

don't expect to get too many likes for it but that's where the modelling is currently headed - fi ops will lead us a merry dance. 

Unless the ecm has a flip in 90mins then I don't expect my stance to change 

I agree, even worse though the strat vortex has returned to the pole and the wave doesn't break high, that's probably why in deep FI the trop PV is once again revving up with LP to the NW.

[chris55]

11 minutes ago, feb1991blizzard said:

I agree, even worse though the strat vortex has returned to the pole and the wave doesn't break high, that's probably why in deep FI the trop PV is once again revving up with LP to the NW.

This Artic/Scandi high has appeared from nowhere and has no relation to the SSW thats happening at 10hpa in the coming days. So for me at least the lower strat pattern is being troph led and the warming at 1hpa is yet to effect the troph. I'd put the deep FI  troph PV revving up down to climatology rather than any link to the Strat!

Edited January 31, 2017 by chris55

[I remember Atlantic 252]

252, lucky number on 12Z, shame though as it's first chart of low res

 

[The Weather Dragon]

Think that we are going COL here tbh

No blocking over greenland - no severe spell

Canadian PV to strong

This is going to let you down - BIG time !

Edited January 31, 2017 by The Weather Dragon

[feb1991blizzard]

1 minute ago, chris55 said:

This Artic/Scandi high has appeared from nowhere and has no relation to the near reversal that's happening right at the top now. So for me at least the lower strat pattern is being troph led and the warming at 1hpa is yet to effect the troph. I'd put the deep FI  troph PV revving up down to climatology rather then any link to the Strat!

But I think if the split we had the other day (yesterday 6z I think) would occur (also trop led), that went right to the top of the strat nearly, to me we would have a longer blocked pattern therefore more time for the block to orientate to advect cold uppers to us, I'm saying the first few attempts are likely to be fails, so we want to give us further chances down the line.

[feb1991blizzard]

GEFS are reasonably good, cant picture them being a massive upgrade in graph form (a few more maybe flatlining??) but more blocked definitely.

[chris55]

16 minutes ago, The Weather Dragon said:

Think that we are going COL here tbh

No blocking over greenland - no severe spell

Canadian PV to strong

This is going to let you down - BIG time !

Blocking over Greenland?? Well of course there is no blocking over Greenland, the charts are clear on that!

There is however a big block developing over norther Scandinavia and its something we should watch with interest, if we can achieve the correct orientation it has the ability to deliver some colder conditions to the UK. Nothing is clear at the moment and the ensembles are not supporting the cold advecting to our shores at present, so nothing is nailed down.

In summary no let down "big time" (how dramatic"!) just a case of watching and enjoying the output. If the cold ends up missing us, so what!

EDIT

and just for reference you do not need a greenland block to develop a colder pattern for the UK

   

Edited January 31, 2017 by chris55

[feb1991blizzard]

I will take a number 4 please.

 

As good a chart as Jan 1987,

 

 

Edited January 31, 2017 by feb1991blizzard

[booferking]

2 minutes ago, chris55 said:

Blocking over Greenland?? Well of course there is no blocking over Greenland, the charts are clear on that!

There is however a big block developing over norther Scandinavia and its something we should watch with interest, if we can achieve the correct orientation it has the ability to deliver some colder conditions to the UK. Nothing is clear at the moment and the ensembles are not supporting the cold advecting to our shores at present, so nothing is nailed down.

In summary no let down "big time" (how dramatic"!) just a case of watching and enjoying the output. If the cold ends up missing us, so what!

 

   

Someone mention blocks over greenland anything could happen fl is as early as this weekend.

[chris55]

4 minutes ago, booferking said:

Someone mention blocks over greenland anything could happen fl is as early as this weekend.

 

One step at a time eh boofer!  

Edited January 31, 2017 by chris55

[Tamara]

On ‎29‎/‎01‎/‎2017 at 12:47, Tamara said:

Taking into account response timelines to -ve mountain torque this advertises an upstream amplification over the Pacific to occur around the 6 day period which will have downstream ramifications in terms of retracting the Azores High westwards and taking the Jetstream southwards across the Atlantic as fuelled by the displaced Canadian lobe of polar vortex

Upstream amplification in the Pacific. Yep

On ‎29‎/‎01‎/‎2017 at 12:47, Tamara said:

However, the upstream jet, is set to decelerate rapidly as pressure rises over the Pacific and re-build the Aleutian Ridge.  In the Atlantic sector, the retrogression of the pattern will tend to angle the Jetstream more NW/SE and, conceivably, enable build of pressure over Scandinavia

Pressure build over Scandinavia. Yep

On ‎29‎/‎01‎/‎2017 at 12:47, Tamara said:

Meanwhile, with (hopefully) a split enabled in the vortex

Split vortex assisted by Wave 2 action Yep

On ‎29‎/‎01‎/‎2017 at 12:47, Tamara said:

With time, as the disrupting trough gets separated from the Canadian lobe of vortex, downstream amplification from the Pacific sector becomes possible

Downstream amplification? Yep - just coming into day 10 period

On ‎29‎/‎01‎/‎2017 at 12:47, Tamara said:

the chances of the jet crossing through the northern arm with spoiling energy to inhibit amplification are reduced (also assisted by tropical signal progressing through Phases 7/8 which would teleconnect to an increasing -NAO signal and help back cold air advection west)

So we move onto the next part of the jigsaw. The eastward propagating tropical signal has been well documented by others today. With the downstream amplification signal becoming increasingly advertised within NWP suites from the day 10 period then we have the double lock scenario that has been AWOL so far this winter in terms of potential ambush from both NE and NW vectors. The amplification key in drawing cold air advection westwards and leading to the prize in the extended period

2 hours ago, Seasonality said:

IDO said:

The GEM moving from one cluster to another:

0z  12z

Which is my point re the models clueless at the moment. Expect changes run to run, cross and inter model.

Yes indeed obviously expect changes in face value intra suite operational detail - but that applies whatever the synoptics

However the models are far from clueless. They are reading the script perfectly - see above

What is key is that the downstream amplification posse is clearly coming over the hill at day 10 into complete model ensemble suites. Look at the wider hemispheric model plots and see the retracted Atlantic ridge providing the ambush of the troughing from the west to squeeze the vorticity energy out, while the continental influence bumps it from the east.

The intra model operational details do not matter a jot at this stage within that time as long as the polar field and NE Europe is modelled the way it is. The jet deceleration downstream will take care of itself as the amplification comes closer into model radar. Then, just perhaps, we can start to think about the prize

So far, so very very good

Edit: Thanks Mr ECM !

The pincer ambush of the Atlantic energy c/o expected downstream amplification perfectly illustrated by 12z ECM - which allows a glimpse of the prize as the deep cold is then backed westwards...

 

 

Edited January 31, 2017 by Tamara

[Day 10]

14 minutes ago, feb1991blizzard said:

I will take a number 4 please.

 

As good a chart as Jan 1987,

 

 

P7 ain't bad either...

[frosty ground]

The ECM day 5 chart has under a slack flow with uppers below 0.... any heavy precipitation could be wintry especially on high ground. 

[chris55]

ECM op with that mega cold pool on a decent trajectory!

Comparing it with the UKMO at the same time id say the ECM is better with the Atlantic low a lot weaker!

 

Edited January 31, 2017 by chris55

[Man With Beard]

Just now, chris55 said:

ECM op with that mega cold pool on a decent trajectory!

More than half a chance of an easterly by T192

[booferking]

 Ecm is an upgrade on last night the high is further North on this run. Also the deep cold to the east is better aligned. We just need the runner underneath now.