Hunt For Cold: Model Discussion - Heading Into Christmas

[karlos1983]

I hope the GFS (P) rolls out a bit quicker when it takes over!!! We will have downwelled by the time this run has finished 

[Ali1977]

What a chart..

P10 is a crazy chart, but again some decent ENS in FI. 

Edited December 19, 2018 by Ali1977

[Mike Poole]

3 minutes ago, karlos1983 said:

I hope the GFS (P) rolls out a bit quicker when it takes over!!! We will have downwelled by the time this run has finished 

It will be a bit slower, overall, largely because it maintains high resolution out to day 16.  Does seem positively glacial this evening I admit!

[Paul]

Just now, Mike Poole said:

It will be a bit slower, overall, largely because it maintains high resolution out to day 16.  Does seem positively glacial this evening I admit!

More often than not, the speed at which the charts load on the web are more about the downloading of the data from ncep, which can sometimes be up and down speedwise. Generally, the data itself turns up at the same times though. 

I'd expect the FV3 to be earlier once it's off of the parallel system. 

[Paul]

1 hour ago, Kentspur said:

Im sure I read on here 1 to 2 days is a toppler? Correct me if I'm wrong 

A toppler is when high pressure ridges north of the uk to allow a northerly airflow, but is then 'toppled' by Atlantic systems from the northwest, sinking it south and cutting off the cold air. That could be on day 1, 5 or more really, so the phrase isn't really related to a timescale. 

Bit of an ancient thread this, but it's all about topplers

 

[bluearmy]

6 minutes ago, Ali1977 said:

What a chart..

P10 is a crazy chart, but again some decent ENS in FI. 

Yes, i detect a step change in the gefs low res ………..

[karlos1983]

Here we go perhaps.....

[The PIT]

I guess there's no time limit so this chart looks promising

 

 

[karlos1983]

5 minutes ago, The PIT said:

I guess there's no time limit so this chart looks promising

 

 

What sort of Stupid model goes out that far.....?

Right honourable speaker, I did not say stupid Model,I said stupid computer!

HONEST 

Edited December 19, 2018 by karlos1983

[feb1991blizzard]

13 minutes ago, Ali1977 said:

What a chart..

P10 is a crazy chart, but again some decent ENS in FI. 

Thats a 17th Dec 2010 redux, the only time in winter proper i can ever recall a chart with the oranges so high in latitude, and that includes looking through a lot of re-analysis, not just the last 10 years.

[Kirkcaldy Weather]

Some last minute additions on my Christmas list to Santa   (expecting more charts along these lines becoming more frequent as we head through Christmas and towards New Year)

trying to link those heights through the north pole / arctic

 

 

POTENTIAL increasing for a starter before the main course and possibly dessert later in January / February? - I hope so

[bluearmy]

8 minutes ago, karlos1983 said:

Here we go perhaps.....

i wouldn't be looking for specifics for the uk yet karlos - just viewing the NH evolutions will show that something could well be afoot in the modelling ……. if so, will take more time to settle down

[karlos1983]

2 minutes ago, bluearmy said:

i wouldn't be looking for specifics for the uk yet karlos - just viewing the NH evolutions will show that something could well be afoot in the modelling ……. if so, will take more time to settle down

No not looking for anything specific, but that's a drop off in the low res we've not seen for a while, so one to watch perhaps. 

[East_England_Stormchaser91]

Small steps, but I feel this could be the start of the models picking up on a change, I.e perturbation 10 mentioned above throwing out a stonker!  

Get Christmas and new year out of the way first, enjoy the turkey and Buck’s Fizz, and then I’ll lay a substantial bet that we should start seeing some real eye candy charts rolling out post new year. 

This year seems to have a 2012-13 ring to it. Quite a changeable zonal setup pre Christmas with the usual wet and windy weather, followed by a possible drastic flip into January, as we saw happen. 

[bobbydog]

12 minutes ago, bluearmy said:

Yes, i detect a step change in the gefs low res ………..

Many showing building HLB, wave 2 activity, strong signals that we'll be seeing some epic eye candy charts in the next few days.

This forum should be buzzing!

[Methuselah]

But, if Snowmageddon tarries for too long, peeps'll start predicting its breakdown...?

[Glacier Point]

Tropical modelling suggests a coherent MJO wave to enter the Maritime Continent during the coming week.

Week 2 forecasts indicate a widespread -ve velocity potential across the central and eastern Pacific, where SSTAs are well above normal and likely to favour enhanced westerlies (weaker Trades). There have been several westerly wind bursts this autumn and early part of the winter and I would expect this to be another one in evolution.

So although the MJO signal is relatively weak, this will transpose onto a an El Nino low frequency base state. Total and relative angular momentum will as a result increase. There's no indication of deposition of westerlies via mountain torques over Asia, so a steady laddering up of angular momentum looks most likely. 

That's a signal for phase 6 evolution in the first week of January.

We should then begin to see westerlies scrubbed from the atmosphere over time returning the GWO towards phases 7 and 8 during week 3 (2nd week January, possibly with the MJO in phase 8).

That could well coincide with the first lagged impacts of the stratospheric warming. With the net ENSO, GWO and MJO signals, I'd suggest mean trough solution across Scandinavia and into Europe with a Greenland type high is the most likely evolution. What do you say CFS ?

[ZK099]

5 minutes ago, Glacier Point said:

Tropical modelling suggests a coherent MJO wave to enter the Maritime Continent during the coming week.

Week 2 forecasts indicate a widespread -ve velocity potential across the central and eastern Pacific, where SSTAs are well above normal and likely to favour enhanced westerlies (weaker Trades). There have been several westerly wind bursts this autumn and early part of the winter and I would expect this to be another one in evolution.

So although the MJO signal is relatively weak, this will transpose onto a an El Nino low frequency base state. Total and relative angular momentum will as a result increase. There's no indication of deposition of westerlies via mountain torques over Asia, so a steady laddering up of angular momentum looks most likely. 

That's a signal for phase 6 evolution in the first week of January.

We should then begin to see westerlies scrubbed from the atmosphere over time returning the GWO towards phases 7 and 8 during week 3 (2nd week January, possibly with the MJO in phase 8).

That could well coincide with the first lagged impacts of the stratospheric warming. With the net ENSO, GWO and MJO signals, I'd suggest mean trough solution across Scandinavia and into Europe with a Greenland type high is the most likely evolution. What do you say CFS ?

So you're thinking a Greenland High more likely than a Scandinavian High, bringing a northerly rather than an easterly? 

[Stuie]

5 minutes ago, ZK099 said:

So you're thinking a Greenland High more likely than a Scandinavian High, bringing a northerly rather than an easterly? 

Still looks easterly to me, perhaps slightly NE. 

Edit: as final evolution

Edited December 19, 2018 by Stuie W

[northwestsnow]

We now have consensus between ukmo ec at 144..

Or at least they look similar

Edited December 19, 2018 by northwestsnow

[Stuie]

2 minutes ago, northwestsnow said:

We now have consensus between ukmo ec at 144..

Pretty much, EC has the colder air more into Europe towards France but splitting hairs really.

Edited December 19, 2018 by Stuie W

[Johnp]

I'm not buying that ECM evolution between 144 and the 168 - seems a bit over progressive?

[northwestsnow]

EC - the block holds on out to 192..

Would be nice to see the back of the lows hurtling across the Atlantic tho..

[cheeky_monkey]

after tomorrow it looks cold or a very cold Xmas period in my neck of the woods...after new year looks a bit messy though

[ZK099]

17 minutes ago, Stuie W said:

Still looks easterly to me, perhaps slightly NE. 

Edit: as final evolution

I'm unsure although SSWs usually do favour an easterly for us as far as I'm aware. GP an expert on this sort of thing though so definitely worth paying attention to. To be honest, I'd rather a Greenie bringing a North Easterly, been far too long since we had a potent one of those. Last prolonged one has to be 2010

Edited December 19, 2018 by ZK099