Winter Model Discussion - Cold Hunting -12Z 03/01/13

[Weathizard]

DONT BIN THE RUN!! BIN LOW RES POST T192 !!

Apologies, that's what I meant.

Hoping to see more of the PTB's trending towards a colder outcome, I have a feeling the OP may be an outlier with regards to its sypnotic evolution after t192. Still within 192 the signs aren't too bad. Ukmo pretty poor but as Fergie said 'unconvincing', although to be fair I'd say that about most models at the moment.

[Cheshire Freeze]

The trop is seeing the signs from the SSW, but at the moment little cold is heading to the UK. FI ends on the 19th so realistically the last week of Jan at the earliest for potential very cold weather. And the signals for that remain average at best.

Arctic High:

Jet ploughs on:

PV piece still stopping ridging in west Atlantic and keeps the quasi-zonal flow over the UK, with highs to our east meaning stalling cyclonic westerlies over the UK:

Better than a few weeks ago, as the trough is slightly further south. This pattern has been very strong in GFS FI now, so maybe the second warming is needed for the UK to get something more substantive than transitional cold/snow.

No, what I believe is happening is as the SSW gets closer to T 0 the GFS is correcting itself slowly but surely towards a blocked outcome and I don't believe that this metamorphasis has ceased yet.....it's a dynamic situation. I've also spotted a trend for that chunk of PV west of Grenland to want to shift further west and weaken. It's only a matter of time now before we see an op run deliver.

Just take the 10th for example...only 24-36 hours ago there were no height rises to be seen to the north.......now look at this......

An evolving situation as I said. By the 15th I really wouldn't be surprised to see the UK being affected by some pretty frigid weather.

[Azores Hi]

Some agreement between 06z and 12z at day 6-10 with regards to trough stalling out to our west, ridge forming betweem UK and East Greenland, then some residual high pressure to our NE giving a brief easterly.

A step in the right direction and all we could really expect or hope to see at this stage. The runs this weekend will be very interesting I hope!

[SMU]

One thing that will certainly effect the modelling is the strength & positioning of the arctic high- Expect lots of inconsistencies in this region as its data feeds are sparse....

S

[latitude]

The trop is seeing the signs from the SSW, but at the moment little cold is heading to the UK. FI ends on the 19th so realistically the last week of Jan at the earliest for potential very cold weather. And the signals for that remain average at best.

No idea how you get to that conclusion when a proffesional forecaster has just dismissed their own model. Its the 3rd today and you say very cold weather after the 19th!! haha...dont think you have any idea what inpact the SSW will have...........just like me.

[bluearmy]

maybe even earlier BA. i would advise anyone hanging on the GFS later stages to stop doing so and start reading Ian Ferguson's posts!

well tell i'm dreaming cos he doen't seem to have grasped it !!!

[latitude]

well tell i'm dreaming cos he doen't seem to have grasped it !!!

Exactly, reference my post #30!

[Cheshire Freeze]

P.S anyone hanging on output post 168-192 hrs in this situation is delusional. We're just about getting to the stage now where phase 2 of the pattern change is approaching the hi res (about 10th Jan) which sees the heights increase to the north. Anything (and I mean anything) past this point is pure conjecture at this stage for the time being. There will be enough changes inside 192 hours, nevermind past this juncture!

[fergieweather]

maybe even earlier BA. i would advise anyone hanging on the GFS later stages to stop doing so and start reading Ian Ferguson's posts!

A senior colleague literally just reiterated this key, key point: "No NWP will get a grip until SSW effects feed lower-down into model synthesis." Ignore -in effective sense of preventing any coronary - all GFS output post around mid-late next week. UKMO model equally showing considerable inter-run flux at longer reaches too (it goes to T+168 internally) and all of this is expected / symptomatic / characteristic of how they struggle with the complex dynamics of what is still at an incipient phase. Nothing, as yet, is offering anything surprising nor unexpected. So, please: NO MORE posts bemoaning any lack of profound cold showing at longer range of GFS, or EC, or whatever. It is all - stress ALL - considered effectively unreliable. Period.

Sit tight....!

P.S anyone hanging on output post 168-192 hrs in this situation is delusional. We're just about getting to the stage now where phase 2 of the pattern change is approaching the hi res (about 10th Jan) which sees the heights increase to the north. Anything (and I mean anything) past this point is pure conjecture at this stage for the time being. There will be enough changes inside 192 hours, nevermind past this juncture!

HOO-RAAH

[Weather Boy]

No idea how you get to that conclusion when a proffesional forecaster has just dismissed their own model. Its the 3rd today and you say very cold weather after the 19th!! haha...dont think you have any idea what inpact the SSW will have...........just like me.

...or indeed the professionals themselves given that the only prediction that we have from Ian F is that the Met say things are going to be very unpredictable mid-month!

[johnholmes]

very sensible that Ian and I would totally agree with the Met forecaster (I presume that is who you refer to as a senior colleague?). The only guidance at this range, dare I say it, will be the anomaly charts at 500mb. They are starting note I said starting to show the first signs of a ridge developing north of the UK, Svalbard region maybe ESE or possibly NNW of that area, hard to be even half sure of this yet. By Saturday IF this is going to happen then it will be fairly clear on them that it is going to happen. Chasing each model run, jumping from model to model to see which might show the coldest option will not solve anything for another 48-72 hours minimum, probably 120 hours before the synoptic models at something like T+192-240 begin to get some kind of grip on the set up.

Edited January 3, 2013 by johnholmes

[The Eagle]

Ensemble member 5 folks *drool*

Edited January 3, 2013 by The Eagle

[itsnowjoke]

Droollinggggggg

[Bobby]

At +192 pretty much every ensemble run is totally different lol. Models clearly haven't a clue.

[SMU]

For those wondering how to interprete Ians response- I would say this-

The models will start to gather more & more data associated with the SSW- as a result the NET should be the models slow the jet more & more & push it even further towards the equator / poleward even more- by splitting-

Whilst I think we can ignore the sematics at 192- the H5 anomlies showing on the GFS at 168 -240 will be the first heads up as to where things are going & Svalbard seems a good locale for one + anomaly, the extension SW from that is open to big volatility-

IF anyone wants to know what MAY happen if the jet is predicted to slow more then this is what we are looking for- perfect conditions A La Jan 1985

http://www.meteociel...&carte=1&mode=0

S

( nice to see we are on the same wavelength John)

Edited January 3, 2013 by Steve Murr

[fergieweather]

For those wondering how to interprete Ians response- I would say this-

The models will start to gather more & more data associated with the SSW- as a result the NET should be the models slow the jet more & more & push it even further towards the equator even more-

Whilst I think we can ignore the sematics at 192- the H5 anomlies showing on the GFS at 168 -240 will be the first heads up as to where things are going & Svalbard seems a good locale for one + anomaly, the extension SW from that is open to big volatility-

IF anyone wants to know what MAY happen if the jet is predicted to slow more then this is what we are looking for- perfect conditions A La Jan 1985

http://www.meteociel...&carte=1&mode=0

S

( nice to see we are on the same wavelength John)

Is that the correct link, Steve? Cheers.

[Bobby]

The 12z GEM is not as good as the 00z one and looks like a half-way house between the UKMO and GFS at ~144 so I think that could be a likely setup by then.

[bluearmy]

i'll take the GEFS mean at T276 and move onto the ecm mean later.

EDIT: although later on, i'm interested in the shrinking mean canadian vortex and the v southerly mean jet

Edited January 3, 2013 by bluearmy

[SMU]

Ian I dont think I worded it right-

the link was right for illustrating what could happen- which is on a par with Jan 1985- but I think it read that the link was 1985-

Anyway heres some 1985 early stages-

http://modeles.meteo...4-12-31-0-0.png

http://modeles.meteo...985-1-1-0-0.png

http://modeles.meteo...985-1-2-0-0.png

http://modeles.meteo...985-1-3-0-0.png

THe evolution is the same-

also the Stratosphere temps for Jan 1985 ( one of my analogues for this year that I posted) as it had a SSW

http://www.geo.fu-be...pole/index.html

1-10 Jan 1985 anomalies at 30MB.

Huge negative zonal wind at 50/60n

Cheers

Steve

[The Eagle]

Hard to know whether it's a step forward or back on the 12z models so far. GFS and NOGAPS are fairly good with lots of possibilities as do the GFS ensembles (allbeit they are all over the place post 144). UKMO is yuck. Guess it's down to the ECM.

[Weathizard]

Some seriouis stunners in the ENS, at a glance they look better than the 6z ens, lots of GH and a few Svalbaard heights. Very few look like they back the op to me.

[MR EXTREMES]

Ian I dont think I worded it right-

the link was right for illustrating what could happen- which is on a par with Jan 1985- but I think it read that the link was 1985-

Anyway heres some 1985 early stages-

http://modeles.meteo...4-12-31-0-0.png

http://modeles.meteo...985-1-1-0-0.png

http://modeles.meteo...985-1-2-0-0.png

http://modeles.meteo...985-1-3-0-0.png

THe evolution is the same-

also the Stratosphere temps for Jan 1985 ( one of my analogues for this year that I posted) as it had a SSW

http://www.geo.fu-be...pole/index.html

1-10 Jan 1985 anomalies at 30MB.

Huge negative zonal wind at 50/60n

Cheers

Steve

sorry to be a pain was this a sustained cold spell in 85 i remember the 80s winters and there were some cracking winters in this decade.

and was the warming of this winter stronger than the warming projected now?

[Ian Brown]

One thing that will certainly effect the modelling is the strength & positioning of the arctic high- Expect lots of inconsistencies in this region as its data feeds are sparse....

S

This is very true, the most difficult area for the models to try to predict High pressure is directly to the North of the UK. I hope we are not reliant on the Arctic High having to come into play to influence our weather as the chances of shortwave spoilers are far greater than a rerun of January 1987.

[IDO]

...or indeed the professionals themselves given that the only prediction that we have from Ian F is that the Met say things are going to be very unpredictable mid-month!

Quite right, but then again the models may not be far off the mark. I prefer to give them the benefit of the doubt and although it is easy to ignore the micro scale FI charts I do try and reason the long wave patterns, if nothing else but to learn from any mistakes they may make.

CFS is interesting. Siberia and parts of Russia v. cold (Feb):

Obviously cannot be taken too serious, but a trend on the CFS has been to shift the axis of cold from mid-USA to NE Europe. With strong heights:

But the UK on the wrong side of the block maintaining a westerly flow with significant rainfall:

CFS Anomaly charts of late have not shown the UK getting anything that looks like cold let alone brutal cold. I would have thought the lack of such, for a fluctuating model like the CFS, is significant in itself. Yuk:

GEFS for London:

No real changes there. Mean around seasonal average. Some mild ens and some cold ones. No strong sign of cold, especially if you take out the two early cold outliers.

[Glacier Point]

Every model run developing the strength of the +ve H5 anomaly to the north as it latches onto the downwelling -ve zonal wind anomaly.

GEFS 15th January now showing a very coherent -AO signal:

and compared to Baldwin's composite, this is just for starters. Imagine in another 10 days time what the potential is here when the stratospheric signal matures.

With the continued modelling of the main PV lobe into Scandinavia and secondary lobe lifting out of Hudson with solid ridge straddling the Pole, composites for this suggest a blocking signal centred over Iceland. The best analogues for the upper stratosphere right now are 1979. 1982 and 1987.