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

[Ali1977]

4 minutes ago, blizzard81 said:

Oh dear! The scandi high gets a battering on this run. Bad trends so early in the run.

I think this was a given after the ECM and METO thoughts, beyond day 10 is when some form of Easterly looks more like happening so it's how that comes about.

cold floodgates still look primed to pounce.

Edited February 1, 2017 by Ali1977

[blizzard81]

2 minutes ago, DJ RY said:

Sunday's low much shallower on GFS 18z 

Plenty of cape with slightly negative lifted values around the south & west and over much of Ireland though by the afternoon so heavy, thundery showers might get blown inland on the breeze especially near the coasts where cape remains the highest from Saturday evening onwards. 

Yipee! Let's have some thundery showers in Feb lol

[Methuselah]

4 minutes ago, blizzard81 said:

Oh dear! The scandi high gets a battering on this run. Bad trends so early in the run.

Repeat after me: the trend is our friend!

[blizzard81]

I don't know about anybody else but it just looks like the 18z doesn't know what to do on this run lol

[johnholmes]

1 hour ago, Man With Beard said:

Must add this one to the discussion. Thoughts @knocker @johnholmes?

It is an interesting chart and does have considerable possibilities in terms of getting cold air into the UK. All 3 I use are going along with something fairly similar, whilst the NOAA 8-14 is not that different from the chart shown.It is for sure not what could be termed a mobile Atlantic. Just how it will pan out is not really clear yet but I would suggest the last 2-3 days of anomaly charts are probably the most supportive this winter of cold weather. How long it might last? Well sticking my neck out IF it develops then 5-7 days would be a reasonable bet at this stage!

[blizzard81]

2 minutes ago, Ed Stone said:

Repeat after me: the trend is our friend!

Lol, not today it isn't

[ACCOUNT DELETED]

3 minutes ago, blizzard81 said:

Yipee! Let's have some thundery showers in Feb lol

Lol we had plenty of those during the last few Winters in S Wales. They came rolling in on and off all day and night from the Bristol Channel! 

[blizzard81]

2 minutes ago, DJ RY said:

Lol we had plenty of those during the last few Winters in S Wales. They came rolling in on and off all day and night from the Bristol Channel! 

This is the flavour of our present day winters lol. No snow but at least some juicy thunderstorms to drool over. This is what it has come to lol.

[winterof79]

Scandi high takes a deep breath and puffs its chest out laughing at the Atlantic....is that all you've got big lad?

[winterof79]

The taming of the Atlantic continues

 

[blizzard81]

We are fast approaching the "boring" easterly option. Cold but dry and not feeling too bad in any sun lol.

[Ali1977]

Easterly in by day 9, still looks cold and still wintry showers feeding in, could be a great FI but I'm happy that all looks good for next weekend being cold at the minute.

scandy high about to get a WAA reload maybe 

Edited February 1, 2017 by Ali1977

[winterof79]

2 minutes ago, blizzard81 said:

We are fast approaching the "boring" easterly option. Cold but dry and not feeling too bad in any sun lol.

Unfortunately the drum you are beating is downwind of the easterly and not being heard.I will take a boring Easterly to start with.

[booferking]

Slow burner this run hope UK model is right as it is by far the best option known are luck when it come to cold snowy weather it will revert in the Morning to the lesser evil.  One thing this winter regarding every cold spell uk Model has been spot on thats my last hope im hanging onto for the quicker solution.

Edited February 1, 2017 by booferking

[blizzard81]

3 minutes ago, winterof79 said:

Unfortunately the drum you are beating is downwind of the easterly and not being heard.I will take a boring Easterly to start with.

Not beating any drum, just stating what the models are showing. That chart is so tame it would hardly pass as an easterly at all lol.

[snowray]

And the failed easterly is followed by a......hold on what do we have here.......ahhh false alarm its a failed northerly.

[Scandinavian High.]

Cold moving in from east easterly flow maybe snow showers for south east it's a start going right direction..

[Methuselah]

2 minutes ago, abbie123 said:

Cold moving in from east easterly flow maybe snow showers for south east it's a start going right direction..

No matter how cold it gets, an 'east easterly flow' can never be trusted!

[blizzard81]

1 minute ago, snowray said:

And the failed easterly is followed by a......hold on what do we have here.......ahhh false alarm its a failed northerly.

Lol, it really is a merry go round isn't it. We are all mad in this shared crazy love for snow. That's why I find a bit of humour is essential to lighten the load and disappointment

[snowray]

Is that what an east easterly flow looks like then? All these technical terms, I give up!

[Catacol]

So - perhaps for one last time this winter as we approach the final few weeks of proper cold potential time to try and draw a road map. Tamara has already done a better job than I can do, but I'll give my take on it nonetheless.

It was said a while back that there was a window of opportunity in mid Feb for something wintry to develop: the thinking was based upon signs of stratospheric wave 1 attack combined with seasonal expectations of the expected progress of the MJO. The return of the aleutian low and euro ridge combo set up the precursor pattern for the strat assault as illustrated here

and zonal winds are dropping dramatically if temporarily.

and this kind of temperature differential at 10mb is forcing a distressed vortex into a major wobble... always a good thing if consistent flat westerlies is what you wish to avoid.

 

Perhaps more important for us though in the medium term is the evolution of the MJO. Very pleasingly - and rather against the forecasts of a few days ago - the MJO is now set to go into a higher orbit. Strong current anomalies are obvious here

and the sustained amplification of the signal is clear through the Wheeler Hendon plots.. though let's remember these havent been great at being consistent this year

 

The combination of the stressed vortex and growing rossby amplification courtesy of the MJO burst looks potent. MJO phase 7 forecast for next week is a good match for the general forecast 

but more excitingly phase 8 at a decent amplitude is forecast soon afterwards, and this is the February holy grail

 

To sum up therefore - Canadian vortex segment in charge for a while as the combined vortex wobble/potential short term split combines with pacific forcing to drain energy from the atlantic and promote heights to our north (or more specifically NE via a retrogression of the cold arctic/siberian high.) In my observational experience the models often rush these processes a bit - so I'm not expecting next week quite to deliver the goods. But in the 10 - 14 day time frame the block looks well set to push west and enough residual energy from the current surge of the atlantic should have undercut by then to provide the basis to advect the cold west. Looks by far and away the best setup of the winter so far. John Holmes call of perhaps a 5 - 7 day spell of cold looks a good one to me, though as ever we have to wait and see if the flakes will fall or whether a slack flow will be more dry than damp. However I think the storminess of the next few days will work very much in our favour. We could do with these systems zipping into Europe and helping to significantly lower heights to our south. With that in place a Feb 91 type scenario becomes a distinct possibility.

All good news. Ignore op run wobbles - the trend looks a strong one. I'd value the view of @Glacier Point at this stage. Every other heavyweight on here seems to be leaning toward cold and it would be good to get his input too.

 

 

Edited February 1, 2017 by Catacol

[booferking]

Exeter go with there own model (fax chart)

[Mucka]

It is a tortuous evolution.

JMA just about there by day 11  

[Geordiesnow]

Variations from each run are showing a classic west east battleground but you got to say from most runs I seen, its initially the westerlies will win out but the easterlies does fight back but I do think expectations have to lower a bit though, I have seen very little evidence we are going to head into a snowy convective easterly and nor has there been much evidence the true cold air will reach the UK and if they do show this, its too far out to have any confidence in.

I think even if the westerlies look like winning, then unless the projected blocking high gets wiped away quickly then its far from over for the potential for some colder weather. Can't help but feel we been here before this winter though with projected height rises to our NE but in terms of the UK, its only affecting our shores in a slight fashion rather than anything significant.

[Daniel*]

1 hour ago, blizzard81 said:

We are fast approaching the "boring" easterly option. Cold but dry and not feeling too bad in any sun lol.

We are not fast approaching anything yet. The orientation of the blocking constantly shifts from run to run, it is as you'd expect we could well do, see a snowy easterly who knows. The only thing certain is an inflation of +ve heights to NE with cold air being relatively nearby. I don't understand why so many frame their outlook on one set of evening output it's repeated time and time again, quite infuriating. We will see change after change over the coming days. The models are struggling with such disparity even with 'storminess' in the days ahead the more vigorous LP systems the better, into Europe encouraging lower heights & aiding cold air advection. 

Edited February 1, 2017 by Daniel*