Model Output Discussion - 10th Jan Onwards

[Panayiotis]

Sorry but saying it again .

If Greenland heights don't exist ,it's very difficult to bring cold eastwards .

Shortwaves appear closer to the time and those are hurdles models don't detect to nearer off the time .

Next week not just going be not as cold here ,central Europe also missing a eastward push .

This chart brought my location(look at distance asl) 5-10cm of snow, I see no +ve heights over Greenland?

Edited January 10, 2014 by Panayiotis

[Yarmy]

Would it be facetious to point out that the 2 incoming lows are - literally - pear-shaped?

 

[Chris K]

 

I think that you are being unnecessarily critical, cc, or have unrealistic expectations of strat FI charts.

 

In fact Tim, there has been a warming of the stratosphere around now - yes, not as severe as the charts initially forecast - but perhaps more in line with others pre winter expectations for around this time. And without this stratospheric warming that has resulted in the split in the PV, we would still be talking about the next bout of severe storms hitting the west coast. Instead, we now see the first signs of a Scandinavian high influencing our weather pattern. We may not see the easterly that was initially programmed, but we have seen a big change in the pattern in our sector that will assist for the rest of winter. It appeared earlier this week that we has rolled a 6 at the first throw, but now (in line with earlier expectations ) that that is not the case. But, as Tamara has pointed out earlier today, we still will probably have more throws of that dice that will possibly drag that Siberian high further westwards as winter progresses. Hopefully.

 

Added below is current 10 hPa chart showing minor strat warming from wave 2 forecast that has induced split.

 

 viewimage.png

 

Interesting chio....

 

I do like the 'rolling of the dice' analogy because it puts it into perspective for me. Whilst Strat warmings look to be beneficial in increasing the likelihood of bringing cold conditions to the UK...to me it is almost a thing of pot luck whether we actually get it or not. We are after all a small blob in the whole of the N hemisphere and nothing is guaranteed, with small changes often meaning larger differences in outcomes for the UK - As I am sure all of us here know by now!

 

It is encouraging to see warming still forecast in the models, as I feel it means there is still opportunity down the line for this remaining winter. I am sure it is also fascinating for those (including yourself) to research the effects of stratospheric influences on weather patterns for us and other parts of the Northern Hemisphere.

[draztik]

think its important to point to the change in the ecm ens over the last 24 hrs. Yesterdays 12z mean indicated below average conditions at the 5000ft level across much of Europe... Today, the model shows something of a flip, we see a weak positive anomaly for western and eastern Europe!

6-10 day temp anomaly ecm ens (12z today, & 12z ystday)

Moving frwd, the outlook from naefs continues to signal a westerly flow, with the 10-15 day heights conducive for this setup. The temp anomaly keeps the UK around average for this period. A pretty bleak setup for end of january, and of course this will change... But we must accept a return to a more mobile period has been the favored medium term route for days now from the ens, with troughing to our nw & n, a consistent feature from naefs, gefs and the update from ecm monthly into this time period.

11-15 day heights naefs 12z

Edited January 10, 2014 by draztik

[bluearmy]

Draztik makes the salient point. At the outset, this easterly was predicated on heights dropping to our south and remaining low. That's twice that the ECM ens have got this wrong but to be fair to the model, is time the gefs and gem ens were in complete agreement. Although a different situation to the failed dec '12 easterly, the surprise is almost the same. I recall that being blamed on something solar by Stewart.. Any takers this time?? It just seems that the inability to get euro heights to drop in a sustained fashion is the key here. Oh, and the Norwegian shortwave doesn't help but that always seems to happen nowadays.

[damianslaw]

Complex set up at the moment and the models are struggling with the reliable timeframe at best about 72 hours. With this in mind, expect wild fluctuations from run to run at the 96 hr timeframe. We have three factors which don't sit particularly well together i.e. heights building to the NE, but an unknown just how strong and where they will settle, a very southerly tracking jet which in turn is resulting in a very slow moving trough feature from the west - with nowhere to go it seems, and a polar vortex which has lost its oomph.

 

Its a very messy set up with a number of possible outcomes - interesting to see some of the models toying with the idea of mid atlantic block eventually - whats the betting some of the models show up a screaming northerly instead of the easterly, I wouldn't be surprised.

 

Conditions generally are becoming much more conducive for a cold spell but we are not quite there yet.. but we all know the latter part of January through until March is the period of the year when sustained colder weather is much more likely - the SST profile is very conducive for a negative NAO at the moment..

[mulzy]

De Bilt ECM ensembles continue to show a reduction in the number of colder solutions.  However, a few of them (maybe 10-15%) still remain at days 6-10.

 

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.php?run=12

Edited January 10, 2014 by mulzy

[Yarmy]

Draztik makes the salient point. At the outset, this easterly was predicated on heights dropping to our south and remaining low. That's twice that the ECM ens have got this wrong but to be fair to the model, is time the gefs and gem ens were in complete agreement. Although a different situation to the failed dec '12 easterly, the surprise is almost the same. I recall that being blamed on something solar by Stewart.. Any takers this time?? It just seems that the inability to get euro heights to drop in a sustained fashion is the key here. Oh, and the Norwegian shortwave doesn't help but that always seems to happen nowadays.

Solar activity has ramped with the solar flux well over 200 the past few days. Saying that, it's hard to imagine what if any impact it's had on this failed Easterly (assuming it has failed, of course).

[swilliam]

The ensemble mean has changed quite a bit a might be expected (especially for the 850s). However the debilt ensembles still showing some cold runs so still some possibilities although the METO 10% is probably about right.

 

 

The mean at 240 still shows to my untrained eye a split jet to the WEST of the Uk  - perhaps someone more expert could clarify. It also shows the PV moving menacingly towards Greenland

Edited January 10, 2014 by swilliam

[Summer Sun]

GFS 12z ensembles have virtually scrapped any cold now maybe a day or 2 at best of something slightly below average

 

 

The continued positive signal from the ensembles is lower rainfall totals which should enable flood hit parts to start and dry up

[Eskimo]

If it's any consolation, the 18z is looking slightly better than the 12z. Energy digging further SE, slightly higher heights over Scandinavia & slightly more ridging in the Atlantic

Edited January 10, 2014 by PerfectStorm

[Eskimo]

Slightly lower pressure over Italy, come on 18z, show us why you're the pub run!!

EDIT: Am I on my own, narrating the model run lol?

Edited January 10, 2014 by PerfectStorm

[East_England_Stormchaser91]

This run looking better to set a trend for a Svalbard/Greeny high so far. We also see more of a pressure drop over the Med. We need to get a deep San Siro low! to advect cold air, and allow for height builds over Scandi too. This run is also good in respect to not allowing those Northern heights to phase with them over S Europe, and as a result they stay put instead of being dragged down. 

[karlos1983]

this is much better,

shame it's not the 12z, but I'll take it! 

[Allseasons-Si]

Slightly lower pressure over Italy, come on 18z, show us why you're the pub run!!

EDIT: Am I on my own, narrating the model run lol?

Everyone is hiding behind the sofa with no access to the keyboard lol!

 

as for the 18z i do notice at bit more forcing from the scandi hp (tip of norway)@108hrs

 

18z 12z

 

whether this is a good thing who knows(still learning)

[Duane S.]

Second pub run in a row to be the best GFS run of the day? More determined looking Scandi block midweek

[Purga]

Higher pressure to the NE on this run

But even if 18z shows a decent pub run who is going to believe it?

 

Seriously!

[Panayiotis]

Yes its a much better 18z compared to the 12z, images below really show why!

[Allseasons-Si]

Look at the differences @144hrs

 

18z 12z

 

this is a lot lot better,the football has gone through the window and has come out looking flat

 

 

[Panayiotis]

The 18z is still sinking the high however, question is will it actually verify like this?

[Weathizard]

Well thats predictable, after all hope is gone and the sailors were lost at sea the GFS throws us a rope... Unbelieveable really, its not perfect but within 144hrs a few minute changes could really help us, even if we don't get what we long for at the first bite, we do not want a reset of this pattern again, if youre a coldie that is. Key differencs on this run looks like the drop of pressure in the med, as (Steve? I think) said earlier, without the some energy there we have no real way of moving the low pressure into a position were it can undercut.

[bobbydog]

i thought we'd established that the differences in input data between runs is negligible, therefore the "pub run" thing is a myth.

 

never mind, i find the school run has much less childish behaviour.....

[Rocheydub]

i thought we'd established that the differences in input data between runs is negligible, therefore the "pub run" thing is a myth.

 

never mind, i find the school run has much less childish behaviour.....

Superb!!!

 

Anyway, this is just like one of the ensembles, (Can't for the life of me remember which one!) and it ended with a strong Scandi HP, and it regressed to a Greenie HP…. 

 

If only! 

[Ice Day]

Not a bad chart at 180, perhaps this is the run that stops the rot?  Upgrades for the next two days then bingo!

 

[Allseasons-Si]

I know it's @186 but there is more hight's to our north,i see this low in the north atlantic diving se,we shall see.