Model output discussion - 21st Jan Onwards

[Singularity]

In other words, we know they are coming with great certainty  Fantastically informative post Lorenzo, as we have all come to expect 

Just comparing the GFS and UKMO 12z det. runs and given how quick UKMO is to get the MJO going while GFS falls flat, it's perhaps not surprising to find the pattern less flat on the UKMO run (the right-hand chart):

 

The UKMO run would have looked even more amplified over the U.S. had it now been for that shortwave in the NE Pacific... trust one to turn up 

Notice too how the Aleutian trough is focused further west in the Pacific in the UKMO output. Another anticipated change as the tropical forcing comes into play. A stronger Siberian high and I suspect Kara ridge at the higher levels is another bonus... thank you UKMO!

 

Thinking longer term again, there is a bit of a discord between the signs of residual low heights over eastern Canada from the models and the notion that the change to a negative NAO could start off west-based. So the Canadian lobe has to be vacated from NE Canada ahead of the anticipated neg NAO establishment. If this happens with the low heights being drawn east to the main vortex lobe just NE/E of the UK, then it will be a case of whether the associated cyclonic circulation is close enough to our east to compensate for the west-based neg NAO. This does seem to be the scenario that the models are more keen on trying to have unfold - even the somewhat disfunctional longer-range GFS output is starting to explore the idea to some extent.

An alternative scenario sees the Canadian lobe pulled back west by shortwave development over the western U.S. or Canada. This would help to produce a less west-based neg NAO, but it appears that the stratospheric displacement will encourage height rises in that region (and up through Alaska) to such an extent that shortwaves punching into the region look likely.

 

Via this logic we arrive at the theme of the flow first becoming more NW, then N, with time; seasonal changes support the movement east of blocking in the vicinity of Greenland as we head toward mid-Feb, bringing about a more east-based neg NAO. 

At which point, it will be a matter of how much cold air there is to come our way. For that I suspect achieving a draw from the NE as the polar vortex shifts further south into Europe (this being the expected progression)  would be our best bet - but now I'm getting way ahead of myself!

 

In the meantime, we should keep an eye on the MJO, because a faster kick-off into a new cycle such as UKMO is going for opens the door on achieving more in the way of mid-Atlantic ridging even as the pattern sorts itself out over the U.S., which would offer the chance of some transient back-end northerlies. Not of much value away from the north I know, but miles better than tropical maritime muck in my opinion.

[SMU]

Afternoon all -

so another day drifts past with nothing of interest for our little plot of land. It seems all around are celebrating snowfall & bitter temps - were back in the westerly mire.

There seems just a hint or irony in the air over the last few days - the more some have promised - whether that be through the mystical ball of teleconnections or relating to the stratosphere the more the real time models have produced the inverse - IE strong positive heights to the SW & South & strong zonal winds & low heights to the north.

This is already going down as your typical twenty 'tens' winter, over promised - under delivered -

whether it be the magical 1983 template that never appeared ( infact almost 100% opposite ) or the warming of the strat - the reality is nothings touched the sides.

we will need something biblical to split that vortex this year - its as a tight as ever before & sadly the waves & or minor warming are having minimal impact - perhaps at best bringing the zonal winds back closer to average - but average doesnt cut the mustard-

 

Jans out the game now - so reality is 4 official weeks of winter left - so plenty of time left? No ....

some time left- some time to scrape 1 more blocking high in the right place...

I project 1 more dip in the AO towards valentines circa -2 & the NAO hopefully will cooperate enough to give us another go at cold-

if im honest as ive put a couple of times this winter - I had low expectations from day 1 - & the record december CET cemented that ...

 

could this be the mildest winter on Record - .......

S

[Derbyshire Snow]

Hi,

Just a quick look at the models, will have an in depth look later this evening.

No change as expected yet, Strong jet, large bartlett high , no heights to the north. Not good. I think we were very lucky to get that cold spell we had this year in an El Nino winter. I think we are going to have our patience tested

If anyone interested this is the 5.15pm image downloaded off my dish of the big snowstorm, cold front clearly shown.

[Swave Snow]

17 minutes ago, Steve Murr said:

hippieAfternoon all -

so another day drifts past with nothing of interest for our little plot of land. It seems all around are celebrating snowfall & bitter temps - were back in the westerly mire.

There seems just a hint or irony in the air over the last few days - the more some have promised - whether that be through the mystical ball of teleconnections or relating to the stratosphere the more the real time models have produced the inverse - IE strong positive heights to the SW & South & strong zonal winds & low heights to the north.

This is already going down as your typical twenty 'tens' winter, over promised - under delivered -

whether it be the magical 1983 template that never appeared ( infact almost 100% opposite ) or the warming of the strat - the reality is nothings touched the sides.

we will need something biblical to split that vortex this year - its as a tight as ever before & sadly the waves & or minor warming are having minimal impact - perhaps at best bringing the zonal winds back closer to average - but average doesnt cut the mustard-

 

Jans out the game now - so reality is 4 official weeks of winter left - so plenty of time left? No ....

some time left- some time to scrape 1 more blocking high in the right place...

I project 1 more dip in the AO towards valentines circa -2 & the NAO hopefully will cooperate enough to give us another go at cold-

if im honest as ive put a couple of times this winter - I had low expectations from day 1 - & the record december CET cemented that ...

 

could this be the mildest winter on Record - .......

S

Sincerely hope not.  

 

And hopefully this would be the reverse psychology needed after that request to ignore all the models backfired a few weeks ago.

 

Let's be honest this winter has made fools out of weather models and professionals and ametuers.

 

If the weather does turn much colder what will it look like for all those now writing off the remainder of winter.

 

 

[chris55]

At face value if this Strat pattern at 198 subsequently trickled down to the lower levels then surely some better overall charts should show up during Feb.

The renewed warmings later in the run seem to displace the vortex again. but into the wrong place.

 

So as a layman, common sense would suggest the displacement at around day 8 would have a more meaningful effect on our patch once it feeds through, than the one later in the run.

So to summarise if the 10hpa charts do ultimately effect the trop charts then i can see where Ian is coming from re, feb. If the lag is around 10-15 days?

Edited January 23, 2016 by chris55

[MR EXTREMES]

I agree Steve murr the models show nothing of interest to be honest and I also felt the El Niño 98 was very similar to December 15 and west QBO I'd be inclined to suggest winter is over here in the south.

and long range models have been spot on and they look to continue the theme.

bring on the spotless sun this coming year. 

[SMU]

19 minutes ago, Swave Snow said:

Sincerely hope not.  

 

And hopefully this would be the reverse psychology needed after that request to ignore all the models backfired a few weeks ago.

 

Let's be honest this winter has made fools out of weather models and professionals and ametuers.

 

If the weather does turn much colder what will it look like for all those now writing off the remainder of winter.

 

 

If only I could go back to that day to show you what the day 6 GFS showed V what actually verified - you would be surprised at how close the cold air was....

i just cant be bothered to look but feel free to find my post & I will do the rest

s

[mb018538]

30 minutes ago, Swave Snow said:

Sincerely hope not.  

 

And hopefully this would be the reverse psychology needed after that request to ignore all the models backfired a few weeks ago.

 

Let's be honest this winter has made fools out of weather models and professionals and ametuers.

 

If the weather does turn much colder what will it look like for all those now writing off the remainder of winter.

 

 

I don't think it has made fools really....most people expected a mild to very mild winter, and that's what we've ended up with!

[IDO]

Yes whatever is going on in the background there is absolutely no sign of it showing up in the GFS. As Steve says, quite the opposite. The GFS op and Control are flat with zonal through to D16 and looking like there is little potential from there. The GEFS mimic the higher resolution with a very flat pattern in keeping with heights to the south and lower heights to the north. The D16 mean is similar to this morning: 

  w3 +w4 CFS: 

If anything the CFS w3-w4 anomalies are very strongly in favour of strong heights to the south (as above).

I do expect the 06z and 18z runs in FI to maybe be more meridional but anything after D7 from them is really not interesting without support from the two main runs. The GEFS temps and T850s are looking to be above average:

London: 

The T850's show the classic zonal waves as PM and TM air interchange over the UK. The mean suggests that we don't really get on the cold side of the jet.

I still have little hope of a change pre D10, pretty much locked in IMO. After (D11-15) that I would still suggest a zonal flow as the most likely scenario (nearly 100% on the GEFS), but with the experts expecting big changes then I would probably have to draw a line at D10 for the moment and wait for a few more runs.

[SMU]

Well despite the overall very poor output, this little fella would need keep an eye on-

a spell of heavy snow for areas north of the lows centre point -

S

[Jason M]

Yep, this is one of those occasions where the day 10 mean charts are a very good representation of the outlook (normally isn't the case). From where we are now I'd say the winter record is a gonna. December did so much of the heavy lifting in that regard that we only needed two moderately mild months anyway. 

Assuming a more northerly / northwesterly flow late on in Feb peeps in the north and northwest are still in the game. For us down south though that would probably mean game over down here in terms of anything meaningful. The combination of warmer than usual ssts, warmer than usual soil temps and a stronger sun mean that it's going to be hard to get laying snow in the 2nd half of Feb down here (not impossible but difficult).

To my mind GFS comes out of the last few weeks with some credit here. Yes it struggled last week with the detail like all the models, but it was adamant for the most part of pressure being high to our south and that tendency was brought all the way through the timescales to the present day. Of course it didn't nail all the detail, but it sure nailed the basic pattern.

 

Edited January 23, 2016 by Jason M

[egret]

14 hours ago, mb018538 said:

I don't think it has made fools really....most people expected a mild to very mild winter, and that's what we've ended up with!

And many were looking at global patterns and saying, colder towards the end of winter - We are still in mid winter ( just it doesn't feel like it today!)

I continue to watch this particular period of models with great interest as I expect a rapid change during the first week of February and  then what might be seen as an unexpectedly swift return to Northerly regime.

It is remarkable how often  there will be a couple of hints a week to ten days ahead,  a swing away for a week or more and then a suddenly reappearance at 48 hours or less.

Put another way projections at 240 hours seem to to keep edging away in time with each run and then suddenly rush forward with a flourish like important bits of jig saw falling into place and allowing the picture to be suddenly completed.

 

Edited January 24, 2016 by egret
typos

[nick sussex]

The ECM has a little interest possibly!

We have to be a bit wary of projections showing the jet further south at longer range, with the PV still in relentless mode this is hard going but in an effort to find something remotely interesting the ECM has a low running east and then a weaker shortwave.

The first low could give some snow on the northern flank, this second shortwave might also develop in future outputs. The ECM does at least try and displace the Euro high.

It does look reasonably amplified in the east Pacific at day ten and is a little better than this mornings 00hrs run.

Overall tonight however still no sign of low heights lifting away from Greenland and even if the main PV goes to Scandi unless any lobes get displaced well away from Greenland and not ne Canada but further west towards Hudson Bay then little chance of any deeper cold.

We are now entering last chance saloon time and have to hope that something happens with an SSW or the MJO can get its skates on.

The PV is very strong and will take some shifting, but hopefully will at least weaken with some of those strat warmings, whether that's sufficient we'll see but we don't really have time for any more " the strat warming was in the wrong place, the PV didn't displace favourably, or any other strat hard luck stories".

For something that's been the subject of much debate its really dragged out this whole warming episode, with so many caveats to it that really one wonders why it all has to be so complicated!

 

[lukemc]

Nick,

Just a quick question for you any ideas to why the PV is so strong at the moment as usually towards the latter part of the winter it weakens and so does the Jetstream meaning a greater chance of blocking - isn't it unusual to get such raging zonality as we enter zonality.  Do you think it is related to the El Nino or is it, as you have suggested related to the minor stratospheric warmings? Do you think a scenario more akin to 1998 or 1983 would be more likely for February?

 

Luke

 

[nick sussex]

1 minute ago, lukemc said:

Nick,

Just a quick question for you any ideas to why the PV is so strong at the moment as usually towards the latter part of the winter it weakens and so does the Jetstream meaning a greater chance of blocking - isn't it unusual to get such raging zonality as we enter zonality.  Do you think it is related to the El Nino or is it, as you have suggested related to the minor stratospheric warmings? Do you think a scenario more akin to 1998 or 1983 would be more likely for February?

 

Luke

 

The El Nino has been by far the over riding factor in the winter. Normally as you go through February the PV should weaken but of course looking at it now it looks on steroids!

Although of course you want to see these strat warmings they can have the effect of initially increasing the zonal winds as the PV responds.

We really need a knock out blow but its going to be difficult, currently I think a minor SSW is looking like a good bet, this should weaken the PV and if the MJO can get a move on you might get these combining to provide a window of opportunity.

A major SSW is more up in the air, the problem however with these SSW's is the trop response and it can still be a bit of a lottery.

Even though I'm underwhelmed by the current outputs there is still time to salvage something from the winter but we don't have the time for anything else to go wrong!

February has in the past delivered and if you get the right synoptics then the increase in solar energy can be overcome but of course that's the big question, will these right synoptics appear during February or will it be a case of March producing those " if only it was winter outputs"!

[northwestsnow]

Still over 5 weeks left guys.

The warming high up is underway , lets see how the models look in another couple of days, although i do agree Jan is looking a dead duck insofar as cold for the UK is concerned.

ECM is looking ripe for some decent PM shots at day 10

edit :I know its been another tiresome winter so far for the coldie brigade but 3 cheers for the coldies, we have kept a stiff upper lip in the face of adversity- i have a good feeling our patience will be rewarded come mid Feb .

Edited January 23, 2016 by northwestsnow

[wishingforsnow]

If we get decent winter synoptics and conditions in February and March I won't be complaining

Edited January 23, 2016 by wishingforsnow

[northwestsnow]

Personally i put a lot of stock (and hope) in what Fergie and the meto are implying for Feb-mid Feb can still provide something very decent from a northerly.

Im expecting to see upgrades in the coming few days

[nick sussex]

5 minutes ago, wishingforsnow said:

If we get decent winter synoptics and conditions in February and March I won't be complaining

I don't mind March snow if the winter has been okay because then you're not frustrated that those synoptics didn't appear in the winter.

The only thing IMO that can salvage the UK winter is the following during February.

2 cold spells of at least 5 days each, ice days, snow UK wide and no marginal slush.

Unless that happens then I will place the winter of 2015/16 in the rubbish category.

[Singularity]

I am slightly shocked that posts on here haven't yet picked out just how much progress ECM has made toward the theoretical evolution tonight (but Nick has at least seen something, for which I offer a virtual handshake). 

I mean, it finally sends the jet properly south over the U.S. and develops decent high latitude blocking across Canada to send that vortex lobe into the Atlantic via Greenland. Correction to the wavelength in the Atlantic has allowed a better dig south of the main vortex than we have seen on any of the other det. runs over the past week, even getting ahead of what is a similarly promising 12z GEM det. run.

In order to comprehend the level of progress, one has to consider two things. First is the fact that a realistic target for conditions to start becoming cold enough for lowland snow in places south of Scotland is somewhere between 7th and 14th Feb, 5 days beyond the end of the ECM 12z det. run. Second is the very real possibility that trends could continue, with further upgrades to the dig south of the vortex lobe in our vicinity for the first two days of Feb. It's not something I'd be willing to bet on yet, but certainly on the cards.

Now, I know many will look at the disturbance just west of Greenland and the low coming across the U.S. and see low pressure development south of Greenland causing frustrations. That's exactly what I see as well - but IMO this is almost inevitably going to be a part of the process while we wait for seasonal adjustments to how the tropical forcing feeds through to shift the pattern further east and get those height rises into Greenland.

That's where Lorenzo's west-based NAO risk comes from, as a transitional threat to the sanity of those who find it hard to play the long game. Yes, I'll admit, I'm not going to be all that happy with a mid-late Feb cold spell unless it involves some exceptionally cold air to compensate for the increased solar input, but what can you do?

Edited January 23, 2016 by Singularity

[Frosty.]

11 hours ago, Paul_1978 said:

 Personally a north westerly doesn't hold much interest, as I'm sure is the case for many on here :-(

Personally, a switch to a meridional pattern with robust mid Atlantic ridging holds plenty of interest to me as it wouldn't just be polar maritime NW'ly flows, it would also include Arctic air sweeping south so I hope the met office continue to firm up on this on future updates!

[nick sussex]

Singularity yes I agree the ECM is an improvement however I don't trust outputs with the jet projected south with the PV still in that location.

Model bias re southwards jet placement has to be factored in at longer range in this type of set up. For this reason I'll be more confident when its shown within T168hrs.

As I mentioned earlier the ECM looks quite amplified in the east Pacific at day ten and yes the ECM after that point could develop more favourably but I'd like to see a consistent signal for this.

If the jet does get further south then theres a chance of some interest more especially for northern areas as low pressure runs east but I've been reluctant to overplay this until the jets southwards projection is shown within T168hrs.

Looking at the ECM ensemble spreads the main one relevant to the UK from T192hrs to T240hrs is the track of low pressure in terms of how far south this gets.

 

Edited January 23, 2016 by nick sussex

[John Badrick]

36 minutes ago, northwestsnow said:

Still over 5 weeks left guys.

The warming high up is underway , lets see how the models look in another couple of days, although i do agree Jan is looking a dead duck insofar as cold for the UK is concerned.

ECM is looking ripe for some decent PM shots at day 10

edit :I know its been another tiresome winter so far for the coldie brigade but 3 cheers for the coldies, we have kept a stiff upper lip in the face of adversity- i have a good feeling our patience will be rewarded come mid Feb .

I would say we still have around 9 weeks left for the search for proper cold and snow. My search for proper winter weather will end on the 31st March, when the hunt for warmth begins, but until then there's plenty of time yet for things up top to get interesting.

[Frosty.]

The Ecm 12z op run ends on an increasingly promising note for coldies with the jet digging further south and lots of cold / very cold air to tap into from the NW / N as we head further into February. I hope we do see a marked pattern change to meridional with strong mid-atlantic ridge and an opening of the floodgates to much colder conditions through the last third of winter and into early spring too!

[IDO]

21 minutes ago, Singularity said:

I am slightly shocked that posts on here haven't yet picked out just how much progress ECM has made toward the theoretical evolution tonight (but Nick has at least seen something, for which I offer a virtual handshake). 

I mean, it finally sends the jet properly south over the U.S. and develops decent high latitude blocking across Canada to send that vortex lobe into the Atlantic via Greenland. Correction to the wavelength in the Atlantic has allowed a better dig south of the main vortex than we have seen on any of the other det. runs over the past week, even getting ahead of what is a similarly promising 12z GEM det. run.

 

The GFS has the same wave from the Pacific as the ECM around the same time and also deepens the US trough, however after D10 it flattens the ridge as the Asian PV lobe pushes east and this kills the meridional flow before it can work its magic downstream (Atlantic). We do not see D10-15 from ECM but we do the GFS and GEfS and the latter currently says that the Pacific wave will generate some residue heights towards the Arctic but will not sustain any EPO. Remember the models played with the U.K. to Scandinavia ridge several days ago at that sort of range and backed off, and ECM at D10 where heights are concerned is notoriously unreliable. Not saying it cannot happen but until evidence says otherwise I am not holding my breath.

Edited January 23, 2016 by IDO