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

[snowray]

No sure what the ECM is up to this morning but a bit of deja vu from the GFS 0z, coming on board with GEM I see. 

Very cold easterly, lots of snow IF it verifies.

[booferking]

Please be true Ireland would be buried.

[chris55]

Heavy snow moving in from the west

[northwestsnow]

Very snowy gfs6z, lets hope this is the correct evolution ...

[Ali1977]

3 minutes ago, chris55 said:

Heavy snow moving in from the west

Ice days, heavy snow/Blizzards, sliders and what looks like a WAA reload - not a bad run.  Please be correct.  This isn't a full on RAMP as way out in FI.

Now - will this be a standout outlier or have some support in the ENS I wonder.

Edited January 31, 2017 by Ali1977

[mb018538]

I think we all know the 6z is going to be a MASSIVE outlier when the ensembles are out. At the moment, the majority of members don't back this solution, and as Fergie mentioned, not all models even back it at all.
One to keep note of for sure, but not to get too hung up about, as amazing as it looks.

[northwestsnow]

Just now, mb018538 said:

I think we all know the 6z is going to be a MASSIVE outlier when the ensembles are out. At the moment, the majority of members don't back this solution, and as Fergie mentioned, not all models even back it at all.
One to keep note of for sure, but not to get too hung up about, as amazing as it looks.

Its plausable though, but i agree probably an outlier, we desperately want to see this gather momentum and its important ecm goes a similar route over the coming 24 hours..

[numbnutts(uk)]

1 minute ago, Ali1977 said:

Ice days, heavy snow/Blizzards, sliders and what looks like a WAA reload - not a bad run.  Please be correct.  This isn't a full on RAMP as way out in FI.

it may be way out in fi but surely its got to come off at some time 

[chris55]

ECM 00z ens, that one outlier from the 12z has gained some support and the control goes very cold in the extended.

 

[chionomaniac]

On 1/29/2017 at 12:59, chionomaniac said:

Ahh well that is the difficult bit. But what @Singularity and @Tamara allude too. Scandi Block moving westwards with undercutting southerly displaced jet. It could happen with this type of set up, I guess as ever we just need the resultant daughter vortices to be in the right position and strength for that to occur, because we all know that near misses are far easier to achieve than a direct hit. But there is definite interest in this projected set up.....

I think that the 06Z has followed the script!

[Scandinavian High.]

Here we go THE BIG FREEZE OF 2017 IS COMING..OR WILL IT BE ANOTHER BIG LET DOWN I HOPE NOT.

Edited January 31, 2017 by abbie123

[Weather Boy]

27 minutes ago, TEITS said:

Classic example of why I don't use the ensembles.

The 0Z for Berlin was a massive outlier and yet 06Z continues with the trend.

Dave,

The implication of your post is that the ens are wrong and the op is right.  Of course, we don't know that in this instance, but are you just saying that it is your experience that the ops drag the ens round?

Each to his own, I suppose, as I recall GP used to say 'stick to your ensemble means'!

Good to see you back, btw

WB.

[bluearmy]

The ecm suite is so not seeing what the gfs and gem ops are that I can't believe they could verify 

[Ali1977]

At 150 the Op only has a handful ENS as support, MMM not so sure on this.  That said still a good Scandy block on most so a good outcome still very much possible.

By 216 there is still some support and there are other options which look fanntastic or even better than the Op going forward.  PV in tatters, split flows, Greeny highs and Scandy highs.

There are going to be some crazy FIs, the Control has a 3000 mile Easterly feed coming in with -28c uppers into Poland at day 11.  Sorry no pictures Mods

Edited January 31, 2017 by Ali1977

[MR EXTREMES]

12 minutes ago, bluearmy said:

The ecm suite is so not seeing what the gfs and gem ops are that I can't believe they could verify 

I must admit I'm very skeptical I hope the ecm tonight is better as gfs been very progressive and normally it's the ecm that gets heights excited.

We shall see over the next few days into the weekend we should have more clarity.

Although it could be we get a close but no cigar moment with heights hold lows over the uk.

[A.J]

ramps to the correct thread please....discussion in this thread...thanks

[NorthYorksWeather]

Here's the big 3 for next Monday morning

GFS clearly the most progressive with send the cold air westwards towards the UK.

UKMO very nice with vertical WAA up towards Svalbard, what we need to see next is lower heights over central Europe to help advect that colder air towards us.

ECM probably the "worst" of the 3 however cold air is marching already into eastern Europe, again lower heights over central Europe around Germany/Poland is what we are after which doesn't quite happen as the colder air starts to sink down towards SE Europe at 168 (surprise surprise).

All in all not a bad set of runs as we head into the final winter month, can we hit the jackpot for snow and cold? No idea, sorry.

[nick sussex]

ECM not really interested in a quicker route to cold, the GFS and GEM more so but its very complicated with the troughing stuck to the west and shortwaves running east and north.

If there was more amplitude upstream at T144hrs then we wouldn't have to be waiting several days more to get the cold west. The issue I have with both the GFS and GEM is the very low margin for error as you're relying on just enough energy going se'wards between T168 and T192hrs.

I'm not sure this thread can cope with that much stress!

Anyway putting my reservations aside the amplitude of the MJO continues to be upgraded on the MacRitchie forecast, originally this had the signal scraping around close to the COD but todays continues the trend of recent days in developing more amplitude.

The differences in the op runs could well be in relation to  whether they're reacting to the correct MJO signal.How close that remains to the COD as it progresses eastwards.

Theres also some uncertainties with how the IOD and yes we have another new term to add to the many! The Indian Ocean Dipole! Interacts with the MJO.

A brief description:

The Indian Ocean Dipole (IOD), also known as the Indian Niño, is an irregular oscillation of sea-surface temperatures in which the western Indian Ocean becomes alternately warmer and then colder than the eastern part of the ocean.

NCEP in last nights update had this to say:

 The MJO is anticipated to influence the evolution of the global tropical convective pattern, and may contribute to enhanced convection over the Maritime Continent. The interference of the IOD pattern, which will also continue to play a substantive role, increases the uncertainty.
 

So good news that the MJO is expected to have an effect but some caution in terms of how much impact because of that interference.

At this stage its impossible to rule anything in or out, we may see the models accelerate the cold west or on the other hand drag out the whole process which seems to be more what the ECM wants to do.

PS this about the MJO and IOD:

The characteristics of Madden Julian Oscillation (MJO) development and propagation during Indian Ocean Dipole (IOD) events are presented in this study. We find that MJO activity over the Indian Ocean and Maritime Continent is enhanced during negative IOD and subdued during positive IOD. MJO events occurring during positive IOD have weaker convection and less organized wind anomalies than those occurring during neutral or negative IOD. These differences are starkest over the eastern Indian Ocean where the IOD has the greatest effect on low-level humidity. Based on these observations and current MJO theories, we posit that the IOD primarily influences the MJO through its modulation of local low-level moisture.

Right I'm going to try and find out whether we're seeing a negative, neutral or positive IOD! Does anyone get the feeling that this is turning into an SAS type assault course to cold with hurdle after hurdle!

PSS The current state of the IOD is neutral and expected to remain in that area during February.

 

Edited January 31, 2017 by nick sussex

[Doctor96]

The timing of mid February reminds me of the ? 1978 easterly around same time , we just need to get the easterly in with sub zero temps day and night  and then snow will follow

Looks great potential but need to see this on charts still at weekend

[jvenge]

Most of the GEFS from the 06z are not so willing to bring the colder air to the UK, like the OP is. The OP tends to bring the cold pool further west than its ensembles, but even the ensembles are mostly showing something on the cooler side of average.

 

 

[Ali1977]

So a decent set of ENS with several great charts, but FI does seem very early.  If anything an FI trend is for a ridge into Greenland on options from the North rather than North East.  All in all, very very positive for Mid Feb onwards I'd say but from many different angles.  

Edited January 31, 2017 by Ali1977

[iapennell]

17 minutes ago, abbie123 said:

Here we go THE BIG FREEZE OF 2017 IS COMING..OR WILL IT BE ANOTHER BIG LET DOWN I HOPE NOT.

As with the other promising weather charts for cold through January (which were typically ten days to a fortnight- or more- out) this promising set-up could well go the way of those other forecasts. However, as we speak the mean wind-speeds at the 10 mb level along the 60N parallel are falling to near-zero in the Stratospheric forecasts over the next few days and there is considerable warming in the Stratosphere over the high Arctic. That should feed into a weaker Circumpolar vortex below with weaker westerlies coming off the North Atlantic, other things being equal. However, at the end of January 2017 as things stand, Arctic pack-ice extent is recovering to near seasonal normal positions in the North Atlantic sector whilst the far North Atlantic remains warmer than usual for the time of year. This acts to intensify the temperature and pressure gradients up-stream of Britain that drives North Atlantic storm activity; this is not what you want for blocking highs to persist over Scandinavia delivering very cold easterlies to Britain.

The Quasi Biennial Oscillation, that pattern of alternate easterly and westerly winds high up in the Equatorial Stratosphere has been in a record Westerly phase for three months now, this is not conducive to weak westerlies and more blocking patterns in higher latitudes. It does offer an explanation as to why some promising potential cold-weather patterns for the UK have failed to materialise over the last couple of months. Had the Quasi Biennial Oscillation been strongly easterly we could well have had much more blocked colder weather affecting the entire country.

My take is that February 2017 is going to reverse the trend of earlier this winter (in the South, in particular). It will be wetter and (overall) a bit milder. Sure, there will be a cold frosty spell mid-month (I don't think it will be more than what this winter has produced so far and it is liable to affect England and Wales but not Scotland). For the northern half of the UK we will have to look west for any cold weather and snow, likely to be short blasts of Polar or Arctic Maritime air from west/north-west following the passage of some of the deeper depressions. These storm-tracks will finally race across the North Atlantic to the south of Iceland and bring stormier conditions to the North and Scotland at times. For northern locations there is real hope for cold and snow from the west, sea-surface temperatures over a large area of the North Atlantic south-west of Iceland are some 2C colder than the seasonal norm so it means that very cold air crossing from Greenland or NE Canada is liable to still be cold on reaching- at least the northern half of- Britain.

[Man With Beard]

8 minutes ago, iapennell said:

As with the other promising weather charts for cold through January (which were typically ten days to a fortnight- or more- out) this promising set-up could well go the way of those other forecasts. However, as we speak the mean wind-speeds at the 10 mb level along the 60N parallel are falling to near-zero in the Stratospheric forecasts over the next few days and there is considerable warming in the Stratosphere over the high Arctic. That should feed into a weaker Circumpolar vortex below with weaker westerlies coming off the North Atlantic, other things being equal. However, at the end of January 2017 as things stand, Arctic pack-ice extent is recovering to near seasonal normal positions in the North Atlantic sector whilst the far North Atlantic remains warmer than usual for the time of year. This acts to intensify the temperature and pressure gradients up-stream of Britain that drives North Atlantic storm activity; this is not what you want for blocking highs to persist over Scandinavia delivering very cold easterlies to Britain.

The Quasi Biennial Oscillation, that pattern of alternate easterly and westerly winds high up in the Equatorial Stratosphere has been in a record Westerly phase for three months now, this is not conducive to weak westerlies and more blocking patterns in higher latitudes. It does offer an explanation as to why some promising potential cold-weather patterns for the UK have failed to materialise over the last couple of months. Had the Quasi Biennial Oscillation been strongly easterly we could well have had much more blocked colder weather affecting the entire country.

My take is that February 2017 is going to reverse the trend of earlier this winter (in the South, in particular). It will be wetter and (overall) a bit milder. Sure, there will be a cold frosty spell mid-month (I don't think it will be more than what this winter has produced so far and it is liable to affect England and Wales but not Scotland). For the northern half of the UK we will have to look west for any cold weather and snow, likely to be short blasts of Polar or Arctic Maritime air from west/north-west following the passage of some of the deeper depressions. These storm-tracks will finally race across the North Atlantic to the south of Iceland and bring stormier conditions to the North and Scotland at times. For northern locations there is real hope for cold and snow from the west, sea-surface temperatures over a large area of the North Atlantic south-west of Iceland are some 2C colder than the seasonal norm so it means that very cold air crossing from Greenland or NE Canada is liable to still be cold on reaching- at least the northern half of- Britain.

Much respect to you Ian as you completely ignore the hype and trust in your methods (very often correctly).

But I will very slightly contest the bit in bold. If you're speaking about long-range models e.g. ECM 46 - then yes, agreed.

But the shorter term models - on balance, I think many of them have actually underestimated eastern blocking in the D8-D15 range. End of December looked like a zonal-fest at first - but just a few days in, the easterly block was back. The past two weeks have been endless attempts by the models to send storms towards Scandinavia in the mid-term - it's in reality been two weeks of constant set-backs and although we're getting a few storms now, we are the very end of the line. 

What I'm saying is, if the models are now going for even stronger north-eastern blocking and disrupted Atlantic lows at D8, I am very much inclined to believe them. Paticularly the GEM, which has not shown any HLB at all in FI until now - and now it's really putting the foot to the floor!

Must comment on the GEFS as they are trending, trending, trending towards the NE block winning out.

that's not bad at this stage, not bad at all.

[Summer Sun]

9th to around the 14th the 06z Op is very much on the cold side of the mean and control

[Luke Attwood]

4 minutes ago, Man With Beard said:

Much respect to you Ian as you completely ignore the hype and trust in your methods (very often correctly).

But I will very slightly contest the bit in bold. If you're speaking about long-range models e.g. ECM 46 - then yes, agreed.

But the shorter term models - on balance, I think many of them have actually underestimated eastern blocking in the D8-D15 range. End of December looked like a zonal-fest at first - but just a few days in, the easterly block was back. The past two weeks have been endless attempts by the models to send storms towards Scandinavia in the mid-term - it's in reality been two weeks of constant set-backs and although we're getting a few storms now, we are the very end of the line. 

What I'm saying is, if the models are now going for even stronger north-eastern blocking and disrupted Atlantic lows at D8, I am very much inclined to believe them. Paticularly the GEM, which has not shown any HLB at all in FI until now - and now it's really putting the foot to the floor!

Must comment on the GEFS as they are trending, trending, trending towards the NE block winning out.

that's not bad at this stage, not bad at all.

Hmm don't really agree,no strong block to the east and the UK left in southerly to southeasterly wind.not particularly cold!