Model Output Discussion - 19th - 25th December

[feb1991blizzard]

It WAS that cold though.

And here on some days only very briefly that warm, and was back down to -12 by 1900 hours and -15 by 2200 hours.

[Chris D]

It WAS that cold though.

LOL. It was indeed. -13c and 25cm of snow for a very flat coastal location like mine was extreme enough for me.

With regards to tonight's model output, the ECM 12z is completely uninspiring with a fairly ordinary "zonal" outlook all the way through and the GFS continues it's northerly outbreak from in FI from +300hrs on the 18z run. Nothing to get excited about atm IMO for a while yet.

The Stratosphere is what should be watched at the moment, for those who have patience.

Edited December 26, 2011 by chris93

[West is Best]

Morning everyone. Happy Christmas to all, especially my old buddies on here.

I apologise for not posting on here for months but I basically stayed off given the Atlantic-driven weather. Despite a few blasts from the north-west this remains an Atlantic dominated weather, assisted by what is essentially a Bartlett set up. I see no signs of change in the immediate or medium term. I'm still a cold weather fan and I'm afraid we were spoilt last year. This winter looks like a very mild set up to me, at least for the first half (with little signs of change beyond in the models at the moment).

One hell of a storm brewing for Tues/Weds up north though. That's going to be a humdinger.

[Frosty.]

A very disappointing gfs 00z for southern britain with a generally unsettled and mild outlook and only blink or miss it cooler incursions, further north across scotland it would be colder at times with wintry showers but also a lot of mild or average temps in a very fast moving zonal pattern, high pressure hardly gets a look in so frosts would be at a premium. In a bit more detail, it looks mild again tomorrow in the south but the north will turn cooler but also drier and brighter but it's only the calm before the midweek storm. The stormy spell midweek will also herald the briefest of cool snaps before it becomes mild again during friday, then further on it's a mix of mild and cool zonal, occasionally cold further north across scotland with hill snow but with regular thaws.

[bluearmy]

Must be seeing things - ECM op splitting the vortex as early as day 10. Probably progressive but the fact that it does it should alert us to how quickly the p/v is weakened in such a short time period. Gfs looks rather different !!

[snow drift]

A very disappointing gfs 00z for southern britain with a generally unsettled and mild outlook and only blink or miss it cooler incursions, further north across scotland it would be colder at times with wintry showers but also a lot of mild or average temps in a very fast moving zonal pattern, high pressure hardly gets a look in so frosts would be at a premium. In a bit more detail, it looks mild again tomorrow in the south but the north will turn cooler but also drier and brighter but it's only the calm before the midweek storm. The stormy spell midweek will also herald the briefest of cool snaps before it becomes mild again during friday, then further on it's a mix of mild and cool zonal, occasionally cold further north across scotland with hill snow but with regular thaws.

Merry Christmas one and all.

The summary you have given is fair reflection but things are starting to hint at a change. I will be looking for some interesting output to start to show it self as we turn in to the New Year. Having looked through all the models and the output, there is little at the mo to make my eyes widen with anticipation.

However, IMO there are signs and indications that things will improve. One could argue that when your at the bottom, the only way is up!

[Frosty.]

Merry Christmas one and all.

The summary you have given is fair reflection but things are starting to hint at a change. I will be looking for some interesting output to start to show it self as we turn in to the New Year. Having looked through all the models and the output, there is little at the mo to make my eyes widen with anticipation.

However, IMO there are signs and indications that things will improve. One could argue that when your at the bottom, the only way is up!

Yes, from the position we are in now, the only way is up..but it looks like being a bumpy journey

[KTtom]

ECM +240 seems to be the chart of the morning again at day 10 as it has been for the last couple of days, trouble is, its not getting any closer! I'm not the most patient of guys but by the time the Stratosphere gets itself sorted out we should be in for some impressive blocking come April!

[chionomaniac]

Just a reminder today, Christmas is over now, Ian B has gotten away with his procrastinations about his theory after a half bottle of rioja so please keep on topic!

Ps I hope all had a good Christmas!

Edited December 26, 2011 by chionomaniac

[bluearmy]

Just a reminder today, Christmas is over now, Ian B has gotten away with his procrastinations about his theory after a half bottle of rioja so please keep on topic!

Ps I hope all had a good Christmas!

Is the wine relevant to you or him !!! Seriously, I pose the same question in the strat thread - surprised how the strongest vortex in years can be split within 10 days by what is our highest resolution model at that timescale ??

[chionomaniac]

Is the wine relevant to you or him !!! Seriously, I pose the same question in the strat thread - surprised how the strongest vortex in years can be split within 10 days by what is our highest resolution model at that timescale ??

Him- I had a lot more, I'll go back to the strat thread.

[Troubleatmill]

Def best chart of the winter so far from the ECM IMO, as has been said already, showing pv splitting nicely, absolutely no guarantees for anything but if this were to happen, chances of some WAA creating a decent block to our our west/ northwest will improve massively.

Edited December 26, 2011 by arron123

[Grimsby Snow Lover]

ECM +240 seems to be the chart of the morning again at day 10 as it has been for the last couple of days, trouble is, its not getting any closer! I'm not the most patient of guys but by the time the Stratosphere gets itself sorted out we should be in for some impressive blocking come April!

I would say things are improving with the ECM charts, here is an example to show what I mean.

Here was the 10 day chart from yesterday http://hw.nwstatic.c...npsh500.240.png

Compared with the same chart today we can clearly see an improvement with the strength and size of the Arctic high http://hw.nwstatic.c...npsh500.216.png

What is more pleasing this morning is that the charts are not getting further away like they normally do. The impressive looking 240 chart from last night is now just as impressive but at the 216hr range.

Edited December 26, 2011 by Grimsby Snow Lover

[IDO]

GFS still stalling on cold but it is surely only a matter of time till the whole UK gets colder. Next week, with the origin of the jetstream coming from Northern Canada there should be, comparatively, a lot colder weather for Scotland, and possibly a little further south. However this is still zonal weather and we need to lose this to get more interesting stuff. With the AO/NAO both forecast to be moving towards neutral, the delayed effect of stratospheric warming, the coldest part of the winter, these are all positive signs of a change. The best call is for the change in 3-4 weeks but ECM are a bit more presumptuous, so any change could start to show up in FI quickly. How much cold, and for how long is the the big question?

[mountain shadow]

ECM +240 seems to be the chart of the morning again at day 10 as it has been for the last couple of days, trouble is, its not getting any closer! I'm not the most patient of guys but by the time the Stratosphere gets itself sorted out we should be in for some impressive blocking come April!

This is exactly what I was alluding to yesterday. An arctic high offers far more prospects then a raging PV over the pole. Does anyone know what the furthest poleward ensembles location we can get?

Now we need to see GFS show a bit of support.

[Tom Montalbano]

Morning all,

Yes, quite a lot of difference this morning amongst the models, out in FI.

http://www.wetterzentrale.de/pics/Recm2401.gif

Our resident high has pulled west out into the Atlantic, with the jet tilting more NW/SE and some interesting developments in the far NE of that chart.

http://www.wetterzentrale.de/pics/Rtavn2401.png

GFS having none of it and maintaining a stubborn high pressure cell over France.

Right off to work, how I hate Boxing Day! Kauto Star for the King George, come on old fella. What is that man rambling on about!

Regards,

Tom.

[nick sussex]

Morning all

Hope you all had a good Xmas. Santa has delivered us the best chart of the winter from the ECM at 240hrs, the GEM is looking okay at the same time frame and even the wayward BOM shows some promise!

The GFS is like the gatecrasher at the party who isn't welcome, that for the timebeing doesn't want to know and keeps its PV love-in over Greenland. Could the ECM be too progressive with its change, thats still a possibility.

We'll just have to wait and see over the coming days.

[bluearmy]

Given that the ECM op at t240is the warmest of the 51 run suite, i doubt the pattern over the arctic is correctly modelled.

[Duane S.]

ECM digs us out of the 00z mire with a very interesing last couple of FI charts.

The state of the Northern Hemisphere in 24 hours time...

Then how the ECM sees it in 10 days...

It certainly sees things breaking up quicker than is likely IMO but it's the most promising chart of the winter in terms of potential down the line.

Surely we are going to see the AO start to take a downwards hike in the next few days. This is its forecast presently going into Jan, watch this trend Neutral then negative in days to come I suspect...

I posted a few weeks back I could see an Arctic high forming and that we at least had a chance (albeit a real outside chance) of it effecting us later on down the line. I know some are continually pointing out that Strat warming and its effects on our weather is no direct path to UK cold and I couldn't agree more. But... that's in the details further down the line. Before we can even consider getting there this monster vortex has to be weakened and like it or not what we have setting up for January is going to makes some in-roads into doing just that. Think of it as the big enemy at the end of the level on a video game. You don't come waltzing in with your pistol take a shot and down he drops! You load up with ammo, bring the heftiest weapons and pelt him till, eventually, he topples over and the job is done! Sometimes a few plum shots and he goes down quick, other times a continual barrage seems to have little or no effect and after what seems like an age you're out of ammo and you lose!

Edited December 26, 2011 by reef
Model thread, not Ian Brown thread

[nick sussex]

Given that the ECM op at t240is the warmest of the 51 run suite, i doubt the pattern over the arctic is correctly modelled.

Maybe the others have the jet further south? The operational run drives a sw flow into Holland on days 9 and 10, if the troughing is further south and east that might explain the others.

If you look at the ECM ensemble maps at 168hrs quite a few reduce the influence of the Azores high and also some bring higher pressure at a more favourable angle into northern Scandi.

http://www.ecmwf.int...t!2009112700!!/

Edited December 26, 2011 by nick sussex

[bluearmy]

Maybe the others have the jet further south? The operational run drives a sw flow into Holland on days 9 and 10, if the troughing is further south and east that might explain the others.

If you look at the ECM ensemble maps at 168hrs quite a few reduce the influence of the Azores high and also some bring higher pressure at a more favourable angle into northern Scandi.

http://www.ecmwf.int...t!2009112700!!/

The mean looked ok with ridges east of svaalbard and west of Alaska trying to split the vortex in a similar way to the op. Guess I was just trying to put a brake on things a tad, especially with naefs not really interested.

[nick sussex]

I can understand why, otherwise we could get a runaway hope train! If we see those pressure rises within 168hrs then I'd be happy to hop on board!

We can just hope that this initial strat warming might do the trick and then we don't have to wait for another one to finally send that PV packing from Greenland.

[nick sussex]

The GFS 06hrs run continues with a similar trend to its earlier 00hrs run especially in its lower resolution output. Although it did have a similar pattern to the ECM before the drop down into that lower resolution.

I think the key is whether the ECM can deliver those pressure rises over the Arctic into the 168hrs timeframe or whether they keep remaining stuck at the 216-240hrs like the pot of gold at the end of the rainbow.

Edited December 26, 2011 by nick sussex

[ITSY]

GFS not yet on board with ECM - which I reckon is overplaying the downgrade of the PV in any case. Certainly change looks like it's nearing the horiZon, but to what remains uncertain until GFS and ECM sit in the same ball park

[OldMetMan]

Hope everyone had a good Christmas.

I've picked up a couple of things from today's runs. First, the GFS is taking the jet further S after Wednesday's intense LP, with pressure much lower across the UK. Beyond that, the model reverts to the familiar SW zonal flow but with LP running further S before then, it brings the possibility of cold air breaking through.

The other thing I noticed was HP once again being forecast to start building over W Russia by the GFS. That, combined with the more southerly jet, again suggests a possibility of colder air breaking through.

Still no sign yet of any major long wave amplification.