Model Output Discussion - Tuesday 20:25 -->

[mountain shadow]

Ignore GFS Ops it has been all over the place. The new paraellel has been rock solid and is an absollute belter this morning.

Meto 144 unlikely IMO.

ECM Fantastic.

[Duane S.]

A very strange looking evolution @ T+144 on the UKMET. What do others think? Is the UKMET scenario plausable?

Good however to see ECM is having none of it and yes the ensembles have had a bit of a blip. We are coming into the critical stage, this is where cold spells are made or lost

[Fozfoster]

We seam to be getting 2 of the big 3 to agree over the last few days, so as the song goes ......... 2 out of 3 ain't bad

[Duane S.]

The head guy at Exeter will have to make a decision this morning based on his own-output. The question will be is it or not going to become very cold in the outlook period ?(ie ) from 144 HOURS. I think his/her wordings will be interesting at Mid -day. Knowing what extra information they have at their disposal, a decision will have to be made today before the media get wind from other sources, if you know what I mean.

C

Yep, agree with that totally. They are either going to have to side with their own output or effectively discard it. It'll be interesting if nothig else!

[TEITS]

How typical we have excellent model output from the GFS/ECM and now the UKMO decides to throw a wobble!

This doesn't surprise me because the important phase of the model runs is still around +144 which is always subject to change and due to the synoptic pattern even more so. I believe the reason why they struggle with this kind of set up is due to many reasons. The first reason being is that its well known these models struggle with blocking to our N and secondly im sure historical weather patterns are built into these models and lets be honest such synoptic patterns are very rare.

Probably best to assume that there will be blocking over Greenland/Iceland. However don't make any assumptions how cold it will be or will the flow be NE/E,ly or even S,ly. This will not be resolved today because the pattern is still evolving and probably won't be resolved until Thurs/Friday.

[snowmadchrisuk]

You lot make me laugh, the UKMO +144 is just one chart out of millions and it also hasn't verified all week. The UKMO is a good model but that doesn't mean it is at +144 .. +144 is the Meto's version of deep FI . I am loving the charts this morning , GFS has come back on board , Ecm has continued good from it's 12z which is the first time this week we have had 2 good ECM runs in a row.

Edited December 9, 2009 by snowmadchrisuk

[Frosty.]

Today is the CRUCIAL day, this is probably the day when the models decide whether the wintry spell gets the green light to proceed, in the usa, bitterly cold spells are as regular as london buses in winter time but for us poor saps in the uk, everything has to be just perfect. The GFS & ECM 00z are showing a big freeze taking hold next week but the ukmo has suddenly got the wobbles (although carol kirkwood says a siberian freeze will arrive next week..bless her) all the models have stuttered at some point in the last few days but the odds now favour a cold spell which is looking more likely to develop into a mega cold spell. As roger said, he's not totally sold on our cold spell yet but he believes if it does come, it will last until the end of december.

Edited December 9, 2009 by Frosty039

[nick sussex]

Hi C,

Agreed. Funny how the ECM00Z is a big improvement over last nights, GFS00 is good and now the

UKMO throws a bit of a wobble at T144!!!

Overall good overnight runs from ECM & GFS but still caution needed as UKMO144 bit wobbly.

Regards

Yes its just typical! it seems to be each day one model decides its going to be the nerve shredder! What we dont want is for the block to the north to set up too far west. Looking at the other models they do seem to have taken the jet further north, so its really this morning the gfs and ecm against the rest.

The ukmo is a big concern this morning after being so consistent with the pattern, lets hope it's a one run wobble.

[Glacier Point]

Huge northern blocking being advertised today by all models.

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html

The GFS ensemble mean shows at 410m height anomaly over Greenland t144 through t216 and a day 11-15 anomaly of 258m with a souhward displaced jet and classic -AO pattern. That is cold and the wedge of cold air to our east will have to back west under such a regime - which is why the UKMO is not a problem as the milder Atlantic air would get deflected southwards over time.

I think you can appreciate just how much the idea of high pressure to the south or west of the UK as programmed by the last two 00z ECM operationals was bogus, based up a non-weather model based assessment.

The composites for GWO phase 4 plus enhanced northern blocking continue to represent the likely pattern for the forseable future.

This means that unlike so many of the recent cold events, getting precipitation will not be a problem.

Meantime, I'm seeing some real goodies being brought into the January shop, to be unwrapped mid January on.

[West is Best]

I know the UKMO T144 might not look that great, but it actually still is! Several people have noted that it contains the same huge northerly blocking. There is no way you switch from that to a south-westerly overnight. It would quite likely lead to just as much of an easterly set up as the ECM/GFS.

A word about the 0z ECM: truly remarkable charts.

We've had some great charts down the years but nothing quite so dramatic as this. It's a shame that it still isn't in reliable timeframe for the really cold sourcing. But all very encouraging. Something fairly significant must now be over 50% I would think, but by no means 'nailed' yet.

[nick sussex]

You lot make me laugh, the UKMO +144 is just one chart out of millions and it also hasn't verified all week. The UKMO is a good model but that doesn't mean it is at +144 .. +144 is the Meto's version of deep FI . I am loving the charts this morning , GFS has come back on board , Ecm has continued good from it's 12z which is the first time this week we have had 2 good ECM runs in a row.

Sorry Chris I wish this was the case but unfortunately at the moment its the top model at 144hrs:

http://www.emc.ncep.noaa.gov/gmb/STATS/html/acz6.html

It's a very close run thing though,a case can be made for all the models as they are doing well after a blip a few days back. IMO if the ukmo doesn't come on board this evening then the alarm bells will be ringing, of course we don't know what would happen after the 144hrs, the high to the ne might deal the low a knock out blow but we don't want any further hurdles to overcome.

[Nick F]

Great ECM and GFS synoptically, the block over Greenland/Iceland is excellent news for a protracted cold spell from the east and NE. The easterly is brought forward to start over the weekend, though a quick look at uppers shows that really cold air over NE Europe is held back from advecting west to the UK, particularly on ECM - which develops a low over the N Sea. Though these more mesoscale features will not be resolved yet.

00z ECM T850s: http://www.ecmwf.int/samples/d/banner/page.html

FWIW and will change, 00z GFS suggests snow across the south by early next Tuesday ... though the easterly is by no means set in stone given the UKMO.

[TEITS]

That is cold and the wedge of cold air to our east will have to back west under such a regime - which is why the UKMO is not a problem as the milder Atlantic air would get deflected southwards over time.

I was going to mention that but was wary of being accused of misleading members.

What some need to realise is if the HP block remains to our N you would eventually pull in the bitter airmass and would be a question of when rather than if. This is what caused some of the major blizzards in 1947. The LP systems moved into SW England and gave some awesome blizzards before finally the block to our N pushed the LP systems away.

[Geordiesnow]

I know the UKMO T144 might not look that great, but it actually still is! Several people have noted that it contains the same huge northerly blocking. There is no way you switch from that to a south-westerly overnight. It would quite likely lead to just as much of an easterly set up as the ECM/GFS.

A word about the 0z ECM: truly remarkable charts.

We've had some great charts down the years but nothing quite so dramatic as this. It's a shame that it still isn't in reliable timeframe for the really cold sourcing. But all very encouraging. Something fairly significant must now be over 50% I would think, but by no means 'nailed' yet.

Yep i feel if the UKMO went to 168 hours it could be classed as a good run i feel. It's not that far away from being a good run though, only need things to be further South.

Looks like the models are struggling to decide what the potential height rises means to us so expect some different scenario's being played out but whatever model you look at. They all have height rises!

Edited December 9, 2009 by Geordiesnow

[snowmadchrisuk]

Sorry Chris I wish this was the case but unfortunately at the moment its the top model at 144hrs:

http://www.emc.ncep.noaa.gov/gmb/STATS/html/acz6.html

It's a very close run thing though,a case can be made for all the models as they are doing well after a blip a few days back. IMO if the ukmo doesn't come on board this evening then the alarm bells will be ringing, of course we don't know what would happen after the 144hrs, the high to the ne might deal the low a knock out blow but we don't want any further hurdles to overcome.

If I bring this chart up from No Gaps it is very like UKMO to our North , but as you can see the block as displaced the mild Atlantic se away from our shores and IMO that is the most likely outcome if we were to get that far , Yes we have had failed easterly's before but they haven't had a block like that over Greenland . Also Nick , If it has top marks at +144 and the 00z is right then you could say it has failed badly on it's 12z last night.

Also if West Is Best is saying 50% then something must be brewing lol , his posts have been very negative all week which may come back to haunt him .

Edited December 9, 2009 by snowmadchrisuk

[ChartViewer]

Meantime, I'm seeing some real goodies being brought into the January shop, to be unwrapped mid January on.

What a quote lol. I assume that the warming event you are starting to see now will promote

more Blocking come Mid Jan...and with great synoptics now imagine if a Mid Jan cold spell came off

[East Herts Snow]

Sorry Chris I wish this was the case but unfortunately at the moment its the top model at 144hrs:

http://www.emc.ncep.noaa.gov/gmb/STATS/html/acz6.html

It's a very close run thing though,a case can be made for all the models as they are doing well after a blip a few days back. IMO if the ukmo doesn't come on board this evening then the alarm bells will be ringing, of course we don't know what would happen after the 144hrs, the high to the ne might deal the low a knock out blow but we don't want any further hurdles to overcome.

Nick, to be fair the ECM is still overall the best performing model. Every one of the major models have now had a wobble, but have quickly reverted back to cold synoptics.

The only concern is that this is the first of the major models to wobble in the 'almost' reliable timeframe.

This is the time when meteorologists really get to earn their corn and my respect if they can accurately predict complicated and potentially very cold set-ups.

Edited December 9, 2009 by North Londoner

[VillagePlank]

EDIT: OK - a year too late :blush: Note to self - if you are going to make a joke make sure you get the punchline right The year in question (63/64) posted a more or less average CET of 3.5C. Very cold by today's standards.

Edited December 9, 2009 by VillagePlank

[Cal]

Huge northern blocking being advertised today by all models.

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html

The GFS ensemble mean shows at 410m height anomaly over Greenland t144 through t216 and a day 11-15 anomaly of 258m with a souhward displaced jet and classic -AO pattern. That is cold and the wedge of cold air to our east will have to back west under such a regime - which is why the UKMO is not a problem as the milder Atlantic air would get deflected southwards over time.

I think you can appreciate just how much the idea of high pressure to the south or west of the UK as programmed by the last two 00z ECM operationals was bogus, based up a non-weather model based assessment.

The composites for GWO phase 4 plus enhanced northern blocking continue to represent the likely pattern for the forseable future.

This means that unlike so many of the recent cold events, getting precipitation will not be a problem.

Meantime, I'm seeing some real goodies being brought into the January shop, to be unwrapped mid January on.

Thanks for that Stuart , at last we see a major cold spell within our grasp and with precipitation thanks to the STJ, it would be sweet to see a nationwide snow event rather than the localised offerings we have had over the last few winters. The ECM is a cracker this morning :blush: .

[Barometer Obama]

Wow some great charts this morning with the GFS and ECM showing awesome potential. I was concerned when I saw the UKMO with the west looking to wake up, but I feel reassured by some decent comments backed up with evidence and examples of why, even if it isn't an outlier it won't be bad news!

[West is Best]

Also if West Is Best is saying 50% then something must be brewing lol , his posts have been very negative all week which may come back to haunt him .

I've updated my facebook profile to say that a serious cold spell looks to be heading our way. When I do that it means I've begun to believe!

Seriously not at all worried about that UKMO - that northern blocking is superb and quite unlike anything we've experienced during recent letdowns, so I would suggest being relaxed. The real problems would come if we lose the blocking to our north and north-west.

[Cloud 10]

The "problem" with the ukmo is that our high is hoovered up to quickly by the arctic high leaving us in a sort of void which leads to a partial attack from the atlantic at +144.

No such problems from gfs and ecm,and has been said,the big 3 models all come up with a huge block over greenland.

[Frosty.]

The GEM 00z is a real snow fest later next week, bitterly cold air easing it's way into the uk from the northeast early next week and then becoming entrenched, a pretty good NOGAPS at T+144 as well, we seem to have very good model agreement now for a very wintry spell to engulf the uk during next week and some areas would have blizzards and drifting snow if these charts or similar ones verified.

[Cecil Hogmanay Melchett]

TREMENDOUS output this morning.

Ithink people are being too negative about the ukmo run,that lp is diving SE and the block to the North looks

very strong.

Indeed good old carol the ramper kirkwood talking about siberian blasts next week earlier this morning.

GET IN!!!

[snowmadchrisuk]

I've updated my facebook profile to say that a serious cold spell looks to be heading our way. When I do that it means I've begun to believe!

Seriously not at all worried about that UKMO - that northern blocking is superb and quite unlike anything we've experienced during recent letdowns, so I would suggest being relaxed. The real problems would come if we lose the blocking to our north and north-west.

Well that's always the case , No blocking , No cold. But the 10 day blocking forecasts look great.

http://www.cpc.noaa.gov/products/precip/CWlink/blocking/real_time_nh/mrf2.nh.shtml

And the Two website have flipped again today and gone from cool and dry to cold and snowy .

The GEM 00z is a real snow fest later next week, bitterly cold air easing it's way into the uk from the northeast early next week and then becoming entrenched, a pretty good NOGAPS at T+144 as well, we seem to have very good model agreement now for a very wintry spell to engulf the uk during next week and some areas would have blizzards and drifting snow if these charts or similar ones verified.

The Gem is another good example of why UKMO +144 is unlikely to happen , the Atlantic creeps up towards our shores , but as it get's closer it get's shoved further and further SE and we end up in a Snowy Easterly.