Winter Model Discussion - 12/01/13 06z Onwards

[Duane S.]

Interesting to see where it comes from about +102. the 00z had some energy driving up the west of Icelend through the east of Greenland. The 06z has it on the eastern side of Iceland and as a result sinks the block a bit.

[Iceni]

Now that did make me laugh is that a technical term, maybe Shannon in action. It certainly sums up the difficulties for both themselves and the MO. IMO it translates as, even when the models look like they are showing some consistency we are still are still very likely to see some rapid swings. Talking of which, I can’t buy into the ECM this morning the transition from the 72hr chart to the 96hr chart looks too progressive and if that’s wrong the rest will be as well. UKMO looks the best of the bunch but the GFS has the possibly the best snow action just corrected slightly so we don’t lose the cold air.

Peanut Gallery? Is that something about the shape of pressure systems or is it a term for dumb Southern state peanut farmers? I think we should be told.

[iowpompeylee]

Take a look at post 569 in the SW regional thread, Ian F has very kindly given us a chart from Exeter regarding Thursday.

I love this chart. :-) very good for southerners

[Jonan92]

Black hole in eastern USA

That's a lot of energy for the atlantic lows

[weather eater]

06z much more progressive, I wouldn’t dismiss it completely but then I wouldn’t be surprised to see it dropped by the time we get to the 12z either.

[Summer Sun]

Round 2 Friday?

[BLAST FROM THE PAST]

06z going very much towards the ECM, is this cold spell just a taster and not the real deal? Had a conversation with RJS and what is starting to be shown doesn't come as too much of a surprise now. Not saying its right but lets look at a couple of things here. ECM has edged slightly towards what GFS and UKMO were / are showing BUT not very much and has been rather stubborn [cannot be ignored]. GFS was bullish but now churns out a movement towards ECM [albeit the 06z]!,MetO not really interested in widespread snow, are they thinking along the lines that we will see some assault/attack from NW to edge the real cold air away?

RJS index model still shows a warming ahead before the real cold blocking structure and has and does remain a big thorn in my side re the outlook during Jan.

So with models still not agreeing I'm thinking we have some further hurdles to clear before we settle in to maintained/uninterrupted cold...oh and it looks like the far SE on this occasion isn't a favoured location.

UKMO - Solid output

ECM - slight movement, given way a bit but not enough for sustained deep cold

GFS - sided with UKMO solidly but has just jumped towards ECM

GEM - in UKMO camp

MetO - Global warmists so will seek the mild solution.

BFTP

Edited January 13, 2013 by BLAST FROM THE PAST

[kev238]

Even this more progressive run has a battle over the uk... Minus 5 line off to the east but I would imagine the woule be snow around in the east on friday afternoon based on that run

[Kentish Snowman in Yorks]

And the 06z proves why it's useless - the energy going over the top of the high this time:

http://www.meteociel...&ech=102&mode=0

Hopefully will revert back in the 12z

Having said that, the ECM did the same at T+96 then became a little more favourable.

The models are having real difficulty in deciding what to do with the jet energy - split it north east and south east, only push it south east, or only push it north east.

This is just my opinion, but unless a chart similar to that shows up on the majority of the T96 output this afternoon, I feel that chart is very unlikely to verify, and is likely to be a case of the GFS just 'going off on one'.

Famous last words...

[Frosty.]

The Gfs 06z looks way too progressive in shunting the cold block away to the east and pushing us into a less cold zonal outlook, i'm not buying what this run shows at all. Expect the cold block to hold on for several days longer than the 6z shows.

[nick sussex]

I think given the large variety of solutions on the ECM postage stamps within 120hrs I really wouldn't want to say the UKMO fax chart at T84hrs is a given.

There still seems to be uncertainty around Iceland with how much energy gets pushed east and until this gets resolved we won't know how the ridge to the east and ne will develop.

These uncertainties are within T72hrs and manifest themselves greatly later on.

[Snowman.]

Overplayed the atlantic a bit too much on this run as the purples creep northwards.

[simon29]

I wouldnt worry to much about what the GFS is showing at present, it will all change GFS = Good For Snow

[resectoscope]

Do you have a direct link to those snow depth charts please?

the link to this chart is http://www2.wetter3.de/Animation_00_UTC/186_35.gif

but to access output go to http://www2.wetter3.de select Standardkarten Tool 1 then "Schnefallgrenze,Schneedecke" at the bottom of the pull down menu foot of page in the middle. 06's rolling out now

[BLAST FROM THE PAST]

That is true Blast - and I am a big RJS fan... but his index also showed a cold snap in middle December precisely at the time that it warmed up and got very wet. I am getting to grips with his methodology slowly on his separate thread - but it certainly isnt bulletproof.

Indeed not but we have to look at overall pattern and the real response for northern blocking isn't due yet and thus it mustn't be too surprising if we see not what GEM/UKMO shows just yet.

BFTP

Edited January 13, 2013 by BLAST FROM THE PAST

[IDO]

Anyone want the PV piece over the UK:

[bluearmy]

This is a Deja Vu, similar to what happened in December

No it isn't. different sypnotics and different modelling. If you mean the atlantic jet powers up - well thats what happens in the atlantic with a strong canadian vortex segment. Its where the energy goes thats important. I can see some charts that reflect the general shape we saw then. But its not the same jonan.

Anyone want the PV piece over the UK:

Not from that angle - no. Wet and windy.

[Frosty.]

This is a Deja Vu, similar to what happened in December

No it's not the same at all, this week there is more snow around than during that cold dry snap, and the background signals are much improved. This is just the 6z op run and not gospel, most of the models show a more robust block and some indicate undercutting and snowfests, like the gfs 00z did, lots still to be resolved yet.

[Mark Bayley]

It might be me but in recent days the most progressive of all GFS runs seems to have been the 6z? I would certainly be more worried if the 12z showed something similar. The UKMO and GEM have remained mostly consistent, whilst the ECM has moved ever so slowly towards them. The GFS seems to keep showing some sort of middle ground. Great uncertainty at the moment but i would lean closer to the UKMO/GEM solution, especially until the 12z runs.

Interestingly the GEM goes for Greenland height rises at the end of the run. This fits in with the projected MJO phase 7 (e.g. UKMO), although some seem to be struggling past phase 6. I'm guessing that although nice the GEM is probably being to progressive, although its a trend to watch in the long term.

Edited January 13, 2013 by Mark Bayley

[weather eater]

I think given the large variety of solutions on the ECM postage stamps within 120hrs I really wouldn't want to say the UKMO fax chart at T84hrs is a given.

There still seems to be uncertainty around Iceland with how much energy gets pushed east and until this gets resolved we won't know how the ridge to the east and ne will develop.

These uncertainties are within T72hrs and manifest themselves greatly later on.

It’s why I keep saying that looking with any confidence beyond 72hrs is fairly pointless, other than as an emotion feeder for those that want to get their knickers in a twist every run and appear to be disappointed if they can’t.

[Long haul to mild]

Not a good GFS this morning but its only the 06z run and to be honest, it's the one I tend to ignore as I often find it to be the most inaccurate. If these synoptics are showing on the 12z then I'll sit up and listen, but until then I am not going to give it much credence.

[nick sussex]

It’s why I keep saying that looking with any confidence beyond 72hrs is fairly pointless, other than as an emotion feeder for those that want to get their knickers in a twist every run and appear to be disappointed if they can’t.

Yes its the large differences we keep seeing that continues to make me a little nervous. Ordinarily you'd look at the UKMO fax chart at T84hrs and think the forecast should be pretty accurate but if you look at the ECM postage stamps they're all over the place even at T96hrs in terms of the placement of the high and what sort of flow the UK will have.

The UKMO shows a very strong ene flow with heavy snow showers driving well inland, the GFS even on the 00hrs and now the 06hrs has a very short window before the flow slackens. Sum total its the difference between some big snow totals and very little even for eastern areas.

And it all comes down to the modelling of energy near Iceland within 72hrs and then like a domino the effect is felt much later with a less favourable angle of Atlantic attack.

Edited January 13, 2013 by nick sussex

[BLAST FROM THE PAST]

On the strat thread Matt Hugo voices big concerns re this as unitl the vortex is utterly blitzed the Canadian Lobe sends too much energy into the Atlantic to prevent an assault. As it stands now, confidence of early sustained cold and blocking 'building' to north is lower than yesterday BUT 06z is another version again. It looks more cold than not though and there clearly are some hurdles to leap over yet...but we are heading in the right direction for sure.

_BFTP

Edited January 13, 2013 by BLAST FROM THE PAST

[IDO]

I think the only reason anyone bothers with the 6z is because there's nothing else going on at this time of morning.

Is anyone surprised with the 6z output? It's not inconsistent if you compare it with yesterday's 6z and has been the most progressive all week. The 12z will go back to slightly more blocking and the 18z will live up to the stella billing.

The ens suggest a host of possibilities from midweek, this is probably one of the them; the 0z another (in the cold cluster). This maybe closer to the mean Atlantic movement than the 0z and hence closer to the most likely scenario. The updated ens will clarify but I expect to see variations till this is resolved in the next 24 hours or so. Lots of forecasters suggesting a vortex lobe will be over the US as a result of the SSW so the placement of this is crucial as it will effect downstream and probably dictate the weather for the foreseeable. If it sits in Newfoundland (as per 06z) we are likely to have energy pumping up the Atlantic and the rest of Winter we may be on the wrong side of the block.

Edited January 13, 2013 by i'm dreaming of...

[weather eater]

Yes its the large differences we keep seeing that continues to make me a little nervous. Ordinarily you'd look at the UKMO fax chart at T84hrs and think the forecast should be pretty accurate but if you look at the ECM postage stamps they're all over the place even at T96hrs in terms of the placement of the high and what sort of flow the UK will have.

The UKMO shows a very strong ene flow with heavy snow showers driving well inland, the GFS even on the 00hrs and now the 06hrs has a very short window before the flow slackens. Sum total its the difference between some big snow totals and very little even for eastern areas.

And it all comes down to the modelling of energy near Iceland within 72hrs and then like a domino the effect is felt much later with a less favourable angle of Atlantic attack.

Yes it’s certainly a twitchy time, it would be a mistake to believe that just because we have this record uncertainty going on, that it follows that it is automatic that it will translate as a cold synoptic evolution for us, still we have seen some pretty big climb downs from the models this last week and I don’t expect that to change.