Model output discussions pm 31/12/15

[TSNWK]

22 minutes ago, Mucka said:

ECM day 10.

 

 

Can we dare imagine a chart tomorrow where decent residual Scandi heights link up with arctic heights over Greenland with an Atlantic ridge reaching out to reinforce?

The search for cold continues, and why not?

I always look at those purples and imagine it to be so much colder than it is. I mean is that really part of the polar vortex covering Scotland..and why not indeed

Edited January 1, 2016 by TSNWK

[tinybill]

i  think we  should more worried  about the  one coming jan  6  the gfs has  it now  955  over  Ireland  more south than this afternoon

[J10]

The latest ski blog has been issued for the forthcoming week, at last some decent snow seems likely for parts of the Alps.

https://forum.netweather.tv/blogs/entry/4915-alps-ski-and-snow-forecast-blog-issued-1-january-2016/

[nick sussex]

Just now, bobbydog said:

hi nick, the evolution is not unlike the GFS. the ECM however, makes less of the LP system in the atlantic at t240 and virtually cuts it off. it will be interesting to see where it goes with that - if it sticks with the same theme...

Yes its still far out but NCEP have suggested a positive PNA, negative AO and NAO pattern. The nor'easter type low normally sees the Azores high displace to the nw in response to that. You won't get that type of low with a flat upstream pattern as you need the amplification for that to run ne up the eastern seaboard of the USA.

The debate surrounding the MJO given what NCEP have said has clearly impacted the NH pattern. In the mid December update they mentioned that their January outlook looked to have derailed because of the MJO. No seasonal forecast saw this as having much impact on the NH pattern. They have just updated their January outlook

THE MADDEN-JULIAN OSCILLATION (MJO) STRENGTHENED MID MONTH AND CONTINUES TO
INFLUENCE THE PATTERN OF TROPICAL CONVECTION. PROJECTIONS BASED ON LAGGED
COMPOSITES OF MJO DURING DEC-JAN-FEB IMPLY A TRANSITION TO A COLDER PATTERN FOR
THE CONUS. TOOLS SPECIFICALLY TARGETING WEEK3/4 CONDITIONS, BASED ON MJO AND
ENSO PHASES, INDICATE A PROLONGED COLD PERIOD.

SHORTER TERM (THROUGH 14 DAYS) OUTLOOKS INDICATE A TRANSITION TO A COLDER
PATTERN FOR THE CONUS. GIVEN THE SHORTER TERM OUTLOOKS AND THE INFLUENCE OF THE
MJO, THE ODDS FOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE NORTHERN CONUS HAVE
BEEN REDUCED AND COVERAGE DECREASED, WHILE ODDS FOR BELOW NORMAL TEMPERATURES
OVER THE SOUTHERN CONUS HAVE INCREASED IN COVERAGE.

Their mid December thoughts:

THE MADDEN-JULIAN OSCILLATION IS ALSO A POTENTIAL CONTRIBUTOR TO THE
VARIABILITY OVER NORTH AMERICA DURING JANUARY. CURRENTLY, THE REAL-TIME
MULTIVARIATE MJO INDEX (RMM) INDICATES ENHANCED CONVECTION OVER THE MARITIME
CONTINENT. SOME MODELS INDICATE AN EASTWARD PROPAGATION OF A RELATIVELY STRONG
SIGNAL TO THE WESTERN PACIFIC, WHICH WOULD DESTRUCTIVELY INTERFERE WITH THE
ONGOING EL NINO AND POTENTIALLY DISRUPT THE DOWNSTREAM RESPONSE OVER NORTH
AMERICA. THE UNCERTAINTY RELATED TO THE MJO LEADS TO SOMEWHAT REDUCED COVERAGE
AND LOWER PROBABILITIES THAN IF THE FORECAST ONLY CONSIDERED EL NINO AND
DYNAMICAL MODEL OUTPUTS. 

We'll just have to see how those changes over the USA effect us in Europe. NCEP also mention a slight decrease in SST anomalies regarding the El Nino.

 

[That ECM]

18 minutes ago, nick sussex said:

 

The debate surrounding the MJO given what NCEP have said has clearly impacted the NH pattern. In the mid December update they mentioned that their January outlook looked to have derailed because of the MJO. No seasonal forecast saw this as having much impact on the NH pattern. They have just updated their January outlook

 

 

 

maybe they should have just ignored and binned it eh Chino? Oh hang on they would have a back handed repost even with a little NLP "like you" throw in. Tushay!! 

 

Edited January 1, 2016 by That ECM

[mountain shadow]

Surely, good news about the MJO and perhaps colder period in phases 7-8-1 from mid to late January.

[nick sussex]

11 minutes ago, That ECM said:

maybe they should have just ignored and binned it eh? !! Oh hang on they would have a back handed repost even with a little NLP "like you" throw in. Tushay!!

 

Whats NLP? I'm not sure I understand what you're trying to say? Regarding the MJO the debate around that was whether it was a false signal being hijacked by Kelvin waves. I don't remember binning any output especially not the MJO which I've been talking about for weeks.

Oh I see  you've edited your post now! lol I get it now.

Edited January 1, 2016 by nick sussex

[West is Best]

Really interesting suite of 12z runs. There's some consistency about height rises over Greenland and a much more meridional flow with polar maritime influences and the UK north of the PFJ, the polar vortex going on walkabout and a LOT of potential from the set ups with rampant easterlies just north of the UK.

I'd suggest that in some ways these are the most hopeful runs for quite some time. That doesn't mean at all that the potential will be fulfilled but there's lots of encouragement to find.

[Man With Beard]

Nick - my thoughts entirely. A window of interest, I imagine, coming up between D10-D15 as air filters down from the N Atlantic. This of course is rather tentative and as usual the UK will probably be on the edges of things - but that huge Euro High anomaly will be banished, I imagine.

As for next weeks cold, tonight's op runs continue a move away from the very best "cold" charts we have seen - the cold pool hit complications over Scandinavia, as often happens, and does not link up favourably with the low coming from the Atlantic - Scotland could still do well for snow but will need a bit more assistance to get anything further south, and time is running out now. But the whole event is a pattern changer, I believe.

Hats off to the ECM/GFS op runs actually - no seriously dramatic twists and turns, just normal variability - virtually every one has got fairly close to the money in the last 7 days.

[karyo]

1 hour ago, chionomaniac said:

So Steve, I know that you put a lot of effort into this post, but that 24 hours is almost up, and from the moment that you posted your thoughts the reverse signal of the pattern change that you suggested has pretty much occurred. I love the fact that you justify your explanation and I, like you, would love to see a cold and snowy easterly, but, if ever there was a case of someone putting forward a case that they want to see rather than using all the models at their disposal to actual create a reasonable forecast of what is most likely to occur, then this is it.

So, being the model thread, I would like to take this opportunity to say that it may be rather foolish to bin all the GFS and ECM suites and that those who try and base long wave teleconnective patterns aren't wasting their time. Instead we should keep on analysing all the model runs, use the ensembles and trends, MJO forecasts that have been so expensively assembled. Perhaps, the reason that the GSM's weren't suggesting a cold easterly was because it isn't going to happen. It is blatantly obvious that the WAA into the Arctic has set up a block too far away for an easterly to make it. The Scandi block was never really there - the WAA was far too successful in reaching deeper into the Arctic and that is where the block formed (Kara Sea) and this ultimately is the downfall of any real easterly before it has even started. Our best hope may be that we can get a back end northerly but even this is looking less likely every run, as any Greenland block is being produced from Arctic heights pushing our way, rather than a fresh bout of WAA from the Atlantic sector.

 

I am not saying that the models will be right all of the time, but perhaps this was one time when the block was too far away to ever give us the realistic chance of a freezing easterly. More a case of warm winter rain being replaced by a slightly colder variety.

So it seems you are saying that the netweather winter forecast is wrong also - no cold January!

[nick sussex]

Into next week and the incoming Atlantic low and possibilities of some snow.

Looking at the UKMO at both T96 and T120hrs that's  colder than what the ECM shows especially for the ne of the UK.

A lot will depend on the surface flow ahead of that low and also what happens initially with the UK low which heads se.

Theres a big difference as to the angle that Atlantic low could approach the UK if the UK low can separate from upstream energy.

The ECM postage stamps are out soon so we'll see what mix of solutions that has.

 

[Duane S.]

Just now, karyo said:

So it seems you are saying that the netweather winter forecast is wrong also - no cold January!

For goodness sake, where does it say that?? Read it again.

[bluearmy]

56 minutes ago, TSNWK said:

I always look at those purples and imagine it to be so much colder than it is. I mean is that really part of the polar vortex covering Scotland..and why not indeed

Just a deep system with fairly cold air aloft which gives uppers around 530

to get an idea where the vortex segments are look at the thickness chart on the NH profile

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=204&code=0&mode=3&runpara=1&carte=1

the lowest thickness readings generally equate to where the vortex is residing

[knocker]

I see the GEFS has dropped the height rises in the eastern Atlantic and moved towards the ecm.

 

[TSNWK]

6 minutes ago, bluearmy said:

Just a deep system with fairly cold air aloft which gives uppers around 530

to get an idea where the vortex segments are look at the thickness chart on the NH profile

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=204&code=0&mode=3&runpara=1&carte=1

the lowest thickness readings generally equate to where the vortex is residing

Thank you.. So we need those purples to be thickness purples and not upper purples  If its the polar vortex over the Uk we want.. I think we did actually get a lobe of the PV over the south east of England the Friday before Christmas 2010.. London was sitting at -2 mid afternoon which must be very unusual even more so when not coming from the east.

[Eskimo]

11 minutes ago, TSNWK said:

Thank you.. So we need those purples to be thickness purples and not upper purples  If its the polar vortex over the Uk we want.. I think we did actually get a lobe of the PV over the south east of England the Friday before Christmas 2010.. London was sitting at -2 mid afternoon which must be very unusual even more so when not coming from the east.

A very small area of snow pushed up from the south, giving Hertfordshire their first ever and only red warning from the MetOffice. 

[chionomaniac]

24 minutes ago, karyo said:

So it seems you are saying that the netweather winter forecast is wrong also - no cold January!

Lol - as the middle of the month cold spell relied on a strat warming and this isn't likely until the end of this month at the earliest then probably. But it has held up so far and there is a world of difference between a seasonal forecast and one for 5-6 days time, though I am sure that you realised that when pointing this out, didn't you Karyo?

[Duane S.]

16 minutes ago, knocker said:

I see the GEFS has dropped the height rises in the eastern Atlantic and moved towards the ecm.

 

Not really the full story though is it. Absolutely pointless showing mean charts from the low res GEFS that far out. There are plenty showing decent ridging in that area, the mean is skewed by those showing very deep low pressure in the same area, this chart better reflects it better...

 

[knocker]

12 minutes ago, s4lancia said:

Not really the full story though is it. Absolutely pointless showing mean charts from the low res GEFS that far out. There are plenty showing decent ridging in that area, the mean is skewed by those showing very deep low pressure in the same area, this chart better reflects it better...

 

Actually it doesn't if you are following the day by day evolution of the GEFS and ecm anomalies. It would give you a false picture. Tonight's ext ecm for example isn't a million miles away from the GEF anomaly. In any case I wasn't attempting any meaningful insight, I leave that to your good self and others, it was merely an observation. But let's not go down the mean discussion yet again.

Edited January 1, 2016 by knocker

[bluearmy]

30 minutes ago, TSNWK said:

Thank you.. So we need those purples to be thickness purples and not upper purples  If its the polar vortex over the Uk we want.. I think we did actually get a lobe of the PV over the south east of England the Friday before Christmas 2010.. London was sitting at -2 mid afternoon which must be very unusual even more so when not coming from the east.

You need the SLP to be 1000mb for the purple dam to equal the surface thickness value.  so the purples are ok depending on the surface pressure.  The lower the pressure, the deeper those  purples have to be to get low surface thickness. 

[Mucka]

18z GFS, where did the Atlantic low go?

[bobbydog]

2 hours ago, That ECM said:

maybe they should have just ignored and binned it eh Chino? Oh hang on they would have a back handed repost even with a little NLP "like you" throw in. Tushay!! 

 

what the hell does that even mean? are you suggesting that a long range forecast being a little off the mark, (not yet wrong) deserves the same derision of someone claiming that all the major models and their ensembles are wrong and will 'flip' to 'winter wonderland' within 24 hours?

 

i really hope that one day the 'emperors new clothes' will be revealed...

[bluearmy]

10 minutes ago, Mucka said:

18z GFS, where did the Atlantic low go?

Don't worry mucka - it'll be along in a minute.  With all the bells and whistles 

[Mucka]

6 minutes ago, bluearmy said:

Don't worry mucka - it'll be along in a minute.  With all the bells and whistles 

 

Quite happy not to see it develop Blue and just spit a couple of shortwaves into the mean trough that develops over us.

Certainly less vicious and more conducive to maintaining some blocking to our N.

It is the difference between this and this give or take.

 

 

Edit

this would sting a bit though. Loving the blizzards for N England as well ah ha.

Edited January 1, 2016 by Mucka

[radiohead]

960mb and deepening over the SW.