Model output discussion pm 13/01/2016

[cowdog]

16 minutes ago, TSNWK said:

agreed! - I certainly felt that the hidden models are suggesting a continetal drift over the south-easten part of the uk for the foreseeable...

 

I really wish we had at least a simple snap shot of output from those models as it does seem the Met is going for a below average dry February yet all the long range models that the general public has access to are showing nothing of the sort. Although the 6z GFS as Mucka points out is showing the possibility of the cold never really going.

[karlos1983]

8 minutes ago, TSNWK said:

Unable to show charts as I'm sugggesting that the hidden charts ( MOGREPS / GLOSEA etc ) are suggesting no Atlantic.

actually, I think you'll find that they have members showing both solutions, much like what we see, so as such, confidence is low.

UKMO and GFS are both possible solutions

Edited January 14, 2016 by Polar Maritime
To move discussion on.

[SMU]

Mucka add 06z NAVGEM to that...

 

Afternoon All - 

So tucked away in the detail of last nights post was still the gap of model error between 96-120 for the track of the undercutting low-

The overnights still have it undercutting- however now there is some more residual vorticity left in situ in the mid atlantic in between the Main low south of Greenland & our undercutter low

This could develop & could be an over reaction - however this has made our retrograde high a little weaker & thus sees more toppling of the high sooner....

However with the primary driving fact of undercutting becoming somewhat resolved now ( more 72 -96 ) so that first phase is nearly over- but phase 2 still represents huge swings - especially for the UK who sit on the cusp of mild air & cold air- 200 miles at day 6 can make a world of difference to our little island !!

I wait with baited breath for the 12s....

S

[Methuselah]

TBH, I find all this talk of 'hidden models' very reminiscent of the 'missing balloon-data' assumptions of old...So discussion of such entities is surely off-topic, and wondering just what they might be saying (assuming they exist) is pure hypothesis?

[phil nw.]

Talk about model uncertainty.The 00z runs ramped that up alright.

Certainly that GFS and to a lesser extent the ECM got a move on in pushing away the Arctic air early next week.The UKMO although less bullish on amplication to the nw still keeps the blocking around the UK to day 6 so again the lone voice this morning.

GFS 06z run has now pulled back on it's progressive Atlantic push showing how tricky this balance of milder Atlantic v Cold block over Europe/UK is to resolve in modeling.

I think we have to bear in mind that this cold spell was always likely to be of around 7/8 days duration which would take us to around 20/21st and looking at the latest GFS Ens graphs- rather than the differing Op. runs- that still looks the case.

we can see pressure rises quite quickly across the UK by Monday and the supply of the coldest upper air is cut off soon after the weekend under slacker high pressure we retain surface cold until near the end of the week.

A look too at the combined London 2mtr ens-red is the ECM op,blue the GFS and the grey is it's 50 ens.members.

pretty much the same message less cold by 20/21st,note some cold clustering for 2/3 days longer.These probably keeping the high from drifting se a little longer,which may be what the UKMO run is suggesting in it's less progressive outlook so far.

The UKMO is keeping a high over us until day 6  and seems reluctant to sink it quickly but whether it can continue to plough this lone furrow much longer against all other ensembles remains to be seen.

 

[Singularity]

1 hour ago, Nouska said:

Yes, this is important as whatever the NHC track shows, it is a blend of the models based on their expert opinion. Little differences in individual models have a big impact when such a surge of warm tropical air is introduced into the winter atmosphere.

Just like the difficulties last summer, when the reverse was true - models introducing large shots of Greenland cold into the warm summer atmosphere.

Will take a few runs yet to settle down.

Alex becomes the first hurricane of 2016.

AL, 01, 2016011412, , BEST, 0, 308N, 287W, 75, 981, HU, 34, NEQ, 120, 130, 100, 30, 1012, 300, 15, 0, 0, L, 0, , 0, 0, ALEX, D,

Last time a January hurricane was seen was 1938.

Such a rare sight - pic for posterity.

Well this is among the most remarkable things I have seen in since I started seriously following the weather.

So the models need to handle how the remnants of this interact with a full-on wintertime jet and wave pattern. Good luck to them!

For whatever reason the GFS and ECM det. runs seem to be delaying the trough disruption in a few days time compared to yesterday's efforts, meaning it takes place further north and is also in a less ideal environment hence the threat of residual vorticity that Steve Murr has highlighted. 

UKMO is having one of that and from what I've read the Met Office have a similar line of thinking. It's going to a hard pill to swallow of that combination of guidance is wide of the mark.

[Mucka]

56 minutes ago, Steve Murr said:

Mucka add 06z NAVGEM to that...

 

Afternoon All - 

So tucked away in the detail of last nights post was still the gap of model error between 96-120 for the track of the undercutting low-

The overnights still have it undercutting- however now there is some more residual vorticity left in situ in the mid atlantic in between the Main low south of Greenland & our undercutter low

This could develop & could be an over reaction - however this has made our retrograde high a little weaker & thus sees more toppling of the high sooner....

However with the primary driving fact of undercutting becoming somewhat resolved now ( more 72 -96 ) so that first phase is nearly over- but phase 2 still represents huge swings - especially for the UK who sit on the cusp of mild air & cold air- 200 miles at day 6 can make a world of difference to our little island !!

I wait with baited breath for the 12s....

S

Must admit I don't look at NAVGEM but just took a look and yeah the hints are there Steve even if it doesn't get there.

Not sure I want NAVGEM on my side though. 

Be great to see it modeled anywhere actually though and as you say there is still room for some fairly bug swings in the relative short term, whether they are big enough and favourable enough to see the scenario I painted modeled is another matter but there should be plenty of interest for coldies in the output over the next couple of days IMO - starting with the 12z.

Edited January 14, 2016 by Mucka

[johnholmes]

2 hours ago, weather eater said:

Problem is verification stats tend to iron out the creases and that may mean that particular models may have particular issues in some regards. 2 its ranking also does not mean it is always better than the next on the list, just usually. Why it comes to HL blocking patterns that are directly influencing our weather, I tend to work to the theory that if the GFS is not buying into it, then it will not happen. I cannot recall when this was not sound advice.

Verifications statistics are available on a daily basis for 500mb over the northern hemisphere so your comment is I think not valid. The long wave 500mb pattern is unlikely to be markedly different if shown just for Europe as they cover such huge distances, 4 major waves in 360 degrees=90x60 in nautical miles. Minor waves within that pattern may well not be picked up. However, they normally disappear in the major wave pattern with 2-3 at most about 5 days leaving no marked change in the major pattern. One can always argue that they do not show all the model vagaries but they are the best scientific data used by all the main forecast centres to try and improve their own model and weed out any biases any may have.

[karlos1983]

1 hour ago, Nouska said:

Yes, this is important as whatever the NHC track shows, it is a blend of the models based on their expert opinion. Little differences in individual models have a big impact when such a surge of warm tropical air is introduced into the winter atmosphere.

Just like the difficulties last summer, when the reverse was true - models introducing large shots of Greenland cold into the warm summer atmosphere.

Will take a few runs yet to settle down.

Alex becomes the first hurricane of 2016.

AL, 01, 2016011412, , BEST, 0, 308N, 287W, 75, 981, HU, 34, NEQ, 120, 130, 100, 30, 1012, 300, 15, 0, 0, L, 0, , 0, 0, ALEX, D,

Last time a January hurricane was seen was 1938.

Such a rare sight - pic for posterity.

If Alex hangs around a little longer than expected, before heading north, it would change the track as the Jet is forecast to power up. If it interects with the jet it will scoot off towards Portugal.

If it hasn't cleared the Azores by Saturday afternoon, it won't be paying a visit to Greenland.

I'll be keeping my eye on that.

Edited January 14, 2016 by karlos1983

[fromey]

Any one care to take a punt at the end result of the Cat 1 hurricane heading towards the vicinity of Greenland, what will the remnants of it do to the models? Increased model uncertainty? Surely some WAA to get some blocking going 

[cowdog]

55 minutes ago, fromey said:

Any one care to take a punt at the end result of the Cat 1 hurricane heading towards the vicinity of Greenland, what will the remnants of it do to the models? Increased model uncertainty? Surely some WAA to get some blocking going 

Going to be a fun 24 hours with the models I expect given it wasn't expected to intensify like it has. Could be some interesting output on the 12z runs.

Edited January 14, 2016 by cowdog

[chicken soup]

1 hour ago, Ed Stone said:

TBH, I find all this talk of 'hidden models' very reminiscent of the 'missing balloon-data' assumptions of old...So discussion of such entities is surely off-topic, and wondering just what they might be saying (assuming they exist) is pure hypothesis?

But they do exist..in the form of mogreps and glosea5.

[JeffC]

This shows up TS Alex quite nicely !

http://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=-13.34,44.60,767/loc=-28.842,31.696

[bradymk]

Shocking start to the afternoon from the GFS. Trough more positively tilted, further north too with lower heights to the north. Bleh.

 

[Methuselah]

2 minutes ago, chicken soup said:

But they do exist..in the form of mogreps and glosea5.

Aye, CS - but, as none of us can actually see them, what can we can we really say about what they might or might not show? 

Anywho, the GFS 12Z is now oozing out...And we can see that one!

[karlos1983]

Well I was hoping for a bit more trough disruption, does not appear to be coming

If the UKMO sticks to it's guns, I'll be gobsmacked.

[ALL ABOARD]

12z has Atlantic mobility returned by just 84 hours?

Either its so far in over its head its unbelievable or the met are wrong?? 

 

[Eskimo]

The GFS is surely wrong here, just 90h away and we have this....

[karlos1983]

I'm gobsmacked ..... UKMO @+96

GFS has gone bonkers or UKMO is on holiday

Edited January 14, 2016 by karlos1983

[northwestsnow]

GFS12z is really poor, heavy rain moving in late sunday night into monday.

 

[Eskimo]

UKMO still says otherwise...

[mountain shadow]

GFS simply cannot seriously be taken as a serious model for our part of the world in blocking situations. 

It is monumentally poor.

[ALL ABOARD]

I can never in all my time ever remember difference like this at T96! INCREDIBLEEEEEEEEE!!!!!!!!

 

 

 

[chicken soup]

I would bet my house that GFS is wrong...its so poor when it comes to winter issues, getting to the point now were its hardly worth viewing.

 

[bradymk]

Well glad the UKMO is still decent at +96 and would rather that be the one showing the cold than the other round. But either way, some shocking changes at a normally more "reliable" timeframe, as early as 2-3 days on GFS.

Difference at 96 between these two is pretty remarkable. All good fun though 

Edited January 14, 2016 by bradythemole