Model output discussion - 1st December onwards

[slater]

Where did these charts all come from all of a sudden? Are we all drinking to much sherry lol

[daz_4]

What the hell is happening?  This would be quite a change for us here in central Europe.

[radiohead]

Perhaps not surprising, but only a small cluster of GEFS support the OP at T180. 

[Jason M]

The control run doesn't quite get there, but in general terms supports the opp. There are also a decent number of good GEFS. Synoptically I wouldn't describe the opp run as an outlier against the GEFS out to 186 hours. Don't get me wrong here, there are plenty of the GEFS that are still grim and this is by no means a done deal, but I'd say we are at least in the game 

also worth noting that we are not talking about day 15 here! When the control and opp head in broadly the same direction at days 6-8 it's worth sitting up and taking notice. My gut feel is a close but no cigar scenario but it sure beats what we have.

 

 

[knocker]

A small wave delivers snow to most of the UK in New Year.  And then.................would you Adam and Eve it.

Charts weatherbell

 

 

 

Edited December 24, 2015 by knocker

[Methuselah]

1 minute ago, radiohead said:

Perhaps not surprising, but only a small cluster of GEFS support the OP at T180. 

Which is precisely why I willn't be getting excited until something actually happens.

[booferking]

8 minutes ago, radiohead said:

Perhaps not surprising, but only a small cluster of GEFS support the OP at T180. 

Yes but the numbers are growing as far as i can see hopefully it continues.

[Geordiesnow]

As someone else says, not only the GFS would potentially something more colder than the UKMO, it would also start blocking any Atlantic systems from heading too far eastwards whereas the UKMO would not do that and its a lot more progressive. 

The big deep low has not really been picked up by the Euro models although the GFS still has it but much further West. In all honesty as an weather enthusiast, if we are not going to get the cold, then lets have a good old deep low heading towards us but the UKMO does not produce either and its how you were basically. 

Be interesting what the ECM shows, not bothered if it shows an easterly or not, I would like too see that initial shortwave head eastwards earlier on which seems crucial to what the longer term outlook may show. 

[nick sussex]

The UKMO 12hrs run output isn't as bad as this mornings 00hrs run but the shortwave is taken too far north and theres no way it could deliver the GFS output from there

Why oh why is it always down to a shortwave!

Some news from upstream as to which models they prefer for that low which phases with the troughing to the west of the UK at T96hrs:

SURFACE LOW EJECTING ACROSS THE CENTRAL PLAINS/MID MS VALLEY AND
TO THE NORTHEAST FRI TO SUN STRONG SURFACE FRONT LEFT DRAPING FROM THE NORTHEAST TO THE SOUTHERN PLAINS BY SUN
 

PREFERENCE: 12Z GFS / 00Z ECMWF BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THERE ARE SOME LATITUDE DIFFERENCES WITH A SFC-850 MB LOW FORECAST
TO COME OUT ACROSS THE PLAINS FRI NIGHT INTO SAT...WITH THE 12Z
GFS AND 00Z ECMWF NORTH OF THE 12Z NAM/UKMET/CMC AND ENSEMBLE
MEANS. THE GFS HAS BEEN STEADY AND THE 12Z ECMWF HAS TRENDED NORTH
TOWARD THE GFS WITH ITS 00Z RUN. OFTEN WHEN THE ECMWF OR GFS HAVE
TRENDED TOWARD ONE ANOTHER...THEY ARE OFTEN ON TO THE CORRECT
SOLUTION. HOWEVER...GIVEN THE MEANS ARE STILL SOUTH...CONFIDENCE
IS BELOW AVERAGE.
 

Although the ECM 00hrs didn't develop like the GFS 06/12hrs run it still had a more amplified upstream trough in the earlier stages.

Edited December 24, 2015 by nick sussex

[cyclonic happiness]

25 minutes ago, Ed Stone said:

Which is precisely why I willn't be getting excited until something actually happens.

Did you really say "willn't"?   

[Mucka]

GFS ensembles Central England

 

 

Assuming GFS continues this trend and/or other models come on board (big assumption) and also assuming we can get past the initial shortwave dramas and get a decent Scandi block developing by 120h then there are a couple of key areas to look for if you want upgrades.

 

Firstly at 120h we want as much energy as possible to disrupt SE under the block. If you are learning you are looking at the circled area - notice how the lines point SE showing energy disrupting in that direction.

 

And then again at 168h we want exactly the same thing, as much energy as possible heading SE under the block rather than N/NE over the block.

 

 

If we can get that far then things could upgrade very quickly but of course we need the other models to get on board.

 

Initial stages of JMA are better than last nights 12z so that is a good start.

 

Edited December 24, 2015 by Mucka

[Methuselah]

12 minutes ago, cyclonic happiness said:

Did you really say "willn't"?   

I did...Isn't 'willn't' a contracted form of 'I will n(o)t'?

Edited December 24, 2015 by Ed Stone

[booferking]

Very little difference between ECM & GFS @ 72hrs.

[nick sussex]

The ECM is much better than the UKMO at T72hrs, much sharper troughing to the west. And the shortwave should eject cleanly eastwards at T96hrs.

So far so good, the key timeframe coming up as to where the energy goes from that troughing.

Edited December 24, 2015 by nick sussex

[Mucka]

15 minutes ago, Greenland1080 said:

That's a a huge vortex pushing against the Scandi block Mucka...we'd want that disrupted or being pushed north north east surely... displaced from Greenland otherwise wouldn't energy just push through from the Atlantic? nice 1050 Scandi high on gfs12z

If it goes NE it sinks the block, game over.

You need it to keep chewing chunks of energy off and for them to disrupt against the block. It is fine if some energy goes N/NW up the face of the block so long as we get enough energy going under. As long as we get energy going under the block it won't sink and the high will continue to repel the Atlantic and that chunk of Vortex over Greenland should slowly quieten and lows get disrupted further West. In the perfect scenario that would happen and then block can begin to retrogress toward Greenland.

 

The reason you are seeing the cold "lift out" at the moment is because the lows are not disrupting enough (too ball shaped) but if we get more nergy under earlier then the block will be further West and the lows will then disrupt more whereas if more energy goes NE over the block earlier then it will be further East and South and it is all downhill from there unfortunately.

Edited December 24, 2015 by Mucka

[The Enforcer]

1 hour ago, Mucka said:

I see the ubiquitous pesky mild sector has got in on the act again, so time for the first *MILD SECTOR ALERT*of the season.

At least that polar continental interlude would get the January CET off to a good start.

Edited December 24, 2015 by The Enforcer

[SxK]

ECM says no for now, but improves on 0z run. If the trend continues over next 24 hours then things could get interesting for cold lovers.  

[Mucka]

7 minutes ago, Greenland1080 said:

Thanks Mucka....

You're welcome. Obviously there other factors but if you compare the GFS 120 with the ECM 120 you will see GFS has more energy going SE.

It will be big day tomorrow for more reasons than one for coldies.

[Cheshire Freeze]

2 minutes ago, SxK said:

ECM says no for now, but improves on 0z run. If the trend continues over next 24 hours then things could get interesting for cold lovers.  

Vortex being somewhat pincered at day 6 too so further attacks on the tropospheric vortex looking likely.

[nick sussex]

Too much energy going ne on the ECM and its high is poorly orientated. We need to hope now that the lobe of high pressure near Svalbard can hang on and force the jet more se'wards.

Without the angry PV there would have been more trough disruption but its very difficult to fight the  PV at the moment.

Edited December 24, 2015 by nick sussex

[SxK]

3 minutes ago, nick sussex said:

Too much energy going ne on the ECM and its high is poorly orientated. We need to hope now that the lobe of high pressure near Svalbard can hang on and force the jet more se'wards.

Without the angry PV there would have been more trough disruption but its very difficult to fight the  PV at the moment.

Short term pain for long term gain perhaps. High orientation sends some toasty WAA up into the arctic at T168. Even if we miss this attempt then this may help to weaken the vortex in January. 

[Cheshire Freeze]

4 minutes ago, nick sussex said:

Too much energy going ne on the ECM and its high is poorly orientated. We need to hope now that the lobe of high pressure near Svalbard can hang on and force the jet more se'wards.

Without the angry PV there would have been more trough disruption but its very difficult to fight the  PV at the moment.

Still, that's some blocking feature at day 7- look at its amplitude- ramifications going forward from there you'd think. Also big change occurring within N hemisphere set up. Finally, Russia and E Europe finally go cold!

[Cheshire Freeze]

You can see the pressure the vortex is under from the 192 uppers chart. A patch of positive uppers near the pole 

Surrounded by frigid uppers either side- leaking further and further S

[dbaloo]

question is what to open first in the Moring......presents or the net weather forum and see if the trend continues.....???

just want to take this chance to wish all members,warm lovers and cold lovers alike a very merry Christmas.keep up the good work all,learning more everyday!

[nick sussex]

Overall this evening its a case of the PV versus high with the PV firing missiles and the high throwing a few grenades.

Its quite a difficult set up because the NWP has to balance where the energy goes from that PV. This type of situation is one of those domino effect scenarios where if you can topple one the whole lot go.

If the models are underdoing the trough disruption then more of that goes se, this then allows the high further west and able to exert more pressure on the troughing.

NWP does not like this type of set up so I wouldn't assume any of the outputs have the correct solution, theres been quite a few changes over the last few days with the NWP making a big drama just over that shortwave at T72hrs.

Currently I think you'd have to favour the PV being just a bit too strong for the high but we'll see tomorrow if theres any more mileage in the GFS scenario.