Model output discussion - 1st December onwards

[warrenb]

I think the issue is the PV is going to be shredded, but the models are throwing out lots of ways the parts will be displaced, hence the differences day to day.

Today they are most chucking it at us, other days they hold it slightly more mid atlantic, hence the Easterly, soon they will push it through and we will get Greeny blocking and a northerly.

Just sorting the mess left of the PV. Lots of changes to come.

[Mucka]

5 minutes ago, warrenb said:

I think the issue is the PV is going to be shredded, but the models are throwing out lots of ways the parts will be displaced, hence the differences day to day.

Today they are most chucking it at us, other days they hold it slightly more mid atlantic, hence the Easterly, soon they will push it through and we will get Greeny blocking and a northerly.

Just sorting the mess left of the PV. Lots of changes to come.

That is a succinct and accurate appraisal of where we are IMO.

Re Northerly around mid month? There has been a fairly strong and coherent signal for some time for pressure to build to our South and West heading toward mid month but remains to be seen whether that develops over the UK or further West in the Atlantic which would be better. Aslo mixed signals as to the extent of the build of high pressure North. If I had to make a forecast for mid month I would give a mention to possible colder weather from the North but concentrate more on a less mobile regime with the UK becoming somewhat drier.

 

[El ninyaknow]

20 hours ago, Singularity said:

Tamara's done a great job of summarising the reasons why the potential for a significant period of cold, snowy type weather affecting the UK at some point in the next 30 days or so has risen to levels which IMO have not been seen since late Feb 2013 (prior to that crazy cold March). Thanks as always to her for letting us in on her well-informed thoughts 

Having watched the cold outbreaks of 2008/9, 9/10, Dec 2010 and March 2013 unfold in the models, this is what I've concluded about model and forum behaviour:

Typically, the models struggle a lot in the longer-term when the potential has reached such levels. Usually we see them spending some time failing to effectively produce the feedbacks that carry us toward a cold spell, after which they - sometimes suddenly - 'smell the coffee'... only to start jumping the gun and coming up with mouthwatering outcomes that turn out to have been a bit too soon with some complications to get past first. Then comes the 'refining' period, during which enthusiasts agonise over run-to-run changes in the details despite knowing that really it should be left until very short range indeed before drawing ultimate conclusions. Eventually, the cold, snowy potential is realised to some extent or other. All too often we're left looking back on what it could of been and wondering why it had to be watered down so much - but sometimes we get the full-monty and it's a joyous period to be on the forums.

 

This is just a heads up as to what may well be on the way again in Jan-Feb 2016. Having said that, the models may do a better job with the changes this time around given the upgrades they've had since 2010 for example. After all, they handled March 2013 very well indeed, with remarkable consistency from run to run being one of the key aspects I can recall.

Some big mistakes are still being made these days though. Among the largest I know of in recent times is with regard to the AAM state; GEFS in mid-Dec were suggesting -ve AAM tendencies by late month, yet we've ended up a long way +ve. Laughable really, but almost entirely down to a failiure to spot the propagation of tropical convection through the Pacific in advance.

For those who can read it, here's the latest GWO outlook from GEFS... very, very positive indeed:

With signs of another cycle to follow mid-Jan, it seems that the undesirable scenario outlined by Tamara isn't being put on the table by that model at least. If the AAM can kick back up as high as in the next few days during mid-Jan, I can see that being enough to blow the vortex apart, despite its strength.

It's been a long time but I'm feeling that slight buzz of anticipation at last. Now to sit on it until mid-Jan because I like to keep my hopes in check until confidence levels are into the high range, for the sake of mental stability 

 

Also of note is the model tendency to quickly break down amplitude of MJO events when in reality they may hang around a little stronger or longer, this may give us the window to promote Cross polar WAA and hit the PV twice maybe 3 times during January! Models not yet seeing this in relation to a possible retrogression of the developing Scandinavia high but there is time. Even with a QBOw, which actually is nearer neutral at 30mb, we might flip into a -NAO by early Feb... Old Cohen seems pretty keen on heights rising across the Pacific suggesting possible W2 pattern and subsequent vortex split environment...but we all know which side of the fence he lies... Either way possibly more exciting than was initially expected during such a strong EP ENSO event, speaking of which with convective maximums shifting westwards could take on more of a CP winter back with the implications of that as we are well aware of :-) happy new year mate :-) 2016 lets go! 

#frozenfeb

[shaky]

Jesus!!!the shortwave at 72 hours is much further south on the ecm compared to the gfs!!!its similar to the jma actually!!!this morning ecm had it further north!!

[northwestsnow]

http://www.wetterzentrale.de/pics/Recm721.html

Just shows how close we are to something really nice.

[I remember Atlantic 252]

4 minutes ago, shaky said:

4 minutes ago, shaky said:

Jesus!!!the shortwave at 72 hours is much further south on the ecm compared to the gfs!!!its similar to the jma actually!!!this morning ecm had it further north!!

Jesus!!!the shortwave at 72 hours is much further south on the ecm compared to the gfs!!!its similar to the jma actually!!!this morning ecm had it further north!!

Won't let me unquote this, may as well reply, love your posts shaky!!!!!! and frosty's of course, mods move my post to whiners thread, and how do you 'unquote' posts?

Edited December 30, 2015 by I remember Atlantic 252

[cornish snow]

Just now, I remember Atlantic 252 said:

Won't let me unquote this, may as well reply, love your posts shaky!!!!!! and frosty's of course, mods move to whiners thread, and how do you 'unquote' posts?

Press the command key and right click twice,option will appear to delete quote

[shaky]

Ecm at 96 hours desrupting west of the uk!!!looks better than ukmo and gfs!!!

[knocker]

Looking at the latest GEFs the PV is certainly not shredded but it is still pushing height rises to the west with a trough to the east down into central Europe. Long may it continue.

[Ali1977]

2 minutes ago, knocker said:

Looking at the latest GEFs the PV is certainly not shredded but it is still pushing height rises to the west with a trough to the east down into central Europe. Long may it continue.

That looks a great chart for coldies, am I correct?? Also better for those who are in flood hit areas.

[knocker]

Suffering succotash

[Day 10]

120

 

 

[knocker]

Just now, Ali1977 said:

That looks a great chart for coldies, am I correct?? Also better for those who are in flood hit areas.

No, it looks better for drier conditions

[Polar Maritime]

A little more wording around the charts posted would be helpful please and for newcomers alike.

[Day 10]

for comparison

 

Edited December 30, 2015 by Polar Climate

[Day 10]

Better heights than the  GFS, UKMO at 144

 

[northwestsnow]

ECM actually looks very nice !!!! Last minute upgrades  perhaps  (Wedge of high pressure across the GIN sea forcing the jet further south).

[knocker]

Sorry Polar M

The chart below shows a deep low approaching from the west. What it doesn't show, too broad a scale is another little system 984mbs where the little kink in the isobars is located. This little system and associated fronts run across the country on Sunday bringing rain and strong winds.

Edited December 30, 2015 by knocker

[nick sussex]

7 minutes ago, Polar Climate said:

Better heights than the  GFS, UKMO at 144

 

More amplitude upstream than the 00hrs run at T120hrs results in this better result. With a bit more we might be able to separate that shortwave energy from the troughing over southern Greenland.

Interesting T168hrs not bad! If the shortwave separates sooner this will allow the ridge to back further west and put more pressure on the upstream low.

Edited December 30, 2015 by nick sussex

[shaky]

I did say nick this aint over yet and could still get even better!!this really reminds me of january 2013 right now except 10 days earlier this time!!!over to the 18z in a few hours!!!

[SMU]

After a difficult 24 hours the ECM & GEM 00z

give a VERY good continental feed into the approaching atlantic low

VERY NICE

Snow !!!

Edited December 30, 2015 by THE CHOSEN ONE

[Mucka]

It is a shame the shortwave over Scandi dissects the high at 96h as that ultimately allows a a trough to push through and tilt the high into an unfavourable orientation at 168.

 

Otherwise the high would be better orientated and further NW at 168 to combat the incoming Atlantic

 

Poor JMA tonight after promising start but seems very quick (too quick) to get rid of high pressure to the N and E

 

Edited December 30, 2015 by Mucka

[I remember Atlantic 252]

Weak E'ly at 168, snowfest for NE on next frame 192

[radiohead]

3 minutes ago, I remember Atlantic 252 said:

Weak E'ly at 168, snowfest for NE on next frame 192

Or a rainfest! Mild Atlantic air pushing in...

 

 

 

Edited December 30, 2015 by radiohead

[gottolovethisweather]

25 minutes ago, knocker said:

No, it looks better for drier conditions

And as a coldie whose impartial to either dry or snowy conditions I'm certainly happy should that end up the final reality. The ECM 12z looks especially calmer and colder for those in the Northern parts of the UK. Who bl**dy ray I say! 

 

Should any easterly develop I'd suggest that will also aid the situation, due to them hopefully containing a lot of dry cold air as well. 

Edited December 30, 2015 by gottolovethisweather