Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!

[mushymanrob]

Quiet in here ... more amplification on 06z GFS mid-Atlantic by next weekend compared to the 00z - still not enough amp to head us into a full on northerly though ...

 

tbh nick the quality of posts this morning summed things up better then many of us could, so there was no need to add anything.

[NO LONGER POSTING]

Azores High has been and will be a nusence in winter for coming years I read that back in Summer last year.. 

 

However.. And of course really straight forward... In Summer.. When that ridges up over us.. 

 

Let's just I feel this coming summer is going to be a beaut! 

[fergieweather]

Good afternoon Ian, many thanks for the insight - may I inquire on the unsettled phase 1st half of February please - basically is it what most might describe as standard zonal with lows scooting across west to east to our north on a strong jet, or are there any indications that the unsettled phase will be more amplified keeping the interest going coldies.

Cheers.

Mixed. First we have to see how the more northerly-biased period late Jan unfolds, i.e. the omega-style block with Rossby Wave over E USA causing high pressure to amplify to our west and broadscale trough to E. Some anticyclonic bias thereafter in MOGREPS and GFS ENS. We will see what EC Monthly makes of it tonight.

[MPG]

This chart below is why I am sitting on the fence at the moment.

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-0-1-204.png?6

 

The trough and the Azores HP are far too E. We need to see this set up further W and that bloody Azores HP is getting on my T**s!

That looks great. Settled weather, frosts and above average temps?

[Nouska]

If the models are still going on MJO phasing, I can see where the anticyclonic influences may stem from. Phase six seems to be where the ECM leaves the circle and UKMO looks to be in agreement with the earlier end point.

 

 

Multi-model forecast.  

 

 

 

Phase six composite for Z500.   

 

 

If it does amplify into phase seven, the composite shows what would be a big area high pressure area for NW Europe.

 

 

 

[Frosty.]

Hope the mods allow this because it's potentially important regarding later next week onwards. The Ecm idea of a more significant colder and wintry outbreak now has the support of the latest met office update with an increasingly disturbed and somewhat colder spell arriving by the second half of next week, I like the idea of 510 dam thicknesses hitting the north as the ecm 0z showed with widespread 522 dam..hopefully winter will crank up again as the ecm shows. :-)

[East_England_Stormchaser91]

Simple solution for cold to our shores:

No Azores high = southerly tracking jet + displaced heights to the north, meaning good potential for cracking easterlies/ Northerlies and none of this watered down crud with the jet just going up and over the fat slob of a nuisance high pressure system.

.

Also for summer, it often gives us drab, boring north westerlies which ruin it badly.

The euro high or even a Scandi high deliver the best conditions in terms of heat and storm potential.

Bottom line is, the Azores high is our sworn enemy for preventing exciting weather happening in the UK. Enough said.

[igloo]

its a long way from any type of colder weather with charts like this the azores HP is just spinning like a wheel with a strong PV its just steering those lows from way south with very mild air slap bang on top of us 

 

[Ali1977]

its a long way from any type of colder weather with charts like this the azores HP is just spinning like a wheel with a strong PV its just steering those lows from way south with very mild air slap bang on top of us 

 

-8C uppers and a Northerly 2 days later....you sure?????

[warrenb]

I was just going to say, talk about cherry pick the mildest chart of the whole lot.

Lots of snow for Scotland in a weeks time if GFS came off.

[karlos1983]

-8C uppers and a Northerly 2 days later....you sure?????

 

-8C Uppers and northerlies 2 days later, can you be sure? More likely that the Azores ridges closer to us and off east goes the trough. The Azores High has been the biggest pain in the backside for our cold chances this winter. 

Edited January 22, 2015 by karlos1983

[warrenb]

Europe into the freezer on this run in FI, now we want the ridge to go up, and then sit in Scandi for the rest of the winter.

[rich1]

Not a fan of the azores high out of season (summer) but it can wander about a bit to give some occasional or temporary relief from mild at least. Its the euroslug which is the real winter killer

[Ali1977]

-8C Uppers and northerlies 2 days later, can you be sure? More likely that the Azores ridges closer to us and off east goes the trough. The Azores High has been the biggest pain in the backside for our cold chances this winter. 

 

Too far out to be sure on anything, but next Sat there are Northerlies and it's cold....only going off the charts!!!  That definately looks like a Northerly to me anyway, even if it does only last a day or 2.!!!

Edited January 22, 2015 by Ali1977

[DIS1970]

That's the problem, it is FI and this setup won't be there in 6 hrs time.

[warrenb]

Well at 276 (peers into the distance) up goes my ridge, now get over to Scandi you blighter. But then of course along comes a super low to blow it away. Jocky Wilson at the ready.

Edited January 22, 2015 by warrenb

[frosty ground]

-8C uppers and a Northerly 2 days later....you sure?????

Of course he or she is......... 

Well at 276 (peers into the distance) up goes my ridge, now get over to Scandi you blighter. But then of course along comes a super low to blow it away. Jocky Wilson at the ready.

The cold spell that's almost over started of like that..........

[Captain Shortwave]

Well both the GFS and GEM edge a little towards something a bit colder from the north by the end of the month.

GFS

 

GEM

 

A step towards something more ECM like. Baby steps in the right direction though too far out to even remotely call this the right solution though.

[IDO]

At D10 still a cluster showing something more interesting. It has five members and they are:

 

  

 

 

 

They are what we are looking for to get some early colder synoptics. Hopefully further runs will push this envelope.

[Daniel*]

Well we have circa week or so of mild synoptics (odds on). Rather cold end to January not massively so, but beginning of February might be our next area of interest, with a bitting N'ly been showing in the past few days. Azores high can do one! I foresee at least one more wintery blast till this winter is over, hopefully more fruitful, been disappointed with this cold spell its like crumbs, from the initial projected BLT.

Edited January 22, 2015 by Daniel*

[bluearmy]

Finally the signal comes within a timeframe where gefs pick it up.

The result is rather more week 2 amplification than might have been expected

[Polar Maritime]

Yes the Northerly of sorts has been showing for a number of runs now, Seems an ever growing trend of late. If this set-up played out -10 850's would touch Northern Scotland and Snow showers would push way South of the UK.

 

[kev238]

It seems there is a good chance of something from the North in about 8-10 days-  the azores high is modelled consistently in the models and does not seem to be in the mood to go anywhere so I cant see any real sign of anything significant from the east. I think it highly unlikely we will get a beast from the east this year- that is not to say we wont get some bitter northerly air later in the winter. I think we will get at least one more shot at some snowfall during the winter/ early spring. That is not based on anything- just a hunch!

[legritter]

Yes the Northerly of sorts has been showing for a number of runs now, Seems an ever growing trend of late. If this set-up played out -10 850's would touch Northern Scotland and Snow showers would push way South of the UK.

 

will certainly bank this ,but tonights ecm i hope will be showing an upgrade with our azores high shoved west some .of course Met office models we dont get to see in further outlook are showing colder and wintry flavour IF going by todays further outlook .we need plenty of upgrades and i feel the dice falling in the UK s favour ,so hopefully gang let the hunt commence   

[Tamara]

It appears stubborn, but there is no mystery surrounding the Azores High  .  

 

Easterly winds across the tropics pulsing through the Pacific and Atlantic support robust sub tropical ridge development. The pattern, as controlled by an upstream Pacific amplification (+PNA ridge) and the northward ridging of the sub tropical high pressure belt (the Azores High) steepens thermal gradients and jet flow energy.

 

This pattern, as advertised within the 10 day period. However, the stratospheric signal to displace vorticity eastwards provides an increasing NW/SE tilt to the jet stream to add more and more polar flavour into the mix as we head towards day 10

 

As the mitigating factor towards attempted depth of cold air advection, this cuts to the chase of where the Azores High is perceived as villain for cold and snow lovers.

 

Weakening of those easterly winds across the tropics reduces the strength of the Azores High and therefore makes it easier for greater amplification to occur along the polar front jet

 

As previously posted this winter, the Azores ridge is strengthened by decreasing frictional torques and is weakened when frictional torques are increasing. There is a lifespan (wavelength) to frictional torque phases and these last 3 to 4 weeks. It was believed back in December that torques would increase, but unfortunately there was too much poleward energy transport momentum as a consequence of convection returning to the Indian Ocean (MJO Phase 3) and GWO moving from  amplified Phase states 1/2 into flatter Phase 3

 

This time around there are differences. We have had a more progressive GWO Phase 4/5 orbit which has triggered +ve frictional torque and +EAMT.  In the next week or so I would think that further increases in temperature will be modelled in the stratosphere (as a response to this EAMT) to add to the displaced stratospheric vortex signal. 

 

The atmosphere has responded to these +ve torques and driven AAM downwards and sent GWO through orbit 8/1 towards Phase 2 and is set to initiate the US Rossby wave activity over the US (that Ian refers to) and the amplification signal to our west which is setting the scene for our end of month northerly

 

Ensemble uncertainty revolves around timing and strength of any amplification signal.

 

We need to bear in mind that the signal to diffuse tropical ridges as response to increasing torques has to take account of the lag wavelength (as described above) and also the fact that it is the Pacific sector which sees changed responses first. With this in mind we have to be patient (if we can!) for the signal to feed downstream to the Atlantic.

 

However, with the stratospheric signal displacing the vortex favourably, any upstream amplification that does feed down stream takes on obvious extra importance in terms of potential potency of any northerly incursion.

 

Thereafter, as Nouska posted, MJO Phase 6 into February does teleconnect support for the anticyclonic influence that Ian further mentioned possible. Much depends how fast the upstream signal progresses and retrogresses the +PNA ridge and takes the energy out of the Atlantic sector. This determines how long any cold zonal pattern might last into February

 

As posted and reasoned yesterday, there are credible grounds to expect active, higher amplitude eastward MJO progression as we head through next month. January (tropical convection wise) is proving that bit different to December, and February will be that bit different to Jan...

 

With the bulk of the vortex displaced eastwards, and pipelined further GWO induced warming, then if verified, any high pressure poised at mid latitudes following a cold zonal phase poses the interesting suggestion of retrogression of an UK/NW Europe anticyclone towards higher latitude blocking to our NW towards mid month (perhaps extending towards Scandinavia) as the stratospheric warming log jam takes effect combined with (*she sticks her neck out*) further MJO advancement into high amplitude phases 7/8

 

On that basis, and as stated yesterday, I'll continue to suggest an increasingly meridional pattern as we head through February leading to enhanced upper cold block potential .