Model output discussion - 21st Jan Onwards

[nick sussex]

This looks very much like an ECM monthly/ UKMO MOGREPS versus GEFS view of the MJO.

The UKMO obviously think that the MJO will play a role and for this reason suggest that mid Atlantic ridge, indeed this is looking like together with any minor or major SSW the final chance to load the dice in favour of some colder conditions developing as we head through February.

The NCEP MJO expert has updated his outlook, the bits most relevant to us in Europe:

Over the next two weeks, dynamical model MJO index forecasts favor an amplifying signal over the Maritime Continent. While this amplification may be associated in part with potential tropical cyclone activity over the southeastern Indian Ocean or Timor Sea, the longer range ECMWF monthly forecasts depict an eventual eastward propagation of the signal to the Pacific. Additionally, dynamical model precipitation forecasts favor enhanced convection over the eastern Pacific and western Maritime Continent, which would be consistent with an emerging intraseasonal signal. Therefore, influence from the MJO is anticipated to be weak during Week-1, but may play a more substantial role in the global tropical convective pattern during Week-2.

 There is uncertainty regarding whether an intraseasonal signal will develop, but if a Maritime Continent MJO event does evolve, the downstream mid-latitude impacts would be largely in opposition to the canonical ENSO impacts. This introduces considerable uncertainty to the longer range forecast for the U.S.
 

Theres often a debate about the initial stages of the MJO versus Kelvin waves and the December signal was also the subject of much twitter debate. The reason is its unusual to get a strong MJO during a strong El Nino, you're always likely to get some Kelvin wave activity at the initial onset of the MJO and this again seems to be the issue, but if the MJO does develop Kelvin waves alone would not be responsible for the movement.

We should know by next  week whether the MJO will be a big factor as the divergent model forecasts would hopefully start to converge at that point.

 

 

[Cloud 10]

Looks like another round of Arctic high drama to come in the next couple of weeks which could well lead to some erratic yet exciting model output,as was evident before the last "sort of" cold spell.

 

Lottery tickets at the ready.

 

[bluearmy]

Interesting developments in the eps back end week 2.  Fits in with my thoughts from this morning that coldies might be about to dust of the sackcloth and ashes. 

 

[ukpaul]

Well, they're a small improvement but with a North Westerly regime De Bilt may be unrepresentative, control looks interesting though!

[feb1991blizzard]

1 minute ago, bluearmy said:

Interesting developments in the eps back end week 2.  Fits in with my thoughts from this morning that coldies might be about to dust of the sackcloth and ashes. 

 

Do these interesting developments involve an area in the Atlantic stretching just into Greenland by any chance?

[bluearmy]

12 minutes ago, feb1991blizzard said:

Do these interesting developments involve an area in the Atlantic stretching just into Greenland by any chance?

The upper trough gets to our east (528 dam thickness across Midlands at day 15)

signs of a bit of upper ridging around iceland

The control has a few snow events across diff parts of the UK in week 2 as systems cross England at

diff latitudes. (Not a fan of the control at that range though)

Edited January 26, 2016 by bluearmy

[Nick F]

18 minutes ago, bluearmy said:

Interesting developments in the eps back end week 2.  Fits in with my thoughts from this morning that coldies might be about to dust of the sackcloth and ashes. 

 

Yes, was just looking at the EPS T850 mean anomalies over the UK day 15  which shows negative departures of -2 to -4C. The negative 500mb height anomaly over the UK shows quite a substantial departure at day 12, the most prominent -ve height anomaly in the N Hem which eventually shifts east of UK by d15 - so increasing signal for northerlies? Certainly a colder outlook by Feb 10th.  And no Euro high anomaly post day 10 ...

Edited January 26, 2016 by Nick F

[Singularity]

16 minutes ago, bluearmy said:

The upper trough gets to our east (528 dam thickness across Midlands at day 15)

signs of a bit of upper ridging around iceland

The control has a few snow events across diff parts of the UK in week 2 as systems cross England at

diff latitudes. (Not a fan of the control at that range though)

Very interesting, it seems those ensembles are indeed using the amplification signal from the anticipated MJO event to enhance the Eurasian trough/mid-Atlantic ridge pattern put in place by the preceding vortex displacement... and unless they've suddenly started propagating it since the 00z suite, that's with the MJO getting stuck over Indonesia.

It's nice to see the theory relating to tropical forcing playing out in some model projections at last... but now it comes down to whether it actually unfolds or not! I'm hoping ECM/UKMO give GEFS a good old thrashing again with the MJO this time around, much as they did with the initialisation of the last cycle.

Right now, I wouldn't mind taking a Tardis and jumping ahead to Friday evening (I would go further but, you know, weekends...!).

[damianslaw]

The key trend from the models today is the erosion of heights over Europe, they all show them slowly shifting southwest back towards the Azores - this is significant as we saw in mid Jan, as it allows the longwave trough to anchor through the country and into Scandi, sharpening it up at the same time and enabling greater chance of ridge development in behind to our NW, and most importantly allowing the trough to drop into central Europe - a key development if you are after polar airstreams holding sway against tropical airstreams.

Indeed the models are aligning with many earlier thoughts about February, i.e. a shift towards more of a N/NW airstream predominating with heights building out to our west and possibly in time up towards Greenland as conditions over the arctic become more conducive to allowing this to happen. Met Office longer range forecast has remained very consistent in its suggestion of a drier colder theme by mid Feb - and the way the models are looking today at least suggest such building blocks will be in place.

In the meantime a very topsy turvy spell of weather, Scotland will be seeing some potent polar maritime incursions on occasion enough for low level snow, and N Eng and N Ireland as we move through next week look like being exposed to these as well.

Over the next few days worth keeping an eye on how far south trough action digs into C Europe, Saturday looks like the start of a trend towards ever deeper...and those warm sectors becoming more and more squeezed with a more NW-SE aligned jet in time..

[Derbyshire Snow]

Evening,

One positive before the run gets in to the more interesting stage. This is the jet stream through the US tomorrow. Note the split . This might be only temporary but it would give the Atlantic energy a slow down and maybe allow heights or a stronger ridge to occur which of course could lead to developments taking place near our shores. We need to watch after midrun to see if heights do develop. Previous runs have shown a ridge but never strong enough to keep the jet stream at bay. Lets see. Lots to overcome but lets start on a positive note

 

the interesting time might be about t240

Edited January 26, 2016 by Derbyshire Snow

[Eskimo]

Marginally better on the 18z. Jet Stream marginally further south again, allowing for all of the UK to see -4/-6 uppers. 

[Polar Maritime]

Yes wouldn't take much of a nudge to see some decent Northerly shots out of this set-up.

Edited January 26, 2016 by Polar Maritime

[Derbyshire Snow]

I know its FI but  there are some heights developing in the Greenland, Canada area, and  we are looking for trends towards cold, and not exact predictions of snow, frosts etc, and thats the time scale we are looking at . Apart from some pm air there will be no sustained cold for at least 10days. A SSW is the  fastest way to a freeze now and thats not instantaneous, and even if we are lucky enough to have one of these and the jurys out on that one, there is still no guarantee of severe weather.

The interesting area of the run on its way, what sort of ridge will this run show out of US

 

Updated: jetstream wins again. Not as good a run as the 12z personally.

Edited January 26, 2016 by Derbyshire Snow

[Derbyshire Snow]

The very end of the run shows some dramatic promise however(a winter storm) but that really is in deep FI

 

Jet stream south of us at last, just

Edited January 26, 2016 by Derbyshire Snow

[TomDav]

The frames after this would be interesting. Nice WAA into Greenland as well as low pressure near Italy

[Derbyshire Snow]

4 minutes ago, TomDav said:

The frames after this would be interesting. Nice WAA into Greenland as well as low pressure near Italy

The look of our area of the world does look different at the end of the run, but i get the feeling the jetsstream is going to ruin all the promise again, but happy after all with this run. A bit of a rollercoaster

Edited January 26, 2016 by Derbyshire Snow

[Rocheydub]

It's all good folks, I just found the ultimate chart on the CFS... Just ignore the date and the T-1000000 hours away, and you should cheer up!

 

[Derbyshire Snow]

1 minute ago, Rocheydub said:

It's all good folks, I just found the ultimate chart on the CFS... Just ignore the date and the T-1000000 hours away, and you should cheer up!

 

ah  the ssw at last

[Southender]

17 minutes ago, Rocheydub said:

It's all good folks, I just found the ultimate chart on the CFS... Just ignore the date and the T-1000000 hours away, and you should cheer up!

 

Wont be surprised if this happens. Cold starts to spring seem the norm in recent years. Time to change the seasons?

[SxK]

11 minutes ago, Rocheydub said:

It's all good folks, I just found the ultimate chart on the CFS... Just ignore the date and the T-1000000 hours away, and you should cheer up!

 

LOL, if we are getting this desperate we really are in trouble!

In all seriousness though while the models are dire at present I do see the MJO getting into a high amplitude phase 6 or 7 perhaps even phase 8 later into Feb which should have a positive impact in terms of delivering high level blocking. Phase 8 would be the ideal. Nick mentioned that it is ECM and UKMO vs GEFS on this front. EMON and BOMM both see the MJO getting into phase 7 at least by end of Feb so therefore agree with ECM and UKMO obviously a way off so caution needed but after the next week or so I am reasonably confident we should start to see some improved model output. 

 

[Carl46Wrexham]

6 hours ago, Frosty. said:

There is no shortage of transient rather cold incursions on the Gfs 12z op run, especially further north with some snow at times and night frosts, it's more wintry than the 6z. I think it's encouraging!

I'm all for optimism and that, but for the Midlands and especially Southern England, the last map in particular looks horrendous. Heavy rainfall. Saw enough of that from the previous so called cold spell. If whats to come is anything like similar, then Id sooner it stay mild.

[Chris1986]

It's not all bad From the 00z out in FI land...

 

[Ali1977]

Nice ECM at 192/216 with -8 uppers over the UK, can we get that Atlantic low to slide underneath now I wonder 

[Timmytour]

I expect there will be more of a preference for the ECM at T192 than the GFS   

   v    

Regardless that its FI, it's good see that the the inevitable Atlantic onslaught is perhaps looking a little less than inevitable now and different options are developing
 

Edited January 27, 2016 by Timmytour

[peborant]

6 hours ago, Carl46Wrexham said:

I'm all for optimism and that, but for the Midlands and especially Southern England, the last map in particular looks horrendous. Heavy rainfall. Saw enough of that from the previous so called cold spell. If whats to come is anything like similar, then Id sooner it stay mild.

Yes but for you to stay mild we in the "north and west" need to suffer the relentless train of storms, so I'd sooner you'd bear the cross for a bit so that we can enjoy marginal snow. 

Nah, what we need to see is the infamous train of storms affecting Spain and S France for a while. Good for everyone (bar mildies in Europe)