Nouska

That's the IPCC dragon, Knocker - tsk tsk. This is the one you need for the GFS.

The GFS at +192, with the high just settling in over the UK: cold and grey is what is being shown. That's the beginning - if it stays like that it will only get colder at the surface, irrespective of what temp is up above. The cuts are for central England.

You folk are making me homesick for a good Scottish fry-up. Eggs over easy, a Lorne sausage Scandi high and the omnipotent and essential black pudding of the vortex. Can anyone find the bacon - is there a nicely wound up low that can represent a fine slice of Ayrshire?

I think the remark was more about the lack of any negative height anomalies over the Europe view on ECM32 but uncertainty on what form this might evolve into. People made their own assumptions to suit the desire - can cause a lot of confusion to the casual reader! JMA monthly ensemble, for what it is worth, they are in agreement on a large anticyclonic area for W Europe, week 3-4.

The archive of the airmass satellite shows what looks like a baroclinic leaf development at 5am - quite distinctive to the convective mass of showers ahead of it. An archive of the satellite images from yesterday. http://brunnur.vedur.is/myndir/seviri/2015/01/29/ Some of you will remember this well, it gives a good run down on the post event analysis. http://onlinelibrary.wiley.com/doi/10.1002/wea.740/full Conclusion - "a reverse-shear polar low." - there are multiple types to confuse the situation even more! The 500 mb temperature chart for 06Z

For those mentioning the minimum 500mb temperature for formation (my understanding circa -40C) - the upper temps were very close to that just before initiation.

ECM 12Z positioning for now and then 21Z and midnight. Wider view charts not updated till later.

Just to add, it has a good convective rain rate - isn't that a good signature for it being a polar low?

I would say that the model did well, just a little further west- CF the 15Z model frame with the WV satellite for same time.

ECM have this low - @15Z ....and by T24....

There is now some firming up on the ensembles with regard to likely pattern. The progressive signals were/are, IMO, a variance of the placement of the 'whoosh' in of the jet stream and the corresponding backwash of cold air. The models are not that good at diffluent/Rex block positioning and this seems to be what is on offer. Pretty good agreement for below average, most of the way, in my neck of the woods - this is a time when looking at ensembles for further afield can be more enlightening than those in the back yard. Edit to add that Sylvain has provided more parameters for the DWD ICON model - I particularly like the 'temps sensible' option. This is an experimental type of model so accuracy is questionable but it is the first I've seen with a fog and orage forecast on the chart. http://www.meteociel.fr/modeles/icone_cartes.php

Here's the precip charts - just change the time stamp from the 120 in the link - available in six hourly increments. http://brunnur.vedur.is/kort/ecm0125/2015/01/28/12/ecm0125_nat_msl_t850_6urk_2015012812_120.jpg

The one thing the old GFS was good at was picking out a northerly plunge, at long range - likewise its ensembles which we are currently viewing. The fact the ensembles got this and the last cold spell right is no guarantee that they are correctly modelling the future well; especially if there is to be an easterly component to the weather.

Precip type satellite showing the peppering of heavy snow showers in Scotland and Ireland.

I've finally found the right thickness charts where the calculation is done for the dummy. http://brunnur.vedur.is/kort/ecm0125/2015/01/24/12/ecm0125_nat_msl_thk500_thk500-thk12h_uv700_2015012412_120.png 522 on the coast.

What is the 516 line that is down into France?

Yes, Nick - quite a difference in thickness between ECM and GFS at the 120 mark. Am I reading that ECM chart correctly - the whole of the UK is sub 510?

These IMO four panel charts illustrate this well as they show both values - the usual coloured contour lines and also the thickness. This is a quick comparison of ECM (left) and GFS (right). As usual, these are cached so need to change time stamps after all runs and change the hour for different steps. http://brunnur.vedur.is/kort/ecm0125/2015/01/24/00/ecm0125_nat_gsm025_4panel2_2015012400_006.png

Indeed! The ECM snow charts from the IMO have continuous snowfall for the North over the last four days of the run - some large cumulative totals if that verifies. T+174 as an example and all the six hourly increments are similar.

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.

We've been footering around with a winter that, in reality, has been an extended autumn - real winter in Europe is about to begin and probably extend its grip beyond February. The seasonal models were right in the blanket of warm anomalies for Europe, these are now turning to blues for the early spring period - the background signals are changing. If these charts in todays models come to fruition, there will be plenty to please all flavours of weather enthusiast.

Yes, indeed! I thought the old bones might get through without the need of multiple layers of thermals. I've got a hunch that the old biddy, Auntie ADA, is planning a visit in February - time for a cold weather inventory.

The 12Z HiRLAM is quite bullish with the snow forecast for southern England, wednesday am. The run with other parameters:- http://www.weeronline.nl/vakman-index/130/0

Some snow charts from the 18Z HiRLAM - these are hourly time stamps. Full run on link below. http://www.weeronline.nl/vakman-index/130/0

The 18Z HiRLAM has some interesting disturbances in the flow down the North sea - I rate it for convective precip but still a little early for definitive use as a forecast.