ukpaul

It’s only a short journey to bring them up from Europe via the low pressure circulation. 96h shows them ready to pounce.

Interesting to see GFS and UKMO having the low drift westwards, that keeps lower uppers over more of England and buries Ireland! With GFS starting that from a more northerly position and the UKMO further south it doesn’t appear to give a particularly different outcome. Because of the way the system interacts with or disengages from the jet?

Although we are getting easterly winds it’s probably clearer to talk about movement in a westwards direction (or eastwards) but, yes, your analysis is spot on!

The trend certainly seems to be to bring the first low further north on all the major models, similarly they are also modifying the higher uppers shown yesterday to remain colder, at least for most of the country. The two together are very positive allowing a snow event moving to the far north on Thursday and Friday whilst giving us a fighting chance of those colder uppers returning south. That is the likelihood at this present moment but the trend to a northwards drift of the low and less mixing out of colder uppers is a generally positive one. There is also more of a consensus of what the second low does. ECM on its south west to north east track ovr the country allows for those colder uppers to be dragged south after it moves through. One final trend which is more worrying and, has me concerned is the likelihood/possibility of freezing rain on Friday. Already an ECM chart has been posted but here’s WRF showing it as well. That’s the mother of all disruptive weathers available for this country right there. .

Still scope to keep a lot of the country in colder uppers for a while longer and a slight improvement in pushing colder air down from the north on the 18z. Two thngs to look for, this week’s system not pushing as quickly or as far west as currently modelled and the second low remaining undeveloped and further south and west, delaying its intrusion. GEFS ptb 7 is one of a few members doing that, with good results. GIF below.

Well ECM looks like it wants to curtail anything next weekend by stalling west and instead set up a reload from the north east. A response to the second warming?

PTB 16 is pretty much the perfect way of developing it - moves to our East, skims up the East coast meaning snow for all and doesn't mix out the colder air. Not only that the next system is barely developed. Being the best possible solution you can guess the odds of it happening.....

Still keeping a number of members in the colder air up north until Monday 5th, then a clear split but it does show that the warmup is a 50/50 chance. This is for my locality and the op is the lime green line that goes depressingly high on Sunday 4th.

GEFS brings the warmer uppers further north after 192h, looking at the mean it would seem that more members are bringing in the Atlantic via that second system. Again, if the first one could be pushed into Europe it would improve our long term prospects considerably.

GEFS 192 hour mean for 850s, pretty much identical to the 06z.

Yes, the UKMO is slightly further East although also further North and likely to do the same as GFS later on. GFS just trundling around and mixing out the colder uppers before it gives way to another system doing the same makes it pretty much the worst option so, hopefully, it won't verify. ECM is possibly the saviour here as it keeps that second system away from us so that it allows that colder air north and east to get its foot back in the door again. The first low seems to be quite definitely targetting us but keep it well south and slow that second system down and we have a chance of extending the cold spell.

Definitely, although it's way too far out and it could change hundreds of miles either way. This one has Ireland, the Welsh/English border and around the Severn Estuary in its sights before it calms down.

There's a mass of very cold air just waiting to keep the easterly flow going if we can get over the hurdle of those low pressure systems trending too far north. Swing them south over France and we could be extending things for quite a while.

The south has DPs over zero from Friday lunch until Saturday (at least GFS says so), so about four or five degrees higher than any 850s.

No, the dewpoints are more important, above zero rain, below zero at least falling as snow.

Yes but look at UKMO and GEM, both of which would blanket the north over Thursday and Friday rather than a few inches.

A little request regarding comments being made, as many are on their phones at this time and rely on commentary. There have just been more comments about 'for the south' (and that could have been for elsewhere) and, yes, you are looking at your backyard, but these are countrywide events as shown by the charts. For the benefit of others - these are 'great for the midlands', 'great for Wales', great for Ireland', 'great for northern England' and, maybe a little less, 'great for Scotland'. Just to be clear.

You are comparing a chart for six hours with one for one hour, it's only logical that the six hour one shows six times as much.

It wouldn’t stay north anyway. The likelihood, with it so far south, is that it will miss the UK completely (maybe not the Channel Islands) given the usual direction of travel as we count down to zero hour. The battle at this stage is over whether a northerly incursion gets there first and you can see suggestions in this morning’s output that it will. This might suppress anything next weekend but it gets rid of any potential days with milder uppers and brings new opportunities of fronts working their way down the country. EDIT: Going through GEFS members, everything is on the table equally: missing completely to the south, clipping the south, moving up through the country or so far north it brings a warm sector to southern counties.

You see how easy it is to miss people out!

These are England-wide events (maybe Scotland too), GFS, UKMO and ECM as well. The Louise Lear week ahead charts for example shows the low going right up through England. Understandable that people look for their own area but making it so IMBY is missing the totality of such an exciting and widespread setup. So, on that note. Great for Yorkshire......... (and everywhere else).

Heights starting to build over Greenland by 136 but the 850 chart is very different at that stage, minus twenty four as opposed to minus twelve. Stifling any northerly element?

GFS has the system south of Greenland not allowing the secondary low to separate, thus not allowing it to build heights there. Need to keep an eye on the knock on effect.

Icon still great for the feature crossing the north on Tuesday, maybe better, but it’s losing the Greenland heights and that may have longer term implications.

Not at all, look at 850s winds and instability, good for much further north. I think the 12z is less of a snowmaker at that point, however, but it would lock in extended cold, so swings and roundabouts.