None of the factors you mention in isolation guarantee cold weather for the British Isles. Things are far more complicated than that and anyone who suggests otherwise is just a peddlar of faux news.

your part of Hampshire maybe..

What a load of tosh

If you wake up and its -5c and everywhere is covered in frost and the daytime max gets to 2c its cold …….end of .

Its just another variation of how we get cold to the UK ………...another is a Northerly , an Easterly cold NWlies but the common thing is they deliver low temps 

I understand what the term means, but I pay as much attention to it as giving non tropical low pressure systems names and the phrase ‘mini’. It’s not a recognised term in relation to meteorology.

These GFS charts are unbelievably horrendous but so consistent. It reminds me of 2015, not in terms of the synoptics being the same but in terms of the never ending dross it's serving up. Run after run, day after day, week after week, they are painting a horrible picture for weeks on end.

I won't change my prediction to a switch to much colder weather but clearly it ain't going to happen any time soon.

Mid January showing now and still no crumbs of comfort. That is the half way point of winter and I have had to scrape my car just once so far. Horrendous. Where's Andy W with a "Winter is over" post when you need it.

Just looking at the N. Hemisphere pole view down - 9th Jan - Looks all extremely zonal and westerly and we have that Euro slug there too:

Usually with blocking it will start in the N. Pole or Arctic regions and in below chart or anything from the 7th Jan there are little if any signs of this - all I can see are low pressure systems and a really strong polar vortex still!

The long range forecasts made for this winter are proving as useful as a chocolate fireguard.

The UK January cold and snow shield is in perfect working order, SSW or no SSW. Utterly sickening!

Its woeful , there isn't anything of note …...at all . Plenty of time to change , Darren's link to the Met O's DJF forecast is a read but even they might have got this wrong .

I have to say I was fairly confident of a cold Jan and Feb but that ( The Jan bit ) is looking highly unlikely now , could well be back to the drawing board if this SSW does nothing for the UK 

Thank so much Moomin - But if you're forecast is wrong then so many other models are wrong not to mention the BCC, Meteofrance as well as ECMWF and the Met Office Glosea 5 as well as Brian's forecast on TWO alongside Gavsweathervids - so you wont be the only one.

But they GFS models are so consistent with our weather staying westerly and zonal through first and second week of Jan. If January is forecast to be below average then we ought to see a shift in models soon - Met Office still go for cold weather from mid month- surely it's only a matter of days now before something changes SURELY!! 

As for winter is over' I may do a trend within the next week or so but part of me feels what winter? Exeter or SW has not seen one frosty morning - We had 0.5c on morning of 28th December but no frost or ice and the coldest it's been between Sept, Oct & November was back in Autumn at -3.5c on 27th October. We have yet to reach freezing or below and get a frost yet this winter!

Sorry this is off topic but i'll join Richard in the moaning trend. Soon we could all be there!?

We can all hope for the best and keep our fingers crossed to see or some may say we are expecting too much too soon but time is running out. I was told to be patient until after Xmas and after the SSW has taken place to see something cold, more blocked and snowy but there is still nothing! 

I remember watching the CFS 9 mois - alongside Gavsweathervideos (back during end of Nov and into early December)and as much as I did disagree with the CFS models which had a bias to default the UK and Europe into mild southerly or south westerly which it constantly showed with nothing cold or wintry - I am starting to believe that the CFS 9 mois are/were and have been pretty spot and look like they will be!!

Keeping fingers crossed to see whether this SSW will have an impact on our weather, but time is running out.

By many years, do you mean 2009?

http://www.meteociel.com/modeles/archives/archives.php?day=10&month=12&hour=0&year=2009&map=4&region=&mode=2&type=ncep

The term is not real Ian and you know it it’s unfair to mislead Members.

No cold air source other than the inversion it creates would have been the better terminology Ian, northerlies and easterlies are not always cold for the uk either even in mid winter

Indeed. As I said yesterday most of them are fire and forget publications this year.

The discussion about surface level cold is an interesting one. Others may correct me but from recollection there have been very few good examples of it since TWO started. Usually cloud, breeze or a jelly high prevent it. We'll see what happens next week.

We had a period of "faux" cold about 12 to 13 years ago or so. I cannot be precise, but I was working in Munich that winter and most of Europe was covered by a large HP cell which led to frequent frost and fog, even in the UK.

All atmospheric parameters - not just the headline modelling of surface synoptics - are worthy of discussion and to that end I’m way off changing my forecast of a significant cold spell from mid January.

If it doesn’t happen then fair enough, but major changes in the atmospheric profile in THREE dimensions take time to resolve.

Yes, people have short memories. We've been in this position before many times. Sometimes it's stayed mild the rest of the winter, other times it's flipped cold at relatively  short notice. We just can't say at this stage which it will be.

Yes some hope pt 17 particularly tasty.

AO going so positive after a SSW despite reversal of zonal winds@ 10hpa!

That being said - we have had some negativity in November as well as the run up to Xmas at we haven't seen anything remotely cold either so even a neg - AO will not guarantee colder weather. - Just goes to show!

.... furthermore it is plain daft to worry about GFS output past mid January. Currently we have an op run giving about 15C  max on the 10th and a control run giving a max of about -5C three days later ! The rest are any number you care to stick a pin in so you can't even go on  the mean.

Yes some hope in deep FI and more significant of all we have a Greenland block appearing which is what should be happening! But of course not well supported but nice to see something wintry and cold:

GFSP again looking more interesting from a cold weather point of view.

It's a remarkable run up top, too - how often is the coldest part of the vortex to our immediate south?! Not very often at all, I'd imagine.

January outlook from Meteogroup @WeatherCast_UK
Models are predicting a cold/blocked pattern over the UK with increased risk of snow and NE winds.
This is consistent with the 2-3 week lag in arrival of cold weather after a major weakening of the Stratospheric Polar Vortex 😱❄️ pic.twitter.com/NkfIoPk7EU

— Derek Brockway - weatherman (@DerekTheWeather) December 29, 2018