weatherguy

Apologies for ramping everyone... hints of 1947?

Fingers crossed for the weekend eh?

At first I thought it was toppling, but at +168 there are signs of retrogression in my view, while the jet is heading south...Let's see how this pans out

It's good for short term cold, but without the formation of a greenland high it's not going to be easily sustained ala ECM. Still a fair few frames of hi res left mind

Way I see the GFS is that we get the cold in, but the trough over the atlantic gets cut off, thus preventing WAA from being sent north and supporting a Greenland High. As a result, not as good as the 12z ECM and a long-term cold spell does not result (in the same time period anyway). However! On a run by run basis, the 18z is an improvement on the 12z as everything seems to have been shifted further west allowing us to tap into the cold. Still all fun and games right now though seeing where this will go, simply too far out right now

Don't mean to sound rude, but are you serious? One run on one particular model certainly doesn't undo what all the background signals have been suggesting, as have many ensemble members and op runs over the last few days. I'm sure this will be a mild outlier, and besides, the pattern only flattens out in FI; the NH pattern is full of potential even on this run in the reliable time period.

It's actually very similar, synoptically speaking, to the 06z so far (up to +240). Potential cold is still FI so, and I'm sure I'm forced to say this almost every run now, there's no reward in looking too much at the exact upper temps right now, because it will most certainly be wrong this far out. Edit - and then the high sinks...even if that happened though, still plenty of potential and we need patience.

Is the red line not what has already happened? Already underway.

I do agree with you at the current stage because it still is in FI, but I think the overall cold prospects are less risky due to the simple fact that we have retrogression of the high up to greenland shown on a consistent basis; a Scandi high open to an atlantic attack is certainly never set in stone. (on the subject of which, I think we should declare war on shortwaves...they've been doing my head in for many a year!)

Dear God save yourselves a lot of hassle and don't bother hanging on each frame of each run at this stage! We'll need to wait a fair few more days yet for that to be worthwhile, the effects of the SSW will take time to work their way into the models and the output will be sure to be erratic at best until they get a better handle on things. A -NAO seems most likely, other solutions are questionable (though it may just be that the height rises are merely showing a bit later than other output), but that's before even thinking about where the high will set up with regards to the UK receiving cold...It's just too far out at this stage to get too hung up on specifics!

When looking at the big picture, it's startling actually that the PV is already split more or less, with plenty of high latitude blocking...Just a shame right now that we've not ended up in the right area for cold; looking good for the balkans though! Will be interesting to see what the models start to show in FI after another week or so as the effects of the SSW event start to influence the models more firmly. We'll know then what may be in store for the 2nd half of Jan.

The bold bit is key; when I first joined this site and took a real interest in weather a few years back I would often just look at the very "local" charts of the north atlantic. Of course, I now know it's best to combine this with the Northern Hemisphere charts to actually build up the full picture of the state of things. The same must be applied when viewing the effects of a SSW event. In my mind, it's fairly clear now (of course not beyond the realms of debate yet though) that such events do play a key role in disrupting the PV and producing synoptics more conducive to northern blocking. Northern blocking means a greater probability of cold for the UK, but by no means a certainty for cold. In fact, northerly blocking may actually result in milder conditions for the UK...it all depends on where the block sets up, and where the remnants of the PV are sent. In conclusion, northern blocking (again I will say this correlates well with SSW events) is essentially a twist moment in "stick or twist". If you stick, you stay zonal which may bring PM or TM air to our shores depending on the situation at the time. If you twist and the block sets up nicely, much colder weather in a strong possibility and the much preferred solution I'm sure! If the block doesn't set up quite right for our tiny island in the grand scheme of things, then we just berate our luck and the cold can remain locked everso close but so so far away from us. Happy model watching!

Dare I mention...bartlett?

Yeah, looks like the +24 of the GFS

I'm not suggesting this is a realistic chart in terms of exact synoptics, but isn't this sort of set up what GP suggested before? (wrt heights building near Greenland, and the PV moving east) And no, I refuse to get sucked in to talking about another easterly (yet)!

Hello... We may have an undercut on our hands!

Anyone up for gathering on our western coast and all pushing together? I'd definitely be up for the UK being about 200 miles further east, that's the margin we always seem to miss the cold by! I'm sure Scandanavia wouldn't ,mind...

Well, back to chasing T+240 we go! No real cold here, but the north hemisphere pattern looks very promising. I've had a bout of model fatigue over the last couple of days, but... I'M READY, ROLL ON THE REMAINING 11 WEEKS OF WINTER! PS - I'm really confused where to post now...I've put this in here, but I'm not sure what merits a post in the forecasting model discussion now; surely a moan/ramp is still discussing the models as long as you're basing those opinions off what the models are showing?

Ah well, we still have 10 weeks of winter to look forward to, with promising teleconnective signals...

Irrelevant - all we're looking for is the general pattern at this stage, not snow potential. What that chart shows is -8C uppers over much of the UK (let's not be spoilt, this is excellent!), coming from a North Easterly direction, with an easterly element not too far away.

High pressure? Removed the easterly in its entirety? Are we looking at the same run?

If charts can downgrade, they can upgrade. Critical period still days away yet.

Loses the plot once more in the far reaches of FI GFS style, but huzzah we have yet more consistency in the medium-term!

Even if there is a downgrade (chances are there will be one, simply due to the extremity of cold shown in the last run), that isn't to say we won't still get extreme cold - The ECM 12z has given us plenty of breathing space in that regard! Plus we have plenty of agreement on at least some form of easterly taking place, it really is just the severity that is yet to be decided.

Got a nice dusting here by the time I woke up, about 1cm, most of which has stuck around throughout the day Now onto more pressing matters...The model output truly is astonishing!