Model Output Discussion. 3/12/2022. How cold will it get?

[CSC]

42 minutes ago, CSC said:

GFS pub run is going to be a cracker.. Blocking established at just day 3. I reckon this could show some singificant precip. Lets wait..!

It did in the end.. but cunjured up some crazy tropical storm. What is going on with our weather?!  This is bonkers.

 

Tonights run really sets it up for an interesting UKMO and ECM 00z. I personally think the 18z is a blip. The ensembles will be worth a close watch..

[Johnp]

A second tropical type storm then appears at 252hrs!

[seb]

I go out for a few hours and come back to the most bizarre runs I’ve ever seen. Very, very interesting times ahead.

[Anon90]

We've seen this time and time again, there's always a fly in the ointment that seems to scupper things  but this just makes me all the more keen to see what the next set of runs will bring for better or worse!

[CSC]

To be fair to the MetOffice, it has stuck to its guns and tonight has trended colder. It hasn't moved for days. It's the most accurate one right now!

[Kentspur]

18 minutes ago, sorepaw1 said:

Very impressive 18z GFS a T+87 hrs

Wednesday I wouldn't rule out snow showers for London and the

South East Wednesday night .

Trying not to come across as ramping but it's getting impossible not to mention snow in posts with what's showing .

Which model is this run by?  

[seb]

1 minute ago, Kentspur said:

Which model is this run by?  

Mainly GFS.

[Met4Cast]

The GFS det bombs that low by 20mb in just 4 hours, that would break the world record. Even the strongest tropical cyclones haven't reached that level of bombing. So.. given the GFS det appears to be pushing the boundaries of the laws of physics there I am certain we can bin that idea as not  remotely realistic. 

Funny to see, but no.

[TSNWK]

So as another day of model watching concludes i believe we have strengthened the cold a little for end of week and weekend. 
 

for longevity we are risk by the ex tropica storm approach day 8ish.. still far away that we can adjustment south and less extreme pressure.. the 18z disrupted better and a snap comparison I took at day 9 had the 0 850 around south coast on the 12z it was Newcastle to Carlisle, a nice 300 mile correction. Same again over the runs tomorrow is not unrealistic at the time range 

[Howie]

1 minute ago, Met4Cast said:

The GFS det bombs that low by 20mb in just 4 hours, that would break the world record. Even the strongest tropical cyclones haven't reached that level of bombing. So.. given the GFS det appears to be pushing the boundaries of the laws of physics there I am certain we can bin that idea as not  remotely realistic. 

Funny to see, but no.

I don't think this update did the GFS any good, that's actually ridiculous for what's supposed to be a top model. Not even the likes of hurricane Dorian with perfect tropical cyclogenisis conditions achieved that level of rapid intensification 

Edited December 3, 2022 by Howie

[seb]

Just now, Met4Cast said:

The GFS det bombs that low by 20mb in just 4 hours, that would break the world record. Even the strongest tropical cyclones haven't reached that level of bombing. So.. given the GFS det appears to be pushing the boundaries of the laws of physics there I am certain we can bin that idea as not  remotely realistic. 

Funny to see, but no.

The perfect-perfect storm lol. You’re right though… it’s borderline impossible.

[Kentspur]

3 minutes ago, seb said:

Mainly GFS.

I thought so, Thank you was quite shocked if im honest! Didn't expect anything here im sure it will change I find Met app usually the most accurate for us here in the lowland urban heat island by the Thames noticed its yet to even mention sleet for here. Anyway model talk- Hope GFS is right in that case!

Edited December 3, 2022 by Kentspur

[Bristawl Si]

GFS has thrown up dartboard Lows for as long as i've been a member on here - they always turn out as complete baloney. 

Shannon's out on the town for her pre-Christmas party.

Edited December 3, 2022 by Bristle Si

[Allseasons-Si]

4 minutes ago, Met4Cast said:

The GFS det bombs that low by 20mb in just 4 hours, that would break the world record. Even the strongest tropical cyclones haven't reached that level of bombing. So.. given the GFS det appears to be pushing the boundaries of the laws of physics there I am certain we can bin that idea as not  remotely realistic. 

Funny to see, but no.

Yes it's hidious

I would expect further corrections south over the coming days because it would be WEEKER.

just to add,it is further south on this run than the 12z so that's a step in the right direction

Edited December 3, 2022 by Allseasons-si

[CSC]

Icon 18z has temperatures widely -2 by 6pm this coming Thursday 8th December. GFS is the only one currently gone bonkers -  I think its had too many pints watching the world cup!

[Notty]

1 minute ago, Met4Cast said:

The GFS det bombs that low by 20mb in just 4 hours, that would break the world record. Even the strongest tropical cyclones haven't reached that level of bombing. So.. given the GFS det appears to be pushing the boundaries of the laws of physics there I am certain we can bin that idea as not  remotely realistic. 

Funny to see, but no.

It is odd that the model runs are published with impossible/unprecedented situations. I would have imagined that really silly modelling would be highlighted and reviewed by humans. It is a bit like poor payment systems that send ridiculously high payments out to people. Where is the common sense check?

[Anon90]

I know we always say this but the next set of 00z runs will give us a big indicator as to whether this will turn out to be a cold snap or an actual proper cold spell for once (please lord!)

[damianslaw]

Time to start looking at the good old UK Met FAX charts from here on in, see where any convergence lines, troughs, frontal features pop up... looking an unstable polar airmass ahead. There is a cold front set to move through the UK on Wednesday and its this which is causing the Met to forecast a yellow warning for in N Scotland. This feature could easily give general snow to much of rest of Scotland and N England, but probably lose intensity. 96 hrs about as far as I'm looking at present.

[Mike Poole]

GEFS 18z ensembles T120, and it is still about half that cut the low off, half keep the NE flow.  

Change is there is support for the latter from ECM op, and some ECM ensembles, now.  Should be resolved tomorrow.

[Bristawl Si]

One suspects we are approaching a nowcast situ re snow prospects.

[Wold Topper]

25 minutes ago, seb said:

I go out for a few hours and come back to the most bizarre runs I’ve ever seen. Very, very interesting times ahead.

Same here, as an amateur my head is my only take from this evenings runs is, are we on the cusp of something.....?strange but interesting times ahead!

Edited December 3, 2022 by Wold Topper

[MattStoke]

Normally I’d agree that it’s just the GFS and it’s love of dartboard lows, however, other models show similar. Such a strong system or not, though, whether it’ll actually directly impact the U.K. and dislodge the cold is another question and not the most likely outcome at present.

[Eagle Eye]

47 minutes ago, Notty said:

The storm can’t spin up out of nowhere. It must be seeding somewhere, usually off the West coast of Africa. 

Ayy yes, seems to form in the mid Atlantic (ish) from an elongated wave of air from just off the coast West Africa.

The forcing that seemingly pushes it more extreme seems to almost be contaminated.

Look at all of that shearing churning around it, surely scuppering the low's development significantly?

The speed at which it forms is quite incredible in itself, a slightly lifting of forcing from the south and we see an almost immediate reaction.

SST's wise and we're above average in that area but it's still on the borderline for tropical cyclone development and I know we aren't close enough yet but I'm not seeing too much in the way of a loop current where it forms and that would be my only explanation other than significant forcing counteracting the shearing but as we get closer I think the track should start to shift. That shear is going to shift the Low Level Circulation (LLC) away (in my opinion and that's if it forms in the first place) from the Convective Centre (CC) meaning that the Storm essentially, shouldn't be able to increase it's strength and so shouldn't become too much of a problem except maybe helping dump some snow for us with some slight changes to it's track (only a couple hundred miles and it favours us really).  For whatever reason though, the GFS sees it's tail strengthening, perhaps it thinks it's entered a zone of significantly less shear and the LLC and CC push back together and therefore it follows the upper winds.

SST's

Upper-winds

The upper-level winds flow like that, not on their own but due to a divergent wind pattern just above the Amazon Rainforest which pushes up and eventually interacts with that Tropical Atlantic jet.

There's so much that can still go wrong with this potential disturbance that I think we could see a flip by tomorrow or Monday on either it's track, intensity or even it's formation.

Edited December 3, 2022 by Eagle Eye

[Allseasons-Si]

P10 would be crippling at just 96

-12.

infact,..it shows -14 for my area on the ens graph at 84 hrs.

 

Edited December 3, 2022 by Allseasons-si

[badgerhud]

22 minutes ago, CSC said:

To be fair to the MetOffice, it has stuck to its guns and tonight has trended colder. It hasn't moved for days. It's the most accurate one right now!

Not necessarily the most accurate, it maybe wrong and underestimating the storm! Time will tell