Model Output Discussion - Colder but how cold and for how long?

[January Snowstorm]

That's one angry looking pv on the ecm at 192hrs!! Stormy looks to be the outlook as far as is reliable!

 

 

 

[TwisterGirl81]

1 hour ago, ANYWEATHER said:

Nope, January 2nd 1976.....

What happened then?

[mountain shadow]

47 minutes ago, Ali1977 said:

This will stir things up - a cracking Feb on the way hopefully - and March. As per the long range METO really ️

All this potentially means is a -AO.

The form horse would be for the Trop PV to move into Canada and the States firing up the jet and leaving us under zonal conditions. 

 

[ANYWEATHER]

11 minutes ago, TwisterGirl81 said:

What happened then?

Gusts to 90 mph to 100 mph across the Midlands and Northern England.  Very rare to get wind speeds of that kind inland . Probably a once in a lifetime wind storm! 

[January Snowstorm]

Ecm @ 240hrs, deep purples over Greenland and the ever present Iberian high in situ

[AO-]

I get some February 2012 vibes with the big difference that in 2012 the big freeze was present over Russia. It looks like the beast from the East might retrogress. But it's a long way ahead.

 

Edit. The chart is januari 25th 2012. 

Edited January 15 by AO-

[Nick2373]

12z still continues the theme of something dryer from the 24th onwards also PPN spikes dropping on each run at this rate it will look like a short lived unsettled period, where it’s clear at night will deliver frost etc. 

[TwisterGirl81]

7 minutes ago, ANYWEATHER said:

Gusts to 90 mph to 100 mph across the Midlands and Northern England.  Very rare to get wind speeds of that kind inland . Probably a once in a lifetime wind storm! 

We got that in 1990 burns day storm in the south west, we also had some strong storms during winter I think in 2013 that were severe but not as severe as 1990.

I have noticed that gfs does tend to over blow these lows several days out but occasionally they get it right. Some exciting weather none the less hopefully. A cosy day indoors I think 

[SilverWolf]

Interesting reading the thread.. Sure posts reflecting what some of the models are suggesting are being posted as is… but the big variation in possibilities are reflected in the posts. Very interesting times ahead, even this week (Wednesday still has interest in the south, and that’s not IMBY as it’s pretty unlikely for me). For the last week, and going forward, this has been a the most fascinating model watch for some years, even for someone like me who relies on the knowledge of others.  

Edited January 15 by SilverWolf

[PiscesStar]

Just now, SilverWolf said:

Interesting reading the thread.. Sure posts reflecting what some of the models are suggesting are being posted as is… but the big variation in possibilities are reflected in the posts. Very interesting times ahead, even this week (Wednesday still has interest in the south, and that’s not IMBY as it’s pretty unlikely for me). For the last week, and going forward, this has been a fascinating model watch for some years, even for someone like me who relies on the knowledge of others.  

That includes myself so yes it is interesting to find out what people can see in the model outputs 

[alexisj9]

12 minutes ago, TwisterGirl81 said:

We got that in 1990 burns day storm in the south west, we also had some strong storms during winter I think in 2013 that were severe but not as severe as 1990.

I have noticed that gfs does tend to over blow these lows several days out but occasionally they get it right. Some exciting weather none the less hopefully. A cosy day indoors I think 

It has support from the 0z meto, so I will keep an eye on this now.

[alexisj9]

1 hour ago, sunnijim said:

I think we started like this in October before the Storm corrected South on future runs and effected Channel Isles and Northern France.

Depends on any belt of high pressure over the continent as to Sothward shifts.

GEM and ECM not interested so still an outlier solution anyway.

 

To be fair it does look similar, however that doesn't leave this area out of the woods.

Edited January 15 by alexisj9

[sunnijim]

11 minutes ago, alexisj9 said:

It has support from the 0z meto, so I will keep an eye on this now.

It did, but the 12z has dropped it and ecm is still not interested.

Latest m.o thoughts for the weekend show a standard blustery day on Sunday.

If I was a betting man I would suggest GFS has gone off on one here and the weekend will pass without incident.

[Mark Parsons]

1 minute ago, sunnijim said:

It did, but the 12z has dropped it and ecm is still not interested.

Latest m.o thoughts for the weekend show a standard blustery day on Sunday.

If I was a betting man I would suggest GFS has gone off on one here and the weekend will pass without incident.

Business as usual for GFS, the possibilities are often endlessly cataclysmic week in week out atm.......

[TillyS]

9 minutes ago, sunnijim said:

It did, but the 12z has dropped it and ecm is still not interested.

Latest m.o thoughts for the weekend show a standard blustery day on Sunday.

If I was a betting man I would suggest GFS has gone off on one here and the weekend will pass without incident.

I’m confused. The 12z UKMO still has a pretty fiery squall line, no? Or did you mean a different model output? Here’s the 12z Met Office output:

 

So GFS and UKMO both have something fairly stormy for some regions. ECM doesn’t it’s true. Maybe that’s what you were referring to. And, yes, the GFS does indeed seem to go off on one often with these storms.

Of note though, that I think the GFS has performed more accurately than the other two this past fortnight. 

Edited January 15 by TillyS

[nick sussex]

Re the Atlantic low , normally once things start correcting south they don’t stop.

That tends to happen though when you have strong blocking , in this instance the block is weakening .

So that’s why  we’ve seen these small north and southwards shifts and even at this stage given the margin for error that could be anything from 50-75 miles further north or south .

It could be a total non-event or bring a decent covering to southern coastal fringes .

Further north there’s that shortwave moving se and then after that further snow showers .

The cold air hangs on to Friday before we sadly see the PV taking its revenge ! 

 

[Cheshire Freeze]

58 minutes ago, January Snowstorm said:

That's one angry looking pv on the ecm at 192hrs!! Stormy looks to be the outlook as far as is reliable!

 

 

 

That’s a runner LP and would be more violent than it appears due to the sharp pressure differential.

[swebby]

48 minutes ago, TwisterGirl81 said:

We got that in 1990 burns day storm in the south west, we also had some strong storms during winter I think in 2013 that were severe but not as severe as 1990.

I have noticed that gfs does tend to over blow these lows several days out but occasionally they get it right. Some exciting weather none the less hopefully. A cosy day indoors I think 

Normally that was because it had the habit at 6-7 days out of dumping all the energy into a dartboard low without resolving that low into multiple centres and shortwaves.

This instance however... it already has a complex system for the longwave trough and has now put a frontal wave under the left exit of a jet streak in the mid atlantic on saturday evening - so very definitely one to keep an eye on! Those GFS gust charts are hopefully over egging the pudding for Wales and Western England but probably an idea to make sure the trampoline in the back garden is bolted down anyway!

Edited January 15 by swebby
added charts

[Stephen W]

2 hours ago, Catacol said:

For those looking further out, JMA monthly published yesterday for February.

UK, as usual on this one, at 10 o clock.

Otherwise the current situation is not what many on here would have hoped for. This GFS for tomorrow screams all kinds of wintry wonders:

but closer examination shows that much of central and southern UK is stuck in a col, neither fed by the strongest and coldest winds from the N and/or NE nor quite in line for the channel runner. There is a day or so to go for surprises to turn up, and as we speak Scotland is getting pasted....but the snow hungry majority in the south are left gasping. Feels like rolling a double 1 and damnably unfortunate.

Then comes week 2. 22-29 Jan approx was always flagged as a week of greatest concern because the impacts of lowering momentum would be greatest and the need to gave got a block cemented in a good place would be highest. But that double 1 effect may be about to land again. (is that like rolling 4 x 1s?!) The strat splits tomorrow

and the zonal mean is much below average, even close to a technical (if very short lived) SSW

- and we could be excused for thinking that there is little better context for ongoing northerly blocking. But look how steep the recovery is, and with little to no model disagreement. Back to average in a flash, and GFS largely puts the vortex back together again by the end of the weekend.

So - what's happening?

Factors leaning towards a cold and blocked outlook have had to work pretty hard to get our blocking pattern in place. Even with a favourable pulse of momentum, a good GWO orbit, and lagged impacts of an amplified MFO through the west pacific we have not quite got the block in place. Meanwhile, as soon as those signals fade into a period when it was well noted that things would get less automatically "good" for winter, we get a collapse of the pattern that is on the crazy side of fast. We go from the good chart at the top of this post to this within 4 days:

No obvious lag here for the flatter MJO phases!! And a reforming vortex has helped support an atlantic pattern in double quick time. It is almost as though the wax wane nature of the atmosphere has been placed on a hill. To get to a blocked phase we have to sprint up the hill on our bike, in first gear, legs pumping and burning once at the top. But then to return to the starting point it is an easy cruise downhill, hands off the handlebars, freewheeling.

Maybe this is CC in action. Or maybe it is just a reflection of some very poor luck for the coming week and the one after. I don't know. I guess in the end, other than to take the learning from it, I don't really care. It has never been easy to get snow to this country and 1988 to 2008 was a 20 year run of misery punctuated by a couple of good moments. Hunting those rare major snowfalls would be no fun at all if they came every year.....but it would be good if the fates could allow us 1 in 5!!

This winter is not done. I read some guff on this thread that I find annoying, folk announcing the default return of a period of westerlies as though there is something wise and significant in doing so. Saying the UK will usually have westerlies and that the best way of approaching UK winter weather forecasting is to say "westerly" each time because you will usually be correct is both lazy and daft. I don't put my money on Ronnie O'Sullivan to win the snooker each time "because he usually does." I do it because I analyse the context and decide it is the most likely outcome....and I might still put £10 on a young outsider with half a chance of making it based on analysis and form, as per Luke Littler in the Darts. If Ronnie is ill the week before Sheffield I probably don't back him at all, despite the past run of success!

And this is where we are right now. January 15, half way through winter. We had a decent start, a disappointing Xmas/NY and now sit in 4 days of frigid air but without widespread snow forecast. Bugger. Westerlies to return for a while. But the analysis doesn't change, and the weighted approach to appropriate forecasting remains. The next momentum cycle is underway, signalled by rising frictional torque as of a couple of days ago. The MJO will be back in the west pacific pretty quickly looking at model forecasts, and while the vortex returns to average it doesnt appear to launch itself into an above average phase. Read Tamara's work rather than mine on this - she expresses the technical aspects of wind flow much better than anyone else on here....but in essence we are set to have more wave action return, a meridional pattern embed and poleward flux that should bring blocking back to the table quite quickly. I haven't seen a seasonal do anything other than go with a negative AO for February and the combination of high momentum and a favourable MJO in a Nino year will bring things back. I had said 3-5 days of atlantic westerlies. That was based on the cold hanging on until Sunday as I had it down as a cold week....but it appears the cold is fading faster than we might reasonably have expected....so it pushes longer. I do think by the end of week 2, that's somewhere around 26/26/28 Jan, we will have a more favourable context back on the table....or at least sitting on the hot plate waiting to be served.

Winter hunting in the UK has never been easy. C'est la vie. But we continue to look, and search, and roll those dice despite the fact that 80-90% of the time they don't give us what we seek.

 

This is a superb post. Thank you for taking time to put this together in such an informed, clear and honest fashion. I always enjoy reading your analysis and your posts are always explained in easy to understand language despite the complexity of our weather. And you are always so humble especially when things don’t quite go to plan. We’ve been unlucky this time with snow chances frustratingly close this week for those south of the border. And the quick return of the westerlies is a bit of a kick in the proverbial too. But, I will keep returning to the models and the excellent posts written by the likes of you and hope that we get that next lucky roll of the dice into February.

[ribster]

1 hour ago, mountain shadow said:

All this potentially means is a -AO.

The form horse would be for the Trop PV to move into Canada and the States firing up the jet and leaving us under zonal conditions. 

 

That's the spirit! 

[feb1991blizzard]

This is what we need to be seeing more of in the coming weeks.

[Cambrian]

Just for fun at this range, but interesting to see the end of the 12z GFS control run obliging our winter interests by getting the jet stream north all the way through Svalbard, a very solid build of heights and a surface high over Scandinavia, an easterly flow and a most interesting T850 chart! 

   

Support from the ensemble mean for a sustained rise in pressure and for the northward extension of heights into Scandinavia.

 

One door closes and another one opens….

[MATTWOLVES 3]

Zonal winds look a tad weak to me and the blocking signal remains...where it sets up shop is yet to be decided.

[Don]

I know these change a fair bit, but the EC46 does seem to be continuing to back away from its idea of HLB in February.

Edited January 15 by Don

[sunnijim]

40 minutes ago, TillyS said:

I’m confused. The 12z UKMO still has a pretty fiery squall line, no? Or did you mean a different model output? Here’s the 12z Met Office output:

 

So GFS and UKMO both have something fairly stormy for some regions. ECM doesn’t it’s true. Maybe that’s what you were referring to. And, yes, the GFS does indeed seem to go off on one often with these storms.

Of note though, that I think the GFS has performed more accurately than the other two this past fortnight. 

My bad, I only checked lunchtime on Sunday ukmo wise, there seems to be a timing difference GfS early afternoon UKMO toward evening 21st.