Model output discussion - proper cold spell inbound?

[shaky]

Way more progressive with thursdays front!!sad to say but unless it upgrades on the 12z then ecm even though its an outliar at the same time frame will probably be right and thursdays front will be all rain!!00z gfs improved on the 18z aswell so its really frustrating!!

[Evening thunder]

40 minutes ago, BLAST FROM THE PAST said:

So this really cold air coming in....an anyone explain why the Beeb are forecasting 4-6c in the SE on Monday?

The models are showing pretty low temps yet it isn’t seemingly getting translated in forecasts.

 

BFTP

 

29 minutes ago, cyclonic happiness said:

Because they are incompetent nowadays, ditching the metoffice proves my point

 

Actually the GFS is also predicting temps of 4-5C in the SE on Monday so that's not very far fetched.. (although the BBC's 7C for London on Monday that I saw looked a bit high)


ECM a bit more like 4C for most

GFS/ECM shows 3C maxima quite common in the S/SE on Tuesday

The Met Office forecasts look about right with 4C on Monday and and 3C on Tuesday for London.

Edited February 3, 2018 by Evening thunder

[shaky]

Big changes on arpege just compare 78 hours chart from 00z to 72 hour chart from 06z!!much more of a push from the continent!!

[karyo]

10 minutes ago, shaky said:

Big changes on arpege just compare 78 hours chart from 00z to 72 hour chart from 06z!!much more of a push from the continent!!

I see only a small change but at least it is for the better. The whole pattern is slightly further west which can make a difference.

[bluearmy]

2 minutes ago, karyo said:

I see only a small change but at least it is for the better. The whole pattern is slightly further west which can make a difference.

I would say it’s nothing much more than inter run variances although it’s better to see it varying from the continent rather than the Atlantic!  Small acorns and all that .......  we are in a situation where falling the right side of the fence makes a big difference on the ground 

Edited February 3, 2018 by bluearmy

[That ECM]

31 minutes ago, shaky said:

Big changes on arpege just compare 78 hours chart from 00z to 72 hour chart from 06z!!much more of a push from the continent!!

More inline with the fax charts? I would say so. Sevenoaks under 6 hours of heavy snow Monday morning. Small changes but hey, let's worry about next Saturday....... and now under a warning....

Edited February 3, 2018 by That ECM

[mulzy]

GFS FI is rather interesting - we *could* be heading in that overall direction.  Support from both ensemble suites.

[MattStoke]

It is oddly quiet on here. May not be looking at large amounts of disruptive snowfall, or even significant snow but quite a lot of places could see a dusting to a few cm next week. For some parts of the south that will be as good as its got the past few years. Also likely to be harsh frosts where winds fall light, and a bitter wind chill where and when we have the breeze.

Been banging on for days about how I think the models will come to some sort of middle ground with Tuesday's front, and they are slowly doing so. The ECM (least progressive) is inching it eastward and the GFS (most progressive) is edging it a bit further west meaning the mild sector would be mixed out more quickly. The likes of the Aperge, ICON and NMM all show is crossing all of the UK as snow.

Then there is the risk of some snow showers in the east, particularly Kent, and flurries more widely across Eastern and Central England on Monday. Could bring a covering to parts of the South East that have seen little to no snow in recent years. Perhaps also some snow showers for north western parts after Tuesday's front.

Edited February 3, 2018 by MattStoke

[MR EXTREMES]

Well you rarely see the deep cold from the polar regions like on the GFS incredible.

I think people are to quick to dismiss any wintry potential.

Fair few surprises and cold.

I'm still happy and the GFS has filled me with slightly more confidence that it's a prolonged cold spell not a cold snap.

[Weathizard]

Disappointed with the output this morning (relatively speaking) as it really feels we are missing a beat with the uppers on offer, shame the flow is so slack, cold and predominantly dry for most looks the heavy favourite.

Not the end of the world as we have a SSW predicted and possibilities down the line but I think the snowy easterly looks very unlikely now, PM incursions could deliver for the usual places.

 

 

[Methuselah]

I'll be interested to see just how the models handle the expected SSW, and whether it's that that's making the MetO suggest a possibility of very cold easterlies around mid-month? Ought we be looking for some kind of cross-model trend, in the far reaches of FI? 

Or, might a twenty-thousand-strong flock of flying pigs be closer to the mark?

[Man With Beard]

Op runs generally looking less wintry for next Thursday/Friday, but I'd suggest 2 of the 3 clusters on the ECM ensembles are colder for the UK at that stage with the Atlantic trough digging in more. We can't tell if this would increase the snow chance, but it wouldn't take much of an improvement on the op to achieve this. A late developing slider would help!!

[Rayth]

5 minutes ago, Ed Stone said:

 

I'll be interested to see just how the models handle the expected SSW

 

Something that really interest me this , didn’t lurk on here when the last major one occurred , I’m presuming the models will go into a meltdown just like the Strat ? 

[MR EXTREMES]

Gefs has snow possibilities and would suggest be patient.

138 has warm sector with in the front from the north west but hold on a minute there's like a 6hr warm sector, but where's all the enriched surface cold.

And with such a small wedge of milder air and at 138hrs just seems a very unlikely outcome.

But also gefs has things slightly west and with each run the Azores becomes much more subdued.

And in any case prediction of snowfall is very much a now cast situation especially if it's showery in nature.

I'm not throwing my towel in just yet let's see what changes come over the next couple of days.

But both charts have snow event.

[Northern Sky]

14 minutes ago, mulzy said:

GFS FI is rather interesting - we *could* be heading in that overall direction.  Support from both ensemble suites.

Yes indeed. I would imagine we will see some intriguing FI charts over the next few days and possibly weeks given that the strat vortex split at 30hpa is modelled at around 180hrs and the warming seems to continue and even intensify right up to the end of the run.

What the implications will be on trop patterns is beyond my knowledge but surely some HLB is going to set up somewhere?

[ALL ABOARD]

I will just leave this here to cheer everyone up. 

First signs of SSW starting to show up? 

 

[Catacol]

12 hours ago, johnholmes said:

Deleted the charts to save space.

Looking at those charts C and it shows something that other 500 mb anomalies have shown before this winter. That is an attempt to give the flow from the Greenland area at 500 mb but with any Atlantic blocking being well west. Not what we usually see connected with deep cold.

Agreed - Nina profile. But baby steps - the reason for posting them was to look at the position of the azores high first of all. Signal for withdrawal... and I am punting on it being an underestimate. In the same way if (and it is till a bit "iffy") the pacific AAM kick being given by the current MJO is sustained (and I have to keep pointing out that at Xmas it died... and it might do so again) then the signal for height rises to the NE may also be undermodelled at present. End result of the 2 processes would be a more meridional profile and less flat than the EPS currently suggest.

but - hey ho - let's keep it real. None of us know for sure: it is all best guess stuff based on learning profiles of various posters and different stages of learning. I'm comfortable with where my knowledge (or lack of) sits at present and if it goes pear shaped then so be it. In terms of more concrete data we have steadily rising GLAAM still

and synoptic patterns suggest an east asian +MT in process 

so for now I'll stick to the script. Cold month coming anchored around height rises to the NE and a fading azores presence underpinned by MJO impact on pacific equatorial AAM. Positive torques to follow. Enhanced by strat split perhaps... and in the outer realms of FI the possibility of that split creating a SSW and reversal that would really put the cat amongst the pigeons. See end of month MetO text forecast. 

[Jonathan Rhodri Roberts]

Some very low windchill charts next week on the GFS but just how reliable are they? I'm currently in Merthyr Mawr on the S Wales coast (shown in the red circle) for example and it shows 2C however the sun is out with very light winds and I've had to take my fleece off as it feels very mild. So personally I wouldn't rely too much on them. Therefore next week while the thermometer is low the "feel like" temperature could be considerably milder if the sun is out and the winds are light with the sun now rapidly gaining strength again at this time of year as well as the daylight hours becoming longer. 

[MattStoke]

Higher res models also show snow showers/flurries getting right across England and Wales on Sunday and Monday. So could be a few surprises.

 

[shotski]

36 minutes ago, Ed Stone said:

I'll be interested to see just how the models handle the expected SSW, and whether it's that that's making the MetO suggest a possibility of very cold easterlies around mid-month? Ought we be looking for some kind of cross-model trend, in the far reaches of FI? 

Or, might a twenty-thousand-strong flock of flying pigs be closer to the mark?

Sorry if off topic but didn’t I read yesterday from the met office that they were confident there wouldn’t be a SSW in February ? 

[Snowman.]

Back end of the GEFS are beginning to look interesting once again. PV is beginning to look distressed. 

[Frosty.]

The Gfs 6z certainly isn't without interest, following the very cold spell for most of next week it then shows frequent cold incursions from the w / nw with lots of snow at times, especially further n / nw and plenty of frosts / ice..just short-lived milder wet and windy interludes.

[karlos1983]

Cold runs starting to appear again in the outer reaches 

Expect them to grow in number over coming runs.

 

Edited February 3, 2018 by karlos1983

[MattStoke]

6 minutes ago, shotski said:

Sorry if off topic but didn’t I read yesterday from the met office that they were confident there wouldn’t be a SSW in February ? 

Check the tweet from IF I posted in the News/Media thread - 

 

Edited February 3, 2018 by MattStoke

[Methuselah]

1 minute ago, shotski said:

Sorry if off topic but didn’t I read yesterday from the met office that they were confident there wouldn’t be a SSW in February ? 

The 30-dayer didn't mention an SSW at all, shotski - just that there's a chance of very cold continental air coming our way, around mid month.