Model Output Discussion - Spring Has Sprung

[TEITS]

Speaking of SSW. The chart below from Dec 2009 brought a memorable day for here in Peterborough. One foot of lying snow, continous heavy snow showers, max temp -4C. Never expected such charts to be repeated one year later.

As far as i'm aware neither 2009 or 2010 had a prior SSW to these events. Infact many didn't see this coming except the Met O as I recall their LRF mentioning well below average temps, snowfall and many of us were puzzled as this wasn't appearing in the output at the time.

[Chesil View]

 Eagle Eye That was exactly my point and why I made it with the greatest of respect.

Edited February 14 by Chesil View

[TEITS]

 Eagle Eye Certainly has but I continue to be very impressed with your knowledge and quality of posts. 

[Met4Cast]

13 minutes ago, Chesil View said:

As you say Tamara's unbiased posts that are made with out a required emotional outcome are valuable in keeping ones feet on the ground although even here Tamara's suggested shuffling hieghts scenario has not really come to fruition either and I say that with greatest of respect because it simply goes to show how ultra sensitive our uk based outcomes are to small changes in the background drivers.

Indeed, unfortunately one of those situations where short-term changes completely reshuffle the entire pattern. Covered this in my post yesterday in the Post Mortem thread but broadly the SSW reflected back off the trop allowing the Canadian vortex to shift east into the N Atlantic, those "shuffling heights" were then blown away and the cold spell came to an abrupt end. 

Quite a rare thing to happen but something that's just not possible to forecast at longer ranges despite the best intentions/attempts, frustrating but is what it is!

Ironic really.. all the winters we've chased SSW's in the hope of cold, one comes along and then ruins what was otherwise a very, very favourable tropospheric pattern 

[MP-R]

 Weatherman_93 If it were accompanied by blue skies and sunshine, I think more of us would be enamoured by the idea. Having said that, I've never had temperatures that high AND cloud/rain in Feb, so I think it'll be either/or in reality.

[WINTRY WALES]

1 hour ago, TEITS said:

Being she made the wise move of leaving the UK I know her opinion is 100% based on science and 0% based on bias.

But if she made the move for a warmer climate then that would indicate Tamara does have a bias towards what the weather could be.

But I do value Tamara input and she has championed the clod weather this year which strengthens your point mate.

 

Edited February 14 by WINTRY WALES

[Met4Cast]

4 minutes ago, WINTRY WALES said:

But if she made the move for a warmer climate then that would indicate Tamara does have a bias towards what the weather could be.

I think the point being made is that Tamara doesn't live in the UK and therefore the weather the UK sees has absolutely no impact on her personally regardless of personal desires for particular weather types, given she's not in the country, that alone removes any bias and allows her to be completely objective & scientific when it comes to UK specific weather.

[baddie]

A concern about the SSW is... It could just lead to another March 2023 which nobody wants considering how dull February has already been!!!!

[Downburst]

 baddie March 2013, what a terrible month that was. Dublin airport mean an insane 3.1c for the month. April and May were cold too. Vile month that and one I am scared of seeing again. 

[jamesthemonkeh]

CFSv2 is very keen on higher than normal pressure to our north in March - one assumes it is reacting to the probable SSW, and perhaps reading too much into it.

Taking even less notice than normal until the SSW happens and we see how the dice roll, but seeing hints of northern blocking into April and May doesn't fill me with hope, as a warmth-seeker.

  

Certainly been an interesting winter synoptically, if it hasn't delivered what many on here desire.

[alexisj9]

 Met4Cast to me it's simple, I don't chase probable triggers,  I just watch what is there and what evolves. No disappointment then if a ssw happens or doesn't, or on what the out come of one actually is, whether good or bad.

I remember point out last year we didn't need a SSW, and it would change the atmosphere if it happened, and boy did it just, lol. Haven't paid attention this year, but sounds like from your post, sames happened again.

[baddie]

 Downburst With the fact we are due a settled month, I would like to see a March version of Feb 2021 (or 2012) or otherwise a March version of April 2021

[Downburst]

 baddie I'm not considering the SSW even one bit myself, as I believe the interest in that is related to snow, so for those that want that only discussed on here apologies. But as to the actual weather over the period, it's probable first half of March will not be settled overall in my view. The ECM weeklies will be dismissed of course in favour of SSW not being computed, and I'm not sure if that is the case. But they are not pointing to a major shift of an upper level trough in this region, with the general global view looking possibly stuck in my view, long wave pattern. Time for change in the forecast for sure. Perhaps mid month might be sudden catastrophic high spell  SCH

The ECMWF weeklies

The precipitation is looking wetter than average. We shall see though. 

[Kirkcaldy Weather]

Wanted to do this post which will be addressing those who continue to disregard us who use the teleconnective aspects.

A few crucial areas here which have been prominent for weeks.

• The Stratospheric Warming - Sudden Stratospheric Warming didn't 'fail' I've already shown the timeframe in which this reversal of zonal winds at 10hpa DID occur I'll link that post below.
• The MJO progression didn't 'fail' or become 'unsupportive' those who regularly follow my posts can gleam that the MJO and resultant patterns have been in line with expectations.
• Winter 2023>2024 hasn't 'failed' or been a 'bust'
• There hasn't been any occasion of being led up a 'garden path'
• The teleconnections as a whole haven't 'failed' or been 'misleading'

 

Latest data on the El Ninò temperatures are in at +2.2C which takes the 2023-2024 event into Super Ninò status. (Credit JMA)

December 2023 monthly heights

January 2024 heights

Typical heights during a strong El Ninò

The warm and cold episodes have correlated excellently in line with the Arctic Oscillation 

Leading on from this post

 

'We'll continue seeing patterns which link to El Ninò throughout March and I'd favour potentially the first few weeks or so of April, following that time it's a gradual move into ENSO Neutral with some themes continuing of heading into La Ninà by late spring and particularly Summer 2024.'

Doing a VERY extended outlook.

We see the transition from El Ninò >> La Ninà again everything pretty much as expected of course I'm showing an 8 - 11 MONTH period here so will it resemble this 100% probably not to a T but overall good representation.

Note the precip changes which are particularly noticeable in Australia and the Southern United States

This shown very well globally on CANSIPS

This switch also displayed by looking at the 200hpa U-winds

And with the 500hpa heights

And of course one of the most important the Sea Surface temperatures 

Whilst the MEI is one part of the ENSO spectrum we see that this Ninò has been running effectively parallel to 2009-2010 [also 1991-92 to some extent] which adds credence to that being my #1 analogue through this winter and the hurricane analogues continue showing this.

Returning to February we've got a couple of significant 500hpa evolutions to watch as the same cyclonic system which became the significant winter storm across multiple US states, this looks to be the main influence across the UK & Ireland by the 22nd & 23rd.

Goes with expectations with a strengthening positive NAO.

Following on from this I'm seeing a trend for a possible transition into yet another of the precursor setups for further stratospheric warming.

Current timing looks to be the very last days of February into March week 1.

Thanks for reading. KW

[alexisj9]

 Kirkcaldy Weather I'm not actually having a go at the forecasting method, just really explaining why i don't use it. What seen in advance eventshows in normal charts, regardless, however if something counter acts a singnal seen in advance, and expected co ditions don't show up, basically i avoid the nasty comments a lot of others get. What seems to not be understood is a long term forecast, is just that, and will not be 100% ever. So why people get annoyed when this does happen because of something else, I'll never understand.

[syed2878]

 Kirkcaldy Weather you’re right of course winter 2324 hasn’t been a bust for you a lot in Scotland for the rest of us down south it has been a bust I meant 20,23, 20,24 as for telly, connections less said about that the better it is

[WYorksWeather]

Looks like 16.5C at Hereford is the max for today, unless there are any higher readings not on Netweather's tracker. Before my usual post later on, just a bit of a UKV forecast for tomorrow. As mentioned previously, it's been a while since I've seen lime green on these charts!

In reality, these typically under-read by at least 1C for local maxima. I would expect a widespread 15C for most central and eastern areas, and an isolated 17-18C is very much possible. I think tomorrow will be the most widespread mild day of the year so far. Of course we did see 19.9C in January, but that was an exceptionally localised Foehn effect, so not really comparable. Unfortunately tomorrow will see a fair bit of wind and rain, so conditions may not be the most useable from that perspective.

Beyond that, the mild theme very much continues. Not quite as crazy as Thursday, but Friday, Saturday and Sunday will all be extremely mild, by day and night.

  

 

 

[Starsail]

 syed2878 just to clear up a little misconception. It has not been a snowy winter for large parts of Scotland.

I live on a hill at 200m a.s.l just South of the Central belt of Scotland and have seen very little lying snow all winter. Certainly not enough to build a snowman. I have seen very little frost either.

The 'you lot'  that you refer to relates to the North of Scotland primarily, Aberdeenshire, Highland and the Northern Isles doing reasonably well this year 

Geographically this represents possibly about half of the land mass of Scotland but in terms of population a significant minority.

I suspect that Kirkcaldy Weather has seen very little snow himself this winter. 

Keep up the good work KW. Much appreciated.

Edited February 14 by Starsail

[Mcconnor8]

Very uninspiring ECM at day 7, looks worse than the GFS and other models cold wise and the GFS 12z ensemble also seems to have downgraded somewhat 850s wise for the end of next week onwards albeit the OP and Control still look okay.

 

Edited February 14 by Mcconnor8

[Uncertainty]

What’s the ecm up to here?

It has high pressure clinging on well into midweek next week. All other output pushes a trough through at this time. 

@Mcconnor8 I see your point mate but I would rather the ec op than other output, it maintains dry weather for longer for the vast majority, seems to avoid a nasty storm midweek, and still looks like it might end up chilly and blocked by the end of the run - especially if the Atlantic trough disrupts enough…

192

[minus10]

12z Gesf's 850s showing the lessening of the cold signal for the last week of Feb or so...

...although still represents a cooler than average period nothing exceptional...although op and control dipping later...

..the pressure shows the the op to be at lower end eg trough further south than the mean ...

...mean more in line with the way ecm has been going...

...not very encouraging for the last chance saloon for cold...

...the anoms still showing an atlantic ridge towards end of the month..

...trough to the east and over north eastern Canada but what jumps out at you is the trough over the Aleuticians..bit of a monster and responsible for real cold over that area...

...the amount of above average temps over Europe and Eurasia is quite incredible by late February..

...the Tropical Tidbits animation of temp anomalies over the hemisphere really shows the problem with getting cold in from a uk point of view..

850s

2m

..the real cold is being shunted east over siberia and round to the Aleuticians and although the Atlantic ridge and trough over our part of the world is bringing sonewhat colder air it seems to be being watered down over time..

..the main takeaway though is just the amount of warmth in the atmosphere over our side of the hemisphere..very hard i think to get any meaningfull cold with this situation..and time fast running out...

[feb1991blizzard]

The models at the moment remind you of when you first have a go on the decks, you post a chart with a PM -4c flow at 384  and go 'not bad, not bad - there might be a dusting on Ben Nevis or Scafell Pike', like when you mix a tune in and the pitch control is about -2 away from where it needs to be and go 'not bad', but really it sounds like feeding time at the zoo.

Edited February 14 by feb1991blizzard

[KTtom]

 feb1991blizzard using that anology, how would you describe tonights ECM

[Met4Cast]

Yuck.. 

Absolutely no sign of anything of interest on the ECM det (or the GFS, really)

[feb1991blizzard]

 KTtom

If i'm kidding myself like stated above, not bad, not bad, a ridge does get to within 1000 miles of where it needs to be.