Model Output Discussion - Spring Has Sprung

[chrisnoy]

ECM , UKMO and GEM looking very different to GFS this evening. I know which I prefer....BFTE anybody?

Edited February 11 by chrisnoy

[Ali1977]

Oh yes 

[TEITS]

 Met4Cast I think this is one of those occasions when rather than looking at all the complex teleconnections we just use some basic instinctive forecasting using the models.

You mention no sign of any cold spell for the next 2 weeks and yet UKMO/ECM at +168 disagree. I don't need any teleconnections to tell me that the +168 charts will go on to develop towards a cold spell for the UK.

Knowing our luck it will be showing a SW,ly tomorrow morning!

[Anthony Burden]

Evening all,has SSW finally come to the rescue ECM/GEM/UKMO all showing northern blocking 168hrs onwards hopefully following on tomorrow with this positive move towards a cold end to this winter.

[Met4Cast]

16 minutes ago, TEITS said:

You mention no sign of any cold spell for the next 2 weeks and yet UKMO/ECM at +168 disagree. I don't need any teleconnections to tell me that the +168 charts will go on to develop towards a cold spell for the UK.

Yes, because following the whims of individual det runs through this winter has been a complete success.. 

I can't say I care much for what the det runs show if I'm honest, they could show the next BFTE and feet of snow across the whole of the UK but if it's beyond day 3 it may as well not exist. 

[Mike Poole]

Run of the day is the KMA 12z, here at T216:

The key to this, as I’ve said before, is getting the initial push of heights north to take place west of the UK and not over the UK.  Will be interesting to see what the EPS show in terms of the likelihood of this.

[Jordan S]

The latest Ecmwf and Gem both show that with the right orientation to the high pressure over and to our east/northeast and jet stream pattern to our west,  very cold air upper air temperatures that seemingly look distant before 8-9 days can quickly return west/southwest across the continent.

The Gfs looks way to progressive and quick again with those lows moving through the UK and high disappearing to our northeast completely during the following week beginning 19th..

half way house similar to my post yesterday being more likely, steady progression to milder and unsettled conditions in the west southwest, but could raise snow potential slightly in the east late on in the week even if being drier here.
 

Yes although the colder than average conditions that where possibly expected until recently look to be a distant memory and milder conditions generally more likely overall to see out February, I wouldn’t rule out a colder than average final few days of February at this stage even if currently less likely as there are hints of this being a possibility.

What is more likely similar to what was hinted at by my post yesterday is for a colder northwest airstream for now and subsequent wintry shower risk in the north, high to our southwest, weak heights to Greenland/Iceland during final week or so of February, temperatures not far off normal for southern regions but it’s too far out for certainty on that evolution yet.

Edited February 11 by Jordan S

[sunnijim]

 TEITS Models starting to sniff out a reaction to the progged SSW on the 19th/20th maybe?

Would be a rather quick reaction but not impossible, effects normally take longer to show their hand.

Alot would need to fall into place to stop a slushfest at this time of year.

2018 landed on the 22nd Feb, if this scenario has legs then it is my opinion that we will be looking at the weekend of 24th/25th as an arrival time.

First time I have felt moved to get a little interested in cold possibilities since the early January farce.

Perhaps because date wise, SSW wise, memory's of 2018 come flooding back.

One last chase perhaps that could save a winter that promised so much and produced so little ( for most)  from being consined to the bin.

[minus10]

The gefs 12z still showing the colder pattern for last week of Feb..

this is what i am checking now to see if this stays in the modelling or gets put back/watered down etc..kind of last chance saloon really..

...looking at the 850s 12z today compared to yesterday for when the mean drops though the long term mean to get an idea whether this is remaining or being  pushed back...

 

...berween 22nd and 23rd still seems time slot for this...however we shall see...interesting ecm 12z though..

Edited February 11 by minus10
Wrong chart

[WYorksWeather]

 sunnijim My big concern really is that overall levels of warmth this year might end up meaning that it is a slushfest regardless. We need one of the coldest ensembles in the current set to verify (around -10C at 850hPa), in order to avoid that scenario when we're looking for cold at this stage. I'd really like to see more ensembles go below -10C before I start to think we have a chance of getting a mean down that low.

[Metwatch]

ECM also going for a UK ish high but it would be on the chillier side of things as there is a brief northerly just beforehand. Can we please get something dry at last

Edited February 11 by Metwatch

[stodge]

Evening all

Still seeing a distressed 10 HPA vortex in the last week of the month and fans of cold will be hoping for a rapid downwelling but I still think early March is the favourite for a pattern change.

To be fair, plenty of the 12Z output teases at height rises to the NE (KMA tries the Greenland HP approach which looks too much too soon) but none of this is yet within the reliable so another portion of eye candy for the cold weather fans and another week of mild weather for the rest of us.

 

[Frosty.]

To be honest, I’m looking for early heatwaves now! …no sign of that on the models so far though!!!!!…but maybe there is a chance of colder weather returning during the last third of feb!…I have tremendous sympathy for the majority of members on here, especially those who are in the south of the u k who have endured, for the most part, a stinky winter, I really do!..hopefully the cfs brings hope of an Easterly! …being serious, I think the early meteorological spring could bring some wintery spells..well, according to Exeter anyway..until. Tomorrow at least, the models are making mugs of all of us let’s be honest, so much chopping and changing..glad I’m only an occasional poster now, I don’t have the stomach for it anymore! Cheery bye!    

 

 

Edited February 11 by Frosty.

[Blessed Weather]

2 hours ago, raz.org.rain said:

it would appear that we're getting a somewhat clearer impression of how an SSW will impact lower latitudes, and it seemingly isn't good news if you want cold in our location. Regional factors such as a strong jet just go against any incursion potential. The safe bet would be to assume that the cold incursions strike the northeastern US instead. I'd imagine we'd get more of the same of what we've already got.

Hi. I'm wondering who this 23 year old person is that you're quoting, but I'm surprised to see anyone confidently predicting what the tropospheric impact will be at this stage from a SSW that won't occur until the 20th Feb, assuming it does indeed happen. If it does happen it's going to be a Wave 1 induced SSW which typically means a lag of at least 10 days for any impact to show. 

Here's a few snippets from recent research that indicate the extent of the challenge. Click on the title to go to the full paper.

The role of North Atlantic–European weather regimes in the surface impact of sudden stratospheric warming events (2020 paper)
While the stratospheric forcing often projects onto the North Atlantic Oscillation (NAO), the tropospheric response to SSW events, if any, is highly variable, and what determines the existence, location, timing, and strength of the downward impact remains an open question.

Using large ensembles to quantify the impact of sudden stratospheric warmings and their precursors on the North Atlantic Oscillation (2023 paper)
We find that there is little information in the precursor state to guide differences in the subsequent NAO behaviour between one SSW and another, reflecting the substantial natural variability between SSW events.

[Mike Poole]

ECM clusters tonight show some movement, T192-T240:

The op is in cluster 2, which has the ridge go up west of the UK - it has 14 members.  Cluster 1 similar but doesn’t get as far north.  Cluster 3 pushes the ridge over the UK and it ends up to the east.  Clusters 4 and 5 don’t really push the ridge up much at all.

T264+:

Roughly even split between the two clusters.  Cluster 1 has a strong block which is also well positioned.  Cluster 2 with a weaker ridge that eventually moves west of the UK, but maintains heights to our south.

[swfc]

The comment ssw has been used a lot this winter. From an early cold spell in December it ran into jan ie eqbo etc. Its at a stage now where there is nothing in regard to a ssw could in effect do anything until March? Why is it when the models look poor people post 10+charts looking for cold. When its showing bang average fi is 7 days? I love cold weather and synoptics but there is nothing to suggest anything unusual for febuary heading into march imo

[damianslaw]

Just taking cursory glances at the models presently given the rather uninteresting benign conditions on offer for mid Feb, despite signals earlier in the month for far more different fayre.

In the reliable all models show weak ridge development in the vicinity of Iceland taking hold, along with the omipresent Iberian height rises and a rather weak jet inbetween.

GFS continues to show the heights to our south being the greater force, with the atlantic trough backed to our west pumping in mild south westerlies before possible signs for something very different by tail end of the month.. I wonder if SSW induced with the trough pushed east and strong height development to our NW.

UKMO though is trending with ECM showing heights building up through the UK merging with the Icelandic heights.. which would bring pleasant conditions albeit quite cold at the surface unless the draw is from the south which would result in early springlike conditions. Given ECM is opposite to GFS I'm putting little faith in either.. I suspect the GFS is showing a deeper trough to our west than will manifest, and likewise ECM building heights too strong. We will probably maintain a mild westerly/south westerly feed before a possible marked change by months end to something much colder - if the effect of expected SSW delivers high to the NW and low to the SE.. but from this juncture its not clear how we would get there and the theme of the winter has been for anticipated long term developments to implode by short term unforeseen developments, so equally we might see a very mild southerly draw with everything set up wrong for late season cold.

In the meantime its rather slow going in this thread in sync with the slow going nature of the synoptics. Much more cursory glancing of the models in the days ahead I feel..

Edited February 11 by damianslaw

[Allseasons-Si]

The ext'd cpc anomalies look good to me

here is last evening's v's this evening's...

you can see a better marked trough to our NW over Scandi and more of a retreat of the mid Atlantic trough,...notice the Iberian height's have also vanished.

we see how we go towards months end.

 

[markw2680]

Nice to see most of the models giving us a glimmer of hope before the end of this winter, but we have been here quite a few times this winter for it all to either water down or completely disappear, let’s hope it actually happens but let’s be honest we are talking 10 days away as usual so I wouldn’t get any hopes up

[Rain All Night]

8 hours ago, Rain All Night said:

0z/6z deterministic runs, Sun 11th to Sun 18th (day 7)

We begin with our current northwesterly flow, followed by a brief weak ridge from the south. It then remains unclear exactly when and how the little Atlantic low will intrude itself upon us later in the week.

GFS, please don't be a trendsetter (again) with your denial, on both your 0z and 6z runs, of even the most modest build of heights northwards after the little Atlantic low has passed. ICON sort of seems to agree with GFS, which I seem to remember also being the case the last time the GFS started to dissent.

Those models which do allow the heights northward insist on that annoying "kink" to the northwest (I don't have the vocabulary to describe what it is! It's visible on the ensemble means too)

0z/6z ensemble means, Sun 11th to Mon 26th (day 15)

For anyone looking out for a dry spell, we look like we could just about stay under a mean ridge from roughly 17th to 20th Feb.

GEM almost wants to bring back our phantom Scandi high.

ECM 0z and GEFS 6z disappoint by weakening the eventual Scandi trough signal seen on the GEFS 0z and the previous ECM ensemble suite, though it has not disappeared completely.

12z deterministic runs, Mon 12th to Sun 18th (day 7)

I really don't fancy the ARPEGE's version of our little late-week low; ECM's take on it is not hugely dissimilar.

Miserly old GFS has recently been grooming its callow sidekick ICON to join it in showing the most miserable possible outcomes, and here they broadly agree that heights shall not pass to our north. For now, the other models ignore their dissent.

GEM, JMA and CMA (perhaps not exactly the holy trinity of models) have all gone back to the idea of a Scandi high of sorts.

12z ensemble means, Mon 12th to Mon 26th (day 15)

Hooray, the full ECM ensemble is coming out at a reasonable speed again.

ECM seems willing to give us a fair few Atlantic-free days from 17th Feb onwards, the other two models preferring just three or four days max by the looks of it.

The tease of cold troughing to our northeast is still making an appearance, from around 24th Feb. But if this does transpire, then it may be that high pressure to our southwest will be waiting in the wings to keep any cold air flows away from us...

Bonus

2024's second brief and shallow dip below zero for the zonal mean zonal winds at 10hPa looks likely for around 19th February.

Edited February 11 by Rain All Night

[blizzard81]

 Allseasons-Si ECM agreement. 

[suxer]

 blizzard81 actual agreement zero

[Lukesluckybunch]

Gfs sticking to it's guns..flat as anything at day 7!

[blizzard81]

 suxer Good agreement. Trust me, you don't see that often in the ens suites. 

Edited February 11 by blizzard81

[Don]

59 minutes ago, Rain All Night said:

2024's second brief and shallow dip below zero for the zonal mean zonal winds at 10hPa looks likely for around 19th February.

I take it that's a downgrade on recent runs then?

Edited February 11 by Don