Model Output Discussion - Spring Has Sprung

[Daniel*]

1 hour ago, WYorksWeather said:

I'm still quite pessimistic about any looking further ahead into March. The reason is that the lack of any cold to work with means that we really have to imagine we're 2-3 weeks ahead in the year in terms of temperature. The temperature over the Northern Hemisphere is already more characteristic of a typical late February or early March. By the time we get a major SSW, and even with a QTR of say a week, and then assuming it works out in our favour as far as blocking and cold goes (already essentially granting that we get a near perfect dice roll), at the absolute earliest you're looking at the last few days of February. 

You say that but Northern Europe/Scandinavia is expecting coldest winter since 2009/10. The deep cold has been persistent in upper Europe, potentially accessible to wider Europe things have just not aligned at least yet. Again an illustration in a warming world… persistent cold anomalies can occur regionally. I personally don’t see the value in looking at entire Northern Hemisphere you need to look at areas with relative proximity to UK where the cold originates to our north and east. I don’t see why for example a very warm Canadian winter means much to us.    

 

Edited February 9 by Daniel*

[Kentspur]

CFS keeps persisting with this cold Easterly lately and it's not like a million miles away but it is just the CFS. With the downwelling from the SSW to come I can see us having some dramatic changes so I'm not holding up the white flag for winter just yet. Hopefully the shorter range models will come up with something for us before March proper is here

Edited February 9 by Kentspur

[feb1991blizzard]

GEFS starting to show a stronger cold signal this suite and last.

 

[KTtom]

Overnight ops sobering us up after last nights party as usual. Pretty bog standard late winter / early spring set up as the winter vortex breaks up yet the UK still manages to remain in a south westerly courtesy of the high to the south west.

The 'UK low' really has been a killer in terms of Feb, after hanging around the UK for an eternity, it then trundles off to Norway to prevent a nice little barrier to the arctic high trying to head in our direction!

 

Edited February 9 by KTtom

[Jordan S]

This will be a wordier post with less charts attached than I normally do but hopefully it doesn’t effect the quality of the post

Looking at these two Gfs charts for the 21st February, yesterday evening’s Gfs should be closer to the mark in terms of the synoptic pattern in theory, with higher pressure to our north and east with low pressure systems stagnating over the North Atlantic, producing at first winds from a milder south/southwest direction though not exact by any means and a more southerly tracking series of lows is more likely by this period as will mention later on in this post later in the post..

Yesterday evening’s output for the 21st..

This morning’s output for the 21st..

I admit, I amongst a few others highlighted the significant chance of colder than average conditions for next week with increased snow risk up until just 3 or 4 days ago personally, that does not look to happen, was quite a change of events, the low pressure system effecting us today now being the main reason though obviously not the sole reason, it’s sudden projected path change for example and evolution in subsequent model output, being difficult to anticipate.

 

Looking longer term, at the moment it looks as if it may of purely just delayed a colder pattern by a week or so, but not without a now less clear cut evolution to it as I will mention near the end of post..

Referring back to my previous post for next week for a second below..

On 06/02/2024 at 22:55, Jordan S said:

winds from a more southerly quarter bringing rising temperatures into the south and southwest and an increasing risk of low pressures gradually moving into the southwest and west of England as the week progresses next week seems more likely now, but higher pressure still looks to build to our northeast then northwest at this stage.

 

On 06/02/2024 at 22:55, Jordan S said:

Its all very messy but the north should atleast cling onto slightly colder air first half of next week from the east or southeast though fairly dry at the moment

the main change to it looks to be a more westerly element to winds across northern uk at the beginning- middle part of next week but the rest of the quoted sections still holding onto some accuracy, with slightly colder air hanging on over northern areas at first, but not from a southeast direction and low pressure systems and their associated milder air gradually making its way into southern and western areas of the UK though looking wetter earlier on here than previously anticipated, also temporary drier signal emerging for end of the working week next week more widely but probably very brief.

Now if we refer back to the last section of my previous post mentioning the outlook for end of next week onwards..

On 06/02/2024 at 22:55, Jordan S said:

high pressure to our northwest beyond though remains more probable for now, allowing potential very unsettled conditions into the south, battleground snow for central areas and a possible return to cold conditions enough for wintry precipitation for northern areas, last part similar to my post last night.

it’s clear that its largely still the most likely way going forward, taking a look at admittedly but still mainly accurate yesterday’s NOAA 500mb height anomaly charts for the northern hemisphere for the same sort of period as an example and you can see the likelihood of the blocking to our north and northeast and low pressure gathering to our southwest..

but given the likely presence of high pressure around Spain, at the moment it looks as if it will probably largely prevent colder than average conditions over southern UK perhaps even milder than average in the far south and southwest and with low pressure systems likely to be sandwiched in between higher pressure developments to our north and that slow moving high to our south, and very similar to what my previous post said, it’s a recipe for some very unsettled conditions over southern and central areas, the battle ground snow scenario for central areas I mentioned in two of my previous posts would be the result of colder air making it’s way south and southwest over the north of the UK at the end of next week/ early the following week. Though what’s become evident to me is in this case the pattern does not look instantly liable to bring wintry conditions on the boundary with the first low pressure systems that move across us during this possible change to colder conditions from the north, it’s more likely going to be a case of lows behind the initial one or two that cross over central UK providing the highest risk for significant battle ground snow over central/northern areas. 
 

After this possible change to colder conditions over central and northern uk towards the end of February, I would say on balance it is more likely to turn very mild more widely by the beginning of March with drier conditions for southern and eastern areas. But more an educated guess at this stage. 

[daz_4]

Quite a flip from the models for next week in the last hours. High pressure from the east is gone and once again warm SW winds are blasting through Europe.

[Gowon]

Consistently wrong, or right?

[Kentspur]

Blimey a Day 9 instead of day 10 chart from ECM with -6c uppers over the Eastern side of the country is the model feeling alright?

Edited February 9 by Kentspur

[mountain shadow]

 daz_4 The Iberian High rules supreme. 

Nothing can stand in its way.

[carinthian]

Morning all. Not all doom and gloom on this mornings runs . A cold polar burst into The British Isles on Monday could provide some snow, especially at elevation and temporary at lower levels. Later in the week a warm front moves in again. However, cold air lurking not far from the North of Scotland for much of the week. Obviously, mild outcome for most of Europe ( apart from the Nordic countries ) has been the winner for much of this winter. Maybe the coin could flip in favour for cold for once as shown in the latest ECM run.

Currently, worryingly so unseasonably warm in the Alps. Defo need to see cold ❄ on the horizon soon.

Rock on UK ! Expecting some surprises in the models over the weekend !

 C

[Chesil View]

Weirdly there is some continuity on the Ecm 0z from last nights 12z in terms of Greenland and the arctic although not quite as  out there as last night. Could be some interesting developments over the weekend output I think. 

Edited February 9 by Chesil View

[chrisnoy]

 Chesil View GFS and UKMO actually has this setup at a similar time.....it's the progression from here we need to hope for good things for.

Edited February 9 by chrisnoy

[bluearmy]

 Singularity. It is open to interpretation.  This winter is quite strange high up and perhaps difficult to make judgments upon.  If you look at the 00z gfs op, you will see a neg AO in the trop which is nothing to do with the reversal high up that occurs at the same time. The positive flow sitting between in the mid to lower strat  

 

in the past, we have seen reversals take place with a positive AO in place and within a few days a big ridge is thrown up on the pacific side which punches across the Arctic and affects our side of the NH.  That would be visible as the blue negative flow in the cross sectional chart working down top to bottom. That’s what a QTR is.  This winter with the trop and strat generally in tandem it’s probably not so relevant. It’s been tough to see whether the impetus for neg flow has come from a downwelling wave or is instigated from the trop and then quickly upwelled. Mike has posted on this a fair bit. 

fwiw, next weeks reversal is currently uncertain in how it plays out. I think that until we get a handle on that we can’t set much store in the modelling for week 2. 

[DavidS]

 carinthian yes for the Alps, the hope of a couple days ago would be lower pressure would push east or south east from the UK and at least bring down the 850s next week, but that scenario seems to have gone from the models. 

[feb1991blizzard]

Wonder if yesterday's ECM 12z op would split if it went further.

[blizzard81]

As others have already mentioned this morning, good continuity from ecm and ukmo. In fact ecm has us BACK IN THE GAME! this time next week. 

[Ladyofthestorm]

I'm always suspicious of the GFS spuriously throwing out Atlantic based lows , signally wind rain and mild , when the NAO would suggest otherwise.  Neutral possibly slightly negative doesn't tie in with those areas of low pressure. 

 

I know some people have knocked it this year, suggesting  that it can't be used on its own, but in hindsight it's been a very good predictor / indicator of whether the Atlantic is a big influencer or not of our weather this winter, especially for us in the North. 

 

My suggestion is take  the models with a huge pinch of salt  post 150 hrs , 

I think the NLy blocking has this. 

[Penrith Snow]

 Daniel* that's a really interesting graph for Finland and I am surprised how many months in the last 14 years have been colder than average.

I suspect a similar graph for London would show far fewer cold months.

It shows that warming in the UK is racing ahead of other countries, due I think to persistent Iberian Heights which act as a block to UK cold weather in any season.

Andy

[carinthian]

 DavidS Yes, frustrating David. The UKMO chart below does show some frontal activity widely across the Alps this coming weekend. So perhaps some welcome snowfall, especially above 1000m is possible. However, further down the coming week a return to those crazy warm SWly back on the agenda for a time. Hopefully , ECM comes to the rescue !

C

[Man With Beard]

Pretty spectacular capitulation on ECM ensembles in the past 48 hours wrt to Scandi/Sceuro high for the 16th February being completely tossed out - the mean was up to 1035mb at one point but has now been replaced by a Scandi low! Thankfully for nerves on here it never looked right for UK wintry weather anyway. 

Perhaps the lesson is that the models are struggling big-time at the moment over something, and possibly more changes to come?

[Gowon]

 blizzard81

Check out the Asian models, they're very similar to the ECM 

The JMA

 

[Mike Poole]

I reckon the JMA has this nailed at day 9 this morning:

[joggs]

Hope allowed, just read on the weather channel in US they expect a flat zonal set up from next week replacing the record warmth in parts with a trough in the east.

That'll trigger up the jet won't it?.

[Singularity]

 bluearmy Good points. Possibly a reversal never truly propagates down faster than a week of time, with apparently faster proceedings being when troposphere led events have turned the lower stratospheric NAM negative within a few days of the SSW.

Back to the model runs and the deterministic runs on each side of the argument regarding the low by the Azores next week have slightly moved toward each other. Result looks a bit half hearted on both sides but there are more emphatic scenarios to be found in the ensembles.

Really a watching brief for now. What we can say for now is the abrupt change picked up on by UKM & ECM’s 12z runs yesterday does have credibility to it. 

[bluearmy]

 Singularity there have been a couple of gfs ops recently that downwelled within a couple days on the cross sectionals - tended to be those that developed a large split vortex later on with the Arctic ridge dropping into the Atlantic ridge pushing north.  I suppose that the weak strat vortex this season makes it prone to that. Of course that’s not a standard NH strat winter profile 

for developments next week, still uncertainty around how the ssw will manifest itself. Currently backing off a split solution (of any note).   The eps clusters look better in the extended.