Model Output Discussion - Spring Has Sprung

[Met4Cast]

 Addicks Fan 1981

They show the recent decayed MJO signal & expected start of the next cycle over the Indian Ocean, albeit they have been a little inconsistent of late, largely down to modelling struggling with the MJO (SSW related I presume). 

Can certainly see the uptick in Pacific trade winds. 

[Addicks Fan 1981]

 Mike Poole the question is will it be backed? Or is it having a meltdown? Sometimes NWP has its flaws and isn't perfect which is why someone like @Tamaracan shed some light on the goings on and that.   

Think in Portugal where she is is having a very disturbed pattern under a massive low pressure area.  I don't think we are in a dissimilar position to what we were in 2015-16 or 2018-19 to be honest with you or even 1994-95 either.    

It will be very interesting with what our el niño decline does to our weather from now on, also the hovmoller plots we need to keep a very close eye on too.   

[Addicks Fan 1981]

 Met4Cast I reckon then we are in a similar position to what we were during these years then of 1994-95, 2015-16 and 2018-19.   

 

[raz.org.rain]

 Ali1977 I have to say I'm liking where this could be going 

[Theresnoway]

 Frosty. Having been on this forum for a very long time and gained a feel for peoples weather preferences, you actually got me there!

I was thinking well of Frosty’s thrown in the towel, we’re all doomed!

Edited February 27 by Theresnoway
Duplication

[Sun Chaser]

GFS keeps pushing a trough to our west at around roughly T192, giving us a southerly airflow and potentially some nice sunny and dry conditions! What happens after isn't clear yet - this could either be our way into spring proper HOPEFULLY like the 00z suggested with it staying settled and a high building in (widespread 17c suggested by T240), or it could go back to unsettled after as the trough moves east as on the 06z, or it could move southeast and we get cold dry (and probably cloudy) continental easterlies as the 12z suggests. Either way an interesting synoptic situation looking into the second week of March.

  

[KTtom]

Very nice gfs mean for middle of next week with what could be a warmish, dry spell, just hope it lasts until the following weekend. The opposite of what we look for in winter..an Atlantic trough Scandi high combo = southerly

Edited February 27 by KTtom

[Metwatch]

A very nice looking 12z GEFS ensemble graph there for Nottingham, a drying trend from mid next week then also milder, as high pressure is modelled to build in from Iberia and join up to somewhere around Scandinavia.

The GEFS height anomaly showing the possible pattern clearer:

There is quite a bit of uncertainity on what the high will do and how it will be shaped. A subtle shift northward, with the trough sinking southward could mean a more easterly feed, but not exactly cold as there isn't much in the way of a notable cold pool forecast for western Russia and into eastern Europe. The GEM has the high quite far north, but at the same time with the low also further north in the Atlantic, a milder feed of air reaches the UK.

Certainly interesting to see where this goes, and at last something finally different compared to the constant record breaking mild temperatures and excessive rainfall of recent with that semi permenant Iberian - Azores ridge.

 

Edited February 27 by Metwatch

[Cloud 10]

ECM 12z keen for something wintry on the first day of Spring.

 

[Ali1977]

 raz.org.rain in ready for some warmth, but hoping to squeeze a surprise snowfall on Friday or Saturday first. 

UKV upping my confidence of a covering even more !! 

[Cloud 10]

ECM 12z classic respone to a SSW?

 

[Chesil View]

Ecm has some trough disruption to our west and some cold air coming round the Scandi High at the end. 

Only ten days to reel it in.  

[Uncertainty]

I am very wary about modelled scandi highs, they tend to be fictitious. However, the one developing next week does seem likely but there are still question marks around its influence over the U.K.s surface conditions. The trend today has been to have it more influential, bringing a very welcome drier trend. Even the gem, which has been annoyingly consistently unsettled has started to entertain the possibility of the scandi high exerting more influence.

But, it could very easily shift back to being a hindrance to such a trend by manifesting too far eastward and allowing a trough to stall up against it - one of the autumn storms did that and brought some severe rainfall totals to eastern Scotland. We don’t need any more storms or stuck fronts.

Beyond that the gfs and, were it to continue, the ecm, suggest a colder pattern could establish with some retrogression and the transport of a cold pool.
 

Ec day 10

Gfs day 12

At this stage, such an evolution is highly fanciful and would require thread the needle style synoptics to force a snowy March scenario. A watching brief then.

On a purely anecdotal note, my own observations tend to gauge these persistent wet spells as generally 6-9 month iterations. The current deluge began with the weekends of July 2023 and has continued ever since - broken only by the Sept and Jan short high pressure visits. The last such super wet spell we had was July 2019 - March 2020. A very dry period followed and broadly continued to June 23. Previous to that it was, with a similar timeframe, in 2015-16. Again we were drier rather than wetter after that. Given we once again have a La Niña on the horizon one would hope that the current now 8 month super wet spell should hopefully come to an end soon and we could have a more generally drier long term period ahead. 

[stodge]

Evening all

Certainly some interesting charts in tonight's 12Z suite albeit a very long off but nice to look at for now.

There's still uncertainty over the more immediate developments with the LP disrupting south on Friday but enough energy phasing back into the Atlantic over the weekend to maintain an unsettled theme but at the same time the Scandinavian block is intensifying and this causes an initial stand off with the British Isles in a mild to very mild S'ly flow but with the heights building to Greenland, the LP is forced south and a SE'ly regime sets up across the British Isles with 12Z GFS OP offering a real tease in far FI of some colder air (-8 850s in March anyone?) moving in.

The 12Z OP 10 HPA shows a strong European based warming which you don't see every day of the week suggesting further amplification.

Let's be fair - northern blocking in March isn't unusual and for those looking for an early spring the orientation of such a block is crucial as the difference between a warm-sourced SE'ly and a cold-sourced E'ly will be considerable. It should also be noted 12Z GFS Control isn't interested and some keep northern blocking but the trough much closer to or over the British Isles.

That's the thing with spring heights - if you want dry, you don't want the heights to be too far north and angled too directly east-west as that traps the trough over us but a stronger Scandinavian block keeps the trough more to the south west or south.

[Penguin16]

 raz.org.rain I’d put money on beast from the east after reading that ha 

[stodge]

 raz.org.rain I can certainly believe warmer for a while especially if we get into a stand off between the Atlantic LP and the Scandinavian block and we get a S'ly feed but the models don't show that last ing long and unlike most of these "battles", the Atlantic loses as the trough weakens and is forced south by heights bulilding toward Greenland.

[Kirkcaldy Weather]

 

Extremely pleased how the patterns have & are developing there's a few timeframes I'm focusing on ATM.

On 21/02/2024 at 20:17, Kirkcaldy Weather said:

This connection will be brief at this stage with new trough developments close to the UK & Ireland During the last days of February into the beginning of March

 

On 21/02/2024 at 20:17, Kirkcaldy Weather said:

During week 1 of March with further influence from phase 7 of the MJO this could see further connections between the Canadian Maritimes Blocking and the Block to our East Northeast with potential this evolves into a Greenland High

As this next low becomes a cut off low first across the UK and Ireland with below average temperatures at 850hpa and surface levels with fronts wrapping around the low this brings potential for snow event(s) for the UK and Ireland.

I had mentioned in a number of my posts that week 4 of February was the next significant opportunity for patterns which could favour wintry conditions and I'm extremely happy seeing such evolutions.

As the thickness levels begin to lower once more this sees the showers from the Atlantic becoming steadily more wintry and once the low begins to develop into that of a cut off and the cold air continues to intensify as it undercuts frontal precip current trends show potential for snow event(s) in particular for Wales, Northwest and Northern England [Pennines] and pushing into Scotland.

In these areas seeing snow / wintry precip there will also be frosts and an ice risk maybe even an ice day with snow cover.

As the pattern across our side of the Northern Hemisphere begins to develop retrograding tendencies we'll see a few big and interesting developments.

As a high which is currently building further to our East begins to strengthen once the retrograding begins this will move westward to sit to our East also during this our cut off low also retrogrades westward into the Atlantic, this combination suggests a plume setup during week 1 of March is a real possibility.

Into week 2 of March with further retrograding the connection of blocking to our East Northeast and the -PNA high across East Northeast America and Canadian Maritimes begins to centre in across Greenland.

With the MJO having progressed across the Western Hemisphere, South America and Africa and currently residing within the Indian Ocean this gives feedback in line with the above patterns and suggests there is a possibility for a colder flow from the Northeast > East though how much influence this has in the UK TBD. 

Plenty of interest as we head closer to Mid March I suspect.

This ongoing cycle of the MJO carries importance with regard to El Ninò though there are still a bit of discrepancies with how amplified the MJO becomes within the Indian Ocean with the GEFS seeing a strong event whereas the CFS is much less amplified.

The GEM & JMA are more akin with the GEFS

I'm more familiar with Westerly Wind Bursts which are the warmer ones however we're looking at Easterly Wind Burst event here which could further speed up the ongoing decline in the El Ninò temperatures.

 

Also worth noting once more with the precursor patterns continuing we've got good signals for a new reversal of zonal winds at 10hpa (possibly 50hpa though no agreement on that just yet) with this looking like a stronger reversal than the previous 2 of winter 2023-2024.

Thanks for reading. KW

[feb1991blizzard]

EPS signposting a decent ridge.

[Rain All Night]

8 hours ago, Rain All Night said:

0z/6z deterministic runs, Tue 27th to Tue 5th (day 7)

All looking pretty much as expected up to the final day or so, when the ensemble means leave me optimistic that the GEM solution without the high over Portugal will not verify.

0z/6z ensemble means, Tue 27th to Wed 13th (day 15)

I'm liking this! It seems our fortunes may be changing for the drier around 6th March (day 8). The mean surface low does start to look a bit more iffy around 11th March perhaps, but that's way out at day 13 so we can disregard it for now.

12z deterministic runs, Wed 28th to Tue 5th (day 7)

12z ensemble means, Wed 28th to Wed 13th (day 15)

Earlier on I'd take the GEFS as it looks drier, but later on, we've got a new signal - the demise of the block to our east, and in the case of the GEFS, a significant flattening of the heights profile. ECM and GEM prefer to hint that the heights may be moving over to our west side.

Bonus

The mean zonal winds bottom out at around -18m/s on around 10th March (day 12) on this morning's EC46. That's certainly much more significant than the previous two reversals.

Edited February 27 by Rain All Night

[Ali1977]

GEFS Mean through Friday

[baddie]

An SSW??? You gotta be kidding me. I do not appreciate cold weather after the equinox

Edited February 28 by baddie

[raz.org.rain]

 baddie an SSW is not a guarantee of cold weather, fortunately. It could just as easily deliver warmth.

[baddie]

 raz.org.rain High pressure of Scandanavia the whole month bringing sunny Easterlies would be nice

[Daniel*]

I don’t think I’ve posted here in over a week… there are evidently strong hints of weakened Atlantic flows into early March quite a strong blocky signal in EPS. Pressure also looking higher over Scandinavia, it points to me an above average chance of winds to draw from east or southeast, there is though a big spread in potential temps but definitely drier. Meteorological winter might well end shortly, but as we saw in 2013 and 2018. March on occasion rare thing down here, can remind us of proper winter, which this winter has failed to do so.

NAO

Edited February 28 by Daniel*

[offerman]

I was just looking at charts and I used the slider at the bottom to progress the charts in almost like an animation. Then I slid it back to the beginning again and ran it through sliding my finger. 
 

what I found astonishing is you can actually see the effect of the warmer ocean temperatures that have been around and you can notice how fast any cold incursions not just near the UK but even off the eastern seaboard of America and down from the Western coast of Greenland, the cold shots that come down there everything that’s coming into the Atlantic from either there or from Iceland direction or cold that comes down Ireland to the western coast of United Kingdom even a brief Easterley all the cold incursions just evaporate so quickly when moving the animation you can see it’s quite incredible . just give it a go and you’ll see what I mean, and this has been part of the issue this winter with such strong anomalies in subtropical region such strength down here and weaker heights and a disrupted arctic has all put pay so far to any real cold and longevity. I just found it fascinating and white to share it as I couldn’t believe how quick each cold blast just evaporates as soon as it hits over the Atlantic right the way from eastern US over to us

.