Model Output Discussion - Spring Has Sprung

[Lukesluckybunch]

Gfs will probably be pretty awesome by day 9/10 with the low engaging with the trough over scandi..let's see..having said that..the low is very rounded and organised..we could do with a sharper looking one

Edited March 2 by Lukesluckybunch
Adding

[Mike Poole]

25 minutes ago, Cambrian said:

The clusters are useful, but there we are still working with a mean representation of the cluster and at a relative probability in terms of the whole ensemble that can at times be quite modest.

Good post.  However, the clusters are not a mean representation in the graphics.  This, for me, is exactly the thing that sets them apart from other representations for the week 2 range.  The graphics are from the representative member, not the mean.  

ECM website explains: ‘The most representative member of each cluster scenario is the member of the cluster which has the minimum difference from the RMS of all the ENS members in that cluster.’

Because it is an actual calculated solution and not averaged, it is therefore as physically possible as any op run.  

[ANYWEATHER]

Models are really struggling on how much influence the Atlantic is going to have on the increasing build of pressure to our north and east . Could well be the case ,and given the time of year that the drier weather is more influential in the days ahead . Could well be a slow start to Spring, and we could still tap into some notable cold from the East ,but to be honest ,I'm ready for some warmer and more importantly dry weather .☺

[WinterOf47]

 Crackerjac 

The timing is everything. Overnight and early morning after a cold first half of the night we can get healthy accumulations into early April (can remember 10cms in Brighton April 4th 2008 - gone by early afternoon) but daytime settling snow becomes harder as we progress into March unless we are under the influence of a genuine BFTE scenario and a frozen Europe.

Next weekend is definitely looking interesting, just want to see the Scandi high pivot in a way that draws air more directly from Russia rather than going via South east Europe. If that happens then the South could see snow if a low pushes up against the cold or drifts across on the Easterly flow.

As a photographer, late snow - as in March snow before the change to BST - is perfect as you can get up early and get out with the camera before everyone else and there is enough light to get beautiful images. 

 

Edited March 2 by WinterOf47

[Anthony Burden]

Morning all,charts this morning continue with this northeastern blocking versus Atlantic lows will be interesting to see if this time blocking wins the battle and keeps the CET for March below average.May take a while yet as usual to see the winner,but keeps the interest on a late spring any bets.

[Cloud 10]

Day 10 ENS. means doing pretty well generally,but a big plunge in the stats for mid-late February.

 

https://www.emc.ncep.noaa.gov/users/verification/global/gefs/prod/atmos/grid2grid/hgt/

 

[CoventryWeather]

 Lukesluckybunch Oh cold rain, everyone loves that! 

[Met4Cast]

Despite the blocked charts there's very little cold on offer to tap into, ensembles across all models are generally sticking to climatology (average) with temperatures gradually rising a little throughout the forecast period.

Blocking to the NE may well retrogress towards Greenland but MJO moving through typically zonal phases and rising AAM suggests a flatter pattern, rather than a blocked one. My expectations are still for the pattern to flatten out rather quickly, at least across the Atlantic sector with a west based -NAO seemingly the direction of travel following retrogression with nothing notable in terms of cold or snow potential, despite the SSW tropospheric drivers are not favourable to produce proper cold weather across the UK. 

Impressive looking synoptic patterns but sadly, no cold.

Edited March 2 by Met4Cast

[Addicks Fan 1981]

 Met4Cast we need @Tamaraon here to tap into the diagnostics before people have this reactive panic on these scenarios because signals obviously lead the models not the other way round.   

[knocker]

 Addicks Fan 1981 Signals do not lead the models and to say this rather makes a mockery of 70 odd years of model development. The sun drives the models via Atmospheric/ Oceanic interactions  using mathematical and physical equations and the teleconnections are part of this complex evolution. And of course forecasting. This is of course a very short and simplistic explanation.

Edited March 2 by knocker

[Met4Cast]

2 minutes ago, Addicks Fan 1981 said:

 Met4Cast we need @Tamaraon here to tap into the diagnostics before people have this reactive panic on these scenarios because signals obviously lead the models not the other way round.   

Total AAM tendency has been strongly negative of late thanks to the MJO decaying into COD, this re-emergence into the Indian Ocean and quick progression eastwards through the Maritimes though has begun to reverse this with AAM tendency now slightly positive.

I do wonder just how much overall +ve AAM will rebound to though, a fast MJO progression as is currently predicted would suggest less westerly momentum being injected into the atmosphere, I'd be surprised if we reached values seen through late January/most of February again, especially with El Nino beginning to fade.

The recent abrupt decline in AAM tendency combined with the SSW is likely generating the blocking to the NE of the UK across Scandinavia and we are seeing a regressive signal towards Greenland within NWP modelling, the only real issue is the lack of cold across Europe to advect into the UK, I do also think, as stated previously, the high might end up being too far NE to really drive Atlantic energy to the south of the UK and the means are now showing this with winds broadly S/SErly across the UK rather than true easterly, this essentially stalls the low across the UK bringing yet more rain.. wont that be nice. 

The direction of +AAM anomalies is equally important and we're seeing +AAM anomalies moving poleward as the previous cycle completes, this is suggestive of a stronger jet and is further evidence of a quicker flattening of the pattern.

I do think we've probably missed the boat here in terms of anything colder, at least through the first half of the month. Continued MJO progression into phase 7/8 later this month could potentially allow for another attempt late March/early April but honestly but that point we'd need a very direct northerly to produce, an easterly at that time of year is very unlikely to cut it. 

For those wanting one last bite of cold/snow, the outlook is poor. For those wanting some early spring warmth the outlook is equally poor. 

[KTtom]

 Met4Cast ill go more basic than that, its currently 2nd March, certainly no signs of any BFTE for the next 7 days. That takes us to 2nd week of March. Continent warms up rapidly at this time of year with any cold uppers retreating north, sun is stronger, obviously whack CC into the equation and anyone hoping for bitter cold and snow before next winter are going to be dissapointed. 

[Met4Cast]

 KTtom
 

Good summary! Rather amusing that we ended up seeing the mildest February on record after a lot of promise during early winter of a backloaded cold one

[Walsall Wood Snow]

20 minutes ago, KTtom said:

 

Everyone remembers the BFTE late Feb/early March 2018, but there was also the mini beast later in March that year. My profile pic was taken 18th March that year and that dates still more than 2 weeks away. Not that I'm expecting as such but just to illustrate we've still got a bit more time for something special to occur.

[Mike Poole]

 Met4Cast February is a fail of epic proportions really.  Whether your long range forecasting method of choice is the seasonal models, the ECM 46, or the GSDM, or ENSO, or the MJO, or the strat, (or tea leaves ), all of them at some stage (or indeed many stages) pointed to a decent spell of cold in February.  The worst offender was the ECM 46 which persisted with it well beyond the point where everything else had given up the ghost.

Edited March 2 by Mike Poole

[Met4Cast]

 Mike Poole

The EC46 has been spectacularly poor this year. I wonder if the now daily updates just highlight this more, was a little harder to keep track when the model only updated twice a week. I don't think i'll be putting much weight into it in the future, it's inability to drop a signal that it's latched onto when it's clear the trend has changed isn't great. 

I think 1-2 weeks it can be helpful to provide support for current trends within other models but as an isolated long-range forecasting tool it's poor.

[Mike Poole]

 Met4Cast I completely agree.  This winter was a major test for the new version of the 46 which, as well as running every day, also switched from being run as an extension to the EPS, to being run separately from T0 on a low resolution 36km horizontal grid.  Which (I think) has actually contributed to its output essentially being reduced to noise long before the timeframe it is supposed to provide guidance on!  ECMWF must surely have a rethink on that one!

Edited March 2 by Mike Poole

[mulzy]

 Mike Poole my tea leaves suggested a mild February

The EC46 was always ropey and it showed this year.  The one driver I normally pay attention was the Strat and somehow (bad luck) it just didn’t deliver.  MJO composites and GDSM are below tea leaves in my pecking order so no surprise it was a massive bust for these flakey predictive tools.

Edited March 2 by mulzy

[Lukesluckybunch]

1 hour ago, CoventryWeather said:

Oh cold rain, everyone loves that! 

Well it didn't turn out good...ecm is the one we want,snow on that chart by day 10

[Sun Chaser]

 Met4Cast  Ensembles looking very wet after day 7, a lot of precip spikes. Time to brace for another wet March in all likelihood

[Lukesluckybunch]

Not too long for the 12z runs..icon first out,hopefully a continuation of its 6z run..it was showing a clean easterly at 120!

[andymusic]

a certain gov org update for the latter part of March 2024 lol now going with "wintry and snowy icy hazards" - "easterly set up" and average to below average temps!

[danthetan]

Something I've noticed is the force of the block to the NE seems to be splitting those lows further to the west of the UK with each run meaning we stay more ESE flow as a result. With no cold air on the continent were relying on the block to retrogress to Greenland and enough forcing to keep the lows to the SW to avoid S or SE flow to allow a shot of cold air around the high.  

[Lukesluckybunch]

Ukmo day 5!

[CoventryWeather]

 Lukesluckybunch would have preferred these in Jan. Not now. 

Still likely to be cold rain for the majority, unless uppers are at -8/9.