Model Output Discussion - Spring Has Sprung

[bluearmy]

@Met4Cast I’d rather hang my hat on the eps suite days 10/15 than telecons at 4 weeks! 
that’s very much not to dismiss the telecons as a macro tool but so far this winter only once have the eps in the extended period got the signal wrong and that was briefly for a few runs approaching the Xmas period 

I’d look at the period post day 8/9 and say that the Nh profile is prone to amplify but until the northern arm relents a little we can’t benefit.  I’d be surprised if we didn’t see a dig of a trough over n America at some point which will allow an Atlantic ridge to go up 

[MATTWOLVES 3]

Boom there it is folks...

Edited January 23, 2024 by MATTWOLVES 3

[geordiekev]

3 hours ago, MATTWOLVES 3 said:

thought the ecm ens look better than what I've seen for some time,yet some are not really convinced! For me weve taken a slight step forward today rather than the usual 2 steps back.

Defo an improvement with the ECM 10 dayer, hopefully not a long drawn out affair this time

[Gowon]

Hmm.. again the UKMO looks even more interesting this morning at day 7:

[Lukesluckybunch]

Yes wedges appearing north on scandi..on the ukmo 168

[bluearmy]

Ukmo is at one end of the envelope re beginning to drive a neg tilt to the upstream Atlantic trough by day 6

gfs at the other 

gem, icon and ecm in between to varying degrees 

you’d say Ukmo looks overdone based on the other models 

[KTtom]

Big differences between the 'big 3' at just 144, at 168 they are worlds apart in relation of what they want to do with the PV. Ukmo introduces a wedge to split it, gfs remains consistent in shifting it to Scandi, ecm splits the difference and leaves NW europe with a south westerly express! Some sort of pattern change as Feb kicks off, hopefully GFS is barking up the right tree!

Edit: ecm finally shifts the PV in line with gfs by day 9.

Edited January 24, 2024 by KTtom

[TillyS]

Whatever the polar vortex is or isn’t shown as doing, the outputs on all 3 x 0z runs all look very zonal for the UK to me. Minor variations on an Atlantic-dominated theme with the persistent heights to our south. I’ve spent previous winters chasing the polar vortex around and in my humble opinion it rarely delivers.

No northerly blocking. High pressure to the south.

= a recipe for ongoing mild, with predominantly westerly flow. 

[IDO]

The GEFS and GEM means are poor. Both are very similar for D8-16:

  

We see the Greenland tPV run across our north to Scandi, but because of the mean Siberian/Alaskan highs, it flows the contours and, by D16, has returned to our NW. This is only the underlying background signal from the models, but it is relatively clean in this range. We do need other factors to dislodge the current state of play, as there appears to be a very low chance of any HLB'ing in the Atlantic/Euro quadrant with that pattern. The best will be wedges and stalling mini-ridges if these means are correct.

The next 10 days look to have high confidence of zonal with NW/SE split:

  

Rainfall for 10 days^^^. The London GEFS suggest mild for the south in that period.

[MJB]

Picked some of the ENS, not to show longevity in any cold snap/spell, there isn't one but we have some shots at cold going forward, get into next week and we should see some change.................hopefully 

 

 

[Purga]

A little bit of hope for relief from the tedium showing in FI this morning maybe?

[Singularity]

We’re at that stage where the modelling as a whole is starting to explore new routes more. Not yet enough to greatly alter the means but it shows that there is some genuine potential afoot.

Now we wait for the next few updates to see if support will grow much further beyond the potential late Jan Scandinavian high outcome, which never really took hold.

[ANYWEATHER]

Looks like a fairly dry period coming up for the southern half of the uk in picticular in the days ahead, which can only be good news. The northern half of the uk ,further away from the European high will alway be more unsettled, with the caveat of some cold incursions, as the gfs shows....it looks like we are moving away from a rather stormy period for now....☺

[Stephen W]

I thought the overnight ECM ensembles had taken a step back with less cold members in the latter stages compared to yesterday’s 12z.  More members inclined to extend high 850’s which suggest an extension of heights to our south over Europe and maintaining mild to very mild temperatures.  Not what I was hoping to see.  GFS shows a bit more interest especially the control run which has a cold northerly in the latter stages thanks to a high pressure centred to the west of the UK and extending north.

Edited January 24, 2024 by Stephen W

[Summer8906]

@TillyS But if the vortex migrates east, wouldn't that leave us in a NWly (=cooler) ?

[bluearmy]

@Stephen W annoying not to have the clusters this morning but having viewed the stamps, I’m not seeing much difference to the 12z set from yesterday 

as such, waiting to see this evening  if the 46 reverts to a more amplified set of charts taking the anomoly further nw 

glosea has clearly pushed the signal back in feb but the eps days 10/15 take precedence imo if they begin to show a faster route. Really wanted to see those clusters !

Edited January 24, 2024 by bluearmy

[StretfordEnd1996]

@bluearmy

I think this is them now updated 



I'll let you analyse them, I'm not so good at interpreting what they're showing!

[bluearmy]

@StretfordEnd1996 thanks

looks ok by end week 2. Assuming we don’t get an accelerated cold solution ahead of expectations, the period week 2 feb and beyond look reasonable as being of wintry interest 

[rwtwm]

17 minutes ago, StretfordEnd1996 said:

I think this is them now updated 



I'll let you analyse them, I'm not so good at interpreting what they're showing!

I know I wasn't the target, but thought I'd have a go anyway.

Firstly, a fairly even split (28/23) across the two regimes. There's a little promise on both, as they show a relaxation in the heights over Europe. There also seems to be a mean flow North of West on both too. 

Cluster 1 has a more impressive looking Mid Atlantic Ridge, but I think cluster 2 holds more promise. There's a strong negative anomaly over the Alps, and a hint of the high migrating to the North East. 

All in all not quite as depressing as the current OP runs suggest. I'd also highlight that cluster 2 shows what many would call a 'locked in' pattern eroding in 4 days. 

(As ever, none of this is a forecast, just trying to interpret the output)

[Jacob]

Incoming cold on the GFS! If only the Canadian lows could get lost 

[Gowon]

The jet has shifted south a bit on this one with some sliders :

[mulzy]

The 6z GFS has a few snow events for central and northern regions in FI - just for fun of course!

Edited January 24, 2024 by mulzy

[StretfordEnd1996]

GFS 06z shows first signs of a small change around D9-11 period as it manages to claw in some temporary cooler air from the NW for a time - this isn't coupled with any notable Atlantic block or other block so it is brief but would turn things much cooler 






Nothing out of the ordinary and this is a separate thing to what some members of the GEFS and ENS possibly indicate (which show various HP to the W/NW, but some time after the D10 timeframe). 

 

Edited January 24, 2024 by StretfordEnd1996

[Cambrian]

The ensemble means have been an outstandingly useful indicator this winter. As noted by @bluearmy last night, only in the run-up to Christmas, when they toyed with the northerly, that got put back and back and then didn’t happen, have they erred. They’re great, but not faultless. For example, they also have the characteristic of often not being able to extend a more decisive trend to days 12-15 due to the averaging out that is incident upon them by their nature. All in all though, I do find them consistently very informative up to date 12. 

So here are the 0z ECM ensemble means to day 12 for heights and pressure, and the T850s. Again, as with the GEFS yesterday, we see the PV getting torpedoed, but here we also see the subsequent setting up of the main lobe over northern Scandinavia and northwest Russia. 

 

Notice the Iberian heights steadily on the wane from day 9. Ideally, for a proper cold shot it would be good to see the trough settle in a tad further west, hanging south into Denmark, but no bones about it, this is a much better prospect now developing in week 2 than we’ve been looking at of late.

The T850s past around day 7/8 are never that numerically informative but are useful for observing trend. The milder / colder zonal pattern that removes the cold air from Scandinavia through the coming week is itself replaced, over Scandinavia at least, by a good push back of the cold air from the northeast from around day 9 through to day 12.

It looks to me that it’s from around there that it begins to get more interesting again in terms of potential wintry weather for northwest Europe. Cold air reinstalled to our northeast, along with a relaxation of the Iberian heights. It still looks changeable but incoming systems are going to have to negotiate interaction with the cold air. 

And the day to day adjustments are getting interesting too. The 0z EPS for day 12 from yesterday, compared with the 0z from today for day 11.

 

Not only is the trough deeper and the low heights further south and west closer to the Finnish border, but the heights up through Greenland and to the west of Iceland are markedly better too. The cold to the northeast is gaining a foothold.

It’s attritional, but bit by bit, the outlook is getting steadily more and more interesting.

[Anthony Burden]

Morning all,GFS starting to show a possible colder period from around the 3rd February early days yet but need to keep an eye on the ensembles will be interesting to see the 6z operational and control to see where they fit against the mean.