Model output discussion - after the beast, what next?

[Daniel*]

ECM is a mild outlier for London for the majority on 18th the mean uppers are twice as cold -8C implying there is limited support for northern strike, could be on for another direct hit.  

[nick sussex]

Remarkable!

The signal for the easterly has been accelerated. I wish I had saved the ECM De Bilt ensembles from a few days back . The rogue few runs showing much lower dew points and then how over two runs the huge shift across to support them.

Anyway barring the differences from where exactly the cold pool hits the big 3 all show lots of interest.

Very exciting for coldies to see these types of synoptics so late in the season . It’s re drawing our view of what is and isn’t possible.

We often do see a real mix of weather in March and cold snaps aren’t that unusual however the depth of cold on offer to the east is sensational.

Edited March 12, 2018 by nick sussex

[Daniel*]

2009 sequel cold upper trough moving in really snowy this would be for London and South East.

 

[feb1991blizzard]

Iconic start to the 6z suites.

 

[Snowman.]

Just now, feb1991blizzard said:

Iconic start to the 6z suites.

 

Defo upgrade much bigger wedge of heights.

[karyo]

2 minutes ago, feb1991blizzard said:

Iconic start to the 6z suites.

 

Yes, an upgrade and much less pressure on the Scandi block from the north.

[SMU]

Total perfection @120 from IKON

[Staffordshire]

Quite amusing how quiet this thread is given the output, i guess everyone must have gotten their fill earlier in the month.

 

Regarding the 6z ICON, the high certainly looks 'tidier'. GFS to follow.

Edited March 12, 2018 by Staffordshire

[Summer Sun]

06z ICON ends on a colder but mainly dry note for the morning run

 

[festivalking]

15 minutes ago, Staffordshire said:

Quite amusing how quiet this thread is given the output, i guess everyone smut have gotten their fill earlier in the month.

 

Regarding the 6z ICON, the high certainly looks 'tidier'. GFS to follow.

A good thing less hyperbole this time round and a better class of posters....except this one! 

Like with many sequels the original is always better,  I think this will be no exception. Cold or very cold but will be tough to match the one from the other week but ICON is trying!

 

Edited March 12, 2018 by festivalking

[Johnp]

1 minute ago, Summer Sun said:

06z ICON ends on a colder but mainly dry note for the morning run

 

Are we really doing this 'it looks a dry easterly' thing again?

[karyo]

2 minutes ago, Summer Sun said:

06z ICON ends on a colder but mainly dry note for the morning run

 

ICON is not great for picking up showery precipitation. In the last easterly it was showing west of the Pennines to stay dry but that was not the case with a covering of snow for me.

[stodge]

Morning all

After what seemed a quieter period in this thread after the very cold spell of a couple of weeks back, it seems a degree of interest has returned and certainly some fascinating synoptics were on offer last week and those arguing for a final blast of winter seemed to have some evidence but where are we this morning looking forward to Thursday March 22nd so on or just part the equinox which can often be interesting for weather.

Starting as always with ECM 00Z at T+240:

Much of the interest on this run comes from the days before with a short but quite intense cold snap forecast for the end of this week as HP builds down into Scandinavia. By this time all that has gone and we are back in a more familiar pattern with a light WNW'ly flow across the British Isles and HP building in from the Azores. Uppers remain below -4 for most as the colder air retreats east so temperatures only slowly recovering but the Atlantic is moribund at this time.

GEM 00Z OP at the same time:

A somewhat different evolution from GEM. The trough remains over or close to the British Isles for much of the ten days and the attempted E'ly is blocked by an LP running SE from the Arctic which disrupts the Scandinavian HP and forces it further south but the British Isles remains by this point in the trough with blocking to the north and energy disrupting SE into Europe. With an LP over the east coast the weather remains unsettled with rain or showers for many and temperatures closer to average. There are signs of a weak ridge moving across but with an LP in mid-Atlantic ready to come forward.

GFS 00Z OP at the same time:

Different again. The British Isles gets a glancing shot of cold next weekend but the HP is constantly moving and moves SW out of Scandinavia than east and finally south east and by this time is well away from western Europe and LP from the Atlantic is moving in though with the jet trending back north it's over or just to the NW of Scotland by this time but its frontal bands of rain and passing showers are affecting all of the British Isles. With uppers just negative temperatures slightly below average. Further  into FI and the GFS reverts to type with a broadly zonal figure as the Azores HP becomes more influential and the jet tracks back further north so the transition to spring would be well advanced.

GFS 00Z Control at the same time:

Broadly similar to the OP in all honesty. Further into FI a much drier and warmer outlook as the Azores HP sets up just to the SW of the British Isles and we can all enjoy spring-like zephyrs in our woodsheds or wherever and with the +8 850 near the south coast temperatures well into the high teens.

The 00Z GEFS at T+240:

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

For all the OP and Control are on the same page, there are other options out there and more spread than I saw last week. There are some colder options but they are the minority and the majority GFS view is a return to the traditional Atlantic-dominated W'ly. That may be the GFS doing what it always does. Further into FI and I'd argue the option of northern blocking remains firmly on the table as does heights building from the south.

In summary, whatever happens over the next few days, it does seem as though by the middle of next week more normal service will be resumed with the Atlantic regaining control albeit without its usual energy. As the colder air drains away or is mixed out temperatures look set to pick up and GFS threatens something much warmer toward the end of the month and the approach to Easter. None of that is anywhere near resolution and to be honest I suspect that until we see more immediate resolution and cross-model agreement we'll be looking at the medium term with even less confidence than usual.

[Optimus Prime]

4 minutes ago, Summer Sun said:

06z ICON ends on a colder but mainly dry note for the morning run

 

We still haven't learnt, have we?

[Summer Sun]

UKMO extended at t168 looks dry and fairly settled

[feb1991blizzard]

Regarding the PPN on the Icon, that last chart would be predominantly dry but a few frames later, once the flow of cold uppers has been established for 24 hours or so, there would be heavy showers making their way West.

Edited March 12, 2018 by feb1991blizzard

[Derecho]

Whilst the 06z is updating...



Swingometer for 00z's is here and that is what I call a swing 

[feb1991blizzard]

London about to get paralysed again - Thames streamer alert!.

 

[Summer Sun]

Unlike beast 1 beast 2 shows the high moving west to the UK if this does happen then the position will be crucial a bit further south and the coldest air could go into Europe after a few days further north and it could last long

[TEITS]

Incredible temp, dewpoint difference between Saturday & Sunday.

[Purga]

Cracking runs this morning across the board !

The ECM Op takes the cold shot further north than the other models but the mean charts score a bullseye!

The Op was one of the milder runs in the EPS suite for London for example

06z GFS looking spot on as well....

[Nick F]

3 minutes ago, feb1991blizzard said:

London about to get paralysed again - Thames streamer alert!.

 

Unless there are fronts involved, I can't really envisage any significant snow developing in the easterly flow shown by GFS, even though it looks pretty cold at 850mb. The intense cold of the last BFTE to begin the month has really dropped the North Sea SSTs to 4-5C, so can't really see any deep convection being generated. Will be some flurries for sure, but nothing significant. Ground heating in the stronger late March sunshine may trigger more wintry showers inland though, which the models probably won't pick up very well, even at short range.

[bluearmy]

Gfs is different to ec to our west days 5/7 re the lw trough and Azores ridge so until that’s resolved, the two models will handle the cold pool differently 

[Daniel*]

Mind blowing for final third of March. I bet there’d be decent land based convection in south just need sunny spells.  

Edited March 12, 2018 by Daniel*

[feb1991blizzard]

6 minutes ago, Nick F said:

Unless there are fronts involved, I can't really envisage any significant snow developing in the easterly flow shown by GFS, even though it looks pretty cold at 850mb. The intense cold of the last BFTE to begin the month has really dropped the North Sea SSTs to 4-5C, so can't really see any deep convection being generated. Will be some flurries for sure, but nothing significant. Ground heating in the stronger late March sunshine may trigger more wintry showers inland though, which the models probably won't pick up very well, even at short range.

Blimey, would have thought a 20 degree difference between sea and 850 and then with steep mid level lapses - low 500mb heights, I would have thought some very big convecntion and as you say surface heating to boot.