Model output discussion - after the beast, what next?

[ANYWEATHER]

2 hours ago, The PIT said:

GFS continuing it's shift away from very cold weather shifting it generally further back north as a new low develops to the south west of the U/k and moves north east slowly killing the cold off eventually away from Scotland. So if it's right cooling down for only brief spells away from Scotland. UKMO more positive in bringing cold too early for ecm.

So what is this cooling down term mean? It's not got warm yet, and looking at the models this morning ,significant cold at some place over the Easter period but as to exactly where and  when people will see more of the white stuff still remains a long way off in forecasting terms

[Frosty.]

I really like the Ecm 00z since it fast tracks the cold next week whereas the Gfs delays it considerably..conclusion..more runs needed!

[Summer Sun]

As like last night the ECM London op is on the cold side of the mean later next week it then goes on the warm side into April

Edited March 23, 2018 by Summer Sun

[snowfish1]

20 minutes ago, Summer Sun said:

As like last night the ECM London op is on the cold side of the mean later next week it then goes on the warm side into April

I like your posts they remain unbiased as much as poss, given your preference for summer and warmth lol hoping gfs comes into line with ECM though for us southerners 

Edited March 23, 2018 by snowfish1

[Summer Sun]

To keep coldies happy I'll post this mornings ICON which has flipped back to the colder option

GEM also shows some colder air later next week for the south this could ease by Saturday (but still below average )whereas further north it holds on longer

 

 

[winterof79]

I am sure that 1976 was a year with no spring....... just saying

30th March

30th April

30th May

Flaming JUNE

It did get a tad warmer thereafter

 

Edited March 23, 2018 by winterof79

[Blessed Weather]

The latest ECMWF weekly forecasts show ongoing below average temperatures over the next 4 weeks (26th March - 22nd April):

https://www.met.hu/en/idojaras/elorejelzes/europai_elorejelzes/

[stodge]

Morning all

Plenty of interest in the model  output yesterday with signs of colder air as early as next Wednesday from both GFS 06Z OP and ECM 12Z. The scenario and evolutions were and remain complex with, to be honest, a lot needing to go right for the coldest air to be drawn through the British Isles so while the north was likely to see colder conditions for the south it was much less certain.

Anyway, this morning's medium term analysis takes us up to and including Sunday April 2nd or Easter Day if you prefer:

Kicking off as always with ECM 00Z at T+240:

A complex trough covers north west Europe and the British isles stretching from the Canaries through southern Britain to Scandinavia. This sits between weak heights over the central Mediterranean and to the NW of the British Isles. Uppers are by this time negative across the British isles with a light NNE'ly flow for most parts. Rain or showers for southern parts with snow likely for hills to the north and perhaps to lower ground as well.

GEM 00Z OP at the same time:

Not too dissimilar to yesterday's run if memory serves. LP over northern France and heights to the NW and NE leave the British Isles in an ESE'ly flow. The coldest air is to the north while the south is in milder air by this time. However, it's likely to be wet in the south with possibly heavy rain and showers while the north sees drier conditions.

GFS 00Z OP at T+240:

Far and away the most progressive of the morning output. While the other models keep the trough in situ, GFS OP is clearing it off to the east leaving the British Isles in a slack but chilly NE'ly air flow. It's worth noting GFS didn't sink the trough to the south or south west but kept it close to or over the British Isles so plenty of rain in the run up and start to Easter. With uppers widely from -4 to -8 if not lower, this would be a cold chart but increasingly settled especially in the west with fine weather by day but a likelihood of some sharp night frosts. Further into FI and heights build to the north of the British isles re-establishing an E'ly flow across the south before at the very end of FI retrogression hints at a more NE'ly flow.

GFS 00Z Control at T+240:

It looks as though the Atlantic is returning with new LP coming from the west and no mid-Atlantic build of heights. The British Isles is under a weak ridge so a fine and warmer day for most. Further into FI and a real hint of spring with pressure building from the south and the jet heading back north so a steady improvement for all.

The GEFS at T+240:

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

I have to say the Control looks on its own with little support, Most Members keep the LP close to or just east of the British Isles with pressure building either in mid Atlantic or SE from Greenland to maintain a N'ly or E'ly component to the wind flow. It will be interesting to see if the Control has picked up a new signal or is a classic GFS "default" to Atlantic westerlies.

In conclusion, those hoping for a sunny and warm Easter look right out of luck this morning. ECM and especially GEM keep it unsettled and often wet and especially so for southern areas. Head to the Hebrides if you want to stay drier if not warmer seems the message. GFS is its usual progressive self and has moved the whole trough to the east by Easter Day. That leaves a residual cold air mass over the British Isles but the OP and Control go in very different directions. The OP is an excellent run for cold fans but drier for us all as heights build to the north while Control brings back the Atlantic and eventually ushers in spring or something spring like. I have to say Control looks on its own for now while the OP is perhaps at the other end of the spectrum. Whether we can or will see renewed or continued Northern Blocking into April seems the big question this morning.

[Purga]

Potential for a good dump of snow over the south on Good Friday (ICON 0z)

We need a correction S/SE from the other models and some more trough disruption to bring everybody into the game.

Not an unexpected scenario in the current regime !

Edited March 23, 2018 by Purga

[EllyTech]

30 minutes ago, winterof79 said:

I am sure that 1976 was a year with no spring....... just saying

30th March

30th April

30th May

Flaming JUNE

It did get a tad warmer thereafter

 

1976. The endless Summer and, endless drought!

[Derecho]

Morning, difficult to interpret where things are going to end up as they stand for next week as the swingometer shows.



However there has been a continuation of the trend in the GEFS to have low pressure developing to our SW instead of cold from the north/east. These are growing in number with a very giving a warm unstable southerly at the end of the month.

However with the UKMO looking potentially cold and the ECM bullish I still get the feeling in the back of my mind that something colder will come along which could persist into April...

Speaking of April, I've got updated swingometers which show the range of potential scenarios for its first week. I categorise the most dominant pattern. So there could be variations but it's essentially showing the take home message.

[Man With Beard]

ECM ensembles for T144: Very complicated over the UK. The link-up between the small low to the east and the growing low to the west represents the dividing line between "Beast 3" and something warmer to the south. As one would expect, the ensembles play around with positioning and intensity of these lows a lot. Every possibility imaginable is out there: lows north, lows south, low to the west stays shallow, low to the west enlarges (brining milder air eventually to the south), or the two lows merge together over the UK.

This means certainty over the ECM op is not yet there. While it does have enough support from the ensembles to not be an outlier (and indeed many members go much further in terms of depths of cold), it's a very tight thing between cold south, cold north, or even no cold at all. 

We may need to get to T96 on this before we can get reasonable confidence on some sort of "beast" for some parts. If that happens, probably T24 to see exactly where the boundary between cold/mild will be!!

But one thing's for sure - the deep cold is most definitely going to be available if the wind swings east.

[ICE COLD]

GFS 6z and ECM are just a tad different at only day 5 - 

[SMU]

GFS flailing around - looking miles off the Euros today-

Complicated set up but ECM \ UKMO blend always favoured-

[bluearmy]

13 minutes ago, Man With Beard said:

ECM ensembles for T144: Very complicated over the UK. The link-up between the small low to the east and the growing low to the west represents the dividing line between "Beast 3" and something warmer to the south. As one would expect, the ensembles play around with positioning and intensity of these lows a lot. Every possibility imaginable is out there: lows north, lows south, low to the west stays shallow, low to the west enlarges (brining milder air eventually to the south), or the two lows merge together over the UK.

This means certainty over the ECM op is not yet there. While it does have enough support from the ensembles to not be an outlier (and indeed many members go much further in terms of depths of cold), it's a very tight thing between cold south, cold north, or even no cold at all. 

We may need to get to T96 on this before we can get reasonable confidence on some sort of "beast" for some parts. If that happens, probably T24 to see exactly where the boundary between cold/mild will be!!

But one thing's for sure - the deep cold is most definitely going to be available if the wind swings east.

Whilst it remains so complex, i’ve not bothered to be analysing in any depth. Pretty well pointless at the moment. It will be really cold somewhere in the uk and it will snow somewhere in the uk in the run up to Easter (away from elevation). that’s about it at the moment . 

[ICE COLD]

And day 6 even more so -

[Chesil View]

1 hour ago, Man With Beard said:

ECM ensembles for T144: Very complicated over the UK. The link-up between the small low to the east and the growing low to the west represents the dividing line between "Beast 3" and something warmer to the south. As one would expect, the ensembles play around with positioning and intensity of these lows a lot. Every possibility imaginable is out there: lows north, lows south, low to the west stays shallow, low to the west enlarges (brining milder air eventually to the south), or the two lows merge together over the UK.

This means certainty over the ECM op is not yet there. While it does have enough support from the ensembles to not be an outlier (and indeed many members go much further in terms of depths of cold), it's a very tight thing between cold south, cold north, or even no cold at all. 

We may need to get to T96 on this before we can get reasonable confidence on some sort of "beast" for some parts. If that happens, probably T24 to see exactly where the boundary between cold/mild will be!!

But one thing's for sure - the deep cold is most definitely going to be available if the wind swings east.

That's always the thing when you get a possible boundary lying somewhere across the UK between cold and snowy and less cold/milder and rainy. MWB. The way I see it at the moment is that the GFS is doing its usual thing that it does at this range. In other words its jumps about screaming at the longer lead time saying look look look snowmageddon is coming then  then it backs off in the medium term before coming back to the snowier outcome nearer the time. It has done this countless times over the years.

The main thing we learn't from the two previous cold /snowy outbreaks earlier this month is that as Steve Murr reminded us the other day nothing will really get sorted until around 96 to120 when the envelope of possible outcomes will narrow markedly. Personally I feel that the boundary for a possible dumping of snow will be further south than currently modelled but how much further south is the big question.

Edited March 23, 2018 by Broadmayne blizzard

[Summer Sun]

00z NASA shows a chilly start to the Easter weekend in the north but temps increase a bit as we move towards to Easter Sunday temps in the south always remain higher and closer to average

[Derecho]

Another swingometer update, the 06z ens have more runs bringing mild air from the south at the very end of March due to low pressure out west (though somewhat warm air misses the UK still). On many runs in fact, some decent warmth spreads across much of central, southern and eastern Europe. There are runs that keep us under a rather cold pattern under low pressure, yuk. A small number going for something wintry now.



Going into the start of April, the picture is very mixed, though below average across the UK the slight favourite outcome at this point in time.

[Man With Beard]

While of course anything is still possible, I had a look at the temperature ensemble for the ECM and I thought it would take a brave person to forecast the deep cold getting south of the Midlands on that:

[Chesil View]

Just now, Man With Beard said:

While of course anything is still possible, I had a look at the temperature ensemble for the ECM and I thought it would take a brave person to forecast the deep cold getting south of the Midlands on that:

Although of course we don't necessarily need deep cold to stream south of the midlands for snow. We just need it to be just cold enough. Still anyones guess though as you suggested earlier. Probably monday before we make any semi- firm predictions. lol

[Derecho]

Hmm the GFS has a stronger block to the north and the mild sector is getting squeezed out more because of trough disruption..........

Edited March 23, 2018 by Quicksilver1989

[Summer Sun]

12z ICON has shifted the cold air away from the south compared to the 00z into Good Friday

12z

00z

 

[Mike Poole]

So it's eyes down for the 12s.  I think the ECM will be important tonight, it's been consistent in the last two runs for the colder solution, compared to most of the other models, my gut feeling is it is on to something and will hold firm later - it looks the sort of complicated set up where the ops will pick up the right solution before the ensembles due to higher resolution. 
The ICON is out, not really going for the deep cold,   ICON at end of run T180:

[Mike Poole]

Interesting GFS quite different compared to ICON at T132 with that string of two or three lows (three in this case) that seem to be causing the models some bother:

These look further East, think this might be a colder run.

Edit: no it blows up the low and leaves us in southerlys at T174

At least in the south.

Edited March 23, 2018 by Mike Poole