Model Output Discussion - Spring Has Sprung

[Weather vane]

 Summer8906 

Couldn't agree more. Here in Ireland, 6 of the last 8 months have been above, or way above, average rainfall, with the other 2 months not much below average. Really wet 8 months overall, and we all need a significant dry period now. To my mind, the charts for the foreseeable continue to indicate a significant risk of yet more above average rain. When will it ever stop !!!!

[Cambrian]

12z GEFS and ECM op - models beginning to look a bit crabby as early as day 4.

  

[Lukesluckybunch]

Pretty good ecm run we maintain the easterly feed from day 6 all the way out..and it progressively turns colder!very quiet in here!

[KTtom]

Looking at the ecm 850's for later in the run and you can see why some think a straight northerly is better if you want a final taste of winter (or a first taste in some cases) as you head into Spring. 

[northwestsnow]

I'm afraid EC 12Z just makes me hate our new climate even more.

[Lukesluckybunch]

Just now, northwestsnow said:

I'm afraid EC 12Z just makes me hate our new climate even more

Wrong time of year nw?

[Lukesluckybunch]

12 minutes ago, KTtom said:

Looking at the ecm 850's for later in the run and you can see why some think a straight northerly is better if you want a final taste of winter (or a first taste in some cases) as you head into Spring. 

You can get some extremely cold 850's from the east/northeast seen it many times..I guess it's dependent of where it's sourced from..where as a straight northerly from the arctic..will always be cold!

[Mike Poole]

ECM clusters T192-T240, there are just two options this evening:

Interestingly, the rain fest of the GFS is in neither of them, so that model seems to have gone off on one this evening.  

Cluster 1 (contains the op, 32 members) stronger block, maintains the flow off the continent until T240.  Cluster 2 (19 members) brings in a southwesterly flow courtesy of the low in the Atlantic.  

My impression is there’s still quite a bit of uncertainty but it seems to me like gradually, the runs with strong Atlantic influence are reducing or getting pushed back - slightly - it isn’t a strong signal.  

[Rain All Night]

11 hours ago, Rain All Night said:

0z deterministic runs, out to Mon 11th (day 7)

It looks likely that the low will fumble its limbo act and spray us with rain as it makes its way under next weekend.

0z ensemble means, out to Tue 19th (day 15)

The noble ECM is putting up more of a fight against the Atlantic than the other two models from 11th March onwards. The GEFS is, again, pretty depressing to see.

12z deterministic runs, out to Mon 11th (day 7)

I won't even try to comment on the mess beyond day 4, I just know I don't want the GFS to verify!

12z ensemble means, out to Tue 19th (day 15)

As has been the case for the last several runs, ECM is putting up much more of a fight against the Atlantic than GEFS. But the two do agree that high-latitude blocking is likely to have disappeared by the end of the second week of March.

Edited March 4 by Rain All Night

[Rain All Night]

Well I'd take this over the 12z run.

I believe the SSW has started today... definitely more "high" than "low" at 10hPa now by the looks of it:

Edited March 4 by Rain All Night

[Don]

 northwestsnow no cold to tap into?

[WYorksWeather]

Virtually all we have agreement on at the moment is near average temperatures prevailing through around the 10th/11th, and after that, just a lot of uncertainty. Modelling seems no closer to resolving it.

Absent any clear signal probably best to just say early spring conditions prevail for the time being. Of course any time sink with average conditions just runs down the clock on any remaining chance of something properly cold, which is why I abandoned looking for it weeks ago. The strength of the sun is now increasing the average lapse rate quite rapidly, so we need colder and colder 850s for anything to happen. In short, this is your regular reminder that BFTE-type conditions would require a consistent signal for 850s of -10C or lower. Snow on higher ground or temporary accumulations lower down can happen without that, of course.

I'm looking forward to the first decent very mild/warm spell of the year when it happens. No sky high expectations, but a few solid days of 15C and sunny would be nice. Just hoping we don't have to wait too long before I have some charts to chase on that front.

[WYorksWeather]

 Don 850s never get below about -6C or so. Falling snow and temporary accumulations for some certainly possible. But at this time of year it's not going to stick around long unless we have properly entrenched cold, I would guess probably -10C or lower looking at things like the BFTE 2018 and March 2013.

[Daniel*]

ECM 12z was rather cold but latest GFS involves a cold pool probably some snow flurries further SE. Still a lot of uncertainty but risk of something colder from east there around 12th remains. 

Edited March 4 by Daniel*

[Lukesluckybunch]

18z is a lovely run!cold air from the east!

[Metwatch]

Can't make its mind up!

[Rain All Night]

 Metwatch SSW-induced confusion?

[pinball wizard]

 Rain All Night possibly, our old friend Shannon at work

[minus10]

 Rain All Night yes now in zonal wind reversal territory...

...expect to see some eractic model runs turning up...perhaps....

[Jordan S]

 Weather vane

Should be drier today aswell as tomorrow, except for the far west and southwest of Ireland then here by Thursday too. 

Anyway,

for the mid month period/slightly before, reiterating the outcome and lows over southern areas as expected, clearing away slowly to our south and east with higher pressure likely moving over large parts of the country drying things out for a time once again for the 12th-14th along with slightly colder upper air temperatures of between -4c to -7c or perhaps -8c and this Ecmwf and now Gfs update shows this well, the window of drier weather may be shorter lived around this time frame if some model runs are to be believed, though more likely a case in reality of rain bearing fronts/low pressure system developing at short notice just to the west of the UK perhaps briefly interrupting an otherwise a developing anticyclonic weather pattern over the UK but the Ecmwf pressure pattern forecast should be largely representative of what will happen.

With the ECMWF above and Ecmwf AI model below you see those Atlantic low pressure systems lining up again heralding the expected return of wetter conditions beyond mid month for mainly southern half of UK. There may be a delay to the unsettled conditions but not by much more than a day or so past mid month. Drier north with Greenland high hinted past mid month, briefly mentioned that likelihood yesterday, so it’s all very similar to my previous posts.

The main takeaway beyond mid month being? Northern UK, increased albeit now lower risk than thought previously of northeast winds trying to establish over parts of the country and increased risk of sleet/snow showers especially on high ground, though unlikely to be anything exceptionally cold, typical spring wintriness to be honest if this does indeed play out, doesn’t rule out more persistent wintry precipitation, this increasingly from advancing north/northeast moving frontal systems from the south and west and whilst trending less settled in the north with winds possibly changing to a milder southerly or southeasterly with time, Again it isn’t likely to be as wet as southern areas of UK, with longer drier spells and higher pressure overall, especially in the far north. But for southern UK frontal systems moving north/northeast is more likely still, with again very mild air trying to establish over the UK, temperatures may trend somewhat above average in sunny spells in the south/southeast but otherwise feeling rather cool in any wet weather even with reasonable upper air temperatures here. Potentially much warmer than average for a time over Western Europe mainly along eastern parts of Western Europe ie eastern Spain and then into eastern France even in an otherwise very wet and unsettled cyclonic pattern overall, with winds likely originating from North Africa and higher pressure traversing northeast from Spain then moving north through Central Europe.

Not much to indicate much has changed with my thinking from yesterday.
 

Goodnight  

[feb1991blizzard]

 Rain All Night

One things looking sure now, this one is properly going to destroy the vortex, every GFS bar one of the last 5 or 6 (to varying degrees) does this and its ticking down, it starts at D10 now and eps mean showing it as well.

Edited March 5 by feb1991blizzard

[IDO]

The mean still wants to have nothing of the cold, and in fact, the 2m temps are on the rise in FI for London:

It does look like any SSW pattern will not bring cold to the UK before the last third of March. There is still some random cold outlier op runs, and even the ensembles have a few brief colder runs for D7-8:

But maybe more runs above the mean, so even that brief cold looks less likely with each run. 

GEM and EC agree that the UK will miss the cold to D10 after a few random cold runs that did not align with the means. The GEFS D8-16 850s sums it up:

With no tropical forcing, we are at the beck and call of the meandering tPV, and that means the UK is caught in no man's land despite sitting north of the jet in the colder potential. Maybe things will change, but the mean has been relatively reliable recently.

[Lukesluckybunch]

The biggest problem throughout the winter,was gaining momentum with the models..and chasing down any cold that was showing up..and that theme has continued the past week..no consistency whatsoever changing day to day!

[mountain shadow]

 Lukesluckybunch But of course, the cold never arrived.

[Lukesluckybunch]

7 minutes ago, mountain shadow said:

But of course, the cold never arrived.

Well exactly..i shouldn't let it get me down,it's a very hard thing to get the cold to cross the north sea!