Model output discussion 10/02/21

[Tim Bland]

Not much support for that op....

[Frosty.]

This is a nice looking GEFS 12z Mean / Moyenne....but only if you’re a fan of high pressure?...it lasts well into early March / Mars.....and on the face of it would produce a good deal of strong early spring sunshine meaning very pleasant surface conditions but also some cold nights with fog and frost.  

 

Edited February 23, 2021 by Jon Snow

[Griff]

Ecm and // 192

Edit: apparently that's yesterday's parallel, not sure why.. 

OK. Must have still been rolling out, here's the //

Edited February 23, 2021 by Griff

[Griff]

Should be a pleasant start to March 

[Mike Poole]

Consensus seems to now be on a UK high for the foreseeable. Yesterday there was a suggestion of the high migrating far enough north to draw in some cold weather, but that seems less likely today, although the evolution is still entirely possible that would draw in winds from the north-east sector.  T240 on the models:

[Griff]

6 minutes ago, Mike Poole said:

Consensus seems to now be on a UK high for the foreseeable. Yesterday there was a suggestion of the high migrating far enough north to draw in some cold weather, but that seems less likely today, although the evolution is still entirely possible that would draw in winds from the north-east sector.  T240 on the models:

Consensus until about 10pm tonight?

[Mike Poole]

5 minutes ago, Griff said:

Consensus until about 10pm tonight?

Won’t be up for the pub run(s) tonight, I think it is now unlikely we get another cold shot, latest NAM plot shows the last imprint of the SSW on surface conditions to be going out with a whimper:

It’s a warm up thereafter and as I have said before once the SSW effects are rinsed through, I favour a quick switch to warm as per 2018, although earlier.  Just to clarify that is the transition from cold to warm similar to 2018, not a 2018 summer - can’t say that - yet - but long range models so far are good for summer.  

[Mike Poole]

ECM mean T240, a 1030 high on the mean, and it has that reload look about it, it can stay until August as far as I am concerned:

Edited February 23, 2021 by Mike Poole

[stodge]

Evening all

Thee doesn't seem a lot to say currently - a pleasant if breezy day in lowland East London.

I'll put up the usual T+144 and T+240 charts from GEM, ECM, GFS OP and GFS Parallel:

T+144 (March 1st):

T+240 (March 5th):

The T+144 charts all very consistent and following the theme, now established over several days, of HP building over or just to the east of the British Isles and pulling in a SE'ly flow but with positive uppers it should mean mild days but of course it's early March so under clear skies frost is likely in rural areas. From there, GEM and ECM keep heights over the British isles but between a ridge pushing up from the Azores and residual heights to the east. GFS Parallel can't have two HPs so introduces a weak LP close to south west Ireland. OP makes rather more of this lowering heights across Europe with a more pronounced LP over Holland and heights to the north so a light NE'ly over southern Britain by T+240 and much colder air with 850s of -4 or lower.

From there, T+312 and T+384 chars from GFS OP, Parallel, Control and this morning's CFS offering:

T+312 (March 9th):

T+384 (March 12th):

Not a raging zonal SW'ly to be seen in all fairness. OP has a decent E'ly in early FI but that's breaking down by T+384 while Parallel finally retrogresses the HP and looks set to being in some really cold air (-20 850s over Iceland). Control has a messy evolution while CFS keeps heights to the north and west into FI so no dramatic cold but certainly not mild either.

A slightly better picture for coldies tonight with clear signs of some interesting amplification beyond T+240. Both OP and Parallel more than hint at something colder and to be fair GFS OP puts us into a much colder evolution as early as T+240. After some dispiriting days there's a new signal of interest and while we're a long way from a widespread countrywide snowfall hints and possibilities anew tonight.

[bluearmy]

Extended ens beginning to sniff a nw euro trough of sorts end week 2.  Depth of cold will depend on strength of Atlantic ridging upstream of it  (if it verifies) 

[Daniel*]

1 hour ago, Mike Poole said:

Won’t be up for the pub run(s) tonight, I think it is now unlikely we get another cold shot, latest NAM plot shows the last imprint of the SSW on surface conditions to be going out with a whimper:

It’s a warm up thereafter and as I have said before once the SSW effects are rinsed through, I favour a quick switch to warm as per 2018, although earlier.  Just to clarify that is the transition from cold to warm similar to 2018, not a 2018 summer - can’t say that - yet - but long range models so far are good for summer.  

Are they really? La Niña summer written all over the ECM seasonal similarly UKMO trough close to NW Europe ridging in Atlantic.

[Singularity]

4 minutes ago, Daniel* said:

Are they really? La Niña summer written all over the ECM seasonal similarly UKMO trough close to NW Europe ridging in Atlantic.

Near normal heights doesn’t equate to a trough in the white area.

Overall the anomalies suggest a typical mixed MJJ in the UK but with more hot and dry weather to the south than usual, probably more so by July than in May-June as the mid-Atlantic ridge relaxes in tandem with the La Niña doing so. I can’t see how else that ridge can be anomalously strong seemingly (but not actually) alongside the Euro one in the tri-monthly mean.

[Daniel*]

27 minutes ago, Singularity said:

Near normal heights doesn’t equate to a trough in the white area.

Overall the anomalies suggest a typical mixed MJJ in the UK but with more hot and dry weather to the south than usual, probably more so by July than in May-June as the mid-Atlantic ridge relaxes in tandem with the La Niña doing so. I can’t see how else that ridge can be anomalously strong seemingly (but not actually) alongside the Euro one in the tri-monthly mean.

Well it might not necessarily be a washout but they’re similarly showing potential for frequent NW/N winds not a warm summer at least first half. Latest CFS forecast doesn’t take us to neutral ENSO this summer, and in fact strengthens La Niña conditions leading into autumn it is rather alone for now, but if this comes to pass it would be a concern for wider summer prospects. 

[Singularity]

13 minutes ago, Daniel* said:

Well it might not necessarily be a washout but they’re similarly showing potential for frequent NW/N winds not a warm summer at least first half. Latest CFS forecast doesn’t take us to neutral ENSO this summer, and in fact strengthens La Niña conditions leading into autumn it is rather alone for now, but if this comes to pass it would be a concern for wider summer prospects. 

CFSv2 is at the cold end of a very wide spread of projections visible in the CPC/NCEP/NOAA roundup (https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf).

We're prior to the spring predictability barrier and on the exit of a substantial event, so can only guess which way things will go. Inherently, neutral is favoured as that happens most often of the three states - but admittedly, that's not a forecast, just statistics.

 

As for those ECM & UKMO maps, rather than 'potential for frequent NW/N winds', I would say 'potential for NW winds to occur a bit more often than usual'. The positive anomaly in the Atlantic isn't strong enough near to the west of the UK to suggest more than that; it has the look of a very 'inflated' Azores High.

La Nina tends to bring such a feature intermittently extending through the UK in May-June. SLP near average overall for most here, while below average to the northeast.

It's not a great outlook if you like long hot spells but it's not one that suggests anything especially cool and unsettled either.

So you are right to challenge Mike on the long-range models looking good for the summer in such a general sense. Weirdly, CFSv2 has one of the warmer outlooks for June, after a dire May. Neither really fit the La Nina regime! 

[Griff]

Pub run looking marginally more amplified, as often the case. Op vs //

[Griff]

Op teasing... 

[Griff]

GFSP churning out eye candy (spoilers not especially cold... Yet) 

[Allseasons-Si]

To the non white flaggers out there,...you know who you are...

@MATTWOLVES @Griff @Battleground Snow @Mike Poole and @Don

the ecm/gfs means lift away the lower heights from our NW from day ten> to relocate to Siberia on the 12z

day ten EPS and cpc latest anomaly charts,it wouldn't take much tweaking to get a back door easterly from here,...what goes up must come around and i will be monitoring this in the days ahead

The EPS trajectory tactile to 192 hours showing some blocking to our N/NW

the fight goes on at least to keep the white flag below half mast,...i haven't got my pole up yet,...ha ha.

[Griff]

2 minutes ago, Allseasons-si said:

To the non white flaggers out there,...you know who you are...

@MATTWOLVES @Griff @Battleground Snow @Mike Poole and @Don

the ecm/gfs means lift away the lower heights from our NW from day ten> to relocate to Siberia on the 12z

day ten EPS and cpc latest anomaly charts,it wouldn't take much tweaking to get a back door easterly from here,...what goes up must come around and i will be monitoring this in the days ahead

The EPS trajectory tactile to 192 hours showing some blocking to our N/NW

the fight goes on at least to keep the white flag below half mast,...i haven't got my pole up yet,...ha ha.

Nail-biting...  

[Allseasons-Si]

I would just like to say that over the last couple of days i am starting to see a trough undercut the high post day ten,...IE:-cold backing W/SW under the block

hang in there coldies

[Allseasons-Si]

^Just to add...

We just need the lower heights under the block to prop the high up,...something to work on but slowly catchy monkey!!!

[MATTWOLVES 3]

Come on guys don't get ruining our cold chase by talking of Summer

How's about what @Daniel* says with some good old Ntlys bringing cool sunny days and frosts and snow showers of an evening....im just dying to have to ramp up the log burner of a July evening under clear starry skies...

Those Heights on the 18s are looking promising guys... a few tweaks here and there and we could be in with a shout.

@Allseasons-si I think @Mike Poole as jumped ship now...he keeps talking up the Summer. Where is your staying power Mike

 

 

Edited February 23, 2021 by MATTWOLVES

[Mark wheeler]

Oh go on then , I’m in one last chase this year . 

[KTtom]

Maybe this high isnt going to dominate quite as long as the models initially indicated? The big 3 all shift it east by day 6 before gfs lets the Atlantic back in, certainly no undercut on the cards but instead the PV sinks south bringing colder air to the north with southerly tracking lows...where the two shall meet?? 

 

[IDO]

The gfs op and control are off on a different route this morning and I suspect that is the Atlantic OTT bias showing so more runs before we take them seriously. The London pressure ens highlight that the op and control are extremes:

The gefs mean and ecm op (and mean) both still have anomalous heights in our region at d10:

ecm op d10>

ecm & gefs mean d10> 

GEM also at the same time but a variation on the theme. This is not a static high scenario, it is a train from the west breaching the UK, so I am not convinced the models can resolve the high position just yet, but the overall pattern looks more anti-cyclonic?

Post-d10 and we should expect the euro trough to be pushed east by the Atlantic highs and a general flattening of the pattern in our region.

NCEP (Feb 22 update) on the MJO: "The RMM index weakened over the past week with little evidence of eastward propagation, indicating incoherent intraseasonal activity" They are not expecting anything other than the La Nina background signal for the next two weeks so no Pacific forcing to a more meridional NH.