Focussed Model Discussion

[Singularity]

 

What really should happen based on the giant WWB in the Pacific, the MJO propagating east at good amplitude, and some decent +FT generation with AAM rising even higher than it's been of late, is that the broad trough mid-next week takes on a negative tilt and allows high pressure to build northwest from Europe.

I can't stress enough how strange it is to see so little appetite from the EPS for that. GFS/GEFS have showed a bit more interest but not as much as could usually be expected. Weirdly it's the 06z for the second day running that's delivering the best effort from a det. GFS run of the past four.

 

Not hard to see how the NAO flip could take place from the left-hand chart (GFS). Let's see if this run can actually resolve it. ECM 00z was not far off to be fair.

Edited February 12, 2019 by Singularity
!

[bluearmy]

2 hours ago, Singularity said:

 

What really should happen based on the giant WWB in the Pacific, the MJO propagating east at good amplitude, and some decent +FT generation with AAM rising even higher than it's been of late, is that the broad trough mid-next week takes on a negative tilt and allows high pressure to build northwest from Europe.

I can't stress enough how strange it is to see so little appetite from the EPS for that. GFS/GEFS have showed a bit more interest but not as much as could usually be expected. Weirdly it's the 06z for the second day running that's delivering the best effort from a det. GFS run of the past four.

 

Not hard to see how the NAO flip could take place from the left-hand chart (GFS). Let's see if this run can actually resolve it. ECM 00z was not far off to be fair.

i think the eps are very keen on extending heights north ……...its just that they are also v keen on retaining them across Europe !  now i would expect one or the other to verify but not both ……..

[Singularity]

3 hours ago, bluearmy said:

i think the eps are very keen on extending heights north ……...its just that they are also v keen on retaining them across Europe !  now i would expect one or the other to verify but not both ……..

Ah - another of those bifurcations?

Interesting adjustments by the 12z GFS compared to the 06z as of +120;

 

This manner of southward trough adjustment and tilt toward the negative alignment means a great deal when the upstream developments are trying to build blocking highs northwest from Europe. Good signs - hopefully the HLB-achieving clusters of both GEFS and EPS will increase this evening... and, for once, be the start of a sustained trend!

[knocker]

Temps quite repeatable today but suppressed a tad by a lot of cloud and bits and bobs of rain in western regions.

[Singularity]

Example of the surface pattern taking time to respond to the upper pattern; ridge out west aloft yet a flat westerly flow across the UK.

As long as GFS doesn't suddenly start broadening the trough, the Euro ridge should have plenty of ability to build north during the following few days. It's a shame GFS has done it's usual thing in losing track of the bifurcating jet on this run as with that in place things would be heading toward the -NAO pattern more swiftly than the 06z, rather than more gradually (and that was a very slow run in the first place!).

Having made positive adjustments early on, this run's made things a lot more difficult than they could have been. Not saying it can't be this way, but I'm hoping to see a quicker establishment of cut-off high edging NW, akin to where the GFS 06z was at D8 but with a faster and more emphatic continued NW retrogression afterwards.

[knocker]

At T150 the Arctic plunge down North America, courtesy of the east Pacific/Alaskan ridge, and here she comes exiting the eastern seaboard.

Resulting in a highly amplified Atlantic/western Europe with the strong energy flows (160kt jet exiting the eastern seaboard) constantly doing battle with the strongly resurging subtropical high thus the position of the high cell vis the UK under constant adjustment

So tending towards a more settle scenario but occasionally interrupted by visits from the west before settling down again

Edited February 12, 2019 by knocker

[knocker]

The back end of the ecm is all about the engagement of the deep atlantic trough with the very resilient high pressure and the distribution of the energy which ends with some very impressive WAA into Scandinavia

.

And generally very mild with max temps around 13C quite widely Thursday > Monday

Edited February 12, 2019 by knocker

[knocker]

One has to say the ext EPS is a thing of beauty this evening and NOAA isn't so shabby either.

[Kentspur]

On 25/01/2019 at 23:30, Man With Beard said:

ECM clusters tonight. I think they show a. what a tight line it will be between a northerly and southerly flow for the UK in the D6-D10 and b. how difficult it will be to predict the phasing of incoming lows, not just once but maybe a few times:

In the D11-D15, ridging still looks set to take over all around us, but where it sets up, well, pin a tail on a Donkey probably easier :

Bear in mind that because of the curve on these charts, ridges far to the top right are actually more ENE than NE. 

Studying the individual ensembles, there indeed some whopping Highs by 8th Feb (1050mb or above), but plenty of the members also have the Highs slightly out of reach to have that much direct input into the UK. The fact that we have ensembles with Highs both to the NW and to the E is the reason for the mean NE ridge - i.e. the mid point (I think) but it doesn't tell the whole story. 

Unfortunately as with our luck this winter it ended up slap bang above us!

[knocker]

The outlook is very similar to yesterday. The Atlantic trough and the high cell centred to our south east continue to dominate proceedings with the UK remaining in no mans land. Ergo a west/east split in our weather as systems track north by north east on the eastern flank of the upper trough with the associated front(s) struggling to move east.

The NH 500mb and surface analysis for midnight and the 0400 UK sir fax chart

As can be seen quite mild this morning with a fair bit of cloud around with some mist and fog patches in central and southern areas. These will clear fairly quickly this morning leaving a mainly sunny day in England and Wales but fairly cloudy in the north with some patch rain early on as the warm front clears away to the north east. But by late morning the weakening cold front will bring more cloud and rain to the north west which will tend to peter out during the afternoon A mild day for all

A similar story tonight with much of England and Wales being quite clear with mist and fog patches again, and another frost free morning, but cloudy and with bouts of drizzle in the north west courtesy of the weak cold front, supported by another associated with a deep low north of Iceland.

A wave has formed on the aforementioned cold front away to the south west and as this moves slowly north the front does like likewise as a warm front resulting with much of the country in a dry and sunny day once any mist and fog has cleared. The exception again being the north of Scotland where cloud and drizzle may linger. Another mild day

Overnight Thursday and through Friday the wave continues to track north east by north and deepen to be 989mb south east of Iceland by midday. This tends to strengthen the south westerly wind over the north of the country and perhaps bring some rain to western Scotland and Northern Ireland as the cold front edges quite close. But it will be warm and sunny day generally with the south westerly breeze having a long fetch

By Saturday the cold front will have struggled south east down the country, but becoming a very weak affair, so generally a cloudy day but again very mild. Bur the next Atlantic trough has arrived west of Ireland.

The front(s) associated with the trough will track slowly east overnight Saturday and through Sunday and will bring cloud and rain to western regions by afternoon on Sunday which will become quite patchy as it progresses further east.

 

Edited February 13, 2019 by knocker

[knocker]

As we move into the 5-10 day period the key element, staying with the gfs, is the trough ejected from the vortex entering the Atlantic at T144 and pumping up the jet between it and the subtropical high to the south.

The trough phases to some extent with the other trough to the north and quickly deepens a it moves into mid Atlantic and by T168 this general movement has pushed some frontal systems across the country, with the boosted energy suppressing the ridge  After a brief come back the ridge is floored once more by day ten

throughout it remains mild with temps on occasion way above average mild

[knocker]

The ecm not so keen to rush the energy through the UK in the 5-10 period with a more amplified Atlantic and thus a different surface analysis. This fits pretty well the EPS anomaly for the same period last night.

It would appear that the gfs may be too keen to temporarily weaken the ridge with it's interpretation of the handling of the trough and the energy distribution but that only comes to mind because the ecm is the better model and doesn't necessarily mean it's correct on this occasion

Edited February 13, 2019 by knocker

[knocker]

Some slight adjustment of the ext EPS as the trough moves a tad east with the ridge taking on a more positive tilt with the flow veering south westerly/ Perhaps portending more of a NW/SE split with temps above average

Are we looking at the last

of winter Sidney

[Man With Beard]

4 hours ago, knocker said:

Some slight adjustment of the ext EPS as the trough moves a tad east with the ridge taking on a more positive tilt with the flow veering south westerly/ Perhaps portending more of a NW/SE split with temps above average

Are we looking at the last

of winter Sidney

I'm still not prepared to go that far, as a 500 mile error with the centre of the high by D11-D15 could make a substantial difference, and it would be foolhardy to think this is not still an option. However, as you know Knocker, I am a realist, and I did take note of the fact there were no cold runs at all for London on this morning's extended eps

so, leaving aside the cold bias of winter, the real interest in the forthcoming 2 weeks is just how mild it might become. As the chart shows, the clustering towards 14C gets quite notable in the last week of February - as this chart shows 12pm temperatures rather than actual maximums, you could argue there will be a number of runs maxing up to 16/17C within that cluster. 19.7C is the all time UK record for February - that would be a bit too extraordinary I think - but a top ten CET month may well be possible.

[knocker]

The cyclone I've been rabbiting on about recently is quite impressive, down to 938mb this evening with the gfs, as is the resultant WAA mushroom

But let's put a stop to this nonsense with some renewed amplification

Edited February 13, 2019 by knocker

[phil nw.]

The Euro block for want of a better term remains steadfast in the face of the Atlantic with only the far north west coming under any influence in the next few days.

A snapshot of Friday shows plenty of warmth wafting up from the sub tropics bringing afternoon highs well above average across much of Europe and the UK

Little changes next week as we view the 5 day mean NH 500 hPa pattern and temperature profiles

 

The mid-Atlantic trough against the Euro block continuing to bring in mild air from the south or south west although the idea of weak fronts crossing the UK is more likely next week with the high retreating temporarily before re-amplifying. 

[phil nw.]

ECM Op.day 5 shows the Atlantic making temporary inroads early next week as fronts move across as suggested by GFS also

but agreement that the Euro heights return pretty quickly afterwards

The Atlantic trough continuing to be renewed from the Canadian vortex-a persistent theme of the Winter. 

[knocker]

Very impressive 216 kt jet followed by an equally impressive amplification

[damianslaw]

1 hour ago, phil nw. said:

ECM Op.day 5 shows the Atlantic making temporary inroads early next week as fronts move across as suggested by GFS also

but agreement that the Euro heights return pretty quickly afterwards

The Atlantic trough continuing to be renewed from the Canadian vortex-a persistent theme of the Winter. 

When will that canadian vortex be scrubbed out - it is a very persistent feature as you say, isn't there more energy over Asian side - might more energy finally be transferred across to Asian side as we end February, or is it all just going to be a slow burner as we move through early Spring - meaning zzzzz time with high pressure meandering around our neck of the woods for some time. Our weather can be very changeable and volatile at times,but it can also be exceptionally tedious, and the last 12 months have been exceptionally tedious in this respect with very slow moving benign patterns - it all needs a kick.

[knocker]

Confirmation, if any was needed of the highly amplified Atlantic/Europe arena in the ext period with a south westerly upper flow over the UK portending temps above average and reasonable dry. Depending on the position of the surface high regional cloud variations may be tricky

[knocker]

Outlook - some subtle changes from the last couple of days regarding the short range. The energy in the Atlantic does gain a tad more traction, vis the ridge, and systems manage to travel further east.

The NH 500mb profile and surface analysis for midnight and the 0300 UK chart.

It can be seen from the latter that there is plenty of mist/fog around in central and southern parts of England and Wales which should clear relatively quickly this morning. And as also can be seen still some rain in the north of Scotland but this also should clear as the front moves away north. Thus a generally sunny and very mild day with temps perhaps reaching the giddy heights of the mid teens in some places, particularly if any Foehn effect kicks in. Worth a look at the 850mb wind streams.

Clear skies this evening and overnight resulting in fairly extensive Stratus and mist/fog patches by friday morning, mainly in England and Wales

These will take a little while to clear but once they have another very warm, again a possibility of some unusual temps, and sunny day ensues. But by 1800 waves that have formed on the elongated frontal system to the west are getting quite close and some cloud and light rain reaches N. Ireland and western Scotland.

Over Friday night and through Saturday one of the waves deepens and tracks north east along the Norwegian coast  which forces the weakening cold front down the country, So although another very mild day, more cloud around. Meanwhile the next deepening trough has appeared on the scene WNW of Ireland.

By Sunday the extensive trough to the west is slowly filling but the energy has slowly pushed the block east and a cold front accompanied by strengthening winds traverses the country bringing cloud and patchy rain.

Any rain should clear by Monday but now the pincer movement of the subtropical high pressure zones has forced the upper trough north of the UK. Thus a much brighter day with plenty of sunshine but there is a surface low just north of Scotland with a couple of troughs in the mix so still quite windy here with some heavy showers

 

Edited February 14, 2019 by knocker

[knocker]

Sticking with the gfs next week which is a period that is causing some headaches vis the detail. The problem, put very simplistically, is the huge amount of energy exiting the eastern seaboard, courtesy of the North American trough and the Bermuda high pressure, coming up against a very resilient block in the vicinity of the UK, and thus a slight problem determining the the energy flows.

Some fronts cross the north of the country on Wednesday so quite breezy and wet but by midnight Thursday the a very intense trough has arrived in the western Atlantic and some renewed amplification of the subtropical high is under way over the next 24 hours. But by day ten energy from the west is gain putting the ridge under pressure. The upshot of all this is a very dry and mild western Europe with temps way above average

Edited February 14, 2019 by knocker

[knocker]

It goes without saying that the ecm has different interpretation of the energy flows so perhaps some cooler temps with less cloud for a time. Of course the detail still to be resolved

[knocker]

The 0800 chart showing a lot of fog (some freezing) and mist Cracking morning down here in Gods Little Acre

Chance to get out and about away from the self-indulgent obfuscation that's creeping into the forum lately

 

Edited February 14, 2019 by knocker

[knocker]

The amplification at sea level