Model output discussion 14/04/18

[Snowjokes92]

Ive just flicked through some of gefs and if they verified the uk could see some records been smashed. Very hot and slack some of those members and very feasible imo. Oh dear this breakdown is really turning into nothing and been overshadowed by remerging high pressue. Ill stick this here

[Frosty.]

Longer term, the GEFS 12z mean is heading in the right direction...increasingly warm and more settled again for the south with heights extending from the azores to scandinavia and potential for hot continental incursion (s) ...so, hopefully the less settled and less hot spell next week will just be a blip and we can soon get back to the kind of weather we have now which has largely dominated this exceptional summer so far!☺

[Cheshire Freeze]

27 minutes ago, Snowjokes92 said:

Ive just flicked through some of gefs and if they verified the uk could see some records been smashed. Very hot and slack some of those members and very feasible imo. Oh dear this breakdown is really turning into nothing and been overshadowed by remerging high pressue. Ill stick this here

Here are the ensembles for nearer your location- a lot more rainfall spikes evident

I've been looking at the longer range today. To me it looks like next weekend may be a flash in the pan for more northern areas with a more NW/SE divide appearing thereafter as the PFJ sinks further S.

Regardless, the background pattern is now slowly shifting, this may be in fits and starts at present but it is evident that ridging from the SW is having a tougher and tougher time becoming as dominant than it has done over the past couple of months. 

[Mike Poole]

ECM holding firm at T192:

It is the coming week that is the blip not what follows.  The predicted increase in AAM is still there over the next few weeks, should act to enforce rather than weaken the pattern.

As always, we'll see.

[Singularity]

Even ECM has now adjusted it's extra diving low such that it's only a glancing blow rather than a direct hit on the UK.

Generally, the trend is toward increased SLP Fri-Sun. That's a good starting point from which to build a more 'plume-flavoured' second half to the summer. As odd as the GFS 12z looks in lower-res with the unusual Scandinavian high positioning, the overall principle of a big area of very warm air enveloping NW. Europe and the UK and the Atlantic struggling to achieve much more than give rise to occasional thundery intrusions is very sound when considering the background signals that Tamara has often discussed in her excellent updates.

With this in mind, I'm wondering how much rain will actually be seen in the S and SE from the more changeable spell when all's said and done. Some have already seen a fair bit, but many hardly anything, and the ARPEGE 12z out to next Wednesday evening doesn't indicate much more to come;

...leaving us reliant once again on heavy, slow-moving downpour potential next Thu-Fri (which ECM actually avoids in favour of more mobile showers via that stronger low brushing past the NE; more of a flow across the UK).

For the record, the changeable spell has so far delivered to me 0.2 mm of rain, and today was sunny from dawn until dusk!

[Gordon Webb]

5 minutes ago, Singularity said:

Even ECM has now adjusted it's extra diving low such that it's only a glancing blow rather than a direct hit on the UK.

Generally, the trend is toward increased SLP Fri-Sun. That's a good starting point from which to build a more 'plume-flavoured' second half to the summer. As odd as the GFS 12z looks in lower-res with the unusual Scandinavian high positioning, the overall principle of a big area of very warm air enveloping NW. Europe and the UK and the Atlantic struggling to achieve much more than give rise to occasional thundery intrusions is very sound when considering the background signals that Tamara has often discussed in her excellent updates.

With this in mind, I'm wondering how much rain will actually be seen in the S and SE from the more changeable spell when all's said and done. Some have already seen a fair bit, but many hardly anything, and the ARPEGE 12z out to next Wednesday evening doesn't indicate much more to come;

...leaving us reliant once again on heavy, slow-moving downpour potential next Thu-Fri (which ECM actually avoids in favour of more mobile showers via that stronger low brushing past the NE; more of a flow across the UK).

For the record, the changeable spell has so far delivered to me 0.2 mm of rain, and today was sunny from dawn until dusk!

Didn't realise dusk has already occurred for you,  days must have really drawn in in your part of the world 

[Frosty.]

The Ecm just gets better and better, what a magical 12z run this turns into..even better than the 00z and back into the glorious weather we have now..what a summer this is..and much, much more to come!..a summer that keeps on giving and that I'm delighted to keep taking!

Edited July 14, 2018 by Frosty.

[Stuie]

Karl, Just looking at the 850`s and the end of the ECM run.....

Agreed, nice enough weather but mid 20`s best? and a weird push East of the really warm weather in the Iberian area which would rule out any plume scenario down the line?

Just an observation, easier to see on Meteociel.

Edit: Weird shift East as in the trough really wants to dig way south. interesting.

Edited July 14, 2018 by Stuie W

[Frosty.]

2 minutes ago, Stuie W said:

Karl, Just looking at the 850`s and the end of the ECM run.....

Agreed, nice enough weather but mid 20`s best? and a weird push East of the really warm weather in the Iberian area which would rule out any plume scenario down the line?

Just an observation, easier to see on Meteociel.

No I think nearer upper 20's c at least for the s / se but probably mid 20's c further n / w..anyway, nothing wrong with mid 20's is there?..loving this summer so far☺

[Stuie]

2 minutes ago, Frosty. said:

No I think nearer upper 20's c at least for the s / se but probably mid 20's c further n / w..anyway, nothing wrong with mid 20's is there?..loving this summer so far☺

Nope nothing at all! Just an observation that the Azores is calmer

[Frosty.]

I think the Ecm 12z ensemble mean is showing encouraging signs further ahead with more azores ridge influence returning..there's plenty of other encouraging signs from today's output, the Gfs / Ecm 12z operational's just two examples.☺

[Stuie]

Agreed looks fine to the end.

Edited July 14, 2018 by Stuie W

[mushymanrob]

10 hours ago, Snowy L said:

Weird how you think the noaa anomaly charts are magically exempt from being wrong. It is nowhere near certain that we will see troughing for two weeks.

They arent.

I have never said they are.

But a detailed study of them from an experienced met man has shown them to be the most accurate model suite for that timeframe.

Ive checked this claim out and found it to be true. Id suggest you do the same thing because itll save false hope the ops do repeatedly.

Of course its not certain that we will be trough dominated for the next two weeks, thats what 'prediction' is all about. 

But you need realism, not hope casting. All to often on here a certain model becomes 'the' model because its showing what someone wants to see. 

I want heat.... but the most accurate suite doesnt give much hope of that, other then transitory 48 hour spells. So ill be very happy for the current output to be wrong. 

[Mike Poole]

The problem I have with the 'anomaly charts' is that I believe they are just an average over a period of time, and also over possibly a suite of ensembles (although this is never made clear).  You could arrive at the same conclusion, or even a more  nuanced one looking at all the individual runs.

Anyway to the 18z runs, here's the ICON at T120 (that's as far as it goes) burgeoning high heights from the south west incoming!

GFS at T192, one configuration leading to some thundery setups for the south, chart

Edited July 14, 2018 by Mike Poole

[Captain Shortwave]

The ECM and UKMO both want to drift a shallow low close to the south of the UK at the end of this coming week. This would probably increase the risk of thundery downpours. Otherwise by next weekend it looks like we will see pressure build across the UK again.

So fingers crossed that many will at least see a little bit of rain over the next few days.

[Frosty.]

I'm sure I said this yesterday at around this time but the Ecm 00z hots up again later following a short fresher blip.☺

[mushymanrob]

8 hours ago, Mike Poole said:

The problem I have with the 'anomaly charts' is that I believe they are just an average over a period of time, and also over possibly a suite of ensembles (although this is never made clear).  You could arrive at the same conclusion, or even a more  nuanced one looking at all the individual runs.

 

absolutely... but surely the average gives those of us who dont view every run and spot the nuances the information to hand. the main problem with the ops is that they can be totally wrong in such a short timeframe. just look at the number of times the ecm doesnt agree with the gfs, and / or the 00z doesnt agree with the 12z.. people naturally let personal preferences creep in, and thats where it tends to go pear shaped. so i view the anomaly charts first, get the idea of what the mean upper pattern is most likely to be, then view the ops for the detail, believing the run closest to the anoms. by using this method its quite amazing just how accurate you can be. no its not fool proof, but % wise and with confidence its imho far better then the ups and downs of the ops alone.

it was said " its nowhere near certain there will be troughing for the next two weeks" ..... but broadly that is what not only the anoms are suggesting, but the ops too, with only transitory ridging. on the plus side, this weeks troughing looks like being more shallow then what the noaa anomaly charts had suggested initially, and indeed imho they have struggled with accuracy over this summer to nail troughing, they seem to be over estimate what we actually get.

we are in line for plenty of decent summery warmth this week, with a few heavy showers, so despite lower pressure its still looking ok.... but theres no quick return to ridging (other then transitory) so no widespread heat, which will suit many who dont like it too warm.

personally, i expect another lengthy high pressure dominated spell , 'the big one' where temps will soar and we will bake for 2-3 weeks - but on that ill probably be disappointed. lol.

[Man With Beard]

No time to post charts but last night's clusters / ECM ensembles swung back to the more settled / hotter scenario not just for D7-D10, but also D11-D15. Will be interesting to see if this is consolidated in this morning's extended. 

One thing happening again and again this summer - lows keep getting downgraded in intensity as T0 approaches. The low for next weekend now looking nothing like the monster it did a few days ago. 

[Captain Shortwave]

General ensemble guidance

ECM

      

GFS

      

It looks like we are seeing signs off the well signposted transition towards an Atlantic trough and Euro/Scandinavian ridge set up with the UK close to the boundary with the jet starting to align more SW/NE across the north of the UK. The GEFs hold a pattern similar to the day 10 charts all of the way out to day 16 so probably a NW/SE split with the north west seeing changeable conditions with near normal temperatures whilst the south east in particular looks to remain quite dry and pretty warm with always the chance of glancing blows of heat from the south.

Given this coming week is supposed to be cooler and more unsettled, I must admit that I am feeling this is being a little too overplayed given that temperatures could reach the mid twenties on any day this coming week in the south and rainfall looks limited to showers so many will probably see no rain whatsoever.

[shaky]

Fantastic model output this morning barr the ukmo maybe with that low to close to the south!!warm humid conditions continue all through the week and now doesnt look like we gona get much rainfall apart from the lucky few who get showers!!then into the end of the week and next week it hots up even further!!

[Man With Beard]

To add to your post CS - latest ECM ensembles have 850s above 12C for many between D8 and D10 - that's heatwave territory (Again!) 

[Frosty.]

Funnily enough, the Ecm 00z ensemble mean looks better.... hotter at days 9 / 10 than it does today when 31c is likely across the SE and 29 / 30c tomorrow...this is a great summer, hopefully the heat will return following the fresher blip..it looks like it will!☺

Edited July 15, 2018 by Frosty.

[Singularity]

The Azores High looks to have one last rally around Friday, with a ridge extending across the UK, but this then evolves into more of an independent anticyclone as the Azores High becomes suppressed as part of the switch toward a Nino atmospheric state.

It’s then that we look to how well ridging can hold on across our lands in the face of Atlantic lows attempting to approach from the W or SW. We can fare pretty well from this setup in the second half of July and well into August - something many recent long range models have been strongly hinting at.

This doesn’t necessarily translate to long spells of sunny weather like we’ve seen in May-June, though; those troughs are likely to get close enough from time to time to introduce some instability i.e downpour/thunderstorm potential. Maybe even a more organised spell of rain on one or two occasions.

On the other hand, the air movements will be more supportive of hot air imports from the near continent. So I’m seeing high potential for shorter (which could still be up to 5 or so days at a time) but more intense heatwaves compared to summer so far. Also more rainfall in between, which will please some.

[Snowyowl9]

1 hour ago, shaky said:

Fantastic model output this morning barr the ukmo maybe with that low to close to the south!!warm humid conditions continue all through the week and now doesnt look like we gona get much rainfall apart from the lucky few who get showers!!then into the end of the week and next week it hots up even further!!

I can`t see nothing fantistic in the models at all stuck in a rut but this week a sort of relief,need much more rainfall than what we`re getting though or else we`re in trouble,never thought I`d say that.

 

[Man With Beard]

2 clusters today for D10. One looks hot. The other is hotter! 

Any unsettled weather restricted to far NW, if at all. 

Beyond that, looking heavily blocked to NE right through to D15.