Model Output Discussions 12z 03/05/2016

[mb018538]

ECM quickly sweeps in the low pressure by 192 hours - though the warm air is still across the UK for 3 days. Could be a thundery breakdown coming!

[Weather-history]

Current charts are the summer version of the battle between continental air and Atlantic air that draws such  excitement in winter. Instead of will we get snow, will the cold air hold on, how quick will the Atlantic bring in milder air; it is will we get thunderstorms, will the heat hold on, how quick will the Atlantic bring in cooler air?

Edited August 9, 2016 by Weather-history

[I remember Atlantic 252]

49 minutes ago, cheese said:

The only thing I'm disappointed with is the weekend. It's looking fine and warm for the south but up here things look iffy - Sunday looking particularly precarious with GFS going for high teens here, despite higher pressure than Thurs-Sat which are all expected to reach low 20s.

yes, I have been monitoring Sunday, 12Z had around 17C here and rain, not much change on 00Z

[coldcomfort]

7 hours ago, Steve Murr said:

Some people getting carried away talking about records & 2003 - theres a reason its a record because the conditions were totally optimal -

The current outlook doesnt look as good - infact the evening trend hasnt been that great - moving the hot uppers eastwards quicker - certainly a hot plume on the cards however its still a few days away yet so the pendulum could swing either way !

Also looks to windy for record breaking heat - ideal conditions are dead calm still stagnent air -

I will go with a punt of 34c being the top temp

Indeed.....the overnight runs have certainly delivered something of a reality check this morning and we really do need to put the upcoming spell into some sort of reasoned context imo. To my mind the weekend looks distinctly average for the majority of the UK, though depending on where the trough ends up the far south could be warm, locally very warm. Even Monday whilst fine and dry for most is not overly warm across the northern half of the UK, pleasant probably best describes things for me, but clearly the southern half will become warm/very warm, locally hot. Tuesday now appears to be the peak of the heat for England, but a good deal more cloud than originally expected looks like pegging temps back on the warm/very warm locally hot category here, whilst further north and west frontal activity will keep it a good deal cooler with rain likely at times, especially later. Wednesday still looks very warm/locally hot across eastern and southeastern England, but elsewhere it quickly becomes much cooler and fresher. So as things currently stand a nationwide heatwave does not look the form horse by any stretch of the imagination, in fact away from England and Wales a brief warm up is probably the best that folk can hope for. One or two members may have ruffled a few feathers lately with their forthright appraisal of upcoming spell, but the fact is the latest outputs back their thought pattern far more that that of those getting carried away over 22c 850's a week hence. We have been here so, so many times in both summer and winter, I'm really baffled why the same mistakes keep getting made over eye candy charts so far into the future, when we all know even nailing down the coming 48hrs is rarely easy. 

Edited August 9, 2016 by coldcomfort

[Matthew.]

Some lovely summer weather coming from the GFS 0z for Saturday onwards. The Uk has the highest pressure across Europe so sunshine would be optimum with the cell overhead. Very light winds. A plume then on the 15th.

Edited August 9, 2016 by Matthew Wilson

[Frosty.]

8 minutes ago, coldcomfort said:

Indeed.....the overnight runs have certainly delivered something of a reality check this morning and we really do need to put the upcoming spell into some sort of reasoned context imo. To my mind the weekend looks distinctly average for the majority of the UK, though depending on where the trough ends up the far south could be warm, locally very warm. Even Monday whilst fine and dry for most is not overly warm across the northern half of the UK, pleasant probably best describes things for me, but clearly the southern half will become warm/very warm, locally hot. Tuesday now appears to be the peak of the heat for England, but a good deal more cloud than originally expected looks like pegging temps back on the warm/very warm locally hot category here, whilst further north and west frontal activity will keep it a good deal cooler with rain likely at times, especially later. Wednesday still looks very warm/locally hot across eastern and southeastern England, but elsewhere it quickly becomes much cooler and fresher. So as things currently stand a nationwide heatwave does not look the form horse by any stretch of the imagination, in fact away from England and Wales a brief warm up is probably the best that folk can hope for. One or two members may have ruffled a few feathers lately with their forthright appraisal of upcoming spell, but the fact is the latest outputs back their thought pattern far more that that of those getting carried away over 22c 850's a week hence. We have been here so, so many times in both summer and winter, I'm really baffled why the same mistakes keep getting made over eye candy charts so far into the future, when we all know even nailing down the coming 48hrs is rarely easy. 

So you think that's it then, because the charts have downgraded the heat that they won't upgrade it again later today or in the next few days?

That is why you're called cold comfort I guess!

[cheeky_monkey]

2 minutes ago, Karl. said:

So you think that's it then, because the charts have downgraded the heat that they won't upgrade it again later today or in the next few days?

That is why you're called cold comfort I guess!

Downgrades are the form horse in both summer and winter..some might call it an upgrade depending on your weather preference...

Edited August 9, 2016 by cheeky_monkey

[Man With Beard]

22 minutes ago, Weather-history said:

Current charts are the summer version of the battle between continental air and Atlantic air that draws such  excitement in winter. Instead of will we get snow, will the cold air hold on, how quick will the Atlantic bring in milder air; it is will we get thunderstorms, will the heat hold on, how quick will the Atlantic bring in cooler air?

Yes that's what interests me and why I think it will be a while before we know the direction of Wednesday to Friday next week. Writing off an extension of the heat at the moment is very premature! This morning's ECM rushes heights very quickly to northern latitudes, so that itself is a little unlikely based upon previous model performance between T192-T240.

Cold comfort - oh, I agree and I'm sure even Karl agrees with you - it takes a perfect evolution to get that GFS 12Z, and odds do not favour it verifying in that exact format - but it's fun to see the potential in the charts anyway (at least for me!).

Having said that, "that" GFS highlighted one evolution I'll not be surprised to see - a stalled attack from the SW on Scandi heights. It's happened many times in winter!!

[coldcomfort]

2 minutes ago, Karl. said:

So you think that's it then, because the charts have downgraded the heat that they won't upgrade it again later today or in the next few days?

That is why you're called cold comfort I guess!

Absolutely not....I think this because it's no different to what I've been thinking all along with regards to this spell. Said as much yesterday regarding both the indifferent weekend and the potentially longevity of the spell, the overnight runs have not changed my mind, but they have injected a well needed dose of realism to the debate imo.  Yes there is plenty of scope for upgrades, in fact the familiar pattern I spoke about often sees original eye candy being downgraded (both summer and winter), only for slight upgrades to then follow across the next couple of days as the models struggle to nail the detail. What I described above is what the charts are showing this morning, a claim that you make frequently to defend your obvious optimistic way of viewing things, but that's not to say things won't change again...in fact I guarantee they will. 

[Frosty.]

2 minutes ago, coldcomfort said:

Absolutely not....I think this because it's no different to what I've been thinking all along with regards to this spell. Said as much yesterday regarding both the indifferent weekend and the potentially longevity of the spell, the overnight runs have not changed my mind, but they have injected a well needed dose of realism to the debate imo.  Yes there is plenty of scope for upgrades, in fact the familiar pattern I spoke about often sees original eye candy being downgraded (both summer and winter), only for slight upgrades to then follow across the next couple of days as the models struggle to nail the detail. What I described above is what the charts are showing this morning, a claim that you make frequently to defend your obvious optimistic way of viewing things, but that's not to say things won't change again...in fact I guarantee they will. 

I may be optimistic but I'm also realistic and I never mislead anyone, I only ever describe what the charts are showing. There is this myth that I only cherry pick the best charts but that's not the case at all. Anyway, the models still show a hot spell next week, how long it lasts is too early to say!

[johnholmes]

Made these comments in my anomaly file this morning

Tue 9 August 2016 ec-gfs

Ec-gfs and both now do seem to show a change from ridge/upper high to more unsettled type flow with troughing perhaps now main feature; noaa on right, not as far down this line but certainly less ridged than the one above

Summation=settled period thur/fri out to mid next week then less so?

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[coldcomfort]

Just now, Karl. said:

I may be optimistic but I'm also realistic and I never mislead anyone, I only ever describe what the charts are showing. There is this myth that I only cherry pick the best charts but that's not the case at all. Anyway, the models still show a hot spell next week, how long it lasts is too early to say!

Which is precisely what I did, so I'm baffled as to why you felt the need to have a dig about my name.  Believe me as the owner of a business that is very dependent of fine weather I just as disappointed as you and many others over what appears to be a downgrade, but I'm not going to let emotion get in the way of what I see in front of my own eyes and as I said before this is far from done and dusted....in fact we are still 5 or 6 days from it even starting for many.

[Frosty.]

11 minutes ago, coldcomfort said:

so I'm baffled as to why you felt the need to have a dig about my name. 

It was a light hearted observation, no need to be so sensitive about it..I'm frosty but I love heat..go figure!

[mb018538]

It's hardly a downgrade, it's still over a week away, and is liable to change. If it's 3 days away and it changes then fair enough, but to get disappointed over something 7-9 days away is foolhardy.

[Chris K]

Whilst I am certainly not writing off any plume chances, from previous time watching model runs in the Summer, it is an all too common occurrence that the Jet adjusts alignment and strength and a lot of the time plumes are swept away relatively more quickly than, for example, what the GFS 12z was showing yesterday. This has become more evident in the overnight runs, with the GFS moving more towards the ECM in my view. It will be interesting to see what UKMO does as we get closer to the weekend.

Our previous plume did back West with time and there is nothing to say that can't happen again. We are still a fair amount of time away in weather terms. The LP that develops in the Atlantic, which eventually ushers in the cooler air, would need to stall more/back West and perhaps be more slack. Ideally you would want it to drop to the west of Iberia to draw up the hotter continental air, rather than develop and push NE directly towards the UK.

Edited August 9, 2016 by Chris K

[coldcomfort]

22 minutes ago, Karl. said:

It was a light hearted observation, no need to be so sensitive about it..I'm frosty but I love heat..go figure!

Probably best to keep any sort of personal comments completely out of the equation, as they don't always come across as intended.

Edited August 9, 2016 by coldcomfort

[A.J]

and probably best for both of you to take this to pm and for both of you to stay on topic......thanks

[MP-R]

Hi all. Can anyone remind me where to go to see forecast cloudcover charts? Thanks.

[Man With Beard]

A little look at the GEFS for next Thursday (looking at T228), any trends? 

Two key issues: how far does troughing over Iceland extend towards Scandi (and therefore ending a continental draw on our weather) - and any sign of a trough stalling to the SW of a Scandi high?

I count 5 out of 22 ensemble members (I'm including the op run in this) that get the trough close enough to Norway to end the continental draw brought on by Scandi heights

8 out 22 runs have a Scandi High in place to sufficiently affect our weather, leading to a continuation of continental influence and warm/very warm weather

And I count 8 out of 22 runs that show signs of a stalling trough just to the SW of the UK - which could lead to a lock-in of the heat for a further day or two (some of these runs have a Scandi High and are counted above, but 2 are supported by a high directly to our north)

So lots of possibilities here. But no runs at all get the main trough beyond Iceland, so if there were to be a breakdown, I doubt truly unsettled weather would follow that quickly behind.

Edited August 9, 2016 by Man With Beard

[summer blizzard]

Euro has a nice settled weekend with reasonable uppers (temperatures look in the low twenties for mos) but is not especially impressed with the notion of the plume. 

[Singularity]

I find its best not to assume anything much with models and plumes these days. The one in mid-July actually seemed to upgrade nearer the time, though this was in terms of peak heat rather than longevity.

Essentially I can see that the models have evolved to the point that the true outcome tends to be a lot closer to the middle of the spread of outcomes, as opposed to often toward the progressive end.

The issue is both where the secondary low develops following trough disruption, and how strong it is. The mid-July event saw a similar feature overcookedby the models in the mid-range, but unfortunately no two events are the same, and even small details could drive a very different outcome this time. So take it easy - don't get too caught up on particular runs. The 500 mb multi-day mean anomaly charts that JH uses are a good way to keep expectations from spiking prematurely

[coldcomfort]

52 minutes ago, Singularity said:

I find its best not to assume anything much with models and plumes these days. The one in mid-July actually seemed to upgrade nearer the time, though this was in terms of peak heat rather than longevity.

Essentially I can see that the models have evolved to the point that the true outcome tends to be a lot closer to the middle of the spread of outcomes, as opposed to often toward the progressive end.

The issue is both where the secondary low develops following trough disruption, and how strong it is. The mid-July event saw a similar feature overcookedby the models in the mid-range, but unfortunately no two events are the same, and even small details could drive a very different outcome this time. So take it easy - don't get too caught up on particular runs. The 500 mb multi-day mean anomaly charts that JH uses are a good way to keep expectations from spiking prematurely

Rather too late for that already... 06 breakdown timing is more progressive still, meaning even across the E/SE of England we are looking at 48hrs of heat tops, whilst in the west 0-24hrs pretty much covers it.  Should this trend continue (not saying it will) there is a danger the vast majority of us will miss out altogether, with upper teens and low 20's rather than upper 20's and low 30's.

[stodge]

Morning all

Lively discussion this morning. As I mentioned yesterday, the "plume", in terms of strength and longevity, was far from certain and 24 hours on, we aren't that much clearer. The GFS 06Z is rolling out so that provides yet more information to confuse or amuse (delete as appropriate).

ECM 00Z OP at T+192 (next Wednesday):

Undoubtedly a step back from some of yesterday's output which had the 20c 850HPA line well across the south. Very warm to hot certainly but transient - 24-36 hours at best in the south.

GEM 00Z OP at the same time:

Interesting, GEM has been much less bullish about the plume but gets to the GLOSEA signal for rising heights to the north and north east. We get a warm and thundery E'ly rather than a plume with cooler air flooding into southern France and Iberia and a hint of a more southerly tracking jet.

So then to GFS and the T+186 off the 06Z OP:

 

The big story is the heat has been brought forward to Monday/Tuesday rather than Tuesday/Wednesday. Just as we saw in early July, the 20c 850HPA brushes the south coast so you'd expect temperatures into the low 30s in the south on Tuesday but the cooler air is already chasing the heat away on Wednesday and only the SE holds on to the heat for a final few hours.

I'm afraid we are no nearer a firm forecast for next Monday - Wednesday than we were yesterday. GFS is arguably still the most bullish about a plume but both it and ECM are now looking at a 24-36 hour transient hot snap (perhaps 48 hours of heat for the SE on GFS). For weather fans, GEM offers the most interesting synoptics with plenty of storm potential from a warm thundery Easterly.

As ever, we need more runs...

[mountain shadow]

Dreadful 6z, which after a couple of days of warmer/hot weather brings the Atlantic fully in control with a couple of very unseasonal low pressure systems.

Could be a very autumnal start to September.

[Scorcher]

18 minutes ago, mountain shadow said:

Dreadful 6z, which after a couple of days of warmer/hot weather brings the Atlantic fully in control with a couple of very unseasonal low pressure systems.

Could be a very autumnal start to September.

What about beforehand though? Number 1, it's the 6z, number 2 it's well in FI. Funny how whenever there's something positive showing people immediately play it down, whereas when something horrid is showing deep in FI it's definitely going to happen. The warm spell could yet be extended.

Interesting you mention the start of September as well- the end of deepest FI is still a week away from September!

Edited August 9, 2016 by Scorcher