Model Output Discussions 12z 03/05/2016

[coldcomfort]

7 minutes ago, cheeky_monkey said:

Agreed ..to my untrained eye still looks to be a fairly mobile pattern with areas of higher pressure moving across then away into the containment then back to square one and repeat...so drier warmer spell followed by more unsettled spell and back to drier warmer spell...

Agreed....given the current modelling struggles I think it equally unwise to get too carried away over todays 00 runs as it was depressed over yesterdays. Really can't see any firm evidence of a proper pattern change, perhaps a pattern tweak would be a more appropriate description, but if that tweak delivers at least some decent warmth I'd be more than happy. All eyes now on the 06, because if anything it was even worse than the 00 run yesterday, so it will be interesting to see if it franks the run from earlier. 

[Weather Boy]

5 minutes ago, coldcomfort said:

Agreed....given the current modelling struggles I think it equally unwise to get too carried away over todays 00 runs as it was depressed over yesterdays. Really can't see any firm evidence of a proper pattern change, perhaps a pattern tweak would be a more appropriate description, but if that tweak delivers at least some decent warmth I'd be more than happy. All eyes now on the 06, because if anything it was even worse than the 00 run yesterday, so it will be interesting to see if it franks the run from earlier. 

Agreed, but at least for the south, only a tweak is needed.  Maybe I'm being a NIMBY here, but in my location, we've just had the driest start to July since at least 2005 and the driest start to any month since June 2013.  Temps no great shakes, in fact slightly below average, but I'm not complaining.  So a tweak to lift the temps courtesy of some continental rather than Atlantic sourced air would make it very good.

Wrt the models, I find yesterday's flip extraordinary, let alone this morning's.  This is a relatively stable time of year and you just don't expect to see that in the models.  You would therefore assume that they are now accurately telling us what this weekend's weather is going to be like at this close range and at this time of year, but if they can flip with 4 days to go, is there any reason to think that they can't do so with just 3 or 3 1/2 days to go?  On the whole, I think not, though.  I don't know what signal the models were (over?)reacting to yesterday, but it seems that it's yesterday's models that are isolated, not the set of model runs that we now have.  So, on the whole, I think it's looking good for the weekend, although I won't be putting any money on it.

Sorry if this post is a bit chart and analysis free, but that's just my take on the general situation.

[northwestsnow]

Well a couple of observations, the 00z runs ARE a vast improvement on yesterdays 00z runs, for warm lovers at any rate.BUT, everything seems so volatile at the moment i don't know if any of the models can be trusted past 96h!!

Despite the above i think we can have decent confidence the south and south east ARE going to be seeing some decent summer weather as we move forward, for those of us further north still some uncertainty..

More runs needed from where i'm sat..:)

[northwestsnow]

Just now, Gordon Webb said:

South and South East well that's the UK's weather sorted then , oh hang on a minute Just remembered the UK exists North of the M4 corridor oops silly me

 

Just now, Gordon Webb said:

South and South East well that's the UK's weather sorted then , oh hang on a minute Just remembered the UK exists North of the M4 corridor oops silly me

Well its generally a given that those further south and south east will have the better weather in summer but believe me i'm hoping those further north will do OK as well.

With such a strong Atlantic and jet the further NW you are one would assume you are more likely to feel the effects of the systems moving across the Atlantic, there are signs the jet will lift north in the outlook, as opposed to what we have seen since the beginning of June, for me, i'm hopeful,lets keep our fingers and toes crossed for the change..

[knocker]

The EPS this morning is not IMO showing any signs of any significant pattern change. Towards the end of 14 day period we still have LP to the NW and HP to the SW with the wind from the westerly quadrant portending still, the dreaded words, a N/S split with temps generally around average.

In the mean time the 2-6 period does see HP poking it's nose over the UK so could well be decent tree or four days but again the better the further south you are, but maybe it will stretch a fair way north.

 

[johnholmes]

With the exception of EC this morning none of the other two show any sign, on the anomaly charts I use, of any real change to the idea of a broadly westerly flow with the main trough over or just east of the UK out to day 14. IF the other two begin to follow EC for 2 or 3 outputs and EC remains with the idea then we can begin to believe that a change is going to take place. In my book not before that happens. Individual days will show an upper pattern not as the mean charts show but the comment above will be what we see most of the time. More changeable the further NW one lives and less so the further SE one lives.

links below

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

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

Edited July 12, 2016 by johnholmes

[Fourty Point Three Degrees]

Good to wake up today and see the GFS 0z has flip flopped out of the horror zone and back onto the summer track for next week with 25c for England . Even the beeb had 'heat on hold' so they must've known it was coming anyway.

[Tamara]

I agree very much with the two posts above me. from Knocker and John Holmes

The update I gave on Friday suggested we should be cautious of the northward extent of the Azores High in terms of the improvement cited from the end of this week - but more especially in the context of not seeing this as any longer term significant pattern change.

Its proved to be the case that intra day operational modelling has oscillated over this, but then as K and JH rather imply, it is not this that should be used as a reliable guide for basing expectations. This leads often enough to disappointment. This time around, while at least in terms of smaller detail, the end of the week and.weekend looks relatively better (thankfully) for at least some than was anticipated in that last update, the overall longer term outlook remains as mobile and changeable as described then. 

Without needlessly going further into the complex issues outlined in the last post about the atmospheric circulation, nothing has changed with these to alter those ideas that are well echoed by the anomaly charts, and which have been singing from a very similar hymn sheet for a considerable time now.

This remains a broadly low angular momentum state, aside from the sort of temporary recoveries such as described previously several days back. This fully supports a continued westerly flow with the Azores High, notwithstanding occasional ridging extending from it as indicated at the end of this week, mainly retracted well to the SW and the upper trough continuing to our North into Scandinavia. This type of pattern does not allow any sustained larger scale warm air advection to occur northwards, and rather like the equivalent of the northerly toppler in winter, its counterpart gets sheared eastwards into mainland Europe

Nothwithstanding that, and not wanting to sound unnecessarily  downbeat, lets hope that there continues to be a window for some fine warm weather in the days ahead and that would be highly welcome. But there is nothing, yet, to suggest this is the beginning of a large scale pattern change.

[summer blizzard]

So it's the American models (GFS and GEM) vs the Euro.. Both models stay warm until about Tuesday but then differ..

[Frosty.]

The Gfs 6z op run would produce the BEST spell of the summer so far across England and Wales with temps rising into the mid to upper 20's celsius. High pressure becomes the main feature for the south, really from thursday onwards but into next week there is a growing chance of heavy thundery showers breaking out but who would mind about that with temps of 27/28c and sunny spells...not me!

[Frosty.]

Here is a look at the weekend, remember yesterday when it looked like the Atlantic systems would be in control...well look now!

[Daniel*]

I'll be quietly surprised, if we don't reach the elusive 30C, just by a small margin sometime early next week. I personally feel the temps are being 'underdone for London and the SE we shall see...

 

[Frosty.]

The GEFS 6z mean shows summery weather for a change, especially from the weekend and well into next week across England and Wales with mid to high 20's celsius. There would probably be some thunderstorms next week as the first half of next week looks very warm and humid...summery for a change!

[northwestsnow]

Metoffice yet again saying no to anything sustained as far as warmth is concerned on their latest update.

So thats me taking anything from the NWP with a lorry full of salt!

[whitestuff]

On 7/10/2016 at 16:11, northwestsnow said:

tomaz shafenakker just aid hints of something much warmer as hit the end of the coming week into the weekend,yaaaaaaaaaay

Ties in nicely with the ECM0z so fingers crossed the trend continues and the red crayon will come out ..;)

 

BBC must watch the models like us and ramp up and down at each outcome! Friday til Sunday we were going to have heat next weekend, then yesterday they said that it was now going to be changeable. Now they've flipped back again .

These super computers they use......are they any  improvement on a sinclair zx spectrum?

[Man With Beard]

3 hours ago, johnholmes said:

With the exception of EC this morning none of the other two show any sign, on the anomaly charts I use, of any real change to the idea of a broadly westerly flow with the main trough over or just east of the UK out to day 14. IF the other two begin to follow EC for 2 or 3 outputs and EC remains with the idea then we can begin to believe that a change is going to take place. In my book not before that happens. Individual days will show an upper pattern not as the mean charts show but the comment above will be what we see most of the time. More changeable the further NW one lives and less so the further SE one lives.

links below

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

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

Having had a bit more time to look at this now, I have to agree this is fair. Studying the GEFS clusters often reveals if the mean is representative or just an average of wildly different scenarios. A good look at the GEFS 06Z members suggests it is, at the moment, representative::

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

No runs at all with high pressure in charge by D10. Best chances in the south

However ... I would caution with this - once a different pattern appears in the short term (such as for this weekend), in my observations it is not uncommon for models to then repeat the same feat afterwards. I'd hold this page before writing off chances for the rest of July.

[Frosty.]

Those looking for warmth / heat have come to the right place because there is plenty of it by this weekend and at least the first half of next week on the GEFS 6z perturbations, some cracking BBQ weather by the looks of it with temps well into the mid to high 20's celsius and it wouldn't be a surprise if some spots reach 30c +....hopefully here comes a spell of genuinely summery July weather instead of the dross we have had for most of the first 6 weeks of summer!

[northwestsnow]

Hope so karl mate, the ecm/gfs look good into next week but the metoffice seem to be having none of it again!

[Frosty.]

2 minutes ago, northwestsnow said:

Hope so karl mate, the ecm/gfs look good into next week but the metoffice seem to be having none of it again!

Well mate this would be a welcome change for the weekend, and the gefs mean looks rock solid summery to next midweek at least..fingers crossed. :- )

[mb018538]

The 6z 850 ensemble mean is above 10c for 5 whole days (16th-21st) in this neck of the woods! Are we actually going to get a portion of summer at long last!!

I think the very fact that the massive flip we've had from Sunday/Monday/Tuesday shows that even the experts can get it wrong. Everyone said yesterday the warm spell had been canned, before having to backtrack on fresh data today. Nobody is infallible eh!

[Frosty.]

5 minutes ago, mb018538 said:

The 6z 850 ensemble mean is above 10c for 5 whole days (16th-21st) in this neck of the woods! Are we actually going to get a portion of summer at long last!!

I think the very fact that the massive flip we've had from Sunday/Monday/Tuesday shows that even the experts can get it wrong. Everyone said yesterday the warm spell had been canned, before having to backtrack on fresh data today. Nobody is infallible eh!

Exactly, even the Beeb pretended yesterday they hadn't shown that warm air pumping north on Sundays forecast. Hopefully it won't flip again and we will have our first proper summery spell from late this week and well into next week. Agree with Tamara that this won't be the major pattern change most of us crave but it could be an appetizer for when it does change and hopefully with plenty of summer to come! :- )

[mb018538]

I'm certainly not getting suckered in thinking this is the big change - all current data points to things flattening out and returning to a more mobile set up by the final third of the month....but I'm just grateful for any crumbs offered up! All eyes on the 12z runs in a few hours time to see if this is getting cemented down!

[Man With Beard]

how one more thought for now, though, everyone seems to agree we aren't seeing a pattern change - but I would argue we ARE looking at a pattern moderation coming up. Compare the present with GEFS D10 mean

The current chart shows a westerly upper flow -  with fluctuations - but its a very southerly based pattern, so these fluctuations rarely have allowed those lovely summery oranges to get up to us. But by D10

In some senses little has changed - westerly upper flow, some ebbs and flows. But look how much further north that yellow line is. In the context of the chart, that suggests to me that there will be far more input from southerly sources into the pattern than we current have. This pattern moderation may be enough to bring a completely different experience for at least southern UK in ground conditions between D8 and D10 - and seeing that D4-D7 already look pretty useful, I think current modelling would represent not a July 2013 style heatwave, but a very different experience of summer nontheless for the second half of July when compared with the first. Check the D10 mean from 10 days ago, compare it to today's D10 mean and I think you will see where I am  coming from.

Edited July 12, 2016 by Man With Beard

[Frosty.]

Things are hotting up again in NE US following a brief cooler blip, temps into the 90's F with severe thunderstorms around too and hopefully we will be warming up by the weekend with an airflow from southern Europe which would last well into next week according to the Ecm 00z and GEFS 6z in particular with temps into the 80's F...long overdue!

Edited July 12, 2016 by Karl.

[Singularity]

4 hours ago, Tamara said:

I agree very much with the two posts above me. from Knocker and John Holmes

The update I gave on Friday suggested we should be cautious of the northward extent of the Azores High in terms of the improvement cited from the end of this week - but more especially in the context of not seeing this as any longer term significant pattern change.

Its proved to be the case that intra day operational modelling has oscillated over this, but then as K and JH rather imply, it is not this that should be used as a reliable guide for basing expectations. This leads often enough to disappointment. This time around, while at least in terms of smaller detail, the end of the week and.weekend looks relatively better (thankfully) for at least some than was anticipated in that last update, the overall longer term outlook remains as mobile and changeable as described then. 

Without needlessly going further into the complex issues outlined in the last post about the atmospheric circulation, nothing has changed with these to alter those ideas that are well echoed by the anomaly charts, and which have been singing from a very similar hymn sheet for a considerable time now.

This remains a broadly low angular momentum state, aside from the sort of temporary recoveries such as described previously several days back. This fully supports a continued westerly flow with the Azores High, notwithstanding occasional ridging extending from it as indicated at the end of this week, mainly retracted well to the SW and the upper trough continuing to our North into Scandinavia. This type of pattern does not allow any sustained larger scale warm air advection to occur northwards, and rather like the equivalent of the northerly toppler in winter, its counterpart gets sheared eastwards into mainland Europe

Nothwithstanding that, and not wanting to sound unnecessarily  downbeat, lets hope that there continues to be a window for some fine warm weather in the days ahead and that would be highly welcome. But there is nothing, yet, to suggest this is the beginning of a large scale pattern change.

Having been informed that my morning post could be interpreted very differently to what I intended, can I just say, I am strongly in agreement with Tamara's take on things - my earlier post referred to the short-term fluctuation that, luckily enough, looks to be in favour of a fine, warm weekend for much of England and Wales... though this is still not a given for all places within, due to the risk of a weather front becoming trapped over the UK on Saturday having moved down from the northwest.

Given the enthusiasm of ECM and GFS this morning, it will be interesting to see how much of a lingering ridge from the southwest we manage to achieve next week, in the face of such an atmospheric state. 

Edited July 12, 2016 by Singularity