Model Output Discussion 22/07/12 Onwards.

[chionomaniac]

Well, as we enter the first Olympic week here is a new model thread.

Please remember to keep posts relevant and on topic. If you are posting only in relation to the Olympics then please use the appropriate thread.

With the start of the week looking good for the South but less so further north, how severe will the trough be forecast for next weekend? Will it be a transitory affair pushed east allowing heights to establish again, or will we see the trend of summer continue?

Tune in here and find out.

[Summer Sun]

Just to add the Olympic thread can be found here -

[Alex]

If you like heat then the GEM model is definately the pick of the bunch, 17/18c uppers during Saturday on the latest run, unfortunately I don't think the teleconnections support an westward push nor do any of the other models. Nice to see though!

[Alex]

Pretty dreadful outputs this morning from Friday onwards, a trough gets locked in on the ECM run away from the far southwest it looks pretty unsettled. The GFS was a temperature outlier so in my opinion can be almost binned but the trend is there in terms of cooler unsettled weather - just in time for the olympics, how unfortunate!

I think a change to the upcoming pattern could come if we have a bit more of an amplified MJO, otherwise limbo land with the trough locked in or close by looks likely.

[Sunny Android]

Between 96 and 144 on Meto, NOGAPS, ECM and GFS the trough looks to get fixed solid between Scotland and Norway.

There certainly isn't any westerly flow showing in any models this morning !

[shedhead]

Between 96 and 144 on Meto, NOGAPS, ECM and GFS the trough looks to get fixed solid between Scotland and Norway.

There certainly isn't any westerly flow showing in any models this morning !

Agreed, nor is there any hint whatsoever that this return to cool, unsettled conditions will be brief. The GFS FI paints an horrendous picture, with the main trough right back over us and all talk of a much better August just looking plain wrong at this stage. Matt Hugo was correct last week when he commented that the ECM32 dayer went for only a short fine spell (for some), before a return to business as usual.

[Cecil Hogmanay Melchett]

Agreed, nor is there any hint whatsoever that this return to cool, unsettled conditions will be brief. The GFS FI paints an horrendous picture, with the main trough right back over us and all talk of a much better August just looking plain wrong at this stage. Matt Hugo was correct last week when he commented that the ECM32 dayer went for only a short fine spell (for some), before a return to business as usual.

yes it does look terrible for most after this week,worse summer of all time?

[shedhead]

yes it does look terrible for most after this week,worse summer of all time?

Well there's still over 5 weeks to go of course and things can change, but given the fact the current output suggests we can probably write off the first week of August and possibly the second as well, it would take a brave person to bet against this summer panning out to be one of, if not the worst ever.

Edited July 23, 2012 by shedhead

[Weather Boy]

Yes, all three models do have a disturbingly familiar look to them, owing much more to the last seven weeks than they do to this one.

There are a number fo differences, but none of them even hints at a settled spell - far from it.

However, I think it is way too premature to start making judgments even for next week (beyond its start), let alone the week after. Teleconnections and other background signals have, as I understand it, been reasonably positive. Further (although these have since been dropped), some runs did look to build pressure back after a relatively short unsettled spell and who's to say that those signals won't be back. Even I have been looking at the models long enough to know that pretty much anything is up for grabs after about a week and things could be showing a very different story in two or three days, maybe even earlier (or they might not ).

[BLAST FROM THE PAST]

Well the thundery trough moving up from Farnce gets absorbe into main trough to our eNE. Its a feature I mentioned to keep an eye on for Friday and models seem to be firming up on this now.

Lot of talk about the change to a more westerly flow and suprise at this now not looking likely. To me the solar cycle situation and and current -ve PDO phase, low sunspots etc the re-emergence of the pattern we have endured with southerly tracking jet with HP to our WNW and trough to our East is pointing to this and seems to be a 'driver' of the pattern.

Not good for early August if we set up like that again.

However, real summer for many at present, hope it spreads so all enjoy.

The GFS 00z from Friday is just plain awful with trough anchoring to our NE..........awful.

BFTP

Edited July 23, 2012 by BLAST FROM THE PAST

[Backtrack]

I do think the breakdown from the North is being somewhat accelerated by the GFS.

We see the jet stream over Northern Scotland with a small low moving down from Iceland. With the jet stream in place over the Northern half of the UK, it doesn't seem plausible that such a strong ridge is moved out of the way so quickly by a small, and rather weak low pressure system.

The GFS takes less time for the low to penetrate the high than the ECM. The UKMO is in agreement with the ECM rather than the GFS

GFS ensembles have the pressure drop around the same time as the other two. Which I still think is a little fast. I have an feeling this low may get delayed somewhat.

Edited July 23, 2012 by Backtrack

[MP-R]

Maybe I'm barking up the wrong tree here but the GFS only briefly brings rising heights to Greenland on its most recent runs. The main pain in the fire exit is a stubborn high over Russia which forces the low to stall over Scandinavia. If this was the case surely emphasis would be on cool, bright and showery weather rather than days on end of dull and wet weather such as the first half of this month.

I would hope that in future runs the low of Scandi would with time fill and the mid-Atlantic heights shown would move a little eastward. Meanwhile, make the most of a lovely week of weather to come.

[Summer Sun]

The Jet is shown to track well south of the UK again into early August

[UV-RAY]

The Jet is shown to track well south of the UK again into early August

A perfect winter chart, in August. August looks like a continuation of June and July for the first half at least. Dismal really, and if the longer range forecast for Autumn is anything to go by, then it looks like more of the same.

[Bobby]

Well the NAEFS sums it up

+168

+264 etc

Big Greenland high, troughing limpeted to the UK, as it as been since April.

There was never any signal shown by the NAEFS and ensembles of a prolonged settled spell.

[shedhead]

Indeed S of N, if ever a chart screamed back to square one this is it........

Edited July 23, 2012 by shedhead

[kev238]

Make the most of this week is the clear theme, if you live south of Manchester that is. Detail by Friday is very hard to pin down. Likely to be showers and storms around, and with low pressure close by the chance of big rainfall events cropping up is quite high.

[shedhead]

Well the NAEFS sums it up

+168

+264 etc

Big Greenland high, troughing limpeted to the UK, as it as been since April.

There was never any signal shown by the NAEFS and ensembles of a prolonged settled spell.

Very much agree Barb- hats off to GFS once again here, you don't have to like it but you do have to admire it imo.

[johnholmes]

Well the NAEFS sums it up

+168

+264 etc

Big Greenland high, troughing limpeted to the UK, as it as been since April.

There was never any signal shown by the NAEFS and ensembles of a prolonged settled spell.

indeed the longer term models including 500mb anomaly charts simply went for a change of type, trough (meridional) to westerly with a temporary ridging at 500mb SW of the UK. What is the surprise, to me at any rate, is the sudden reversal back to the trough/meridional pattern. I am trying to assemble some data and do a pdf with some ideas on this for later on. Hopefully this will generate some discussion and perhaps shed some light on this.

[A.J]

Very much agree Barb- hats off to GFS once again here, you don't have to like it but you do have to admire it imo.

You speak of the GFS model as if it's a living, breathing, sentient being as opposed to the reality of it being simply a computer program comprised of 0's & 1's...lol

but it has to be agreed, the output looks poor in the medium turn & in FI for warmth lovers, with low pressure anchored over or near to the UK with a cool, showery pattern evolving...I suppose the glimmer of hope is that FI is generally best guessed synoptics and not written in stone

[Gavin P]

I've been running through the BCC weeklies and to be honest August 2012 is looking rather disappointing to say the least.

Certainly no sign of anything as good as we've got this week.

Here's the mean 500mbr chart for August;

http://cmdp.ncc.cma....75GL_H5M2_1.GIF

Not that inspiring.

Edited July 23, 2012 by Gavin P

[nick sussex]

I think at this stage we need a miracle to not see the troughing set up near the UK, this trough looks like it could be locked in for some time as pressure builds over Russia basically the trough has nowhere to go.

In terms of the Olympics much now depends on the orientation of this troughing, if this can orientate and elongate running sw/ne and a little further north then we might see a weakish ridge thrown up for southern areas.

Thats really the only straw I can find to clutch onto, as for the Opening Ceremony I notice the BBC are saying very little about this for good reason, there is still alot of uncertainty with how that shortwave behaves and thunderstorms moving up from France.

[bluearmy]

That is an evolution that GP has been suggesting of a trough to the east with a ridge to the west, he also suggested the angular momentum going in more of a niño direction in GWO phase 3. Think there is basically low confidence of how August is going to pan out and the rest of it.

thats not what the BCC chart shows though. all too far west

[Glacier Point]

Quite like the 00z ECM op and with some limited support from the ensemble mean as a 'blueprint' for where we go next week on.

Contextually, angular momentum is steadily rising and the GWO responding with the largest Asian mountain torque for some considerable time. That puts us towards a phase 3/4 type evolution, potentially phase 5 if we continue to see some propagation of westerly winds poleward.

Clearly, next week looks unsettled with cool and showery the order of the day as the longwave trough digs southward and begins to close off over NW Europe.

If we are heading towards a phase 3-4-5 type state (main body of tropical convection in the western Pacific and eastern Indian Ocean), should be looking for both height rises over Scandinavia (that's the interesting part as by and large this summer we've had a definate trough in place) and the ridge to our west still persisting. Hence why the ECM looks plausible.

If this evolution continues, I think we could start to focus on the ridge to the west giving way for hight rises to our NE and E which opens up the potential for a very topsy turvy August - cooler and unsettled to start, warm and sunny to finish ?

[Buzzit]

Looking at the last four runs of GFS ensembles for London, there is a consistent theme of a significantly wide range of scatter from the members with respect to this weekend and beyond (in comparison to the ensemble mean, control and op).

I do not think that any outcome is a certainty at the moment, though rain and lower temperatures will prevail for a time there are definite question marks as to what the ultimate evolution will be over the next two weeks.