Model Output Discussion 18z 28/07/13

[A.J]

What I don't understand about all the model watching that happens on this thread is all the constant point scoring with certain posters ... It's given a nice week slightly cooler at the weekend before the high pressure builds again in FI so why do certain people keep badgering on about a breakdown and No heateave in august etc etc ..... The weather will do what the weather wants to do so why the point scoring !!!

As a learner on here it's very frustrating when your trying to get to grips with the constant technical terms and charts and then someone is chipping in with something that's just simply having a go at others .

Some on here are accused of being biased towards heat ie Frosty but as far as I can see frosty tells you exactly what the charts are showing for example today's output he's mentioned the low at the weekend he hasn't ignored it but I've no doubt that later someone will say he has .

It's silly and as a learner It would be nice to just come on and read about what people have posted about the models .

How I agree, and, no doubtedly the rest of the site team and 99% of members agree with you, but sadly, it seems part of the very nature of online forums that point scoring and bickering are prevelant........still, generally reading this thread is a pleasant and very informative experience, so please don't let the off topic shinnangans of certain members put you off contributing!

 

 

 

......and if you think it's bad now, stick around for a few months when winter beckons!

 

 

and with that, on with the model output discussion!

Edited August 26, 2013 by ajpoolshark

[Cloud 10]

It is true that the best of the summer-like conditions are usually reserved for FI. But what about the ever-present predictions of 'autumnal' weather? I'm almost certain that 'breakdowns' have been wished upon us ever since the middle of June...IMO, even the GFS doesn't pick out trends three months' ahead of time.

 

And, the CFS? Well that picks up more trends than those eejits what think there's a 'system' for playing the Lotto! 

 

The CFS September forecast anomalies look very similar to the MJO phase 1 composite which Snowking posted a few days ago.

 

[Frosty.]

The GEFS 06z mean shows scotland taking a direct hit from the much discussed trough at the end of this week but it soon pulls away to the northeast with pressure starting to rise again, pressure rises much quicker across the south of the uk which is the least affected by the weekend trough, it takes n.ireland & scotland a while to recover once the trough has cleared due to the changing orientation of the building anticyclone from the south, being to the north of the high, more northern areas would be stuck in a blustery westerly or northwesterly flow from the atlantic with some rain and showers persisting but eventually the high builds further and further and northern areas join central & southern britain in another fine, warm and summery spell through early autumn, this run is showing a prolonged spell of fine and warm weather for the southern half of the uk during the next few weeks with just the weekend cooler blip in between, it looks like summery weather is going to dominate until towards mid september at least with the PFJ returning up to near greenland, across to iceland and northern scandinavia once again after that brief weekend trip south.

 

PS..Thanks TootyFruity, much appreciated.

Edited August 26, 2013 by Frosty039

[Biggin]

Much like the ever present predictions of 'hot spells and heatwaves' you mean?

 

One or two in the SE might agrue Sat was a tad Autumnal too...

Nope, wet yes, Autumnal no way.  )))

[Southender]

Nope, wet yes, Autumnal no way. )))

It was like a monsoon in Southend. Over 2" of rain in a matter of a couple of hours. Not seen flooding like it in many many years. Lots of videos on youtube.

[Cheshire Freeze]

The CFS September forecast anomalies look very similar to the MJO phase 1 composite which Snowking posted a few days ago.

 

glbz700MonInd1.gif SeptemberPhase1500mb.gif

 

The CFS is actually a very good tool if used correctly. Alas 99% of people seem to not know how to extrapolate an analysis from it so there's no point trying to explain anything as I've tried that before!

[Summer Sun]

It still looks like Scotland will be the main place to catch the low this weekend the further south you are the more settled it will stay though its likely to be a bit cooler than of late this weekend country wide

 

 

Into Monday and pressure rebuilds along with the warmer air

 

 

UKMO also has the low crossing to the north of Scotland this weekend again the further south you are the more settled you stay with pressure here remaining fairly high, as with GFS a cooler weekend than of late looks likely with temperatures into the mid teens before they should recover next week once the high moves northwards once more

 

Edited August 26, 2013 by Summer Sun

[Tamara]

The weather will do what the weather wants to do so why the point scoring !!!

 

Edited for shortness. You go girl - well said!

 

The jet stream amplification story goes into another day, and another day that appears to illustrate once more that the sharpness of any dig south in the jet stream, that had reasonable consensus as shown yesterday mornning, indeed looks to have been overstated yet again. If we compare this mornings set of EPS members we see that the low pressure incursion for the coming weekend has good agreement to brush NE 'ern most areas and bring a tad cooler air SE but the influence on this system further and further south looks really quite minimal indeed.

 

Then, as shown by the individual members for the start of next week, there is certainly decent enough agreement for a ridge to build eastwards once more and keep the status quo of brief more generally changeable interludes interrupting predominantly fair and seasonally warm weather (certainly for the very start of autumn) carrying on from where official summer has seen us through to

 

The updated UKMO this late afternoon very nicely backs up those ECM postage stamps  - with the residual low leaving NE'ern most parts of Scotland and pressure rising nicely again from the south west Ah...there it is!

 

 

 

 

So some pleasant weather for the rest of this week for many, a bit more changeable further north west with weakening fronts trying to come south eastwards - then a slightly cooler breezier weekend, and then it looks set for further fair and warm conditions once again for quite a few into next week

Edited August 26, 2013 by Tamara Road

[BlueHedgehog074]

Just got a very quick question (and is something I have sort of wondered for a while), but how is the word 'trough' - in weather terms, such as the one that could affect Northern areas during the weekend - meant to be pronounced? I did think it was meant to be pronounced as 'trow', but just wanted to double check.

 

(hope it's okay to ask this here, although very quickly looking at the models like the 00Z ECMWF and 12Z GFS, does certainly look like High Pressure could return in some form once next weekend is through with us, especially for Southern areas, where the pressure seems the highest in those parts. Still however enough time for the High Pressure beyond next week to migrate even further North depending how things play out).

 

@bubsy83: Cheers. Looks like I had it wrong all along. Just as well I checked (lol).

Edited August 26, 2013 by DiagonalRedLine

[bubsy83]

Just got a very quick question (and is something I have sort of wondered for a while), but how is the word 'trough' - in weather terms, such as the one that could affect Northern areas during the weekend - meant to be pronounced? I did think it was meant to be pronounced as 'trow', but just wanted to double check.

 

(hope it's okay to ask this here, although very quickly looking at the models like the 00Z ECMWF and 12Z GFS, does certainly look like High Pressure could return in some form once next weekend is through with us, especially for Southern areas, where the pressure seems the highest in those parts. Still however enough time for the High Pressure beyond next week to migrate even further North depending how things play out).

 

Like cough but with a tr instead of a c.

[Frosty.]

The GFS 12z operational run pretty much follows what the Gefs 06z mean showed with next weekend's depression on a collision course with scotland bringing a cool and windy spell with outbreaks of rain and showers but the further south you are, it looks progressively drier and brighter but we will all notice the drop in temperatures following the warm and sunny weather this week, so the weekend is currently looking rather cool and for the north of the uk, very autumnal for a few days but by sunday the trough to the northeast will already be filling and clearing out of the way and at the same time, pressure will be rising again from the south as high pressure begins to develop the next spell of warm and summery weather, however, for the north it looks like being a slow recovery next week with spells of rain and strong winds for a time although temperatures will start to recover but for the south of the uk the anticyclone builds steadily and brings a renewed spell of increasingly warm and sunny weather by around or just before the middle of next week but before that happens there is also a risk of some showery rain crossing the south but nothing like further north. Through FI the whole of the uk settles into a warm and summery spell with temperatures comfortably into the low to mid 20's celsius with a very blocked looking pattern as the main high pressure cell migrates into scandinavia and stops atlantic lows from breaking through, the latest upstream signals are very promising for lots more fine and warm weather during the next couple of weeks at least with just that cooler blip during the weekend to endure.

 

* You can add 3 or 4 celsius to those gfs 12z noon temps which would make it a very warm september spell.

[Summer Sun]

GFS 12z ensembles follow on from this morning really slightly cooler this weekend before the uppers head back to above average from early next week and rain remains very low

 

 

So looking at the first half of September tonight and a continuation of the warm dry weather looks set to continue with temperatures above average for many

 

Edited August 26, 2013 by Summer Sun

[Milhouse]

Those ensembles have the mean rising higher than it is at the moment so if it can still reach the mid 20s today, we could be adding a couple of degrees onto todays values. Then it stays reasonably above average for the durating of the run. So the GEFS mean is firming up on a cooler weekend as the below chart indicates, but a swift return to something warmer for the start of next week.

 

[Milhouse]

The ECM has a finger of 0c uppers moving across the north of the UK on Sunday so a cool day in store, but with pressure remaing high it should be a dry day for most.

 

[Summer Sun]

The ECM has a finger of 0c uppers moving across the north of the UK on Sunday so a cool day in store, but with pressure remaing high it should be a dry day for most.

 

 

Yep a cool day on Sunday but with pressure remaining high for many temperatures would still be in the mid teens if the sun can get out

 

It doesn't look as if the low will have much of an affect on the UK apart from Scotland where pressure drops to its lowest at around 1000mb for the northern Isles

 

 

Sunday sees the low pulling away and pressure is swiftly rising behind it

 

 

Monday sees the warm air returning from the west

 

[Summer Sun]

Big changes at t192 this evening from ECM

 

 

As that low pulls away pressure rises behind it again but the cooler air remains in place for now

 

Edited August 26, 2013 by Summer Sun

[Milhouse]

The ECM has a much more nw/se tilt to the jet stream in its latter stages which brings more unsettled conditions from the nw. High pressure only temporarily building next week. We will have to see what the mean says.

[Frosty.]

Big changes at t192 this evening from ECM

 

More twists and turns, more high drama...this model watching is very exciting and infuriating at the same time.  

 

Needless to say, I won't be Banking this run

Edited August 26, 2013 by Frosty039

[draztik]

This evenings ECM 12z, is in line with its control model from this morning. An unsettled next week, with showers or longer spells of rain affecting the UK.

[Milhouse]

This evenings ECM 12z, is in line with its control model from this morning. An unsettled next week, with showers or longer spells of rain affecting the UK.

 

But the mean did not support a northwesterly at all, rather it had high pressure building and suggested warm and dry more especially for the southern half of the UK.

 

This evenings GEM has high pressure building throughout next week. Its all too far out to be sure.

 

[Captain Shortwave]

More twists and turns, more high drama...this model watching is very exciting and infuriating at the same time.  

 

Needless to say, I won't be Banking this run

You could take it to RBS, they are full of toxic output 

Well the ECM would certainly blow away the cobwebs, in fact it would probably blow all the garden furniture away.

Still the ECM probably has the pattern too far south, like the other 3 million times it's done that this summer beyond day 7 

Edited August 26, 2013 by Captain shortwave

[draztik]

This evenings GEM has high pressure building throughout next week. Its all too far out to be sure.

 

im a big fan of the GEM model, so you're right to highlight that! More runs are needed, and no doubt there will be changes again come the morning.

[J10]

This evenings ECM 12z, is in line with its control model from this morning. An unsettled next week, with showers or longer spells of rain affecting the UK.

 

For Northern UK yes, SOuthern UK has high pressure close by or in control for the vast majority of the run.

 

A classic north south split IF ECM is correct.

Edited August 26, 2013 by J10

[Summer Sun]

Windy but mild end to ECM this evening completely against the 00z ensemble and anomaly

 

[draztik]

For Northern UK yes, SOuthern UK has high pressure close by or in control for the vast majority of the run. A classic north south split IF ECM is correct.

well, even with higher pressure, the EPS model showed showers/rain affecting the UK. North & South.