Model Output Discussion 18z 28/07/13

[Captain Shortwave]

Both GFS and UKMO now split the energy from that trough, one part goes south east, the other goes north east. The two make more of this than the ECM and GEM which send less energy south east and the rest straight east. Not sure what to think really

Where's Marty Mcfly and the Doc when you need them 

Edit - GEM is now also sending energy south east by T96, after not doing so for every run in the last 3 days

Looking similar to the GFS at t120

GFS control run at t120

Edited August 20, 2013 by Captain shortwave

[Frosty.]

lol Frosty...if you 'bank' too many, you'll need a new safe deposit box?

I need a new safe deposit box pete cos i'm BANKING the Gfs 12z as well,  seems the 6z was on to something, high pressure domination after the briefest of unsettled blips 

[Cloud 10]

Look at the difference between the GEM 00z and 12z chart for Sunday!

 

00z..   12z..

[bubsy83]

Looks like the BH could be alright.

[bluearmy]

Looks like the BH could be alright.

 

based on what bubsy ?  the models are all over the place with the trough energy. specifics are nigh on impossible to predict.  if the ecm and its ens are nothing like ukmo at T96 then today might be one of those days when the fax output is heavily modified from the raw ukmo 12z.

[shedhead]

based on what bubsy ?  the models are all over the place with the trough energy. specifics are nigh on impossible to predict.  if the ecm and its ens are nothing like ukmo at T96 then today might be one of those days when the fax output is heavily modified from the raw ukmo 12z.

Absolutely right ba, nailing the precise weekend evolution is nothing more than shadow chasing and it'll probably remain so for a little time yet.  There it was...........gone!

[Milhouse]

The UKMO shows the entire BH weekend fine and warm so thats probably what Bubsy was looking at. The GFS 12z has a wet day on Saturday followed by drier conditions pushing down from the north on Sunday and dry for all on Monday. Mixed signals from the models but starting off unsettled, getting drier is the general picture at the moment.

[Tamara]

Looks like the BH could be alright.

The upcoming ECM and ensembles this evening with be especially interesting because this morning there were relatively few members who backed the consensus model output (so far) this evening.

 

However, as part of the familiarly poor modelling of this cut off low synoptic as mentioned earlier... and one that often crops up at all times of year in the UK, with equally familiar associated apparent big errors of judgement by the models,  it is in reality the case that relatively modest adjustments in jet stream energy can have large impacts on a small part of the overall large NH...such is the UK. 

 

Hence this evening, those adjustments may also become apparent in the ECM and appear to show a huge backtrack once again.

 

In truth, as stated, the energy adjustments don't have to be that big to give a very different appearance to the pressure map close to the UK and the consequent surface conditions on the ground can change considerably as a result. Its all about how much energy is split NE and/or SE  It is on that basis that the 'fate' of the weather at the B/H weekend lies.

 

The briefly showery and changeable estimate is the one I would back - before pressure rises once more from the south west.  Time will tell however, and the ECM will very soon tell us more in this respect as well

 

There is a little less westerly push of energy on the 12z ECM but it leaves some residual weakness and pressure doesn't link up quite from the atlantic to Scandinavia as a result at t120 like the UKMO and GFS. However, different to this morning...

 

Exactly CS

 

Maybe just too slow to fill the trough..

Edited August 20, 2013 by Tamara Road

[Captain Shortwave]

Well the ECM has managed to disagree with everything, including itself at day 5 (the 00z run)

 

No further comment needed.

Edited August 20, 2013 by Captain shortwave

[Tamara]

Well the ECM has managed to disagree with everything, including itself at day 5 (the 00z run)

 

No further comment needed.

Actually, at day 6, the ECM is not that different to other models. It is just messier with filling the trough between the two High pressure systems. But it has moved away from digging the trough to the north of Scotland south which had suspectly appeared to been through too much amplification this morning.

 

 

And at day 7 it suggests it is about one day slower than the UKMO...

 

Edited August 20, 2013 by Tamara Road

[Captain Shortwave]

I'm so glad that this chart is not likely to verify

 

Nice for all, except the whole day of persistent rain in the triangle of doom   

[Bristawl Si]

Well, look back a week+ from today and the warm sunny weather was meant to be kicking off yday and last for a week to 10 days.

Seems like the chasing of 2nd half August warm and sunny, compliments of a decent HP cell, has been elusive for a while now.

Evening forecasts i've seen this eve, our regional and national, indicate a mixed bag for the next few days and into the bh w/e.

Maybe September will deliver.

Edited August 20, 2013 by Bristle boy

[J10]

The last couple of days have seen some decent weather with plenty of sunshine (Sunday -Tuesday, saturday was wet)

 

As for National forecast, more than a little over concerntration on the bad weather for SE parts on Thursday, when other areas will be far better.

 

Of course it cannot be denied that the High Pressure originally forecast is now now going to happen to the same extent. All in all teh next week though is looking pretty decent but perhaps disappointingly the start of the BH weekend not looking as good as was once the case.

Edited August 20, 2013 by J10

[No Balls Like Snow Balls]

Based on the latest ECM the BH weekend doesn't look to bad. Some rain overnight Friday into Saturday morning. Clearing to showers later. Showers again for Sunday but it could be a lot worse . There is no such thing as bad weather just a poor choice of clothing.

Edited August 20, 2013 by No balls like Snow Balls

[johnholmes]

So what did the anomaly charts seem to suggest for the BH weekend?

 

what did the anomaly charts suggest for the August BH weekend.pdf

 

copied into more technical thread also

 

[Frosty.]

The Ecm 12z op run is not bad at all, high pressure or at least ridging easily has the upper hand apart from a brief less settled blip this weekend which barely registers on the blipometer. I think there are very encouraging signs for next week with ridging from the azores/atlantic anticyclone extending across the south of the uk for most of the next 10-14 days and at least pleasantly warm for most of the time with just the occasional unsettled and cooler interlude but the northern half of the uk it's the other way around with a more changeable, oceanic dominated outlook with peaks and troughs, some weak ridging but unsettled more often than not with average temperatures overall but sometimes a little below and above, all in all it's acceptable for the dying embers of a very good summer, there is the potential for a more significant fine and warm or very warm spell developing as the gfs 06z and to a lesser extent, the 12z showed and the ensemble mean continues to indicate a north-south split, best in the south with a fair amount of summery weather still to come.

[summer blizzard]

No change in my thoughts from yesterday after seeing the ECWMF, westerlies (in this case north westerlies) to follow this pathetic excuse for a settled spell.

[Bradowl]

This heatwave always seems to be this time next week.

 

I wonder if it will arrive in time for Christmas.

[Captain Shortwave]

Whilst there is little to gain from the ensembles for the weekend, longer term the ECM is keen to have the Azores high ridging into the south with the jet blowing through Scotland. This would suggest a north/south split with the south seeing dry and fairly warm weather with occasional outbreaks of light/moderate rain and the north being cooler with rain or showers at times.

 

[East_England_Stormchaser91]

Everything that was looking good a week ago is now a far, far cry away. Even what was looking like a decent cut off low feeding up some decent thunderstorms with humid Southerlies has diminished into nothing now except a typical atlantic front, and we end up with dry, plain old Northwesterlies! You just couldn't make it up!

We could still get some warm weather, but time is really running out now for anything to really write home about. Once I get back from the Balearics during Mid September, classic gales and squally rain is what I'll be looking forward too, and not long after that I will be on the hunt for roaring Easterlies bandwagon . Not been a bad summer all in all though, the best in 6 years at least and not to forget that classic 23rd July night storm which to be fair makes up for the lack of general convective activity this summer. 

Edited August 20, 2013 by East_England_Stormchaser91

[Tamara]

I find there are always at least some people available who give very balanced and salient views that I know are a big help and source of information to me in this thread when I need help to understand various things and also help me with my own opinions of things On that basis I find it strange most times that there are always other posts that illustrate that some don't take any notice of these. Why is this ? Maybe its a case of not everyone finding the same sources as reliable?  Yet somehow I keep doubting this

 

No need to repeat my own little opinions again - they haven't changed this evening

[Captain Shortwave]

I wouldn't rule out anything for the coming weekend, rain, sun, heat, cold, cloud, thunder, wind etc

It's not over until the fat lady orders her chicken vindaloo on a Friday night 

Edited August 20, 2013 by Captain shortwave

[Frosty.]

The models are always testing us, we make a prediction that looks plausible and then the rug gets pulled from under us, we should be used to it by now because it's the nature of the beast, the weather does what it wants but I love it in all its unpredictable glory.

[DTHFCJ]

http://www.meteo.psu.edu/~fxg1/ECMWF_12z/test8.gif

 

okay whos nicked all them black lines off the UK..(GFS) on the right

[john pike]

updated fax charts

 

saturday

 

has dropped the low to our south now

 

sunday

 

fronts over the central belt and northern areas

 

 

ukmo raw fax

 

bottom right is for monday which at present shows high pressure in control

 

does not show troughs etc though

 

i would call monday dry at present according to that however expect changes to appear over the next couple of days