Model Output Discussion 31/07/14 onwards.

[knocker]

The ECM ens really follows the ops line. After Thursday Bertha is either absorbed/dissipated and becomes part of the cyclonic circulation over the UK which is centred to the N/NW.

 

JOMEC takes much the same position although keeps it as a minor feature to the SW.

Edited August 5, 2014 by knocker

[knocker]

Yes well............................................The METO has Bertha weakening rapidly 12z tomorrow.

Edited August 6, 2014 by knocker

[knocker]

Hope its not that bad knocker, but it might be. By the way I checked the CFS and its looking pretty unsettled for a good chunk of this month which doesn't bode well at all.

 

Not with you pjl those fax charts are good.

 

Latest NHC advisory much agrees.

REPEAT...CENTER LOCATED NEAR 37.5N  68.1W AT 06/0300ZAT 06/0000Z CENTER WAS LOCATED NEAR 36.8N  69.3WFORECAST VALID 06/1200Z 39.5N  64.5WMAX WIND  45 KT...GUSTS  55 KT.34 KT...120NE 120SE  60SW   0NW.FORECAST VALID 07/0000Z 42.2N  58.8W...POST-TROP/EXTRATROPMAX WIND  40 KT...GUSTS  50 KT.34 KT...120NE 180SE 120SW  30NW.FORECAST VALID 07/1200Z 45.0N  52.7W...POST-TROP/EXTRATROPMAX WIND  40 KT...GUSTS  50 KT.34 KT...120NE 150SE 120SW  30NW.FORECAST VALID 08/0000Z 47.3N  47.0W...POST-TROP/EXTRATROPMAX WIND  40 KT...GUSTS  50 KT.34 KT...180NE 240SE 180SW  60NW.FORECAST VALID 09/0000Z 48.5N  33.5W...POST-TROP/EXTRATROPMAX WIND  40 KT...GUSTS  50 KT.34 KT...180NE 240SE 240SW 180NW.EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NMON DAY 4 AND 200 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAYOUTLOOK VALID 10/0000Z 48.5N  17.5W...POST-TROP/EXTRATROPMAX WIND  35 KT...GUSTS  45 KT.OUTLOOK VALID 11/0000Z...ABSORBED BY EXTRATROPICAL LOW

http://www.nhc.noaa.gov/text/refresh/MIATCMAT3+shtml/060240.shtml

Edited August 6, 2014 by knocker

[SteveB]

Cool and unsettled best sums up GFS this morning, with it only showing signs of warming up in deepest FI

 

 

 

There are some usable days, Saturday being one of them, but they do look to be far and few between.

 

Could August buck the trend of above average months temp wise? Long way to go though.

Edited August 6, 2014 by SteveB

[IDO]

Not with you pjl those fax charts are good.

OUTLOOK VALID 11/0000Z...ABSORBED BY EXTRATROPICAL LOW

http://www.nhc.noaa.gov/text/refresh/MIATCMAT3+shtml/060240.shtml

 

Hi

 

Yes most models have been forecasting that Bertha will be absorbed by the UK trough for a while now then reacting with the core (extratropical) low. Its how much this reinvigorates the new low that has been the puzzle. No change from GFS op, control and GEM this morning with that same interaction but variations on the theme (GFS further north):

 

GFS op:  Control GFS:  GEM: 

 

ECM op has Bertha back running through the Channel:   and although not disruptive has it at D5 in Holland:

 

 

 I think out of all the models UKMO and ECM are really struggling, the former has ignored it for a few runs now, killing it in the Atlantic, ignoring the expert NHC outlook. ECM has recently shied away from the NHC, with Bertha blowing out or just skirting the extratropical low (this morning).

 

GFS op keeps us under lower pressure right out till D16 though the SE may get 1-2 days of rising pressure. Ends: 

 

The control does not even have the brief ridging, UK trough throughout ending: 

 

GEM at D10 the UK in a cool NW'ly flow with Autumnal uppers: 

 

Both GEM and GFS in the wake of Bertha build Atlantic heights towards Greenland. Having watched the recent Pacific storms, some sort of meridian flow can build after such mid latitude disruption so cannot discount FI.

Edited August 6, 2014 by i'm dreaming of...

[Frosty.]

I've taken a snapshot of the T+144 - 168 hours range and they all show varying degrees of unsettled weather, the easiest on the eye is the ukmo 00z but really the overall picture is of trough domination and a mixture of sunshine and heavy showers with a risk of thunder, also some longer spells of rain, temperatures around average but feeling warmer in any decent sunny periods between the downpours.

[knocker]

The anomalies for next week are all singing from the same hynm book. Upper low centred north of the UK with associated trough. Unsettled weather with the occasional transient Azores ridge with temps generally lower than average.

 

[Frank Trough]

Hi

 

Yes most models have been forecasting that Bertha will be absorbed by the UK trough for a while now then reacting with the core (extratropical) low. Its how much this reinvigorates the new low that has been the puzzle. No change from GFS op, control and GEM this morning with that same interaction but variations on the theme (GFS further north):

 

 

 

ECM op has Bertha back running through the Channel: http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gif  and although not disruptive has it at D5 in Holland:

 

http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gif

 

 I think out of all the models UKMO and ECM are really struggling, the former has ignored it for a few runs now, killing it in the Atlantic, ignoring the expert NHC outlook. ECM has recently shied away from the NHC, with Bertha blowing out or just skirting the extratropical low (this morning).

 

GFS op keeps us under lower pressure right out till D16 though the SE may get 1-2 days of rising pressure. Ends: http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gif

 

The control does not even have the brief ridging, UK trough throughout ending: http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gif

GEM at D10 the UK in a cool NW'ly flow with Autumnal uppers: http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gif

 

Both GEM and GFS in the wake of Bertha build Atlantic heights towards Greenland. Having watched the recent Pacific storms, some sort of meridian flow can build after such mid latitude disruption so cannot discount FI.

 

Sorry, just for clarity (i don't know about the models struggling - i am) you are saying that the GFS/GEM more unsettled conditions for sunday/monday are more likely than the ECM/UKMO version which seems to tone everything down to a virtual non-event?

 

The GEM looks pretty interesting - that's some depression for August isn't it? looks more like october.

 

 

verses FAX chart for the same time:

 

i'm finding it all quite interesting - a very dynamic situation. Presumably the way the low deepens (or not) will have a knock on effect for how the weather evolves next week? Different degrees of unsettled i guess?

[Summer Sun]

Once Bertha pulls away during Sunday UKMO shows a mixture of sunshine and showers which should be fairly well scattered

 

[Nick F]

Still no model consensus re ex-Bertha. Seems to hinge on whether the low moves pole side of strong Atlantic jet and falls under the developmental left exit over the weekend, deepening the low northeastward over Ireland and Scotland, bringing unseasonably wet & windy weather with gales - as per 00z GFS. Or, the ex Bertha low stays warm side of the jet, fails to deepen and just moves as NE across Bay of Biscay as a shallow wave towards N France as per 00z ECM.

 

But in the great scheme of things the track of ex-Bertha looks not to make too much difference to UK weather in the long run, with GFS and EC agreeing on keeping the UK under an unsettled cyclonic westerly flow until at least mid-month and probably beyond.

Edited August 6, 2014 by Nick F

[knocker]

Still no model consensus re ex-Bertha. Seems to hinge on whether the low moves pole side of strong Atlantic jet and falls under the developmental left exit over the weekend, deepening the low northeastward over Ireland and Scotland, bringing unseasonably wet & windy weather with gales - as per 00z GFS. Or, the ex Bertha low stays warm side of the jet, fails to deepen and just moves as NE across Bay of Biscay as a shallow wave towards N France as per 00z ECM.

 

But in the great scheme of things the track of ex-Bertha looks not to make too much difference to UK weather in the long run, with GFS and EC agreeing on keeping the UK under an unsettled cyclonic westerly flow until at least mid-month and probably beyond.

 

The ECM was originally going for this left exit scenario but changed it's mind a day or two ago. NHC doesn't seem that keen on the idea either but as you say in the long run it's not that important.

[Frosty.]

The Ecm 00z ensemble mean is pretty much in line with the 00z operational output this morning regarding the general weather pattern next week with a showery trough being the dominant feature, the 850's look decent enough so surface conditions should be pleasantly warm with low 20's celsius for many but lower in any prolonged rain, a mix of sunshine and showers seems to be the main theme next week and eventually a slow improvement as the trough relaxes it's grip and the azores anticyclone slowly edges closer from around T+240 hours onwards.

 

Jeez i'm looking forward to winter now, lots of frost and snow please

[terrier]

w

Things on gfs to me dont look too bad from tuesday onwards could look a whole lot worse

[shaky]

Massive changes on the gfs 06z!!after being stubborn run after run with a big storm for the weekend it now shows tropical storm bertha dissipating into nothing and we are left with a reasonable weekend!!

[terrier]

looks like gfs 6z has finally woken up. Looks like next week may not be too bad after all looks rather pleasent to my untrained eye.

[Northern Sky]

looks like gfs 6z has finally woken up. Looks like next week may not be too bad after all looks rather pleasent to my untrained eye.

Yes, quite a different run from the 6z even in the short term. I suppose this just highlights the difficulty in trying to predict the potential impact of Bertha. The 6z looks more in line with the UKMO to me?

[Summer Sun]

So GFS finally moves towards UKMO for the track of Bertha this weekend, a side by side comparison to t144

 

[Frank Trough]

Yes, quite a different run from the 6z even in the short term. I suppose this just highlights the difficulty in trying to predict the potential impact of Bertha. The 6z looks more in line with the UKMO to me?

 

it is to my eyes, yes. Still a little way to go to be sure of anything for the weekend in this type of situation but this does look a bit like a GFS capitulation. The UKMO has never really fancied Bertha to be anything of real note over the last few runs and is now supported by ECM and GFS 06z. Just the GEM now.......

 

We await the 12z runs to see if a clearer direction has been found across the models. 

[IDO]

The latest blog from the Met re Bertha: http://metofficenews.wordpress.com/2014/08/06/ex-bertha-more-likely-to-miss-uk/

 

Now 30% chance of Bertha deepening according to Met.

[Frosty.]

Well what a super duper end to the Gfs 06z op run, a fantastic spell of late summer weather there as the azores high builds in strongly bringing increasingly sunny and very warm weather to all areas, the high then drifts over the south of the uk enabling continental heat to drift north into the uk with temperatures shooting into the mid 80's F.. BANK  

[terrier]

Well what a super duper end to the Gfs 06z op run, a fantastic spell of late summer weather there as the azores high builds in strongly bringing increasingly sunny and very warm weather to all areas, the high then drifts over the south of the uk enabling continental heat to drift north into the uk with temperatures shooting into the mid 80's F.. BANK  

Next week looks none too shabby either frosty.

[Polar Maritime]

Next week looks none too shabby either frosty.

Some evidence to back up your statement would be appreciated Terrier. .Many Thanks, PM

[terrier]

well this charts could look alot worse. Not Too bad a run at all in my opnion

[Yarmy]

Well what a super duper end to the Gfs 06z op run, a fantastic spell of late summer weather there as the azores high builds in strongly bringing increasingly sunny and very warm weather to all areas, the high then drifts over the south of the uk enabling continental heat to drift north into the uk with temperatures shooting into the mid 80's F.. BANK  

 

Not wishing to be a spoilsport, but the Control at the same time...

 

 

 

Behold the Atlantic. ANTI-BANK.

 

Anyway, ignoring all the Bertha shenanigans, the main story from the models is the loss of the Scandi ridge which feels like it's been there all summer. What happens then is anyone's guess as the op and control show.

[mushymanrob]

 

Anyway, ignoring all the Bertha shenanigans, the main story from the models is the loss of the Scandi ridge which feels like it's been there all summer.

..

 

...all year mate! it was there quite alot in spring too, and nearly delivered us a beasterly.it never did retrogress as was suggested, but its played a large part in producing a half decent summer and it was the azores ridging and amalgamating with the scandi high that produced our 'hot spell', last month. so im not too pleased to see it go, especially if its replaced by a large trough.