Model Output Discussion 31/07/14 onwards.

[Frosty.]

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.

Well I think most on here know i'm an optimistic chap, always enthusiastic about the weather and i'm hoping the 6z op run is right. I'm fed up of reading miserable depressing comments which is why I try and add a lighter touch.

[Yarmy]

Well I think most on here know i'm an optimistic chap, always enthusiastic about the weather and i'm hoping the 6z op run is right. I'm fed up of reading miserable depressing comments which is why I try and add a lighter touch.

 

Good point. I'll redress the balance and post perturbation 6 for the same time:

 

Edited August 6, 2014 by Yarmy

[phil nw.]

Mixed and changeable is the theme for the UK for the time being.

A look at the T84hrs fax shows a chain or family of lows heading this way from the W.Atlantic.

 

 

these systems with frontal rain affecting us over the next week.

Of course it's not as bad as it looks especially at this time of year with higher thicknesses across the south some weak transient ridges will bring some drier and brighter interludes between the rain bands.

 

The general trend into week 2 seems to continue with some eastward movement of the Atlantic pattern as the Icelandic upper trough is modeled towards Scandianvia by day 10.

We can compare the ECM mean for T96 and T240hrs to see this trend.

 

so likely evolving into the usual north/south split in a westerly flow with some decent late Summer conditions looking to ease north.

Anyway that seems the probable way forward but let's see if the 12z model runs, due soon, continues with this.

[IDO]

Looking at the GFS 06z run, this result has always shown up in the ensembles and it was probably only a matter of time that it figured in an op run. However on the GFS it is not yet a high cluster. The 12z has Bertha back with a direct hit up the Bristol Channel and heads NE. Not a major low at the moment but this could change.

 

Bertha is about to hit the Jetstream and will be entering cooler waters so we should get a better idea how it does or does not develop when that data starts coming in:

 

 

 

On this run more of a concern the rainfall than the wind.

 

No surprise that UKMO has now come on board, Bertha slightly deeper than GFS:

 

 

 

GEM also has Bertha on the jet UK bound, initially in between the GFS and UKMO: 

 

Maybe some strong winds to the south of that:  

 

If ECM backtracks tonight we will finally have a full house. Though still time for further changes.

 

FWIW both GEM and GFS keep us in a trough till around D10, though GEM is the more active.

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

[bluearmy]

i wonder if ecm will finally find bertha for sunday. if so, that will be all four ops in broad agreement for the first time. but will that be the end of the story ?  if it is, it will be a good episode for the american models.

[IDO]

Looking at the GEFS it remains as per the 0z, about 66% for Bertha to hit the UK and 33% a non-event, This has not changed for a few days and matches the ECM & GEM  ensembles split from this morning.

 

London pressure graph for the ensembles: 

 

Navgem:   JMA: 

 

Lots of agreement on the 12z.

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

[Gael_Force]

i wonder if ecm will finally find bertha for sunday. if so, that will be all four ops in broad agreement for the first time. but will that be the end of the story ?  if it is, it will be a good episode for the american models.

 

The 12Z HIRLAM (ECM initiated) has a more developed low coming into SW approaches at the extremity of the run.

 

 

 

Full run here.  http://www.aemet.es/es/eltiempo/prediccion/modelosnumericos/hirlam

[Frosty.]

A quickie from me, the bbc news 24 weather just said they still don't know what track ex hurricane bertha will take this weekend, it could be across scotland, it could be across southern england..it could be somewhere in between or it could miss the uk altogether..in other words..it's pin the tail on the donkey time.

[terrier]

A quickie from me, the bbc news 24 weather just said they still don't know what track ex hurricane bertha will take this weekend, it could be across scotland, it could be across southern england..it could be somewhere in between or it could miss the uk altogether..in other words..it's pin the tail on the donkey time.

true frosty but there own model now backs the gfs 12z run with uk in for a direct hit. Plus I would think the TV forecast won't have the new data in yet. No matter how we dress it up it looks very autumnal for the uk for next 10 days.

[IDO]

A quickie from me, the bbc news 24 weather just said they still don't know what track ex hurricane bertha will take this weekend, it could be across scotland, it could be across southern england..it could be somewhere in between or it could miss the uk altogether..in other words..it's pin the tail on the donkey time.

 

 

I agree. Until we get ECM aboard and then get 2-3 runs it will remain a nightmare for the pros. The ensembles slightly favour a direct hit but I would not put money on it yet. 

 

ECM at T96: 

[Captain Shortwave]

I agree. Until we get ECM aboard and then get 2-3 runs it will remain a nightmare for the pros. The ensembles slightly favour a direct hit but I would not put money on it yet. 

 

ECM at T96: http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gifRecm961.gif

I think we have flipped the probabilities in this afternoons suite, from 70:30 favouring a miss to 70:30 favourite a hit, bad times for us in particular (or good times if wet and windy weather is your thing).

It does look like we will descend into a more westerly and unsettled pattern though after this weekend. High pressure could nose in at times from the south west but that is for later discussions I think.

[Frosty.]

true frosty but there own model now backs the gfs 12z run with uk in for a direct hit. Plus I would think the TV forecast won't have the new data in yet. No matter how we dress it up it looks very autumnal for the uk for next 10 days.

I wouldn't call it autumnal terrier, let alone very autumnal with temperatures just either side of 20 celsius 68 F...and some parts of the south and east will be into the low to mid 20's c at times during any prolonged sunny spells. I also believe the azores anticyclone will build in once the trough departs, perhaps more directed across the south of the uk with the north more changeable. The sst's around the BI are somewhere near their highest levels of the season and the sun will be very strong for a good while yet..so autumnal..nope

Edited August 6, 2014 by Frosty.

[knocker]

If it's of interest the ECM ops sequence. It pops out the left exit of the jet on Sunday before being absorbed in the in situ low without much intensification.

 

 

[Vorticity0123]

I've made a post analyzing Bertha, its demise, the uncertainty associated with it and, finally, the weather in the extended timeframes. For anybody interested, it can be found here: http://forum.netweat...m-bertha/page-3

Edited August 6, 2014 by Vorticity0123

[phil nw.]

I think we have flipped the probabilities in this afternoons suite, from 70:30 favouring a miss to 70:30 favourite a hit, bad times for us in particular (or good times if wet and windy weather is your thing).

It does look like we will descend into a more westerly and unsettled pattern though after this weekend. High pressure could nose in at times from the south west but that is for later discussions I think.

 

Yes Captain latest UKMO Fax's have moved towards a more significant feature coming into the UK compared to the overnight run.

We can see a much deeper low approaching the sw at the same time frame on the T72hrs latest chart when compared with the earlier T84hrs from the overnight run.

 

 

 

still time for further adjustments but as it stands now it's looking more likely that a wet and windy spell will be moving up the country on Sunday.

[ANYWEATHER]

My money is on the gfs with regards to bertha' ecm is a dogs dinner.....

[Gael_Force]

Yes Captain latest UKMO Fax's have moved towards a more significant feature coming into the UK compared to the overnight run.

We can see a much deeper low approaching the sw at the same time frame on the T72hrs latest chart when compared with the earlier T84hrs from the overnight run.

 

 

http:////f1.nwstatic.co.uk/forum/public/style_images/master/attachicon.giffax84s.gifhttp:////f1.nwstatic.co.uk/forum/public/style_images/master/attachicon.giffax72s.gif

 

still time for further adjustments but as it stands now it's looking more likely that a wet and windy spell will be moving up the country on Sunday.

 

Yes, that looks to be very close to the raw UKMO 12Z run.

 

[Frosty.]

My money is on the gfs with regards to bertha' ecm is a dogs dinner.....

Earlier on today apparantly a woman rang the BBC and said she had heard that there was a hurricane on the way. Well, if you are watching, don't worry, there isn't

[phil nw.]

My money is on the gfs with regards to bertha' ecm is a dogs dinner.....

Comparing the 3 for Sunday the upper pattern is agreed wrt the UK trough but ECM goes with a shallower  low.

 

 

they all send the low out into the northern North Sea afterwards as it becomes absorbed by the parent Iceland low.A changeable outlook remains for next week as a more mobile westerly pattern sets up with much fresher feeling temperatures.

[phil nw.]

Earlier on today apparantly a woman rang the BBC and said she had heard that there was a hurricane on the way. Well, if you are watching, don't worry, there isn't

I must admit Frosty i did have a little chuckle at that so i'll give you that one but please keep on topic and talk about the models now.

We do like to keep the thread on track.

I thank you.  

[damianslaw]

As others have stated, reliable timeframe is very short at the moment thanks to the uncertainty regarding how 'Bertha' interacts with the jet and low pressure to the NW. The models do appear to be moving towards the scenario that the storm will track close to the country and become caught up in the jet phasing with the low pressure to the NW. The Jetstream forecasts are for the jet to take a course over Southern Britain which would enable such phasing to occur and kill off the chances of the azores high ridging NE anytime soon - indeed next week could be predominantly unsettled with temps average at best and on the cool side in the north - going against many longer range forecasts at the back end of July which were calling for a swift return to settled warm weather by middle of the month..

 

UKMO is moving towards the GFS and ECM is showing a shallower feature but still the storm moving on track to hit southern Britain.

[Cloud 10]

The GEM is fairly consistent with its 12z run from yesterday in taking ex-bertha for a trip around the UK.

 

 

It then decides to reform later in the run and give Denmark a pasting.

 

[matty007]

Not looking good for this month I have to say. For heat lovers anyway. 

 

Maybe we've seen are last warm/hot spell of this Summer. Of any note anyway. 

[Cleeve Hill]

I would be v surprised if this storm charges into Southern Britain. Still think is will be steered north and for us in the south it will be a breezy south westerly with some decent temperatures and a little rain.

We lived in bermuda for 6 years and these storms are so unpredictable right up to the last few hours.

[knocker]

A quick observation before the espresso hit. The GFS has Bertha 991mbs centred over Cork 00z Sun.and 24 hours later (moving NE) it has amalgamated with the low pressure area north of Scotland into new deepish low 982mb bringing strong westerly winds to the UK. This isn't the METO scenario looking at the latest fax for midnight Sat.

Edited August 7, 2014 by knocker