Model Output Discussion 31/07/14 onwards.

[Frosty.]

The Gfs 00z op run shows the remnants of Bertha targeting scotland through sunday and monday with the strongest winds and most of the persistent rain although it does impact on the rest of the uk too with a band of rain sweeping through. While most of mainland europe continues to sizzle, the uk appears to be in for a more unsettled phase but with spells of fine weather from time to time, mostly across the southern half or third of the uk. The 00z shows atlantic high pressure occasionally building across the south but it seems the remains of ex hurricane Bertha may prove to be a longer term problem at least for the north of the uk with complex troughs swinging south bringing cooler and unsettled weather to all areas during the next few weeks but at least the south and west look fine and warm at times on this run.

Edited August 5, 2014 by Frosty.

[knocker]

The ECM anomaly has much the same set up with the intense upper low NW of the UK bringing very strong westerlies to southern Britain and northern France. This is in keeping with the jet which runs west to east into n. France.

 

Regarding the surface synoptics there is a general area of low pressure to the north of the UK from Friday. Bertha runs along the jet before turning NE into Kent by 12z Sunday by which time it is basically absorbed into the general area of low pressure stretching from Iceland down to the channel. There is no sign of any deepening of the system.Temps are generally below average although warmer air is never far away from the south.

 

Bertha currently

http://www.metoffice.gov.uk/public/weather/storm-tracker/#?tab=map&stormId=03L&stormName=BERTHA

Edited August 5, 2014 by knocker

[terrier]

well this weekend looks very wet indeed. looks like alot of rain and cool for the foreseable future on the gfs 

[Frank Trough]

well this weekend looks very wet indeed. looks like alot of rain and cool for the foreseable future on the gfs 

 

the weekend is comprised of two days, of course. And the outlook varies a bit depending on which model you look at, but as your using the GFS then Saturday doesn't look all that bad at present - a bit blowy but bright and quite usable:

 

Zero sign of any country-wide warm or settled in the operational output this morning beyond the weekend, but then after Jun and July I would find it hard to complain. GFS offers a bit of hope for more southern areas of at least something drier. Looks breezy throughout.

[Summer Sun]

well this weekend looks very wet indeed. looks like alot of rain and cool for the foreseable future on the gfs 

 

GFS rainfall totals to the 13th show the wettest conditions will be in NW Scotland and Northern Ireland, with England, Wales and the rest of Scotland seeing between 20 and 40mm

 

 

Gibby's summary for the next 2 weeks

 

The models have watered down the severity of the earlier programmed storm shown in earlier days output. Instead we maintain a basically unstable but often slack SW airflow through ECM does go for something rather more meaningful albeit briefly wind and rain-wise early next week. In among all this talk of rain will be some spells of reasonable weather too and it will still feel quite warm in the sunshine as winds will continue to be fed across the UK from a warm source.

 

Later in the period the longer term models do try to promote a rebuild of High pressure from the SW as the Jet stream possibly moves back North though the procedure seems slow and arduous with showery troughs continuing to affect the UK at times right out to the end of the 15 day period in attendance with somewhat cooler NW winds. Nevertheless, holidaymakers and campers in particular will not be sorry to see the risk of gales less likely from today's output though I must include the caveat that with tropical air still likely to affect the UK for a time in the 5-7 day timeframe there is still potential for an unpleasant couple of days if the synoptics come together at the given time.

 

http://www.norton-radstockweather.co.uk/NEW-Model-Analysis%282859336%29.htm

Edited August 5, 2014 by Summer Sun

[TSNWK]

well this weekend looks very wet indeed. looks like alot of rain and cool for the foreseable future on the gfs 

Please can this " against what most desire " spin cease MR T. In winter you will only post when the models are showing mild etc and we all know what most are looking for.. In summer most are looking for warm and dry and you appear to again to want to go against that and cherry pick the miserable for most summer charts.

[terrier]

Please can this " against what most desire " spin cease MR T. In winter you will only post when the models are showing mild etc and we all know what most are looking for.. In summer most are looking for warm and dry and you appear to again to want to go against that and cherry pick the miserable for most summer charts.

Im certainly not cherry picking. The gfs 00z is showing a very unsettled theme through much of its entire run. yes i would love it to be showing high summer charts. But it isnt. We live in the uk it was bound to break down sooner or later

[knocker]

The ECM ens is similar to the ops. Perhaps running Bertha a little further north but generally absorbed into the in situ low.

Edited August 5, 2014 by knocker

[Frosty.]

The GEFS 00z mean continues to show a slow improvement next week as the azores anticyclone ridges towards the southwest of the uk, so the south / southwest would eventually become more settled and warmer with sunny spells but the further northeast you are, the unsettled weather could last all next week and beyond.

[Stormyking]

Not alot of warmth on the charts at all this morning, a very unsettled look indeed, with alot of rain on the way this eek, starting tonight! However Friday doesnt look as wet now though, looks mostly showery mainly land based, 

Not to to bad with temperatures now either

But now the weekend into next week is definatly where things turn, with some very strong winds in places and a fair amount of rain too as others have stated

especially over the North and North West.

 

 

The only sort of positive I could find on the latest GFS for any drier and calmer weather is this small ridge of High pressure for the time being in FI over the South of  the UK mainly 

Then its backs off west towards the end with some more cooler and unsettled weather again

This is obviously FI so it is most likely to change

[IDO]

Looking at the GEM ensembles they are much like the ECM at D5, lots of scatter. About 25% support for the op, i.e. Bertha splits and initial impact is minimal. The rest are spit between GFS's take of mixing and deepening and ECM with Bertha skirting southern regions, and some with lesser impact.

 

eg:  Control GEM:   GFS like: 

 

There are 6 clusters at D5 on this morning's ECM highlighting the uncertainties. Op and Control are the same synoptic, a UK trough and Bertha's track around Southern England. The op has about 27% support. Cluster 2 is like GFS where Bertha snags into the trough to the west and deepens, this has about 18% support: http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2014080500!!/

 

ECM op still has Bertha as a wet day for the south Sunday: 6am   Noon:

 

GFS 06z still has Bertha interacting with the trough and a wet and windy Sunday: 

 

After that the UK is under cool uppers, between 4-8c right out till the 18th August with a messy mix of upper trough and ridge. Then there is a hint that pressure builds from the SW.

[mushymanrob]

Please can this " against what most desire " spin cease MR T. In winter you will only post when the models are showing mild etc and we all know what most are looking for.. In summer most are looking for warm and dry and you appear to again to want to go against that and cherry pick the miserable for most summer charts.

 

is cherry picking the most gloomy charts any worse the cherry picking the most optimistic? putting a cold/mild/cool/hot spin on anything wont change what we actually get. im under the impression that this forum is viewed by alot of non members, just to get more information further ahead then what the media likes to predict. surely unbiased accounts are the ones most likely to be the most accurate and will give everyone viewing the best information they/we want.

 

 putting all preferances aside, i know atm most (like me) desire heat, but the sad truth is that as things stand - theres not 1 jot of hope for any in the forseeable future, and with pattern busting bertha apparently about to remove the ever presant scandinavian high, i see no grounds for optimism regarding anything hot. of course that doesnt rule out a fairly average august weather pattern developing post bertha and i think that is the most likely option .

[knocker]

Looking at next weeks ECM 850 means and mslp anomalies I think best described as quietly pleasant. Not that one should take much notice of this at this stage.

Edited August 5, 2014 by knocker

[Summer Sun]

UKMO still suggesting it will be fairly weak by the time it reaches the UK it has pressure no lower than 1000mb between Saturday and Monday

 

 

GFS on the other hand is still going pressure below 1000mb

 

 

Still a lot to be resolved with UKMO suggesting it will be a lot weaker by the time it reaches us

Edited August 5, 2014 by Summer Sun

[Cloud 10]

Crazy operational run from the 12z GEM  with bertha taking a reverse coastal tour of the UK!

 

http://www.meteociel.fr/modeles/geme_cartes.php

Edited August 5, 2014 by Cloud 10

[Captain Shortwave]

So what could Sunday be like?

GFS suggests a write-off

 

GEM shows a showery day with slow moving downpours, rain and wind strikes the south east during the evening.

 

UKMO gives a reasonable day for the south with temperatures around or a little above average. The north sees showers, if the UKMO is correct then the weekend might not be too bad overall.

 

Further on, well the trouble with the GFS is it's not seeing the split flow upstream which the UKMO/GEM and this mornings ECM had, this of course will have drastic impacts further up the road. So potentially the GFS is throwing erroneous output again. The GEM goes off on one of its Greenland high/ Scandi trough tangents very early on which has no support from the other models. Which leaves the UKMO

Which shows a north/south split developing and matches quite well with the metoffice outlook, and probably the solution I think is closest to reality at the moment.

Edited August 5, 2014 by Captain shortwave

[IDO]

So what could Sunday be like?

GFS suggests a write-off

 

 

 

 

Which shows a north/south split developing and matches quite well with the metoffice outlook, and probably the solution I think is closest to reality at the moment.

 

 

Not sure that is a right off Captain, wind gusts:  

 

The control is slightly windier and looking at the ensembles, ignoring timing issues the op has one of the least deepest pressure level for Bertha's passing for London:

 

 

Looking at the ensembles, plenty go for the GEM route, though of course not as intense, than go with the UKMO charts post Bertha:

 

eg.   

 

JMA also similar to GEM re track:  ditto Navgem: 

 

ECM dissipates Bertha as it sends it on the southern side of the jet so is unable to interact with the trough: 

 

To my eyes still high confidence that Bertha's track will hit the UK and I see it as just favorite (from current ensembles) that it will interact with the trough as it leaves the jet and will deepen the trough's core low; this despite ECM's op run. 

Edited August 5, 2014 by i'm dreaming of...

[Frosty.]

There is a lot of conflicting data regarding how ex hurricane bertha will impact on the uk, the bbc forecasters also admit to not really having much clue about the weekend either. For what it's worth, the GEFS 12z mean looks more unsettled and cooler for most of the uk throughout with the azores anticyclone signal rather weaker than the 00z showed.. so it's all up in the air..literally.

[knocker]

The ECM upper anomaly has an intense low centred over the UK. This leads to low pressure dictating things over the UK with the center to the north, at least until Monday when the Azores ridge nudges into the southern half of Britain. Temperatures are generally below average.

 

As far as I can see the ECM dissipates Bertha en route across the Atlantic.

 

[ANYWEATHER]

Ecm ,really makes nothing of Bertha, Gfs on the other hand does by Sunday. Following that, at day 10 or T+240, both models agree on some what changeable and rather cool conditions....Subject to change!    

[Captain Shortwave]

To my eyes still high confidence that Bertha's track will hit the UK and I see it as just favorite (from current ensembles) that it will interact with the trough as it leaves the jet and will deepen the trough's core low; this despite ECM's op run. 

With the ECM and UKMO in reasonable agreement to the contrary then I think that a high confidence forecast is out of the window. As much as the GFS ens back this storm to hit the UK, the ECM and UKMO with the better resolution should at the timeframes involved be closer to the mark. Unfortunately the ensembles backing of the op looks possibly like a herd of sheep which have all made the same mistake earlier on in the run. It would not be the first time this has happened.

I wouldn't be surprised if Sunday just ends up being another day of sun and showers with Bertha nowhere really to be seen.

Edited August 5, 2014 by Captain shortwave

[bluearmy]

anyone confident that the models have a handle on bertha yet ?

Rinse and repeat from 24 hours ago :)It's worth looking at the evolution of the Friday noon fax chart from T96 down to T72 (available for another hour until T96 updates). Fridays wave is, as usual, corrected south and the difference with Bertha is stark. Edited August 5, 2014 by bluearmy

[Gael_Force]

I don't think I've ever seen the UK in the NHC 5 day cone before now.

 

[Frosty.]

Roll on winter..anyhoo we are in for warm rain tomorrow with very humid air flooding the uk, 26c for london, thursday looks fine in the north and west but a ? for the southeast with a risk of thundery rain spreading up from france, friday and saturday could be fair and warm and the latest news on sunday is for a risk of rain and windy weather for the south of the uk, maybe fine further north. The Ecm 12z op run shows next week being unsettled and showery with longer spells of rain with temperatures around average but warmer in any sunny periods.

Edited August 5, 2014 by Frosty.

[IDO]

The ECM op is in the same cluster as its control and this is the top cluster of 5. The second cluster consisting of about 22% is similar to the GFS, that is Bertha as a satellite low running south of the trough (southern England). Cluster 4  (15%) deepens Bertha but keeps it on the southern track. So ECM still has no majority cluster though a small step towards the dissipation of Bertha before it impacts on the trough.

 

GEM ens have about 25% support for the ECM op take, but the rest have a LP system bringing wet and windy weather Sunday-Monday, with different degrees of strength and location. The control for instance:

 

 

You can see for Sunday the Dutch wind speed (ECM) showing that the op and control are well below the mean, with many members higher than the mean suggesting that they are under cooking the low and that the rest of their suite are seeing something more:

 

 

In fact the whole run looks dodgy, the D8 temp is an outlier as well for Holland:  Probably worth ignoring this run.

 

NCEP track highlighted here for T96: 

 

ECM highlighted here for midday Sunday and compared to the 0z where there was significant rain, not a bad day: 

 

NOAA looking much like the ensembles for the 8-14 day period with the UK subject to a trough slowly creeping east: 

 

 

 

 

Edited August 5, 2014 by i'm dreaming of...