Model Output Discussion - 1st August 00z---------->

[Tamara]

What is noticeable about the summer so far, is hardly a Scandi Ridge when one looks at the 500hPa anomaly chart. In fact the opposite is true.

 

The thing that epitomises the summer so far is the omnipresent north Atlantic trough which has led to a north/ south divide, with the further north being closer to the trough, and hence more unsettled. Down here, near the south coast, summer has been quite pleasant with many days of dry summer weather experienced and this is borne out by the chart below.

 

compday.TtiLU0xs5S.gif

 

The extended anomaly charts have continually suggested that the Azores ridge will push the trough further north, but actually the Atlantic trough has recycled and this has never really occurred for any length of time. So why has this situation existed? I think that this is more difficult to answer. It is hardly as if we can point at the MJO which has not stagnated in any particular phase - in fact I see an almost perfect orthodox orbit this summer which has only recently stagnated.

 

phase.Last90days.gif

 

I do think that the answer lies somewhere with the developing EL NIno, Arctic High Pressure - holding the Atlantic trough further south and Atlantic SST's

One key at least is the rut the atmospheric circulation was in before the summer and then the large scale El Nino atmosphere/ocean coupling changes which finally occurred as we entered the heart of it.

 

In this respect the MJO is very key with that massive Phase 7 amplitude at the start of July which achieved that coupling after a long period of stand-off which, in its absence of occurring back then, largely also spoilt winter thoughts and hopes.

 

Despite increasing El Nino ocean signals, negative tendency Atmospheric Angular Momentum (La Nin-esque) had been the cyclical default pattern from last autumn through the winter right till the start of summer - the clue here being that the MJO failed to orbit through Phases 7/8 during the whole of winter when we needed it to, to provide the poleward AAM Rossby wave breaking we needed to take maxiumum advantage of the vortex split and then displacement push in late Jan/early Feb.

 

We relied instead on a negative mountain torque and Phase 1/2 Global Wind Oscillation retrogression of the Azores High to provide an elongated toppler for the best window of opportunity for seasonal interest. There had been a brief retrogression amplification in late December also - but with MJO convection default rooted back to the Indian ocean and unable to progress beyond the West Pacific, at best, then the Azores High only provided temporary amplification northerlies and high latitude blocking was AWOL despite so many favourable indicators which many of us pointed to.

 

So ironically, the high amplitude Phase 7 El Nino atmosphere/ocean coupling which finally arrived late June had been the elusive catalyst we needed last winter to making much more than a northerly veering NE'erly toppler for two days and a few fleeting snow flurries.

 

Ironic too that arriving when it did so soon after the longest daylight of the year, it ensured instead that the pattern amplified in the arctic in the heart of summer to supress the jet stream at mid latitudes just at a time when summer weather hopes wanted a profound sustained amplified mid latitude ridge!

 

In that sense, the amplified Sceuro ridge which marked the curtain raiser to the +AAM regime with the record breaking July temperature on the first day of the month adds to the irony. Without the very high amplitude Phase 7/8 MJO wave which followed, we might have fared better, longer

[johnholmes]

Seems to me knocker the confidence of 6-10 days ahead is average and 8-14 days ahead is below average . This may change though.

 

The average for 6-10 days is some way over 70% correct, so out to 10 days that is quite good if you compare the synoptic output at 10 days, see the daily posts from Gibby. They show ECMWF and GFS at about 33%, not much over 50% at 8 days. At 8-14 days I would still put the anomaly charts I use at not far off 65-70% so they are by far the best indicator when used carefully.

[mushymanrob]

Tonight's NOAA look as if they are agreeing with what the ext GEFS hinted at.

They don't a pretty picture for those looking for late summer heat, with the 8-14 day chart taking a turn for the worse. If further runs support todays chart its looking like our rather dry period might be coming to an end and itll seem rather autumnal with low pressure very nearby.

[Cloud 10]

NAEFS very reluctant to shift those limpet low heights close to our NW.

 

day 6..  day 15...

 

 

Going to take something "big" from the MJO/GWO etc. to shake things up,or maybe an ex-tropical storm as a joker in the pack.

[Nouska]

One key at least is the rut the atmospheric circulation was in before the summer and then the large scale El Nino atmosphere/ocean coupling changes which finally occurred as we entered the heart of it.

 

In this respect the MJO is very key with that massive Phase 7 amplitude at the start of July which achieved that coupling after a long period of stand-off which, in its absence of occurring back then, largely also spoilt winter thoughts and hopes.

 

Despite increasing El Nino ocean signals, negative tendency Atmospheric Angular Momentum (La Nin-esque) had been the cyclical default pattern from last autumn through the winter right till the start of summer - the clue here being that the MJO failed to orbit through Phases 7/8 during the whole of winter when we needed it to, to provide the poleward AAM Rossby wave breaking we needed to take maxiumum advantage of the vortex split and then displacement push in late Jan/early Feb.

 

We relied instead on a negative mountain torque and Phase 1/2 Global Wind Oscillation retrogression of the Azores High to provide an elongated toppler for the best window of opportunity for seasonal interest. There had been a brief retrogression amplification in late December also - but with MJO convection default rooted back to the Indian ocean and unable to progress beyond the West Pacific, at best, then the Azores High only provided temporary amplification northerlies and high latitude blocking was AWOL despite so many favourable indicators which many of us pointed to.

 

So ironically, the high amplitude Phase 7 El Nino atmosphere/ocean coupling which finally arrived late June had been the elusive catalyst we needed last winter to making much more than a northerly veering NE'erly toppler for two days and a few fleeting snow flurries.

 

Ironic too that arriving when it did so soon after the longest daylight of the year, it ensured instead that the pattern amplified in the arctic in the heart of summer to supress the jet stream at mid latitudes just at a time when summer weather hopes wanted a profound sustained amplified mid latitude ridge!

 

In that sense, the amplified Sceuro ridge which marked the curtain raiser to the +AAM regime with the record breaking July temperature on the first day of the month adds to the irony. Without the very high amplitude Phase 7/8 MJO wave which followed, we might have fared better, longer

 

Well, if you talk about irony, the ultimate must have been to see the phase seven amplification in March!

 

 

That too was a record breaker - did it have ramifications in that the run of previous warm months suddenly changed to cooler and north westerly dominated?

[knocker]

EC32 update.

 

Starting Tuesday 18th upper low Iceland with trough orientated south west into the UK and France. Thus unsettled mainly westerly airflow but not too bad in Cornwall. Temps below average.

 

From this point the upper trough rapidly withdraws and by Friday 21st the UK is under the influence of a light westerly flow around the Azores HP situated to the WSW and returning to average temps, possible slightly below in N. Scotland.

 

From here until the end of August this is more or less the analysis although after the 24th the Azores HP tend to slip south and a weak trough mid Atlantic causing a more zonal flow and possible backing the winds a tad. Should be mainly dry with temps around average.

 

Keeping in mind we are in weak signal territory from the end of August until the 11th of September it's the Azores ridge show with LP remaining around Iceland ( I know)  The Azores ridge becoming more dominant by the end of the run. So dry with temps picking up and becoming slightly above average.

 

Summary

 

From Thursday/Friday next week the outlook looks very reasonable until the 11th September but, and it's a big but, we have been down this route before only to find the trough get's a new lease of life. Still hope springs eternal..............................

Edited August 11, 2015 by knocker

[knocker]

This Friday looking a tad wet according to the GFS. The ecm takes the low a little further east/

 

One thing worth mentioning is that low pressure moving north through France as is likely at the end of the week was picked up by the models quite a few days ago as i remember mentioning it at the time.

http://www.tropicaltidbits.com/

Edited August 11, 2015 by knocker

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON TUESDAY AUG 11TH 2015 

 

THE CURRENT GENERAL SITUATION A ridge of High pressure will lie across the UK for the next 24-36 hours. Thundery Low pressure will move up towards the South of England later tomorrow.

 

http://www.wetterzentrale.de/pics/Rtavn001.gif 

 

MODELS-2 WEEK HEADLINE Remaining rather changeable with some rain at times. Some dry and at times warm, humid conditions are likely for all areas as well.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow weakening across the UK in the coming days and resetting to the NW of the UK brieflywith another arm crossing the Atlantic towards Spain. The pattern remains complex through the period with the flow always lying close to or over the UK in a NE direction and occasionally West to East flow across the UK in response to Low pressure often to the North or NW.

 

http://www.netweather.tv/index.cgi?action=jetstream 

 

GFS OPERATIONAL The GFS Operational Run today shows a thundery Low moving North within 48 hrs across the South of the UK and then continuing North to become absorbed by general Low complex to the North or NW with thundery rain and showers for most areas from Thursday to Sunday. Thereafter pressure is shown to build for a time across Southern Britain with warm sunny spells before the end of the period sees Low pressure take command again, centred over the UK with cool, breezy and unsettled weather for all.

 

http://www.wetterzentrale.de/pics/Rtavn1441.gif

 

http://www.wetterzentrale.de/pics/Rtavn3841.gif 

 

THE GFS CONTROL The GFS Control Run shows a changeable week to 10 days to become as thundery Low pressure moves North and as the operational becomes absorbed in genearal Low pressure to the North of the UK. The rise in pressure from the South is shown but more gradual on this run taking until midweek next week to take hold over he South. Then several days of set fair weather under a ridge slowly pulls back South towards the end of the run returning the North to westerly winds and rain at times to end the run.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning still indicate a lot of High pressure out to the SW of the UK in two weeks time with a ridge stretching influence across the UK especially the South. Just a 15% of members show something much more unsettled with Low pressure near Scotland and rain at times for all under Westerly breezes.

 

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

 

UKMO UKMO today shows a thundery Low moving North across the UK on Thursday and Friday opening the door to a fresher Westerly flow with embedded troughs delivering some rain or showers to all at times but with some lengthy dry and bright spells too especially over the South.

 

http://www.wetterzentrale.de/pics/Rukm1441.gif 

 

THE FAX CHARTS The Fax Charts this morning show the same thundery Low moving North with it's attendant warm and humid unstable airmass ahead of a cold front moving east across the UK by the weekend returning cooler and fresher air with more occasional rain and showers across the UK through the weekend.

 

http://www.weathercharts.org/ukmomslp.htm#t120.

 

GEM GEM today is not particularly inspiring if it's a different pattern than of late your after. It too shows thundery Low pressure migrating North later this week which then opens the door to fresher Westerly winds and occasional rain or showers with just brief drier and more settled interludes in the South.

 

http://www.wetterzentrale.de/pics/Rgem2401.gif 

 

NAVGEM NAVGEM too holds Low pressure in control over the UK throughout the latter stages of it's run this morning as the thundery Low moves to the North and then settles a trough near or over the UK in cool Westerly winds with rain or showers at times for many.

 

http://www.wetterzentrale.de/pics/Rnvg1681.gif.

 

ECM ECM this morning looks a little different in it's latter stages. The first week of the run is much as the rest of the output with thundery Low pressure moving North with Westerly breezes moving across the UK in it's wake with showers especially across the North and West. Improvements are then shown to take shape later next week as High pressure builds across the South from the East with warm and humid weather returning to the South though it does look like the risk of a further thundery breakdown may not be far away after Day 10.

 

http://www.wetterzentrale.de/pics/Recm2401.gif

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last evening shows the trough to the NW weaker and less in control over the UK as a large High pressure bias to the South of the UK could ensure plenty of dry, fine and warm conditions with any rain or showers from the trough to the NW focused on the NW.

 

http://www.wetterzentrale.de/pics/Reem2401.gif 

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models trend changeable today with various options between the models still desiring a return to Atlantic airflow domination.

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 95.8 pts followed by UKMO at 95.4 pts and GFS at 94.6 pts. At 5 days ECM is stll king at 86.0 pts followed by UKMO at 84.6 and GFS at 84.0 pts. Then at 8 Days ECM still leads at 58.6 pts over GFS's 55.3 pts. Finally at Day 10 ECM leads GFS at 39.7 pts to 34.4 pts from GFS.

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png 

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.prig

 

MY THOUGHTS The models remain very mixed especially in the longer term though the first week of the output does offer some consistency. In the immediate future all interest focuses on thundery Low pressure advancing North from Biscay and Spain across Southern and Central Britain on thursday and Friday. My own feeling about this is that I'm not convinced there will be a lot of electrical activity from this but there will certainly be some, areas to be determined yet. more likely areas of thundery rain will move North ahead of an opening door to a return of fresher and cooler Westerly winds for the weekend and beyond. When the thundery weather exits the North it looks like all areas will have a mix of sunny spells and occasional rain or showers especially towards the North and West. As in previous days it's from that point on things become much more difficult to pin down as some output wants to build High pressure across the UK at some point while others want to keep a stronger Atlantic influence with a continuation of the North/South split we have encountered of late. Which is right is still impossible to call with I'd say about an equal chance of verifying. I think that until we have moved this continental feature out of the playing field by the weekend conditions for later August may look clearer but unfortunately though there is some waarm or even very warm charts to drool over again this morning they don't come with much cross model support as yet so expect up's and down in long term analysis to continue for some days yet in subsequent runs. What none of the models show is anything particularly out of the ordinary so standard late Summer conditions look more likely than not for most for most if not all of the time. 

 

Next update from 09:00 Wednesday Aug 12th 2015

[summer blizzard]

Well, if you talk about irony, the ultimate must have been to see the phase seven amplification in March!

 

 

That too was a record breaker - did it have ramifications in that the run of previous warm months suddenly changed to cooler and north westerly dominated?

Perhaps better in the Autumn thread but could you give us a brief description of which phases produce Greenland blocking, which produce UK high blocking and which ruin winter. Say for Feb.

[Nouska]

Perhaps better in the Autumn thread but could you give us a brief description of which phases produce Greenland blocking, which produce UK high blocking and which ruin winter. Say for Feb.

 

I think I can safely put my comment in here as it applies to any time of year....

 

I would be a very rich pensioner indeed, if I could answer your question. Powerful computers have done this and the results are here for you to look at a variety of scenarios.

 

http://ds.data.jma.go.jp/gmd/tcc/tcc/products/clisys/mjo/composite.html

 

Three caveats regarding the above, they have been created from an environment when there was more NH ice, more solar activity and less heat in the oceans. You know the small print for investment decisions, same applies here.

[Singularity]

Taking ECM as an example, this morning's model output suggests that the high pressure over Scandinavia may be shifting south by about a week from now, some 3 or 4 days after it arrived there:

 

 

 

Given that this should encourage another intense plume of heat to build across NW Europe, I think it will be worth keeping an eye on how the Atlantic behaves at that time, and of course what manner of low pressure develops to our S or SW, as the models seem quite keen on that as well. 

 

GFS drives an area of low pressure past the NW of the UK just as the plume is starting to build, the effect being to divert the hotter air to our SE while feeding down cooler air from the northwest. A ridge from the west then traps the heat across Spain, Portugal and S. France until a low dives SE from Iceland, interacts with LP over NW Europe and 'lifts' the heat out to the east of the UK while we experience a soggy run of days. I would post the corresponding charts but let's face it, the finer, hotter outcome of the ECM run is more pleasing to observe for many of us:

 

 

...which is largely down to the jet stream tracking further south in the Atlantic, with the Azores High greatly suppressed as opposed to flexing its muscles.

 

So which is more likely to verify? Well, given the affect of events in the Pacific mentioned by M. Ventrice (cheers for the heads up Knocker), it's pretty much an open goal as to who scores the winner to be honest. A consideration of other model output finds GEM not a long way from where ECM ventured, while UKMO at T+144 seems to be a blend of ECM and GFS. So we have ECM as the most optimistic operational output, and GFS as the most pessimistic (of the 'major' models).

 

Looking at the GFS ensembles, the spread of outcomes suggests to me that some runs are near to ECM's output:

 

 

A glance at the 20 ensembles in thumbnail form via http://www.netweather.tv/index.cgi?action=ensviewer;sess= for T+192 hours reveals 10 or 11 perturbations that could do the trick in terms of building some heat from the south rather than blasting it away to our east.

 

Some reasons to be hopeful, then, after a fairly benign run of days Sat-Tue. Admittedly it might tend to be pretty decent for the far southeast during that time, but yet again the NW are looking for ways to shove to one side a stream or rather cool N. Atlantic air. To be honest, I can't imagine living through such summers as this one has been up there!

[Tim Bland]

Still no change in sight to the North south divide.  In the South East it has been a pretty decent summer so far. In Northwestern areas it has been nothing short of dire. 

 

06z GFS continues this theme with 30C possible in the south with the occasional thundery breakdown.  Perfect summer weather as far as I am concerned !

 

 

[mushymanrob]

looking good at day 10?....

well


 

sorry to be  negetive, but the noaa anomaly charts do not support such a pressure rise but suggest troughing over/near our vicinity and being the controling force.

id really like the noaa's to change and support these current op runs, and thats possible, but it is unlikely.

oh and just a note, in winter when i dismiss a big freeze at t240 itll be because its not shown on the noaa charts, like the heat isnt now, and not because im biased against the cold.

[knocker]

True mushy but it has to be said that both the GEFS and ECM are looking to retract the trough around the 18th and push the Azores ridge.

http://www.tropicaltidbits.com/

 

[johnholmes]

A look at the next 2-3 weeks for the upper air patterns

 

A bit beyond my usual attempts but I will give it a go.

The early part is along the very well tried and tested 500mb anomaly charts; NOAA 6-15 days and the ECMWF-GFS 6-10 day anomalies.

The second part will be along fairly new ground for me during the summer months, trying to use the MJO output to give some idea of what 500mb patterns we might expect.

 

Looking at the anomaly charts and they are not totally consistent with each other but not too far apart for some general predictions to be made on the likely upper air pattern 6-15 or so days from today.

Below are the links to NOAA and ECMWF-GFS most recent outputs and comments about their consistency.

NOAA has been quite consistent for some time now. That is for an upper trough to be over or very close to the UK and for any ridging, of anything more than the odd day, to be too far E/NE to be of any major guidance to our surface weather.

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

This is for both the 6-10 and 8-14 day time scales. The output at 8-14 has been as consistent as the 6-10 in showing no sign of any +ve heights of any significance along with no sign of any ridging in the UK area.

The ECMWF-GFS output has been less consistent with NOAA (6-10 day) or with one another. For several days they have both toyed with the idea of a ridge and +ve heights being fairly close to the UK (E or NE) to perhaps lend some credence to one or two synoptic model outputs. Neither has been totally consistent with this and this morning they broke ranks with EC showing more of an influence from the ridging to the E/NE than GFS. Unless NOAA 6-10 this evening shows some indication of any leaning towards this idea I think we can dismiss this idea. Indeed I would be surprised if this did happen based on a good many years of daily checking these outputs.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

So the occasional suggestion from either GFS or ECMWF synoptic outputs of a sufficiently marked ridge along with a marked decrease in the contour flow to allow some kind of surface high to develop giving either a slack surface flow from somewhere between SSW and ESE seems unlikely to me in the 6-15 day period from today.

 

Now to look at the MJO. I am happy enough using this in the winter as I have used it and collated its use to give me reasonable confidence in being able to use it to extend the prediction of an upper air pattern maybe out to about 3 weeks. Not so in the summer but let’s have a look. I am still of the opinion, right or wrong, that unless the orbit shown is of a reasonable size then it gives little if any guidance on upper air pattern other than what we already have. I only use one output, which is the GFS one. No doubt some will feel this is not sufficient but I believe in simplicity where possible. To use one product consistently seems to me to be better than having several outputs and then having to analyse each to decide which seems the most likely. In all honesty it is at the far reaches of my understanding of meteorology anyway.

 

So to the GFS actual MJO, see below. It is in a very shallow orbit as I call it, correct my terminology someone better practiced in this please if necessary? So it is of little use for comparison in my view.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/whindex.shtml

So what does the forecast suggest? Again see below

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foroper.shtml

Neither of the two outputs GFS or GEFS shows the orbit moving into what I call the significant area that is well away from zero. So to me it offers no guidance as to what the northern hemisphere 500mb pattern might be out towards the end of August.

 

To summarize, 6-15 days possibly longer shows little sign of any major ridge development close enough to the UK to change the current somewhat unsettled pattern. This will allow the occasional day of summery type weather, especially for the SE half of the country. But as we are seeing in the short term forecasts this does allow for, assuming the upper trough remains over/just west of the UK, for the odd day of heat/moisture, allowing thundery outbreaks to work their way northwards. Sadly, for those in the north, there is little sign of any major pattern change that might give some improvement in the farming conditions which was highlighted on breakfast TV this morning.

 

sorry it is on the rather long side

Edited August 11, 2015 by johnholmes

[Milhouse]

The ECM mean supports high pressure building around the middle of next week and the low pulling back away to the NW, which has been the general theme of this month so far.

 

[Man With Beard]

As others have already mentioned, growing support for Scandi ridge on the GEFS. It won't guarantee great weather over the UK as disturbances can get in underneath, but it would do two things: First, it may prevent low pressures parking themselves over the north, leading to S'lies or SW'lies in Scotland - so better conditions there. Second, it would give the whole of the UK a fighting chance of a continental influence - so dry and still warm, though the season for extreme heat is probably over now. Here's the T240 mean chart which is better than most charts we've seen this year - and not relying on pushes from the Azores, which have been so badly handled by the mid-term models this summer.

Meanwhile, Friday looks like it could be nasty somewhere - the NMM chart is probably overdone but is that nearly 2 inches of rain in just one hour?

Edited August 11, 2015 by rjbw

[knocker]

The GEFS anomalies this evening really don't enlighten much vis any reliable medium term evolution.

 

By the 17th we still have the Scandinavian ridge with the trough Scotland starting it's retreat towards Iceland, a slack LP France   and Azores HP away to the SW.  That leaves the northern half of the UK still in the W/SW influence of the trough and the south perhaps open to some nonsense from the south drifting north.

 

By the 21st the trough has moved closer to Iceland leaving the two HPs. one to the NE and the other to the SW in charge. The stream lines are difficult but the trough may just have enough influence to back the wind south west bringing warmer than average temps to all of the UK.

 

But surprise, surprise. by the 24th the return of the Jedi and we are looking at a N/S split again.

 

All in all a pretty mixed bag with the southern half of Britain as usual coming off best.

http://www.tropicaltidbits.com/

 

[summer blizzard]

Euro is somewhat poor days 5-7 but improves for the summer lovers days 9-10..

 

 

GEM has a stalemate and then low pressure winning out by day 10..

 

 

GFS is somewhat poor through days 5-10..

 

 

......

 

No massive departure from average however a proper summer spell remains a week or so away at best.

[mushymanrob]

id really like the noaa's to change and support these current op runs, and thats possible, but it is unlikely.

On tablet, cant post charts..

Interestingly todays noaa anomaly charts have shifted significantly in favour of high pressure dominance 6-14 day range, now if the next few days charts continue this theme then maybe summer might end on a more summery note.. But atm great uncertainty reigns.

[knocker]

On tablet, cant post charts..

Interestingly todays noaa anomaly charts have shifted significantly in favour of high pressure dominance 6-14 day range, now if the next few days charts continue this theme then maybe summer might end on a more summery note.. But atm great uncertainty reigns.

 

Yes not dissimilar to the GEFS. 6-10, the latter slightly emphasis on the trough would you believe

Edited August 11, 2015 by knocker

[Singularity]

As the jet stream close to the UK weakens early next week and an area of low pressure finds itself up against a strong high over Scandinavia, there's a wide range of possible paths for that low to follow. The NOAA anomaly this morning reflected a path that was too close to the UK for comfort, the evening ones have adjusted to a path further west with high pressure having more of a say in things. It could just as easily carry on trending that way as it could about-face tomorrow morning. I wouldn't expect massive shifts though, given that they cover 4 days at a time (hence their tendency to be more consistent than the individual model runs).

 

At this end of the UK, events Thu-Fri are demanding a lot of attention, the prospects beyond that taking a back seat for the time being.

[Frosty.]

maybe summer might end on a more summery note.

Nice end to the Ecm 12z

Edited August 11, 2015 by Frosty.

[ANYWEATHER]

On tablet, cant post charts..

Interestingly todays noaa anomaly charts have shifted significantly in favour of high pressure dominance 6-14 day range, now if the next few days charts continue this theme then maybe summer might end on a more summery note.. But atm great uncertainty reigns.

After the thundery low during late week across southern parts of the uk,  which keeps getting shunted east every day , ecm and gfs show us in a broadly Westerly pattern with low pressure in charge situated to the northwest of the Uk, Ecm is picking up on a shortwave development during Sunday sweeping into southern parts .any settled conditions always in Cloud cuckoo land!!!

Edited August 11, 2015 by Nick L
Removing inflammatory remarks

[chionomaniac]

Euro is somewhat poor days 5-7 but improves for the summer lovers days 9-10..

 

 

 

GEM has a stalemate and then low pressure winning out by day 10..

 

 

 

GFS is somewhat poor through days 5-10..

 

 

......

 

 

GFS is poor for who days 5-10? If I am reading this in West Sussex, and, oh I am, and I didn't know better (luckily I do!) then I may be off telling everyone that the weather will be poor from days 5-10. But poor in this case in this area by that reckoning would be no significant rainfall and daily temps improving from 19ºC to mid 20's by the end of the period. Perfectly pleasant and certainly not poor in my book!  A weak decaying trough situated over the UK at this time of year can yeild some potential downpours in some areas, but others can experience perfectly pleasant usuable weather especially with warm uppers. Not risk free, but not necessarily poor.

 

It may change by the next run - but this type of scenario where neither strong ridges or troughs dominate can be very difficult to determine from some time out. As can be shown by this Thurs/Fridays forecast which has was not showing the weak continental thundery low at the end of last week.