UKMO is much faster with the Atlantic trough later next week, which is often the case with systems to our NW in particular. I remember this being pointed out as a known bias during a few of the NOAA discussions last winter.

GFS has slowed it down by a huge amount over the past six runs, which does lower confidence in it's output, but when it comes down to it ECM is not far away from GFS at all, which lends some credence to the idea of the Azores High gaining some influence again with a flatter (i.e. more west to east rather than north to south) jet pattern trying to establish.

Both models go on to show the pattern trying to re-amplify a bit, but the flatter solution for Wednesday to Friday effectively shifts the position of the amplified ridge further east than what we've seen of late, leaving us settled but a little on the cool side:

With Atlantic lows trying to flatten the ridge and height rises starting to occur across Europe, this is a fairly good position to be in if you're looking for the Azores High to extend right across the UK in the 10-14 day range. No surprise, then, that GFS has a fair old go at it on its 12z op run. The high does then pull back west and north late in the run, but with what's taking place regarding next week, I'm skeptical of such signals.

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 SATURDAY MAY 16TH 2015.

THE CURRENT GENERAL SITUATION A Westerly airflow will cover the UK today and tomorrow with High pressure to the SW. Some showers in the flow will affect Northern areas at times.

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

MODELS-2 WEEK HEADLINE Changeable with some showers at times especially over the North and East but spells of dry and fine weather too for all. Generally rather cool, especially by night.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream is currently blowing West to East across Northern Britain. Over the next few days Low pressure from the North changes the flow to a SE one across western Britain down into Europe with the UK falling on the cooler side of the Jet as the pattern of a trough or troughs across the UK is maintained for some considerable time.

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

GFS OPERATIONAL The GFS Operational this morning shows Low pressure moving SE down over the North Sea early next week carrying a band of rain followed by cool and showery weather afterwards. then soon after midweek a short drier interlude for the South is replaced by a second pool of cool and unstable air movng down from the NW and lasting through the Whitsun holiday weekend. In the extended period pressure patterns become more slack and non determinate with a slow shift of the cool and showery weather away from the UK in the wake of a switch of wind to the South or SW very late in the run with warmer conditions moving North from the South or SW.

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

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

THE GFS CONTROL The GFS Control run shows good support to the operational run this morning with the next 10 days weather fairly identical in type with just small nuances surrounding the distribution of rain and showers over the period day to day. late in the run some divergence is indicated with this run showing High pressure building strongly in from the West in two weeks time with dry and warmer weather for most by then as a result.

THE GFS CLUSTERS The GFS Clusters once again are High pressure biased for two weeks time today with the balance of emphasis having a High centre just to the West of the UK or over the NW with less than 30% showing anything more Atlantic Low pressure based and even this most likely affecting just the NW rather than elsewhere.

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 this morning shows a cool and changeable period for much of next week as two separate Low pressure areas move down from the NW, one early in the working week and one in time for the Bank Holiday weekend, each bringing their own version of cool weather with showers and more persistent rain for a time on Monday and probably again towards Thursday and Friday..

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

THE FAX CHARTS The Fax Charts show a cool and blustery West then NW airflow next week around Low pressure to the NE of the UK with troughs bringing rain on Monday and then a cool and showery NW flow. Further troughs are shown to be poised to the West and NW of the UK by the 120hr frame probably affecting the UK over the start of the Holiday weekend.

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

GEM GEM this morning also shows two separate Low pressure zones moving down from the NW over the 10 day period. The first will bring rain Monday and then several days of showers in a cool NW flow. The showers look like dying out in the South midweek ahead of a new Low slipping SE towards the Holiday weekend and becoming slow moving and slack across the North Sea late in the run delivering the risk of cool and sometimes heavy showers throughout the Bank Holiday weekend.

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

NAVGEM NAVGEM follows a similar trend with the cool theme maintained throughout next week and the Bank Holiday with showers in places as Low pressure lies just to the NE and a light Northerly drift lies down over the UK. A High pressure ridge lies close to the West though by the end of the run.

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

ECM ECM is just a little more optimistic longer term this morning at least for Southern areas over the Holiday weekend. It too shows a very cool and showery period next week as the first Low moves SE down across the North Sea towards midwek with several days of heavy showers and sunny intervals in a cool wind. The second Low's trajectory is much further North on this run and only influences the North in any large way where showers continue. In the South under higher pressure and lighter winds a lot of dry weather would likely prevail in this runs setup with just well spaced and lighter showers down here as a result though still never overly warm.

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

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  maintains the stance of a slack Northerly or NW flow with sunshine and some showers in temperatures close to or a little below average generally. The South and West closer to the effects of a ridge to the SW should hold the driest and least showery weather.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The model output trends toward rather cool conditions in Northerly winds slackening later but maintaining temperatures at best average and sometimes on the cool side especially by night..

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 96.7 pts followed by UKM at 96.0 pts and GFS at 95.2. At 5 days ECM  leads UKMO with 85.7 over UKMO's 84.2 pts with GFS at 82.3. At 8 days ECM remains the leader with 52.1 pts over GFS's 51.2 pts. Then at Day 10 GFS gains superiority at 34.1 pts over ECM at 33.3.

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 Once again this morning it's all eyes to the NW for our weather over the coming two weeks as High pressure lies out to the SW and a cool and often showery feed of winds blow down across the UK. Next week looks particularly shower for the first few days with some heavy showers with hail and thunder locally but some compensatory sunny intervals between too but with temperatures certainly nothing to write home about especially at night. Then a respite looks possible across the South for a time soon after midweek before the chance of a resurgence of Low pressure moving down from Northern latitudes towards Scotland has a fair amount of support again this morning. This would have the effect of upsetting the Bank Holiday weather with showers or rain at times especially early in the weekend in a continuing cool feeling airflow. The Southwest always look like seeing the best weather over the two week period with the least showers and some daytine sunshine more enhanced here despite never feeling overly warm in the nagging NW breeze. ECM is the beacon of hope for this morning as it doesn't really support the second Low as close keeping it's effects more towards the North only and meaning the South at least see a pleasant period over the Holiday weekend at least in lighter and less chilly west winds and only very occasional showers. So all in all it's still a case of waiting for temperatures to achieve summer levels as it looks like they won't in the next few weeks with the warm spell of mid April likely for me at least still holding the record of the highest temperatures so far this year even by the end of this run. having said that if you can avod the showers and cool, breezes the sunshine between the showers will feel pleasant enough and should enable most outdoor events to continue unhindered even if that means I'm clutching at straws from within rather uninspiring late May charts.

Next update from 08:00 Sunday May 17th 2015

ECM is the beacon of hope for this morning as it doesn't really support the second Low as close keeping it's effects more towards the North only and meaning the South at least see a pleasant period over the Holiday weekend at least in lighter and less chilly west winds and only very occasional showers.

qutoting Gibby.  

Agreed. Given ECMs legendary better than others verification statistics, if there was one model at 8 days you would want to be on the optimistic side, it would be the ECM.

ECM doesn't look so bad, neither the GFS

Are we there yet? The models have really had a field day trying to sort out what the second of next week's Atlantic troughs gets up to.

It seems to have largely been an issue with how soon this second trough manages to start developing as it interacts with the jet stream. The sooner it does so, the sooner the jet starts to head south down the western flank of the trough.

The strength of the jet in about 4 days time is an important factor; a stronger jet leads to faster LP development. Comparing the 00z (left) and 12z (right) GFS output for this range reveals a substantial reduction in jet intensity in the vicinity of that trough:

So we see the trough developing less rapidly, meaning the jet dives south further east than had been projected on the 00z op run, and it appears that the trough may bottom out as a weaker feature as well, which reduces the magnitude of the northerly that we seem likely to experience:

The 12z on the right also features a much better defined section of relatively flat jet to the north of the Azores High. That has the potential to encourage the high to extend further east - but it may be a case of taking many small steps to achieve a bigger goal. This particular run takes until a fortnight from now to get that high right across but the results are very nice to look at (below-left). Meanwhile ECM's 12z op run (below-right) almost manages to set up a UK high some 6 days sooner - but this attempt fizzles out over the following two days leaving us looking to our SW again for another push from the Azores.

So, some light at the end of the tunnel starting to come into view perhaps. Speaking of light, it's hanging on in the sky out there even at 9:30pm... the long days are with us!

The 18z GFS op run looked at the 12z ECM op run, liked the idea, then made further improvements!

With a better defined trough over NW Africa, the Azores High is able to extend a ridge well into Europe. This brings a vast expanse of tropical maritime air to the UK. While not necessarily the sunniest of setups, it's good for getting temperatures up into the 20's for most places in England and a good number in Wales, eastern parts of Scotland doing pretty well too 

The theme keeps on going right to the end of the run with little sign of letting up - the Azores High being as friendly as it gets without morphing into a Euro High and drifting away from us!

The question now is whether GFS is right to be carrying on with the trend of the past 18 hours. The 00z runs will be of heightened interest given how shoddy this morning's offerings were - except for ECM's of course, and kudos to that model if we do see the Azores High taking control from Thursday onward.

Thanks James. Excellent analysis as always. 

Speaking of expert analysis - I'd be interested to hear Moomin's take on things. 

thanks for calling me an expert!! Lol.....just an enthusiastic shameless amateur!

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 SUNDAY MAY 17TH 2015.

THE CURRENT GENERAL SITUATION A Westerly airflow will cover the UK today with a cold front moving SE across the British Isles tonight and at first tomorrow followed by a showery WNW flow in association with low pressure close to northern Scotland later tomorrow..

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

MODELS-2 WEEK HEADLINE Changeable with some showers at times especially over the North and East but spells of dry and fine weather too for all especially later.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream is currently blowing West to East across the UK. Over the next few days it moves a little South and weakens as a UK trough over the UK moves away slowly East by late week. Then the weakened flow gradually returns to running West to East over the UK later in week 2 as a UK trough develops again.

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

GFS OPERATIONAL The GFS Operational this morning shows Low pressure moving SE down over the North Sea in the next few days carrying a band of rain followed by cool and showery weather afterwards. Then soon after midweek a ridge of High pressure from High pressure to the SW ensures a drier spell in the South while a new Low well to the North of Scotland brings a new trough SE down across all areas late in the week with damp weather for a time then dry weather again for the South. The Bank Holiday weekend looks set fair for many areas under a ridge from the Azores High and this extends into the second week too before the slow return of Atlantic Low pressure and rain at times for all returns late in the period.

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

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

THE GFS CONTROL The GFS Control run shows good agreement to that shown by the operational this morning with a ridge of High pressure stretching across the UK at times after the cool and showery first half of this week to bring fine and dry weather for many. Cloud amounts look rather variable at times and a little rain at times is conceivable over the North but it looks like the High will continue to expand it's influence though the Bank holiday weekend and through week 2 as well.

THE GFS CLUSTERS The GFS Clusters show a roughly 60/40% split in favour of fine High pressure based weather over a NW flow from the other 40%. This means that most areas look like being dry and fine in two weeks if the 60% of members are to be believed under High pressure just out to the SW or over the North of the UK. The 40% cluster would bring a cooler NW flow with scattered showers chiefly in the North and East.

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 this morning shows a cool and changeable start to the coming week with sunshine and showers before a ridge introduces dry and bright conditions over the South soon after midweek. A weak cold front brings a band of rain South late in the week followdd by a scattering of showers again before pressure is shown to build strongly from the SW for the Bank Holiday Weekend with likely fine and dry conditions developing for then.

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

THE FAX CHARTS The Fax Charts show a complex trough moving SE across the Uk tonight and tomorrow with a showery WNW flow following to all and lasting several days before a ridge develops across the South while weaker fronts affect the North by the end of the working week.

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

GEM GEM this morning is not quite so optimistic for the second half of it's run but in full agreement to the conditions shown by other output over the coming 5 days. It then fails to build High pressure is as strongly as the other output and as a result the UK remains affected by chilly NW winds with rain and shower bearing troughs pushing SE across the UK at times in the continuing cool weather.

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

NAVGEM NAVGEM too is a little more tentative as well in it's build of pressure at the end of the week with the changeable weather of the week to come slowly giving way to drier and bright weather across the South under a ridge next weekend but an Atlantic front crossing East over the North would probably bring cloudy and damp weather to northern areas next Sunday and rather cloudy weather as well at least to the South.

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

ECM ECM is much less like UKMO this morning in building High pressure across at least Southern Britain next weekend ensuring a reasonable weekend down here at least. The North will be a litle more disturbed with weak troughs crossing East on Bank Holiday Monday with a litle rain, this then moving slowly South to Southern areas too on Tuesday before the run ends with High pressure having built back across the South and a traditional North/South split in the weather looking like setting up thereafter.

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

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  shows a large High North of the Azores stretching a ridge across towards Southern Britain with set fair weather most likely for the South while a Westerly flow across the North is most likely to bring any rain to these areas alone.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The model output have shifted towards much more influence shown by the Azores High in week 2 first picked up some days ago by the GFS Ensemble pack and extended now across much of the other output too.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 96.7 pts followed by UKM at 95.9 pts and GFS at 95.2. At 5 days ECM  leads UKMO with 85.8 over UKMO's 83.7 pts with GFS at 82.2. At 8 days ECM remains the leader with 51.0 pts over GFS's 50.2 pts. Then at Day 10 GFS gains superiority at 34.1 pts over ECM at 32.5.

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 Reasons to be much more optimistic about the output this morning which includes the Bank Holiday weekend for many as the previous days output of a cool and very showery NW flow blowing down across the UK at that time have been largely replaced by much more dominance from a ridge of High pressure stretching across the UK from our old friend the Azores or North Atlantic anticyclone through the second week of the outlook. The pattern for this week though is as before with a Low pressure zone pushing SE over the North and NE in the coming days ensuring cool and showery conditions for all for several days following a band of rain tomorrow. Thereafter the second advance of Low pressure from the North has been much muted with the Low holding much further North and as a result just a weak front late in the week looks like bringing damp weather down followed by a more pronounced push of a ridge across the UK nicely timed for the Bank Holiday Weekend which on current thinking should bring quite reasonable weather to many, certainly across the South and while not excessively warm the tempered effects of a Westerly breeze over a Northerly should mean temperatures achieve average levels at least. Then as we look towards the end period of the extended output this morning High pressure looks generally in control with fine and dry weather for many with just the far North at risk of Atlantic fronts brushing by at times and perhaps a cooling NE breeze in the SE. It's hats off to GFS Clusters for showing this scenario first a few days back bucking the charts from the highly respected Euro's then and now shown across nearly all output. So in a one sentence nutshell the next two weeks should see sunshine and showers in cool weather gradually be replaced by drier and somewhat warmer weather through Week 2 with just a little rain at times possible over the North.

Next update from 08:00 Monday May 18th 2015

^^^^^^

Thanks Martin.

Looks like we could get away with a fairly reasonable BH weekend. GEM unsettled though and after how it lead the pack Re. the change from April's fine weather to the unsettled pattern for May, I wouldn't discount it.

 I do still remain confident that the pattern will remain in this cool and unsettled vein for some considerable time. The charts just cannot settle down consistently at the moment which to me is a sign of much chaos. The default pattern at present is cool and unsettled and I believe it will be a fairly long time before that changes for the better.

The Meto clearly think high pressure will win out, according to their latest forecast update. Long way out a couple of weeks though. Moomin had wrote off at least the next month and alluded to summer altogether only days ago. A few pointed out at the time a lot can happen in a few days. 

Bottom line is expect the worst and you can't be disappointed 

I have written off the rest of this month Matty yes....and all I say is these patterns can prove stubborn to shift. I said I would not be surprised if it stays locked in for several weeks, but that was not a forecast.  I am actually quite encouraged by the MetO update today and also ECMWF which appears to be more bullish than the others to bring the Azores ridge into play.
As I just mentioned also, GFS 0Z is regularly showing the most unsettled and cool charts which are regularly being modified on subsequent runs.

Moomin, you posted this less than two weeks ago:

"Couldn't agree more Albert. As per usual we are paying a heavy price for a nice April. I would not be surprised if this pattern did not continue well into the summer. Warm April crap summer"

Just earlier this week from Mystic Moomin..

"Every chance that block will go nowhere fast into early summer Albert. Terrible charts at the moment as you say."

To which someone replied: "summers is over then"

Moomin's response..

"Not at all. Whether it actually starts is another question. When was the infamous year without a summer?"

So I didn't actually say "summer is over" - I just questioned when was the last time we had no summer!

Jesus lighten up everyone, I'm just making tongue in cheek throw away remarks (as I always do).

I get hacked off with everyone constantly bitching and sniping at me.

I've been a member of this forum for seven or eight years, and will continue to be so.

Regarding my comments below, yes there is every chance the block will go nowhere fast. There is also every chance that there will be a crap summer.

At no time did I STATE there would be a crap summer. Just offering opinion.

For what it's worth, using the same methodology that I always have used, I am formulating my annual summer LRF as we speak, and no, I do not think summer will be a write off!

I certainly don't expect anything like 2007 or 2012 as it stands, but equally, I don't anticipate a repeat of 2003 or 2006 either.

How about you guys live and let live. I am not on a wind up, I am not a troll, I am merely an enthusiast like everyone else.

And I would expect a little bit of respect for the seven or eight years I have been here, and for the countless times people have praised me for my posts, my thoughtful analysis (whether right or wrong) and for my reasonable intellect.

I stopped being a numpty on this site many years ago, I don't intend to revert to those days.

I am extremely humble. All I would say is please wait until I put my summer lrf on here and shoot me down in September when its wrong. 

The GFS 12z op run is acceptable in the 5-8 day range.

After that it can just fudge off 

Okay, some details might not go amiss - today, the model's operational runs have kept on initiating trough development in the vicinity of Scandinavia in 7-9 days time, forcing a retreat of the Azores High back west, leaving us at the mercy of a cool or even chilly regime with showers for the north in particular.

This tendency is an abrupt change of tune to yesterday's trend, which was toward less LP development to the NE of the UK and the Azores High pushing right on into the UK and NW Europe.

ECM was having none of GFS' new ideas on it's 00z op run today, and I hope that the 12z will continue to do so.

I have to say, with lowering heights in the Greenland area in the mid-range, I'm surprised that GFS isn't throwing out some zonal runs here and there. The level of amplification being projected in the 8-16 day range is unusually high, and comes at a time of year (the final week or so of May to around mid-June) when we often see a 'flat westerly' regime trying to take over proceedings, producing a north-south divide with variable temperatures. 

I suppose we are seeing some evidence of the usual change trying to occur, as a strong jet streak in the middle of the North Atlantic aids the ridge extending from the Azores High to the UK from Wednesday next week through to the weekend.

Maybe this is one occasion where the typical westerlies have the potential to re-arrange the pattern into one that promotes warmer conditions in the UK, with yesterday's 12z and 18z GFS op runs very much in favour of this, this morning's ECM 00z op giving it a good chance, but this evening's 12z GFS op in particular having none of it.

Not even Sherlock could solve this one. More model runs is the only way to do it! 

Best thing to do IMO Moomin is wait and see what transpires over the next three months, instead of either being too downbeat about the summer or talking up the chances of it being a good one too much at this time. That way, no-one will be able to level any criticism at you.

FWIW, I recall that at this time two years ago, and on the back of six poor summers on the trot, some were predicting that summer 2013 would be another horror show. It gave us the best & longest lasting hot spell in this country since 2006. Likewise, last year some were expecting summer 2014 to be a disappointing one, and in the end it was for the most part a pretty decent one, certainly from about mid-June to the end of July. Pot luck plays a big part in what we get in the summer in this country, indeed at any time of year.

Again we see more westerly momentum retained by ECM which with the expected broad-scale setup works in our favour by having the Atlantic troughs make it some way east of us before digging south much.

Based on what's happened with the trough later this coming week, I suspect the developments beyond the weekend will swing about a fair bit once again, but there's no telling if we'll see the same outcome for what would be the third time this month - the one this coming week is cancelled diving trough number two... imagine the toys thrown out of prams if this was the heart of winter! 

Final point today - just noticed how much the 18z GFS op has swung back east with the pattern:

That makes two 18z op runs in a row that have been more keen on progressing the high pressure right through the UK. Coincidence? Most likely, though there are those who speak of each set of runs (00z, 06z, 12z, 18z) having their own mysterious tendencies.