The model output continues to struggle to find the exact way forward as the global pattern is pulled in two opposing directions - toward an early-stage El Nino type setup by the Pacific Ocean, but toward more of a La Nina setup by the remnant impacts of a long period of anomalous warmth in the western Pacific that has only recently subsided (credit to Tamara on NW for identifying this one!).

In theory, the El Nino forcing should have been gaining ground with every passing week across the past four or five, yet we have seen the La Nina type setup manifest much more notably in May than we did in April.

In a nutshell, the La Nina setup favours a jet tracking from the Atlantic to NW Europe, with the Azores High tending to stay west or southwest of the UK.

This theme has been very much in evidence this month, and though has relaxed a little these past few days, it looks like it will attempt to return for a brief spell later this week - to what extent is unclear, with ECM not really taking the low toward Europe, while GFS seems very keen.

The early stage El Nino pattern contrasts strongly with the above over Europe, as high pressure becomes favoured there, tending to stick around for longer than might normally be expected (some refer to this as Euro Blocking).

Recent model output has explored such a transition taking place, but we keep seeing added complications leading to setbacks in the time of change... which to be honest is not at all unusual with major pattern shifts.

ECM has been persistent in building heights over Europe to produce a setup very much in line with the El Nino theme. On the 12z op run for days 8-10, we see the Atlantic trough weakening and the jet lifting north quite rapidly.... too rapidly? We'll see!

A day or so ago, GFS did produce a few runs with such a pattern evolving, but has since been going for some kind of hybrid solution in which the high pressure heads for Scandinavia and low pressure becomes extensive across NW Europe. The UK ends up in a run of often warm, sometimes very warm easterlies, reminiscent of 2014's June and July 'sort of fine' spells.

I'm not seeing much reason to place much confidence in either output over the other, but the recent tendency for the Atlantic troughs to be more troublesome than originally expected could be taken as a sign that ECM may land closer to the mark with this one.

This pattern shift was first picked up all the way back in mid-April, but back then it was being shown to take place in mid-May...! The big delay has made the difference between a notably warm month and a mediocre one 

Darren why trail to alaska forsnow. Glencoe you can take the chairlift up the first part of the hill then it's only a 10-15min dawdle to the snow

 Www.winterhighland.info/cams/glencoe 

 LLTNP 105m asl 

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 MAY 26TH 2015.

THE CURRENT GENERAL SITUATION A light NW flow remains across the UK with a showery Westerly flow across Northern Scotland. A new set of troughs will approach Western Britain later tomorrow..

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

MODELS-2 WEEK HEADLINE A spell of changeable weather in the first week followed by warmer and more settled weather in Week 2.

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow will blow West to East across the UK over the next few days, moving slowly South and then back North after the weekend. Then later in the run the flow weakens and breaks up as High pressure builds near the UK later next week. The flow then remains light and ill defined with regard to the UK late in the run.

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

GFS OPERATIONAL The GFS Operational today shows a spell of breezy and changeable weather up and coming later this week and over the weekend as Low pressure swings East across the North and throws troughs East followed by more showery conditions. From next week High pressure builds strongly across the UK and then to the North with winds switching East with some warm continental air blowing over the UK but with the threat of some thundery showers across the South at times through Week 2.

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

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

THE GFS CONTROL The GFS Control run shows a rather different pattern later in it's run as the innitial changeable and cool spell later this week is shown to be replaced by a ridge of High pressure near the South moving East and sending a cople of days of very warm humid air North across the UK before a breakdown is shown to develop quite quickly with thundery rain. Thereafter Low pressure is back in charge with occasional wind and rain in sometimes cool weather shown towards the end of the run.

THE GFS CLUSTERS The GFS Clusters today indicate an approximately 80/20 bias in favour towards High pressure likely to be lying close to or over the UK in two weeks time while there is just a 20% membership in the lower pressure camp with wind and rain at times under Atlantic Low pressure and troughs.

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 blustery and relatively cool Westerly flow across the UK later this week and over the weekend as Low pressure areas move East to the North of the UK on occasion. Breezy and changeable weather would occur for all with rain and showers at times in temperatures at average levels at best.

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

THE FAX CHARTS The Fax Charts are looking quite changeable still with complex if weak troughs surround the UK at times in a rather cloudy NW flow. Clearer and showery weather on a Westerly flow late in the week is replaced by a further complex array of troughs moving up from the SW later in the weekend.

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

GEM GEM this morning looks equally changeable in sequence this morning with a spell of breezy and changeable weather with wind and rain at times lasting through to the start of next week when drier and warmer weather feeds North over the UK from the South as High pressure builds. The second half of the period then looks set fair with some fine and possibly very summery conditions especially across the North and West though a chilly NE breeze is shown to affect the South on this run.

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

NAVGEM NAVGEM also shows the changeable and breezy conditions later this week lasting through the weekend and start of next week before things improve slowly across the South as High pressure is shown not far away to the South of the UK by the end of the run, restricting windier and continuing changeable conditions more towards the North only.

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

ECM ECM shows a similar theme to the rest as the changeable period lasts through to a weeks time before High pressure builds across the UK from the South from the middle of next week with increasingly warm, dry and sunny conditions for many to end the period.

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

ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last night shows a broad belt of High pressure likely to lie close to the UK in 10 days time with the Jet Stream well away to the NW with likely fine and warm weather across much of the UK as a result.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend shown across the models this morning is for warm and settled weather under High pressure  in a week or so time.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & 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 95.8 pts and GFS at 95.3. At 5 days ECM  leads UKMO with 86.9 over UKMO's 82.9 pts with GFS at 82.1. At 8 days ECM clocks in ahead of GFS at 52.6 over 46.2. Then at Day 10 ECM remains slightly ahead of GFS at 30.3 pts to 28.4 pts.

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 main theme of the models this morning is the change in the weather that looks likely to develop next week as nearly all models support an up and coming period of changeable weather with rain and showers being replaced by something much more like early Summer later next week. We have another day or two of benign weather under a slack NW flow before falling pressure from the West and North feeds some troughs across the UK with rain and then showers later this week. Then over the weekend a further Low to the NW will drive more rain bearing fronts NE over the weekend but it's behind these that conditions look like improving, first in the South over the early days of next week and then more widely as High pressure becomes much more prolific for all. Much of the output well supported by the ensembles indicate that a period of fine and warm or very warm weather is likely as we enter further into June although the risk of a few thundery showers across the South is also a possibility later. So all in all reasons to be optimistic that the UK could see some summery weather soon with the rains of the coming 4-5 days giving ideal growing conditions for many in the coming weeks as temperatures at last look like reaching the 20'C regularly from the middle of next week.

Next update from 08:00 Wednesday May 27th 2015

Excellent, Martin! Starting to look increasingly like another good example of not pinning thoughts on model output beyond a few days is about to manifest. 

Of course that could be equally true of this if it doesn't happen, but it still shows how quickly things can change. 

And this is where I come in with my own "glass half empty" view to balance things out.

Indeed, confidence is growing by the day over this high pressure orientated theme as we go into the first week of June, even though that is still miles away in forecasting terms. My concern is that IF and when it does actually come off, will the high pressure cells have a habit of parking themselves too much to the north of the UK while on the way to Scandinavia? That's what I've been seeing on the models lately.
   If so, the East Coast (including East Kent) may keep picking up neverending clag rolling in form the North Sea while Northern and Western parts end up with experiencing the best of the home grown warmth - AKA just like the summers of 2013 and 2014 with Matty supping beer on his decking while I end up looking like a freshly plucked chicken while sat in my front garden here at East Kent.
  Of course, it'll depend on SST's around the coast, I think they are slightly higher up on this time last year from what I've read somewhere else on the interweb?

But that's assuming if the medium range forecast does actually come off so there is still a lot to play for.  

Thank you Martin. Great output for early welcome summer....

ECM and GFS continue to disagree on significant aspects of the pattern evolution beyond day 5.

In short, there will be an area of low pressure to the northwest of the UK this weekend which will either head east to affect the UK directly (ECM) or be absorbed into another area of low pressure exiting Canada (GFS).

The ECM solution has us waiting another few days for the low pressure to clear away to our NE, after which high pressure arrives from the southwest (day 9 chart shown above-right). That low to the NE prevents a quick transition to a Scandi High taking place with more of a UK/NW Europe High looking to hang about.

The GFS option results in high pressure arriving on the scene in 6-7 days time (above-left) so slightly sooner than what ECM offers. With no low to the NE, the high drifts to Scandinavia by day 10 while low pressure develops over Iberia. Most recent operational GFS runs have featured this sort of evolution, while ECM has been a lot less keen on the Iberian Low theme. 

I know that GFS has convective feedback issues in hot airmasses so that may be a significant factor behind its behaviour. With a broad-scale trough looking to be situated N and NW of the UK by day 10, I'm skeptical of any full-on Scandi Highs being shown, with more of a 'Scuero' high more realistic - this usually manifesting as a ridge from SW of the UK to somewhere near or over the Baltic Sea, the southern extent being important as far as possible Iberian Lows are concerned.

Not by me they won't. It's our bank holiday weekend next weekend and it does seem a bit like sod's law that the fine spell is due to start more or less immediately after our bank holiday...

Thanks. Really pleased to have met you yesterday being as we live less than 5 mls apart. Lets hope the charts this morning verify. I'm quietly optimistic about a good June this year.

A few rippers appearing in the GEFS6z today: 

Hi all,

Here's today's video update;

A Taste Of Summer Next Week;

http://www.gavsweathervids.com/

High pressure may well turn it drier + significantly warmer.

http://www.wetterzentrale.de/pics/Rtavn34811.gif

My favourite chart of 06Z 

Remember James mentioning a few weeks back about a potential summer of hot spells and thundery breakdowns? I wonder.....

We might finally touch 20C next week anyway.
At the moment it looks potentially quite hot first week of June.
A odd 'record' here is how it's not unusual we have the hottest day of the year in late May or early June (then it goes a bit wrong after that....)

is this already a downgrade for next weeks improvement or just a further delay?

Neither. It's always been there. 

There may have been individual charts or even runs, but taking all into account and ens, it was pretty much along these lines. Could all change of course - for the better or worse. 

I wonder because the media have been going on about this in todays papers - I hope its just a delay and nothing worse.

What we see in the ECM 12z op run is yet another area of low pressure refusing to mature and stall out as soon as originally projected. Whether this turns out to be the case with this one or not, we've seen such a trend a number of times lately, with the jet stream proving a bit more energetic than is usual for the time of year.

One look at the Atlantic SST anomaly pattern at the moment reveals a potential driving mechanism:

That's a striking pattern isn't it? Anomalous cold to the north of anomalous warmth. The result is a temperature gradient some 2-6*C greater than we would see in an entirely average setup.

I can see how this could have a large enough impact on the atmospheric temperatures to give the jet stream a bit of a boost, as polar air remains colder on it's way south and tropical air remains warmer... which of course means more vigorous low pressure systems with the potential amount of rainfall and peak wind strength both enhanced.

Interestingly though, we've also been seeing a strong, persistent Azores High this past month. It could be that we find ourselves heavily dependent on it's influence to save us from changeable westerlies this June. In light of which, having strong signals from the models for a setup that favours ridges getting right across to eastern parts of Europe is a very good thing indeed!

As a final thought for the day, all that anomalous warmth to the SW of the UK probably helped produce that very clammy, largely cloudy yet somewhat warm Friday across the far south last week. I can see how we could go through a fair bit of that this summer. Brace yourselves 

Thank you for your detailed analysis 😊