Model Output Discussion - 3rd May Onwards 00z--->

[bluearmy]

I think you are spot on...as it frustratingly appears was my previous carrot and stick analogy. Whilst any major change remains stubbornly in the 8-9 day range it's seems rather foolish to assume anything imo, but hey ho, that's just an opinion.

Looking back through the recent ECM 00z ops and the high has never been modelled to arrive before the 3rd June.

[Frosty.]

This evenings Ecm 12z ensemble mean shows the south becoming settled by the middle of next week and then the fine, dry and warmer weather spreads north to the rest of the UK before the end of next week. This is also what the met office have been saying and it's showing on all the models, it's looking good

[knocker]

I think you are spot on...as it frustratingly appears was my previous carrot and stick analogy. Whilst any major change remains stubbornly in the 8-9 day range it's seems rather foolish to assume anything imo, but hey ho, that's just an opinion.

 

And last Monday's EC32 had the transition on the 3rd of June.

[BlueHedgehog074]

For the 3rd day in a row, the 8 to 14 day 500mb anomaly chart from the NOAA maintains heights rises over the UK and to the East of it, along with ridging to the East/South-East of the UK. As such, it still seems quite confident that a build of pressure will occur. And with the 500mb flow still backing from the South-West over Great Britain, some (much) warmer conditions could be likely at times. Although it's true that any build of High Pressure from the South or South-West of the UK is still locked in the jail of Fantasy Island on numerous operational models, it's nice to see the NOAA anomalies maintain its theme of building heights over the UK. The chart does fit along with the sort of period that some of the models build heights at  - the 7+ day period. It's perhaps worth mentioning that the anomaly chart doesn't seem to think pressure will build quite as far North like it does on the 12Z GFS run (where it builds High Pressure to the North of the UK). 

 

Have attached tonight's NOAA anomaly chart, plus the previous two updates, to show their consistency - could mean that a settled, and perhaps much warmer spell, is indeed very well possible. This could also make an amusing game of 'spot the difference'...

Edited May 27, 2015 by DiagonalRedLine

[knocker]

Last night's ECM anomaly agrees with the transition by the 4th and maintains this into the ext period although with a tendency to split the HP to the NE and western Atlantic with a slack area of LP west of Iberia.

 

More immediate issues this morning's GFS has the fronts into western Britain by 06 Sunday and has the depression northern Scotland 48hrs later. Could be quite windy in the southern quadrant.

http://www.tropicaltidbits.com/

 

[Polar Maritime]

High Pressure continues to show to push North around 3rd/4th by the GFS, With the South possibly reaching 27c by next Friday, Although the far North could remain cooler/cloudier. And again as Knock rightly says, The Low Sun/Mon still looks to have quite a sting in it's tail..

 

[mushymanrob]

For the 3rd day in a row, the 8 to 14 day 500mb anomaly chart from the NOAA maintains heights rises over the UK and to the East of it, along with ridging to the East/South-East of the UK. As such, it still seems quite confident that a build of pressure will occur. And with the 500mb flow still backing from the South-West over Great Britain, some (much) warmer conditions could be likely at times. Although it's true that any build of High Pressure from the South or South-West of the UK is still locked in the jail of Fantasy Island on numerous operational models, it's nice to see the NOAA anomalies maintain its theme of building heights over the UK. The chart does fit along with the sort of period that some of the models build heights at  - the 7+ day period. It's perhaps worth mentioning that the anomaly chart doesn't seem to think pressure will build quite as far North like it does on the 12Z GFS run (where it builds High Pressure to the North of the UK). 

 

Have attached tonight's NOAA anomaly chart, plus the previous two updates, to show their consistency - could mean that a settled, and perhaps much warmer spell, is indeed very well possible. This could also make an amusing game of 'spot the difference'...

noaa 1..gifnoaa 2..gifnoaa 3.gif

i fully agree .

i can understand the caution some posters are expressing, but from next wednesday onward theres consistent agreement across all data sources that pressure will rise from the south, gradually, to herald a spell of settled, dry, sunny and warm weather. ill be happy with that this early in summer! heat can come later (assuming we dont all get it this time).

it also makes the coming fresh, unsettled and wet weather necessary if we are heading for a dry spell.

Edited May 28, 2015 by mushymanrob

[Frosty.]

Not long to wait now guys, the Gfs 00z shows warm and settled weather for southern UK by day 6 with temps around 68-70F, and nearer 75-77F (24-25c) later next week. It takes a little longer for the north to become settled and warmer. Through low res (post T+192 hours) high pressure keeps building in from the Azores. We are on track for a BIG pattern change to settled and warm/very warm conditions.

[coldcomfort]

i fully agree .

i can understand the caution some posters are expressing, but from next wednesday onward theres consistent agreement across all data sources that pressure will rise from the south, gradually, to herald a spell of settled, dry, sunny and warm weather. ill be happy with that this early in summer! heat can come later (assuming we dont all get it this time).

it also makes the coming fresh, unsettled and wet weather necessary if we are heading for a dry spell.

Still need to wait for the currently updating ECM, but the latest GFS remains encouraging whilst the UKMO at 144hrs does not looks anything like as promising.

 

Edit: ECM looks just about OK for the south post this time next week, but much of the country remains relatively unsettled up to the weekend, especially the far north and west.

 

Still nothing fully set in stone yet imo.

Edited May 28, 2015 by coldcomfort

[Captain Shortwave]

Better set of charts this morning regarding the potential pressure build from the 3rd of June onwards.

The ECM at least is now suggesting some warm to very warm weather, especially in the south with unsettled intrusions minimised compared to previous runs.

 

The models have tended to dig the trough on the 2nd southwards to give the south of the UK the most unsettled weather, which then leads to the question of weather we will see a slower and more southerly trajectory of the next low in the Atlantic? Not a bad thing for us as that would give the GEM output this morning a bit more credence.

Classic spanish plume set up with the +18C isotherm getting into England with very warm or hot weather developing before thundery rain pushes northwards.

This set up could be worth watching to see if it is replicated. The other models tend to rush that trough through eastwards, though it never really effects the UK.

[knocker]

Still need to wait for the currently updating ECM, but the latest GFS remains encouraging whilst the UKMO at 144hrs does not looks anything like as promising.

 

Edit: ECM looks just about OK for the south post this time next week, but much of the country remains relatively unsettled up to the weekend, especially the far north and west.

 

Still nothing fully set in stone yet imo.

 

I'm not exactly sure what you are looking for. You are never going to get anything 'set in stone' a week or more down the line. The best one can hope for is consistency in the upper pattern between the main models.. Intense perusal of each ops run is likely to induce vertigo.

[bluearmy]

I'm not exactly sure what you are looking for. You are never going to get anything 'set in stone' a week or more down the line. The best one can hope for is consistency in the upper pattern between the main models.. Intense perusal of each ops run is likely to induce vertigo.

We could always wait until after the faxes come out but then this place would even more of a morgue than it usually is outside of winter and plumes.

this change has been on the cards for several weeks but it has struggled to eventually come to fruition. as I posted a couple of days ago, the idea that the high would just extend ne and bring countrywide sunshine at the flick of a switch wasn't on the agenda.

Even if we end up stuck between the blocking and shallow upper troughing (giving less settled overall) it will still be a different feel to the weather as we will have lost the colder air. Summer is arriving. Bit late but it's coming.

[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 THURSDAY MAY 28TH 2015.

 

THE CURRENT GENERAL SITUATION A Westerly flow across the UK will persist with a trough of Low pressure crossing Central and Southern parts of the UK tonight and tomorrow followed by a brisk NW flow later.

 

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

 

MODELS-2 WEEK HEADLINE Changeable, windy and cool at first then drier, warmer and sunnier for all later.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows an unusually strong Jet flow crossing East over the Atlantic and the UK and this is shown to persist for another 5-7 day if anything strengthening somewhat early next week. The trend thereafter is for the flow to ease North across Scotland and weaken too eventually breaking up and becoming ill defined as pressure rises.

 

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

 

GFS OPERATIONAL The GFS Operational today shows an improving period of weather developing across the UK from the moddle of next week. In the interim period the weater will be far from pleasant and quite inclement at times as Low pressure just to the North sweeps active troughs East across all areas at times with wind rain and showers affecting all areas at times. Then High pressure eases up from the South with fine and dry conditions developing along with more seasonably warm temperatureslate next week and in Week 2 with High pressure likely to lie over or close to the North with the best conditions here and the risk of a few showers at times in the extreme South or SW.

 

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

 

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

 

THE GFS CONTROL The GFS Control run looks broadly similar to the operational this morning  with the theme between the two showing rather less potency across the South of the UK early next week of the Low pressure shown further North than recently. The Control run then shows High pressure in control over or near the UK thereafter with fine and warm conditions developing for all.

 

THE GFS CLUSTERS The GFS Clusters today are quite confusing at first sight with a lot of slack pressure gradients shown across the Atlantic and Europe in general. All this made up from different options of position of High pressure in relation to the UK but still with the fundamental message that fine and dry conditions are likely to prevail over the UK in two weeks time.

 

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 continues to show Low pressure further South than GFS taking a centre across the UK early next week and maintaining cool and unsettled weather across all areas up to the middle of next week before hints of a rise of pressure from the SW are shown on the day 6 frame shown below.

 

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

 

THE FAX CHARTS The Fax Charts continue to show a plethora of troughs affecting the UK between now and the middle of next week driven by Low pressure areas moving across the UK or just to the North periodically from the West in cool Atlantic winds.

 

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

 

GEM GEM shows Low pressure sinking into the UK early next week from the NW with showers or longer spells of rain affecting all areas at times over the weekend and start to next week. Thereafter pressure slowly recovers, on this run from the SE allowing a humid Southerly flow to develop in association with Low pressure over the Atlantic and drawing the risk of heavy, thundery rain to feed North across the UK before things finally looking like settling down more widely by the end of the run.

 

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

 

NAVGEM NAVGEM also shows the Low early next week digging deep into the UK as it transfers East by midweek bringing cool weather with wind, rain and showers across the UK ahead of a marked improvement in both temperatures and better weather in genral as High pressure builds from the South later next week.

 

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

 

ECM ECM also shows the Low across the UK early in the week with rain and showers foremost in the weather in cool and windy conditions. Then a tentative build of pressure develops midweek affecting the South first and then all areas later as High pressure from the Azores eventually is shown to ridge all the way across Scotland to Scandinvia later with a NE flow across the South with dry, fine weather for all but temperatures likely to be somewhat lower than elsewhere in the SE on this run.

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last night still looks favourable for dry and reasonably fine conditions to look likely to be the favoured option for the UK in 10 days as High pressure from the Azores ridging across the UK is maintained.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend for better weather a week from now remains with pressure expected to rise from the South.

 

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 96.6 pts followed by UKM at 95.6 pts and GFS at 95.2. At 5 days ECM  leads UKMO with 86.8 over UKMO's 82.4 pts with GFS at 82.2. At 8 days ECM clocks in ahead of GFS at 52.2 over 45.1. Then at Day 10 ECM remains slightly ahead of GFS at 30.1 pts to 25.1 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 focus of the models this morning is the vast change from the synoptics across the UK early next week to those expected just 1 week later as the message remains that after a period of inclement and unseasonably windy and unsettled weather early next week the pendulum swings to more settled and warm weather with sunny spells under synoptics that generally mean that once established they can tend to last for some considerable time. So after a generally somewhat cool May with some areas having a wetter month than usual too June looks no better to start with as cool Atlantic winds, rain and showers occur everywhere ealy in the month. However, after a few days High pressure building from the South shown by all output brings a change to fine and settled weather with some warm sunshine for all. The most popular consensus is for High pressure to generally end to the North of the UK  with an Easterly flow towards the South. If this sets up as some output shows warm air over the continent should feed West across the UK but as this crosses a cool North Sea we will have to watch for sea haar and fret to affect Eastern coasts making for cool dull conditions here while in addition thundery showers could ease up from the South of Europe later as lower pressure looks like being likely there but all in all it looks like an improvement is still very much on the cards between the models this morning with just the fine detail of positoning of High pressure likely to be instrumental in determining day to day degrees of warmth and sunshine in any one place across the UK.

 

Next update from 08:00 Friday May 29th 2015

[knocker]

We could always wait until after the faxes come out but then this place would even more of a morgue than it usually is outside of winter and plumes.

this change has been on the cards for several weeks but it has struggled to eventually come to fruition. as I posted a couple of days ago, the idea that the high would just extend ne and bring countrywide sunshine at the flick of a switch wasn't on the agenda.

Even if we end up stuck between the blocking and shallow upper troughing (giving less settled overall) it will still be a different feel to the weather as we will have lost the colder air. Summer is arriving. Bit late but it's coming.

 

No argument here.

[knocker]

The GEFS MSLP five day anomalies.

http://www.tropicaltidbits.com/

 

[Summer Sun]

UKMO goes out to 00z next Wednesday and the high pressure still isn't showing yet, infact next Tuesday could see another spell of heavy rain and strong winds, maybe this afternoons 12z from UKMO will show the high a bit closer by Wednesday if not then it should be showing tomorrow

 

 

Before we get any high pressure we also can't overlook Sunday where there is the potential for some wet and windy weather for the time of year with gusts potentially between 40mph & 50mph in some places

 

 

Once the main band of rain moves through brighter conditions should move in from the northwest but in turn further showers are possible, the south may stay cloudy all day

 

Monday then sees another area of heavy rain moving west to east with wind gusts in the west potentially exceeding 60mph

 

 

So before anything more settled arrives, we can't overlook the next 4 days with some potentially heavy rain and unusually strong winds on Sunday and Monday

[coldcomfort]

As yesterday and Tuesday, the 06 GFS remains firm both with it's timing and evolution of the potential change, but any genuine warmth, perhaps heat does remain the preserve of southern areas as we close out next week.

Edited May 28, 2015 by coldcomfort

[Captain Shortwave]

Not too bad for most of the UK, a couple of decent days during the later half of next week.

 

 

The usual suspects in the set up doing the best, with the north west cooler with fronts straddling the area and western parts at times seeing low cloud and drizzle. Mid/possibly high twenties possible in the south which is pretty good for early June.

 

That said it would be nice to see a little more in the way of low heights developing between the Azores and Iberia in this time frame (similar to the GEM operational). More cold air pushing down there would result in a stronger Euro ridge and keep any fronts away from the UK with the main threat of rain coming up from the south in the form of thundery rain.

Edited May 28, 2015 by Captain shortwave

[Scorcher]

As yesterday and Tuesday, the 06 GFS remains firm both with it's timing and evolution of the potential change, but any genuine warmth, perhaps heat does remain the preserve of southern areas as we close out next week.

 

Let's not be too picky- I would take 18C with sunshine over the current muck. Looks odds on now that a much warmer and sunnier spell will begin around the middle of next week, temperatures potentially into the low 20s in these parts which would be a huge change from what we've had over the past week or two.

[Ross Andrew Hemphill]

I had no idea about the warm spell that's potentially coming next week and beyond until my Mum and Dad told me about it the other day! Been too caught up in exams to come on and check. It does look quite promising so far though and Scotland might actually get something other than 12C with showers!!!  

[mountain shadow]

I had no idea about the warm spell that's potentially coming next week and beyond until my Mum and Dad told me about it the other day! Been too caught up in exams to come on and check. It does look quite promising so far though and Scotland might actually get something other than 12C with showers!!!  

Its towards the very end of next week, Friday/Saturday before the North West joins in with the drier weather, so don't get your hopes up just yet. The dry weather hasn't even entered the timeframe of the UKMET runs yet.

 

Still another couple of days runs before I am satisfied Summer is coming.

[mushymanrob]

Still need to wait for the currently updating ECM, but the latest GFS remains encouraging whilst the UKMO at 144hrs does not looks anything like as promising.

 

Edit: ECM looks just about OK for the south post this time next week, but much of the country remains relatively unsettled up to the weekend, especially the far north and west.

 

Still nothing fully set in stone yet imo.

 

 

dont get hung up on any one run... the ops vary , sometimes greatly. the anomaly charts are far more stable and reliable at predicting the upper air pattern 6-14 days time. and they are solid in predicting high pressure will build in later next week.

true, its not set in stone. they can be wrong, and the high pressure build might not be one that delivers heat/plume , but theres a real chance of this happening .... and im often pesimistic!

[Milhouse]

It looks as if the upcoming summery spell will come in 2 parts. The initial build of pressure will begin Wednesday and last until Friday/Saturday with the warmth becoming confined to the south by Saturday. A cold front looks likely to sweep south and the end of the week and second area of high pressure will build down from the north. Not the most ideal origin for high pressure as its not a warm direction. However the GEFS mean still shows some warmth beyond next weekend so there must be a good chance of some sort of easterly dragging some warmth from off the continent.

[Tamara]

The eventual evolution to better sustained mid latitude ridging and pressure rising over Europe and Scandinavia, with the N Atlantic trough eventually easing away, certainly has support from N Hemisphere longer range tools>

 

Low (negative) AAM keeps cold air to the north and results in adding strength to the jet stream. It also means that the traditional Spring-time seasonal northward progression of the ITCZ is delayed later in the season than it is under a Nino circulation>

 

Further progression beyond this of the GWO into Phase 3 would set us on course for a renewed rise in AAM - and it is this which will assist a resurgence of the Azores High NE'wards and the 'warming out' of the upper trough. Current model ensemble indicators are strikingly supportive of suggesting a change in circulatory pattern>

 

So could this signal be correct or is it overly progressive and premature?>

 

At the very least though, there is good support for some increasingly warm weather into the first half of June, to follow the next more widespread unsettled and cool spell to come within the next 7 to 10 days

Highlights from previous post just for continuity of progress

 

The 00hrs UKMO model perhaps fractionally slower, but overall very good model consistency continues for a change in weather type from midweek next week. I agree with the majority consensus expressed on here that there has been no real setback in terms of initial timing for pressure to build from the south and west around midweek - the only uncertainty has been, and still remains, how quickly this process becomes more extensive for the greater part of the UK.

 

The answer lies in the orbit progression of the Global Wind Oscillation - destined to orbit through current low angular momentum Phase 1 and into Phases 2 and 3 over the coming week, but with some present uncertainty how erratic this process may be, which in turn gives just a little current uncertainty about speed of progress extent nationwide of this improvement.

 

GWO Phase 3 and onwards sees the proper pressure build commence as suggested by most NWP modelling. Potential slight delay of extent of improvement is dependant on whether the GWO proceeds to Phase 3 without any backtracking or stalling.

 

http://www.atmos.albany.edu/student/nschiral/research/gwo/gfsgwo_1.png

 

I wouldn't entirely trust the GFS further outlook forecasts in this respect, as I have learned that like the synoptic models they can rather exaggerate track and amplitude in forecasts beyond a week. On this basis, especially in view of the overall background global outlook in terms of El Nino atmosphere/ocean coupling (fully detailed in the previous post) there are suspicions that upcoming low angular momentum transport, that is the culprit for the unsettled conditions in the shorter term, might be slightly overstated - and hence the pressure rise and speed of unsettled conditions clearing away NE' wards might be more straightforward than suggested by present GFS AAM/GWO forecast.

 

Confidence will be higher on this though by the end of the coming weekend

 

Nit-picking maybe, but sensible till then perhaps that the overall improvement suggested in the current 8 to 14 day upper anomalies, should also, just for now, be viewed within this slightly cautionary caveat. It should be remembered that even upper pattern anomaly charts are subject to daily changes through slight forecast uncertainties in atmospheric and oceanic forcings 

 

I think the UKMO model this morning well illustrates that possibility of slight delay - but the overall impression of improvement to follow in the second half of the week is evident here too, even though it is slower than other modelling

Back to the nearer term first though.

As already stated previously, Phases 1 and 2 of the GWO feature a westwards displaced Azores High and an upper trough sinking down from the NW of the UK, flooding the North Atlantic with cold air (cold relative to the season) that has originated from the Canadian Arctic. Natural seasonal changes mean that heat is growing from the sub tropics and over southern Europe, and, as a consequence thermal gradients are increased where these air-masses meet across the Atlantic

.

The progression towards the UK of the rather deep small low for early next week is well modelled in respect of these distinctly contrasting air-masses

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015052800/ECH0-96.GIF?28-12

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015052800/ECH1-120.GIF?28-12

 

Predicted GWO progression from Phase 2 into 3, fully supports and underpins a suggested pressure build eastwards into the UK, and hence the idea that midweek sees the turnaround from the seasonally inclement conditions of Monday and Tuesday, to the warmer and sunnier conditions moving northwards from midweek.

 

All the eight GWO summer composites for JJA are given here below. Being right at the end of May and this close to the start of official summer, I think that being right on such a pinnacle of seasonally changing wavelengths means these are now becoming a better guide than using the MJJ composites

 

http://www.atmos.albany.edu/student/nschiral/research/gwo/composites/JJA/hgt500_1.png

 

Further orbit into higher AAM phases 3 to 5 shows composites suggesting a very different modelled pattern to the start of next week with pressure building towards Scandinavia, and at the same time heights lowering to the west and south west of the UK as we head onwards through Phases 5 into 6.

 

Long range NWP output is already anticipating this type of eventual longer term progression, and starting to advertise and play with these possibilities.

 

I think that slight adjustment of the overall composites are required, with highest heights probably extending through the north of the UK and with continental thermal heat low encroachment possible to threaten thundery activity in the south with time - as we get into and perhaps beyond the second week of June

 

For GWO extra-tropical guidance we can look towards the tropical MJO signal for possible further information as to eventual evolution. There is still some longer term divergence here, but there is some agreement for increasing amplitude of convection eastwards across the Pacific which would support GWO higher momentum phases 5/6. The GFS is bullish about this suggestion, and there is shorter term support in general trend from MOGREPS.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/NCPE_phase_21m_full.gif

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/UKME_phase_23m_full.gif

 

 

The ECM also increases convection amplitude, but is more progressive with re-setting convection back towards the Indian Ocean and less keen with eastward convection progression of the current MJO wave (which would help builds heights most significantly to the N and NE)

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ECMF_phase_51m_full.gif

 

However, MJO composites heading towards Phase 3 and associated suggestions of high pressure adjusted back to the west of the UK need to take account of the extra tropical GWO budget and expected decline in frictional torques, and therefore the type of evolution suggested from todays ECM day at 10 looks about right with that string of mid latitude ridges which will probably adjust N and E between days 10 and 15.

 

GWO Phase 7 for June is composited as a further progressive phase with the unstable troughs, suggesting a thundery breakdown becoming more extensive - but with previous uncertainties still pending, this is much too far away to start to consider at this time. Purely just for interest purposes though, the GEM model is extremely progressive in this regard this morning with the suggestion, already by day 10, of the upper trough to the west engaging a southerly plume as it moves east - and at present should be taken with a large pinch of salt and very unlikely to happen by then

 

To summarise, a very unsettled, blustery and cool first half of next week with an improvement from the south west from mid week, and this improvement *probably* extending further north to much of the UK during the following weekend ( 6/7 June). Thereafter, fine, dry and warm (perhaps very warm) weather continuing   The driest weather though becoming more focussed further north   - as humid and less stable conditions over the continent increasingly threaten thundery downpours for the south and south west of the UK with time

 

@ Knocker - a long term low angular momentum cycle has been driven by the dominant Western Pacific signal as stated the other day which has created a Nina-like atmospheric global circulation that has been at odds with the Eastern Pacific Nino signal. Tropical convective forcing has been in an exceptionally strong state over the western-central Pacific Basin in response to anomalously high SST anomalies over the Indian Ocean and towards the Western Pacific. Negative or low AAM arises because of stronger trade winds over the tropical East Pacific and into the sub tropical Atlantic. These strong trade winds increase earth easterly momentum through torque mechanisms on the Andes in South America and the turning force of the Atmosphere (which is what AAM essentially in a measure of) drives momentum downwards.

 

In summary therefore, the answer is some of both - once the pattern is created it can (and in this case has) become self perpetuating and it is taking the escalation of Nino prospects this year to gradually overturn the atmospheric Nina re-cycling

Edited May 28, 2015 by Tamara

[Captain Shortwave]

CFS 4 week forecasts still consistent through to the middle third of June with high pressure dominating with core heights to the north and east of the UK.

 

After the cooler and more unsettled weather during the next 5/6 days, it should become drier and much warmer with above or well above average temperatures forecast.

 

The Metoffice update is also reflective of the longer range forecasts and the detail shown in Tamara's post above, mainly dry and fine in the north with the south more mixed with thundery showers pushing up from the continent with warm or very warm conditions persisting throughout the extended period.

Edited May 28, 2015 by Captain shortwave