Model Output Discussion - 1st July Onwards 18z--->

[summer blizzard]

Euro relatively unsettled bar Friday. Tries to do something at day 10..

 

[knocker]

Running the GEFS 12z anomaly through for three days starting T264 it can been it's altered it's position vis slowly developing the trough to the west and the Greenland ridge. This leaves the UK in an unsettled regime.

 

The possible good news is both the GEFS and ECM this morning continued to run the trough and HP east in the ext period so the trough moves out of the way with HP to the west of the UK but tending to a flatter pattern, But even this wouldn't be good news necessarily if the trough stuck just to the east.

http://www.tropicaltidbits.com/

 

 

[Stuie]

What a difference a week makes.....  Welcome to the Uk!!!    

Glad you are getting 1 chart a week to love..

[legritter]

Evening all ,just popped in and things seem quiet on here tonight ,looking at current charts this weekend could be good for some but beyond that looks like low pressure will roll in towards Scandy . but as ever the case it all could change on the next runs .

I would at this stage say that out to 144 hrs could go by what most charts currently hint at but beyond that i,m hoping high pressure to our s west could sneek in and perhaps eventually extend east ,by this time its mid summer , are we about to finish upwith an average overall summer or will more Plumes come our way .

Thats one thing with our interest we never know whats over the Horizon ,But its great that we have this forum and so much knowledge to share ,cheers gang   ps What a change to this time last week ,my wife is thinking of putting the gad fire on for a while .

[Captain Shortwave]

It still looks like we will see a warm up at the end of this week (though not to the degree that certain newspapers have stated). So possibly 80F possible in central southern England on Friday and maybe Saturday if the front isn't too progressive in its eastward push. Just one story in the mix of a rather average pattern with some cooler weather mixed with some warm or very warm conditions.

The ECM ensembles tend to keep pressure high over Europe and as such the south looks pretty warm, more mixed and cooler towards the north where low pressure will cross from time to time.

Uncertainty remains from Saturday onwards as to how far north the Euro high can get and as such how the surface conditions pan out.

[knocker]

Inclined to agree with you knocker on that, have seen the noaa anomoly chart for up to 8-14 day output and it's very similar to the charts you've posted. However it's of below average confidence nature, so very much subject to change.

 

Yes pj  I'd had a quick look at the 8-14 and it's not dissimilar to the T360 chart. I wouldn't put a huge amount of confidence in the evolution either.

Edited July 6, 2015 by knocker

[Polar Maritime]

The GFS this morning is showing a cool unsettled N/W flow into week 2. With Heights pushing up towards Greenland, Sinking Lows further South over the UK.

 

[mushymanrob]

What a difference a week makes.....  Welcome to the Uk!!!    

 

whats so amusing about the inevitable?... at least we had a hot spell, the one you refused to acknowlege would even exist.

we all knew it wasnt a prolonged heatwave, but it broke records and provided plenty of classic thunderstorms and whilst the imediate outlook isnt great for settled sunny warmth, its only early july.

[Frosty.]

whats so amusing about the inevitable?... at least we had a hot spell, the one you refused to acknowlege would even exist.

Well said mushy

Looking at the Gfs 00z, thurs/fri are increasingly fine, sunny and warm, still warm in the east/southeast on Saturday and then the Azores high ridges north east across the UK to bring a fine and warm first half of next week.

[summer blizzard]

Euro this morning Is a stinker for those who love heat. By day 10, the Greenland High has reduced the Azores to a 1020mb feature well west of the Azores.

[Frosty.]

The GEM 00z looks good for most of next week with high pressure bringing warm and settled weather with lots of sunshine.

[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 JULY 7TH 2015.

 

THE CURRENT GENERAL SITUATION A depression will move East over Scotland today and away to the NE tomorrow. A cooler and showery West then NW flow will cover the UK after the clearance of a cold front out of the SE this morning.

 

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

 

MODELS-2 WEEK HEADLINE Changeable with some rain at times but driest in the South and East with some warm spells at times.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast continues to predict the flow to lie further South than is usual at this time of year, usually lying across the UK at a NW to SE axis in the next few days and again for a time in Week 2 with a displacement further to the North briefly as ridges cross Southern Britain. The flow pattern is much less clear later in the period.

 

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

 

GFS OPERATIONAL The GFS Operational Run yet again this morning shows little change to the overall pattern with the North/South split in conditions persisting as High pressure never lies far away to the South or West later. Fronts on the Westerly flow over the UK continue to bring occasional rain and showers to chiefly but not exclusively the North while the South sees some fine and warm interludes too. A slack North or NW flow late in the period is again hinted at this morning as pressure builds North through the Atlantic.

 

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

 

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

 

THE GFS CONTROL The GFS Control Run follows the theme to which we have all become accustomed too throughout it's run this morning with South being best for the drier and brighter spells between occasional bouts of Atlantic rain and showers.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters for the 14 Day point continue to point towards High pressure being parked out across the Atlantic in 14 days time with a resultant NW flow down across the UK. A third of members think that High pressure will be dominant enough to ward off a cool and showery NW'ly but the remainder seem to think that showers at least are possible with a cool fetch of winds across the UK from Northerly latitudes.

 

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 is not as good as last night's run which indicated a strong push from the Azores High over Southern Britain from the weekend. Instead we have a flatter pattern with Low pressure close to the North and a Westerly flow across the UK. So rain at times seems the order of the day with the South seeing the best of the dry weather in any warmth. At least a little rain at times is possible even here though on this morning's outlook.

 

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

 

THE FAX CHARTS The Fax Charts show a cool NW flow in the next few days giving way to a ridge from the SW over the South by the weekend. The UK lies mostly on the Northern flank of any ridge still allowing some influence across the UK from fronts with a little rain at times especially over the North.

 

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

 

GEM GEM today shows changeable weather persisting as generally Westerly winds prevail over the next week. Some warm and sunny weather from occasional builds of pressure seem likely across the South before the Atlantic Westerlies regain supremacy after a few days. It's not until the end of the run when a more potent build of pressure builds across the UK with fine and dry weather for most though even thn it looks like thundery Low pressure could arrive from the SW soon after day 10.

 

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

 

NAVGEM NAVGEM maintains the Westerly theme of winds too with occasional troughs passing East over the UK with enough energy to ensure we all see a little rain at times between spells of drier and brighter weather. By the end of the run it looks more generally unsettled as a broad showery trough lies across the UK.

 

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

 

ECM ECM today looks quite poor if it's a return of high summer your after as it has strengthened it's theme on Westerly winds persisting across the UK throughout the run with spells of rain and/or showers as each trough passes or Low pressure to the North but with some drier pahses too especially in the South. It does bottle all the warmth and heat well to the South on this run.

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last evening shows fairly slack conditions across the UK with a slight bias towards Westerly winds and indifferent pressure gradients making for the risk of showers for all in temperatures at least not cool.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend today has taken a step back away from any meaningful return to summer warmth on a UK wide scale but maintains it's desire to keep a Westerly flow across the UK overall.

 

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 96.0 pts followed by UKMO at 95.1 pts and GFS at 94.7 pts. At 5 days ECM is stll king at 85.2 pts followed by GFS at 82.0 and UKMO at 81.7 pts. Then at 8 Days ECM still leads at 50.1 pts over GFS's 47.5 pts. Finally at Day 10 ECM leads GFS at 29.9 pts to 27.9 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 weather over the UK over the next few weeks looks to be controlled by a Jet Stream which refuses to relocate to a latitude that it should be at this part of the year which is near Iceland. Instead it is predicted to lie across the UK in one form or another for some considerable time and preventing any true build of pressure from the South or SW (which is hinted at repeatedly) from lasting any more than a day or so before becoming displaced. So what does this mean in terms of weather? Well I can still say South is best over the coming few weeks as all the Low pressure remains across more Northern areas of the UK but this doesn't mean that the South will always be dry as troughs attached to these Lows will cross Southern areas too occasionally giving outbreaks of rain or showers. Temperatures will be mostly average over the North unless winds switch NW behind any depressions in which case it may feel rather cool at times. In the South temperatures will flutuate a bit as tropical maritime air alternates with cooler North Atlantic winds so here temperatures should range between normal and somewhat above. Unfortunately no cross model support looks that interested in showing any large UK based High pressure over the two week period so it looks like a case of the occasional good day sprinkled with some more indifferent ones as no set pattern looks like lasting long in any one place. So in Summary while it may seem that the models don't have a clue when showing day to day events in the next few weeks the pattern is more solidly set, with as a result a continuing changeable theme being the likely outcome of the weather as we move through mid July and I have no doubt that some folks will feel the weather being a bit of a let down given the time of year but all I will say to end is that it could be a whole lot worse. 

 

Next update from 08:00 Wednesday July 8th 2015

[Frosty.]

I agree with gibby, it could be a whole lot worse. The outlook for the next few weeks shows at least as much fine and warm weather as cooler and unsettled, the further south you go, the better it looks.

Edited July 7, 2015 by Frosty.

[Tamara]

Away from the ebbs and flows of intra day model output and its inevitable surface detail variations, the outlook still continues much as summarised before in terms of what is happening behind the scenes and driving NWP.

 

Part I (the ocean/atmospheric ying) of the massive East Pacific MJO event, which featured the highly amplified Sceuro ridge and heatwave, is completed, and now Part II (the ocean/atmospheric yang) is underway.

 

This features something of a flip of the amplification coin with elongated lower heights across the North Atlantic towards Russia and a -AO profile

 

The last post referred to the record breaking July MJO Phase 7 amplitude tropical forcing on the atmosphere, and the MJO maps depict the sheer steepness of the upward amplitude climb. What goes up, must come down, and we now are embarking on the de-amplitude drop - as the intense convection dies at the dateline

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ECMF_phase_51m_small.gif

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/NCPE_phase_21m_small.gif

 

 

As discussed in detail previously, there is now, unsurprisingly, good agreement in the modelling for the descent drop to take the tropical MJO signal back to the inner circle in advance of next wave of convection.  In tandem, the extra tropical Global Wind Oscillation signal orbits Phase 7 and consolidates towards/into weak low amplitude Phase 0.

 

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

 

This is an inevitable (general) progression that, trend-wise, is unlikely to change - and it makes interpreting the 10 to 15 day period of model forecasting relatively straightforward.

 

The return fall-out from the high amplitude Nino spike leaves a vacuum in the atmosphere which nature must fill in response. Atmospheric and Angular Momentum relative tendency set to drop back, temporarily, as the tropical and extra tropical forcings drop back to parity

 

http://www.atmos.albany.edu/student/nschiral/research/gwo/gfs1.png

 

As indicated above, the high amplitude Phase 7 cycle fully supports the arctic heights profile in both the short and medium term and the elongated trough into Scandinavia - alongside a rather flat jet stream which gives rise to the relatively mobile westerly pattern

 

This flatter, more changeable and relatively cooler passage of weather has been well advertised and discussed for some time, and is no surprise. It predominantly continues to be based on a N/S type of split for the UK and the intra day modelling continues to show variations of the same theme around the boundaries of warm humid air to the south and cooler Atlantic air to the north

 

This passage of weather fully in line with transit to GWO Phase 0, as tropical activity wanes and re-sets. 

 

With that in mind, the key question is where tropical convection properly re-engages for the next cycle.

 

The weather will remain quite changeable until the Global Wind Oscillation emerges, from Phase 0 and, quite conceivably moves towards Phase 4/5 once again as the next ocean/atmosphere coupling cycle commences. This GWO orbit evolution being much as was the case in the middle section to second half of June

 

My own view remains steadfast that that with full accord and synchronisation of atmosphere and ocean coupling now achieved towards a Nino default pattern, we are still set to see in the longer term (precise timing obviously uncertain but quite likely sometime later in the last third of this month) a more defined pressure rise from the south and another sharpened Atlantic trough - as positive frictional torques are re-triggered, with further poleward westerly wind momentum added to the atmosphere as the next MJO convective wave gains amplitude once more on another eastward journey around the tropical hemisphere towards the Pacific.

 

(This, in complete contrast to the winter/spring pattern which featured active convection in the Indian Ocean and weakened eastward progression, in accordance with a Nina like defaulted -AAM/GWO pattern)

 

It is this further evolution as we arrive into the second half of the summer that holds the best chance for another more widespread summer spell of weather. Until this time, furthest south will see the warmest and driest of a mixed spell of fortunes

 

It is understandable that those furthest north are going to feel most short changed from the type of split that the pattern enforces over the coming 10 day period, but then again the perspective should be that on the back of some significant heat which most saw last week, this is the UK, and what we see for the upcoming period is a typical traditional type of summer pattern in this country.

 

Compared to the likes of the summers of 2007 and 2012 it is a long long way better, and, in line with the way this seasons weather patterns look set to keep repeating, there is plenty of time for further more widespread heat  (if temperatures over 30C is what one craves and determines as conditions that constitute a good summer)

 

ECM London ensembles wind-speeds suggest that the depression modelled on this mornings operational crossing the north of the UK around days 7/8 looks to be deeper and, perhaps, therefore a little further south than the mean

 

http://www.weathercast.co.uk/meteo/eps/ensemble-ff-london.gif

 

 

Edited July 7, 2015 by Tamara

[Frosty.]

The Gfs 6z shows a good deal of fine and warm weather during the next 7-10 days, especially for the south of the uk with temperatures into the low to mid 20's celsius range, a smidge higher/lower at times with the southeast having the warmest conditions..e.g Saturday into the low 80's F further SE. The further north by northwest you are, the more unsettled and relatively cooler it looks but it's no washout, there are some fine and warmer spells there too. Thurs/fri look increasingly fine and Friday looks warm with temps around 24/25c 76f. The weekend looks less settled with sunshine and thundery showers, warm Saturday, very warm in the southeast but becoming cooler and fresher sunday but then next week turns fine for a while as the Azores high ridges n/e across the south with temps well into the 70's F. The following week shows high pressure further west and lowering heights to the north east but that's deep into low res and subject to changes.

Edited July 7, 2015 by Frosty.

[Man With Beard]

GFS continues to be pretty certain of a good start to next week:

 

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=174

[Polar Maritime]

Maybe even the 'chance' of a dusting over some Northern Scottish Mountains on Wednesday.

Edited July 7, 2015 by Polar Maritime

[Winter Cold]

Maybe even the 'chance' of a dusting over some Northern Scottish Mountains on Wednesday.

 

Yes PM, insane isnt it for July. BBC also giving a frost risk tomorrow night for NW areas, cant say ive heard that often in high summer! ! !

 

GFS agrees:

 

Edited July 7, 2015 by Winter Cold

[Methuselah]

Yes PM, insane isnt it for July. BBC also giving a frost risk tomorrow night, cant say ive heard that often in high summer! ! !

 

No, it isn't insane: I was in the NW Highlands for more than twenty years. And snowfall, on the high peaks in summer, is hardly that unusual...And neither is frost!

Edited July 7, 2015 by Ed Stone

[William of Walworth]

On the sound annual grounds that slight changes in detail/positioning can lead to very noticeable differences in surface conditions, I'm refusing to 'write off' next week (specifically, w/e of Saturday 18th July) from my own summer-lover's perspective. At least not further South.

 

In any case, anything much beyond this coming weekend is FI. A rule applying just as much to pessimists as to optimists (OK hopecasters ... )!

 

Not just some of Frosty's charts that are leading me to think this, but also those parts of Tamara's reasoning that I can understand.

 

As she rightly says, this is no 2007/2012.

Edited July 7, 2015 by William of Walworth

[Winter Cold]

No, it isn't insane: I was in the NW Highlands for more than twenty years. And snowfall, on the high peaks in summer, is hardly that unusual...And neither is frost!

 

Well fair enough for the highlands but the frost risk is for quite a large area as far as the tv images looked and much lower ground. That must be more unusual? I could be wrong but ive not heard the F word much in July?

[Methuselah]

Well fair enough for the highlands but the frost risk is for quite a large area as far as the tv images looked and much lower ground. That must be more unusual? I could be wrong but ive not heard the F word much in July?

I was in a frost-hollow (150m ASL) at the top of a glen; and I can hardly remember a summer without frost...

[Scorcher]

Yes PM, insane isnt it for July. BBC also giving a frost risk tomorrow night for NW areas, cant say ive heard that often in high summer! ! !

 

 

 

'Insane' would be snowfall down to sea level, which certainly isn't going to happen. A bit of snow on the tops of the mountains is not that unusual at any time of year, and I imagine up there frosts are possible at any time of year.

[Andy Bown]

Yes PM, insane isnt it for July. BBC also giving a frost risk tomorrow night for NW areas, cant say ive heard that often in high summer! ! !

 

GFS agrees:

 

That chart is showing 6c inland in CS England at 08.00 on Thursday morning after the sun will have been up for 3 hours? Therefore how chilly might it be at 05.00!? I cannot see that being accurate at all, if 6c does occur it will be at sunrise and will surely have risen well into double figures by the chart timescale!

[Polar Maritime]

There will only be Frosts in sheltered Highland Glens Thursday morning, And they will be very short lived. Certainly not a 'rarity' Nor is a sprinkling on the highest Peaks during the Summer months. Nice to see in the output all the same..

Edited July 7, 2015 by Polar Maritime