IMO this summer was "fudged" as far as northern areas are concerned from the time 5-6 weeks ago when the models first began to raise heights over Greenland. I know that we've had poor ones in the past (1998 for example) when there hasn't been any substantial, persistent blocking in that region, but as we know from the summers of 2007 to 2012, this is the worst time of year for blocking to occur there. There won't be any chance of a decent, nationwide settled spell until it goes. Not that that is a guarantee in itself of a change of pattern, but it would sure be a help.

I would be very, very surprised if it remains in place continually all the way from now until the start of winter!

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The puddle of cold uppers moving SE over SW England this evening has fired up a few lively showers. An isolated and very local storm has swamped me here in very heavy rain just now after a dry and pleasant if cool day up to then. The fact that a convective shower has such potency in cool inland air after sundown is testament to me what a unseasonal state the air above us is in. Just 11C currently.

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James, two quick [interlinked] questions:

1) the blocking over Greenland/arctic... what's causing this?

2) is the Jet diverted on a more southerly track because of the blocking over Greenland, or is the block allowed to perpetuate over Greenland because the Jet is running on a more southerly track?

 

 

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Good questions SS... I have a theory that the 'blocking' over Greenland has been a consequence of the jet tending to track well south of normal in response to the unusually low SSTs in the North Atlantic west of Iceland.

In the summer months the absence of a trough from a region at the higher latitudes naturally allows for high pressure to build, as the stratosphere features no notable polar vortex to work against it.

Fact is, high lat blocking is by the nature of the atmosphere easier to achieve in summer than in winter. It nearly always crops up somewhere or other - last summer it was to our NE in June and July but then NW for a large part of August.

With blocking to our NW these past 5-6 weeks, there's been a positive feedback where excess solar input over Greenland has enhanced ice melt and in turn that has reinforced the N Atlantic cold pool, or at least that's how it seems - I don't currently have the resources to research it all to a respectable scientific standard.

Whew - longest post by phone I've made on here! You really got me thinking Saint 😉

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I think the scientists must all have their thinking caps on.

The jet stream has been well south in some recent summers even when the Atlantic was warm. If you remember, we had this from the Met Office.

http://www.bbc.com/news/science-environment-19848112

More recently, when there was a study about the cooling in the Atlantic, we had this from the University of Reading.

http://www.theguardian.com/environment/2014/jan/20/gulf-stream-hot-summer-uk-climate-change

 

 

Two words can sum up this summer - El Niño...

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Monday could be quite hot in the South. GFS is going for 30c!

http://www.wetterzentrale.de/pics/Recm1202.html

 

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I can think of another two words F..B.....! but that could describe our whole climate if you are somebody who likes to experience proper seasons.
I'm trying to forecast next week for my daughter for North Norfolk using the main models. Not perfect but she will be in the best place in the UK and should get on the beach!
I'm pinning my hopes on September in Portugal!

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And you can bet your life it'll throw out something absolute crap for the same day at some stage in the next 24 hours. Probably with that low further east. The models have been doing this all summer. 

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Yes.  To be realistic, its been there in the output for some time.  As long as the heat stays down there in the Med all we need is a low to stall out west for a day and yes, the east (at least) will get a burst of heat (albeit short lived) from the reservoir of heat that persists to our south.

 

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like this? 

http://www.wetterzentrale.de/pics/Rtavn1384.html 

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Indeed the output for the SE is pretty good. Sadly not so good for the NW.

 

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Yes, the north-south weather divide is a fact  at the moment and its important that emotion does not obscure what the output is showing.

Here is the ECM's take on the situation in 6 days as the plume clears east.  IF this comes off then the preceding day, Monday, does indeed look hot for some.

Heres the UK chart for the same time (at this stage looks an east-west split instead!!)

 

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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 WEDNESDAY JULY 29TH 2015.

THE CURRENT GENERAL SITUATION. Low pressure to the NE will continue to move away East with a ridge of High pressure slowly building in from the SW through the next 24-36 hours.

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

MODELS-2 WEEK HEADLINE Still rather changeable with some dry and bright conditions mixed with occasional rain or showers. Generally on the cool side but a few warmer interludes possible in the South.

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast continues to show the flow blowing well South over the Atlantic throughout the coming two weeks mostly close to the 50 deg North meridian. The strong West to East flow currently across France will weaken and subside over the next 24 hours with a much weaker flow repositioning in a SW to NE flow across the North at the weekend. the flow then gradually strengthens somewhat again later still close to the UK.

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

GFS OPERATIONAL The GFS Operational Run today can be best summarised as changeable this morning with more than a hint of a SE/NW or north/South split in the weather for much of the time. The warmest and driest conditions will nearly always be in the South and SE of the UK with only occasional bursts of rain from weakening troughs running East across the UK in a basically SW flow. The North and West for the most parts will see much more influence from the Atlantic with depressions to the North and West sending bands of rain and showers across these areas on a more frequent basis leading to cool conditions here at times.

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

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

THE GFS CONTROL The GFS Control Run sends out a broadly similar message as the operational again today with a small but influential High pressure forming across the South for a time next week giving a warmer and more pleasant interlude before the Atlantic makes a return later in the week with occasional rain and showers, again largely focused more towards the North than the South who could end up with a lot of dry weather if never overly warm.

THE GFS CLUSTERS(14 Days) The GFS Clusters at 14 days show nothing alarmist this morning and are a step or two better than yesterdays crop. In essence they show a Westerly flow across the UK in two weeks time with Low pressure to the North and High pressure out to the SW. This would most likely provide the North/South split in the weather that has been prominent for much of this summer thus far.

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

UKMO UKMO today shows slack conditions at the weekend with a band of showers crossing east on Saturday. A Southerly flow sets up on Sunday as pressure falls to the West. While warmer air will be advected North across the UK it isn't long into next week that the Atlantic Low makes inroads across the UK with the return of rain and showers in SW breezes.

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

THE FAX CHARTS The Fax Charts this morning follow the raw data closely and indicate the deepening Low to the West encroaching towards the UK in the Day 4 and 5 time point.

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

GEM GEM shows a fairly quiet weekend with rain or showers in the NW slowly crossing all areas on Saturday weakening as it does to just a band of showers in the South. All eyes then focus to the West next week which features a very deep Low pressure developing to the West of Ireland which sends SW winds and occasional rain to all areas. The low is then shown to fill only slowly and move away North at the end of the period with pressure looking to build strongly from the SW by Day 10.

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

NAVGEM NAVGEM too shows that same depression winding itself up West of Ireland next week transiting it North late in the week with SW then West winds across the UK delivering rain and showers at times especially but not exclusively to the North and West.

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

ECM ECM today holds this feature further out to the West and NW next week and while it will drive conditions over the UK for much of next week the worst of the wind and rain will be towards the North and West while the South and East sees a lot of dry and fine weather with just the occasional shower at times. Temperatures may range from warm in the SE at times to cool elsewhere.

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

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last evening shows a Westerly flow across the Atlantic and the UK from a depression held up to the NW. High pressure out to the SW will likely keep the NW/SE divide in the weather going well into August

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The only trend to be drawn from this morning's output is the desire to maintain a split in the weather from SE to NW with always the best weather likely towards the SE and most unsettled conditions towards the NW.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 95.6 pts followed by UKMO at 95.0 pts and GFS at 94.3 pts. At 5 days ECM is stll king at 84.9 pts followed by UKMO at 82.0 and GFS at 81.5 pts. Then at 8 Days ECM still leads at 55.5 pts over GFS's 51.1 pts. Finally at Day 10 ECM leads GFS at 36.2 pts to 31.3 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 To say the weather across the UK this Summer has maintained a theme is something of an understatement with the differences between conditions over the North and South of the UK being quite stark at times on the same day. Of course of late the South has had to endure the same conditions as the North at times with some inclement and cool wet days down here too. Then we come to this morning's set of output which really hold little chance of any major shift in the weather patterning that has been around these shores for what seems an eternity. Basically we have a Jet stream which is flowing way too far South especially over the Atlantic and with pressure having been high over the Greenland area for ages now Low pressure areas are steered across the Atlantic and into the North of the UK. However, picking the meat from the bones reveals some subtle changes in the coming few weeks. It looks like the very cool West and NW winds of late will soon become a thing of the past as the Jet flow changes it's orientation to a more NE flow across Northern Britain to allow some warmer air to advect NE across the UK, especially the South and East and this process begins this weekend. Coupled with this Low pressure may be held further NW next week than has been the case recently keeping the most unsettled conditions more towards the North and West while overall in the next two weeks the South and East may see a lot of dry weather with just the occasional burst of rain. There's still I'm afraid very little chance of a nationwide spell of fine and very warm conditions over the next few weeks with the Jet flow remaining too strong and badly aligned to allow the North especially to join in the better conditions the South may experience at times in the coming weeks. Still with a lot of useable weather in the South over the upcoming forecast period I think complaints about conditions will be limited but I'm afraid of you live in the North and especially the NW another two weeks of cool and unsettled weather looks very likely for you if today's outputs verify.

Next update from 09:00 Thursday July 30th 2015

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Ah yes... The wet summers of 2007 and 2012. I need to look at the exact SST patterns for those.

Come to think of it we've seen more a displacement of the mean Atlantic trough east than south. Same impacts on Greenland but more to do with a stronger jet perhaps?

After all this hasn't been a wet summer right under a chain of lows. Much more research needed! 

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GFS seems to be quite insistent now that pressure will start to fall over Greenland as we go towards the end of next week. It has hinted at this at times in recent weeks but I think it is doing it with more consistency now. ECM this morning also shows pressure falling a bit in that region by the end of next week.

As I said last night, if pressure over Greenland does eventually drop as suggested, it won't be the whole answer in terms of northern areas getting some slightly better weather, but it would hopefully be a small step on the way. As things stand. we've no chance.

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lo and behold - very next run. 

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Although to be fair, the 06z run throws a wobbly more often than not, which is why I never take any notice of it.   But if the 00z follows suite .....

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Sorry to go OT - But one thing which makes me feel as though summer is over is the presence and number of flies which have come indoors.

Usually this only seems to happen at the end of September.

I wonder if others have noticed this.

 

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Haven't seen one housefly this year yet. This time last year, we were plagued with them.

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After a near-autumnal GFS 00z in the longer range, the GFS 06z keeps the jet just about weak enough to allow high pressure to bring a lot of reasonable weather to the far south, but it's still not enough for areas further north - particularly north of The Midlands.

Even ECM's op run looks like going a bit wild based on the day 10 chart, and this is despite a more helpful looking MJO outlook from that model.

Worth noting that beyond day 7, GFS remains on another planet as far as it's handling of tropical forcing is concerned. It would be satisfying to bin it's output beyond a week's range without second thought, but past experience tells me that would be foolish - it went out on a limb in late January regarding a strong MJO pulse, and in the end it turned out to be nearest to what actually unfolded.

 

While the models continue to frustrate many of us, perhaps you might enjoy a load of theoretical rambling on my part as I take a look at the extent to which the N. Atlantic SST pattern may be held responsible for our lack of widespread (i.e. not just the far S and SE!) fine, warm weather this summer.

You can find it under 'Stormchaser's Guide to Chart Interpretation' or via this link:(http://www.theweatheroutlook.com/twocommunity/default.aspx?g=postmessage&t=14835&f=2)

Thank you to those who have a read - and your thoughts will be greatly appreciated 

 

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I may well be wrong here, but IIRC the GFS was the first model, or one of them anyway, back in mid-June or just after that to start picking up on the development of Greenland HP block that has been in place there ever since. Prior that that, GFS and ECM had actually been producing some pretty decent charts for a number of days with the Azores HP more or less in complete control of the UK's weather, which had they verified would have given northern areas a more than decent spell of weather during the latter part of June. The catalyst for the deterioration up here was a shallow LP system that moved down from the north around midsummer's day, and after that we were left with the pattern that has dominated ever since.

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Thanks James- a very interesting and informative thread!

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Been very few here as well for the first time in years!

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You can bet your bottom dollar that come October/November it will disappear and pressure will drop like a stone with low heights persisting over Greenland until may next year,at least,if it does you up north might be able to say we get the same temperatures all year round,more or less