Model Output discussion 1st September 00z------->

[johnholmes]

The Ecm 00z shows high pressure dominating next week with fine and dry increasingly warm weather with plenty of sunshine and light winds but with chilly nights under clear skies with mist and fog patches forming. Later next week the high slowly drifts away NE but holds its ground long enough to bring a very decent week across the south and east of the UK, gradually becoming unsettled across the far northwest late next week and more widely by the end of the run, especially in the n/w.

 

It will be interesting to see what the NOAA anomaly charts show this evening. Last night they kept the trough well west with the upper ridge the main player. This morning, not unlike the EC run you have shown, brings the trough into play with the ridge moving away east. The GFS version is less keen although it goes some way towards this idea.

To me the EC anomaly has moved the trough too far too fast looking at the past few days and the overall wavelength but it may be picking up something prior to NOAA. It seems to be doing this now and then in the past 9-10 months. It would be really interesting to know what the professionals feel about this apparent 'change' in the anomaly charts?

Looking again at the daily charts I file. What may have happened with the EC output is this. Previously it had a cut off low well south off Iberia. It has dropped this with just one main trough. By merging the two this may be the reason it 'appears' to have moved the main trough so far east.

Edited September 3, 2015 by johnholmes

[legritter]

Well things look like becoming a little warmer and settled then lasting a while before things possibly become unsettled again towards mid month .

But where high pressure sets up and any remains of western Atlantic storms ex or not will have many influences on the UK .so i,m going to enjoy it while we have it ,cheers .

[knocker]

There is a fair difference between the GEFS 00z anomaly and the upgrade.

Charts courtesy weatherbell

 

[No Balls Like Snow Balls]

The cold and snow lovers nemesis is coming back.

 

From Twitter:-

 

Anthony Sagliani â€@anthonywx  8 mins8 minutes ago

Inevitable intensification of the N.H. Stratospheric Polar Vortex is ongoing. Can't stop that train. #winteriscoming

 

 

 

 

 

 

 

[Frosty.]

The Gfs 6z shows a nice warm up during the second half of next week with temps into the low 20's celsius by next thursday across southern UK and closer to 24c by next fri/sat. In the meantime, the nagging northerly continues for another day or so before the cool air supply is cut off by high pressure building in from the west so during the weekend it will become dry with variable cloud amounts and sunny spells but with chilly nights and a chance of ground frosts where skies clear. The high is at its strongest during the first half of next week with plenty of sunshine and becoming pleasantly warm by day but with an on going risk of overnight ground frosts and mist/fog. Scotland and N.Ireland becomes unsettled after midweek and by the end of next week the weather becomes more generally unsettled, at least for the north and west with the south and east staying fine for longest but through low res all areas become unsettled and cooler for a time before high pressure starts to rebuild again after mid month.

Edited September 3, 2015 by Frosty.

[Captain Shortwave]

Looks like conditions will turn dry for the most part by Sunday and the dry conditions will continue for the most part until at least Thursday. So a good 5 day window of fine early Autumn weather.

 

The GFS/UKMO and this mornings ECM favour heights to drift east into Scandinavia setting up a flow from between the south and the east. This should allow conditions to warm up a little after midweek. Of course this will also allow fronts to encroach from the west as the trough edges closer. 

Overall a fine picture ahead after the last couple of less settled days as low pressure to the east allows showers to affect parts of the UK.

Edited September 3, 2015 by Captain shortwave

[stodge]

Evening all

 

I wonder if the GFS is being too progressive with the movement of the HP though we should get a few decent days out of it.

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015090312/gfs-0-192.png?12

 

Battle is joined as pressure falls steadily to the west but the LP wins out:

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015090312/gfs-0-240.png?12

 

Not very inspiring for the middle of the month but into deepest FI, some odd synoptics which I think I'll ignore for now.

[knocker]

Interesting development on this evenings GEFS anomaly. The HP to the NE is now oriented west to east across Scandinavia with the trough digging SE into Europe just the west of the UK. Opens up various possibilities vis the surface analysis although probably ending up with the breakdown of the block and a change to a more cyclonic regime. See what the ecm makes of this.

Chart weatherbell

 

[summer blizzard]

Atlantic wins by day 9-10 on GFS, GEM and Euro..

 

[Scorcher]

Atlantic wins by day 9-10 on GFS, GEM and Euro..

 

 

Yes and what about before that? Any chance of you mentioning something that isn't in deep FI?

[ANYWEATHER]

Atlantic wins by day 9-10 on GFS, GEM and Euro..

 

Many thanks for posting that, Saves me doing it!  In between , we have a quiet spell of weather by Tuesday next week,, Ground frosts a probability and perhaps a lot of cloud cover?

Edited September 3, 2015 by ANYWEATHER

[knocker]

The configuration of the HP and trough differ on the ECM from the GEFs so the evolution of this is still in doubt although eventually it still looks as if the trough will exert the most influence.

http://www.tropicaltidbits.com/

Edited September 3, 2015 by knocker

[Frosty.]

Yes and what about before that? Any chance of you mentioning something that isn't in deep FI?

I was just thinking the same thing scorcher, I don't know why some posters gloss over the good charts as if they don't exist and go straight to the unsettled deep FI, it gives a very misleading picture of what the models are showing..anyhoo

Most of next week looks great on the Ecm 12z op this evening, really nice weather on the way..Looking forward to the prolonged sunshine and pleasantly warm days which lasts most of next week...bring it on I say!

[damianslaw]

Polar plumes and omega blocks... if only this was Jan, alas its early September... A static picture for the foreseeable, temps slowly creeping back to more average levels but with cold nights, hopefully some welcome sunshine and some much welcome dry weather - the latter being very absent since April. Why does early-mid Sept have a habit of producing lengthy dry weather? Its becoming the norm and the time of year I switch off from model watching, things always tend to be benign around now..

Edited September 3, 2015 by damianslaw

[Singularity]

A fairly typical delay in the pushing aside of the Scandi High appears to have occurred, with the breakdown now penciled in for Friday. Let's just see if it holds there or not...

 

We do then look to be at risk of a trough stalling out overhead with some active areas of low pressure rolling in, after which GFS and ECM are keen to raise heights to our NW. If that happens, it will be important in terms of rainfall amounts whether a ridge builds in the mid-Atlantic or the jet simply fires away underneath a Greenland High, bringing lows our way from unusually far south. Needless to say, that would bring the potential for some large rainfall totals - but the mid-Atlantic ridge scenario offers something a lot drier, so it seems our prospects later this month remain very much up in the air.

 

Having found evidence from past years to suggest that the jet stream probably does have the potential to both be drawn south and get a boost from the current North Atlantic SST setup (see page 5 of the 'Summer 2015 overviews and opinions' thread in the weather discussion area of the forum), I get the sense that the more high pressure we can hold onto this month, the better. For what it's worth, CFSv2 and JMA are going for unsettled westerlies dominating in October, followed by a very unsettled November. On the other hand, the Met Office ensembles prefer to keep high pressure over Europe closer to hand, and the Beijing Climate Centre's model brings that high pressure into play quite substantially. So all is not lost - not that these projections are to be taken all that seriously anyway!

[William of Walworth]

The Gfs 6z shows a nice warm up during the second half of next week with temps into the low 20's celsius by next thursday across southern UK and closer to 24c by next fri/sat. In the meantime, the nagging northerly continues for another day or so before the cool air supply is cut off by high pressure building in from the west so during the weekend it will become dry with variable cloud amounts and sunny spells but with chilly nights and a chance of ground frosts where skies clear. The high is at its strongest during the first half of next week with plenty of sunshine and becoming pleasantly warm by day but with an on going risk of overnight ground frosts and mist/fog. Scotland and N.Ireland becomes unsettled after midweek and by the end of next week the weather becomes more generally unsettled, at least for the north and west with the south and east staying fine for longest but through low res all areas become unsettled and cooler for a time before high pressure starts to rebuild again after mid month.

Very last sentence about a possible rebuild of HP in very deep FI : any actual support for this Frosty?

 

I see little model-backed evidence for that myself.

 

But I ask as a hopecasting serial pessimist** ...

 

(**who as a non-coldist, is going to hibernite until Easter from these excellent NW forums after our final 'outdoor event' of the 'summer', this f*st*v*l not due until w/e of Sat 26 Sept ....  in Gloucestershire .... )

 

ETA : I don't seem to be able to bold or highlight anything here ...

Edited September 3, 2015 by William of Walworth

[Frosty.]

Very last sentence about a possible rebuild of HP in very deep FI : any actual support for this Frosty?

 

Hi William, it was just what the 6z showed at the end of the run I was describing but interestingly, the met office keep mentioning a chance of settled and warmer weather returning later this month so hopefully next week's high pressure and pleasantly warm conditions won't be the last of the good weather in September.

[knocker]

The 18z GEFS upgrade has the trough just edging the Battle with the HP and eventually winning out but it's not a cut and dried time table.

chart weatherbell

 

[knocker]

This morning's GFS has the HP moving east about Weds.and depressions nipping into the UK on a quite strong jet.

http://www.tropicaltidbits.com/

Edited September 4, 2015 by knocker

[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 FRIDAY SEP 4TH 2015

 

THE CURRENT GENERAL SITUATION A cool North or NW flow will persist between Low pressure to the East. A weak cold front will move South across the UK tonight followed by High pressure edging into northern Britain from the West.

 

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

 

MODELS-2 WEEK HEADLINE Becoming more settled from the weekend with a lot of fine and dry weather at least for a time for many next week before the chance of more unsettled weather retuns later.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow situated running South ver the North Sea over the coming days, weakening and moving away East to leave the UK away from the main flow to the NW.The trend is then for the flow to slip back South over the Atlantic and eventually towards the UK in the second half of the second week.

 

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

 

GFS OPERATIONAL The GFS Operational Run today shows the cool Northerly flow being cut off later this wekend by High pressure moving into the UK from the West. The trend is then for the High to move away to the NE next week with an East or SE warmer flow developing before further on still Atlantic Low pressure becomes steadily more influential, first in the West and NW then to all areas as the remains of an ex tropical storm come into the mix late in Week 2.

 

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

 

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

 

THE GFS CONTROL The theme of the GFS Control Run this morning closely replicates that of the operational throughout with the next week seeing a lot of dry and eventually somewhat warmer weather as an Easterly flow develops. The shift towards more changeable conditions is slower on this run particularly for the South and East where it would stay dry into the start of the second week before Atlantic wind and rain spreads East across all areas.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show a much more unsettled look with almost total support for Low pressure to be the dominant role player in the weather over the UK in 14 days, most likely positioned to the North or NW.

 

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 High pressure moving gently east across the UK later in the weekend and the start of next week. A period of fine if still rather cloudy conditions look likely with a trough affecting the NW by the middle of next week with some rain while the South and East stay largely dry and less cool than of late.

 

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

 

THE FAX CHARTS The Fax Charts this morning show High pressure moving in too over the weekend. It also shows a cold front wavering Southward early in the weekend with some rain for a time. As the High moves in to start next week we could be chasing rather large amounts of cloud rounding the Northern flank of the High and down over the UK for a while.

 

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

 

GEM GEM today shows High pressure crossing the UK and away to the east over the next 4-5 days. The weather will stay largely dry from tomorrow with some sunshine but quite large cloud amounts at time. Then through the early days of next week the NW will become more unsettled with some rain while the South and East stay fine and dry for a while longer. However, things turn very unsettled and windy with gales for all over next weekend as a very deep Autumnal Low becomes slow moving across the UK with heavy rain, showers and strong winds likely for all at the end of the period.

 

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

 

NAVGEM NAVGEM shows High pressure too moving East across the UK and on into Europe through the next 4-5 days. This then forms a block to the East with winds between East and South for the UK, warming things up and while mostly dry still fronts to the West will be perilously close to Western areas by the end of the period next Friday.

 

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

 

ECM ECM this morning shows the same theme of moving High pressure across the UK from the West towards the end of the weekend displacing the cool Northerly with calm and fine conditions. With the High slightly further North than other output the eventual resting place over Scandinavia makes for a better resistance against Low pressure from off the Atlantic keeping things fine and dry for many away from the NW throughout next week aided by a strong Azores High too. Then at the end of the run the Azores High collapses and makes way for Atlantic Low pressure to enter the UK from the West with rain and showers spreading to all areas by Day 10. 

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last night replicates the raw data quite well this morning as by Day 10 after a period of quiet anticyclonic conditions High pressure moves away to the East with Low pressure moving East into the UK from off the Atlantic.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models have maintained their theme of moving High pressure across the UK late in the weekend and start to next week. Thereafter models continue to vary in the way that any breakdown in conditions occur and to what extent.

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM nudging ahead of UKMO at 96.1 pts to 96.0 pts while GFS lags behind at 95.1 pts at 3 days. At 5 days UKMO is king at 86.6 pts followed by ECM at 85.9 and GFS at 83.2 pts. Then at 8 Days ECM still leads at 61.9 pts over GFS's 53.3 pts. Finally at Day 10 ECM leads GFS at 41.3 pts to 35.4 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 Changes in the outputs are slow again today and all focus on the way they handle any breakdown of the High pressure as it exits the UK next week to the East. There are no changes in the short term and all outputs remain rock solid in predicting High pressure crossing the UK over the coming days and cutting off this cool North flow but probably disappointingly for many maintaining a lot of cloud over the UK and temperatures suppressed as a result. By next week the High should be to the East and as winds settle East or SE things should finally warm up with some warm sunshine for most but still chilly and perhaps misty nights. Then the divergences between the models become all too apparent with a mixture of a maintained generally fine and dry period almost to Day 10 from the likes of ECM at one extreme and a complete diversion into stormy Autumn from GEM by next weekend. Whilst feasible and partly due to the incursion of some tropical air left over from tropical storms over the Western Atlantic the GEM version of such a deep Low over the UK next weekend is probably overcooked and will hopefully be removed or displaced by the next run. The more likely option in my book is something along the lines of ECM where the High moves to the East or NE but maintains a link to an Azores High keeping fine and dry and hopefully warmer than of late conditions across the South and East for much of next week and while a breakdown to more Atlantic based Low pressure is probably favoured thereon it remains nothing of a guarantee as at that range and with tropical storms over the Western Atlantic impossible to predict in their movements the complete opposite may transpire. So what I am suggesting this morning is a lot of uncertainty from the middle of next week with all models likely to change at short notice at the midweek next week range onward. Changes run to run could be quite diverse too as early Autumn synoptics and the increasing differences between a cooling Arctic and the still Summery warmth of the tropics and continent still exist possibly promoting some more potent Low and High pressure areas where the two opposing air masses meet. Having said that GEM aside there is nothing alarmist from a bad weather point of view shown over the next few weeks at present.

 

Next update from 09:00 Saturday Sep 5th 2015

[Frosty.]

 

 

 

 

 

By next week the High should be to the East and as winds settle East or SE things should finally warm up with some warm sunshine for most but still chilly and perhaps misty nights.

 

 

That sounds good to me, there is talk of this being a dirty high but even a dirty high will bring sunny spells between the clouds and then next week gradually warms up by day with increasing amounts of sunshine..lovely stuff

 

[mushymanrob]

Many thanks for posting that, Saves me doing it!  In between , we have a quiet spell of weather by Tuesday next week,, Ground frosts a probability and perhaps a lot of cloud cover?

 

ground frosts and cloud cover?.... talk about trying to paint the most negetive picture you can!

ground frosts are unlikely away from northern upland areas, ( and not at all anywhere near that cold under cloud cover) although IF the cloud breaks, or where it does it will be chilly until midweek when the high gets centered more to our east and we pick up a warmer southerly draft. at least after today itll be dry for about a week.

[Frosty.]

The atlantic high we have been talking about for a while is almost here, the Gfs 6z shows it migrating slowly eastwards across the uk and then NE into Scandinavia and it forms quite a robust block which lasts until the end of next week. This weekend we lose the northerly, in winter that would make me sad but not in early September, once the cool air supply is cut off, our weather slowly improves with many areas becoming dry with lighter winds and although there will be a lot of cloud around, there will be some breaks in it to allow sunny spells. Nights look chilly where skies clear and through next week as the high takes control, there will be gradually more and more sunshine with temps responding, into the 16-19c range but warming up through the second half of next week into the low 20's c across southern UK. It becomes more unsettled later next week across northern UK but only briefly, there is another window of fine weather with just a few showers dotted around with temps in the low to mid 60's F. It becomes very unsettled later in low res and the run ends cool and cyclonic but next week looks increasingly good, especially further south.

Edited September 4, 2015 by Frosty.

[phil nw.]

Yes it will be a pleasant change to be rid of this cool northerly as the high from the Atlantic looks set to cut it off completely by Monday according to the latest fax chart.

 

should allow the days to be feel a little warmer especially later into next week as the high continues to move east turning the winds more south easterly off the continent.This should also help break some of the cloud up as somewhat drier air moves in.Of course as other posts have said any clear spells at night now means colder nights with maybe some local ground frosts in favoured spots.

I was speculating earlier in the week how long the blocking high may hold the Atlantic back and with a bit of luck we could see a dry week nearly everywhere if the ECM mean chart from the overnight run is on the mark.

Here at day 8 we see the first breakdown from the west arriving.

 

so a decent week's weather to come and seemingly quite frequent in September that we get a settled start to Autumn before the Atlantic jet becomes more active.

Could this coming settled spell be renewed after a brief interuption  i wonder with the Azores high maybe coming into play later.

[knocker]

 

so a decent week's weather to come and seemingly quite frequent in September that we get a settled start to Autumn before the Atlantic jet becomes more active.

Could this coming settled spell be renewed after a brief interuption  i wonder with the Azores high maybe coming into play later.

 

I was wondering that this morning but looking at the 00z ext ecm and the GEFS upgrade for 06z it doesn't seem likely at the moment.

Chart weatherbell