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

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Time for a new thread as Summer comes to an end, And we enter the 1st Month of Autumn, That is 'September'.


 


So what are we to expect for September given the Model Outputs?


 


As ever, Please keep it to friendly model related discussion in this thread, And head over to the banter Autumn/Winter thread for moans, groans, ramps and more general chat:


 


https://forum.netweather.tv/topic/83902-model-banter-moans-and-ramps-autumnwinter-201516/


 


We also have the Autumn thread open for wider discussion:


https://forum.netweather.tv/topic/83554-autumn-2015/


 


If you're wondering where you can view the models, Many of them are available here on Netweather, Including the GFS,ECM, Ensembles, our own NetWx models, and others - All available from the Charts and Data page here:


http://www.netweathe...-and-data;sess=


 


Please be polite and respectful to other members on following the Forum Rules here;


 


https://forum.netwea...tion=boardrules


 


Old thread is here.. 


 


https://forum.netweather.tv/topic/83676-model-output-discussion-1st-august-00z/page-33#entry3254151


 


Many Thanks, Please continue.  PM


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Very briefly (mainly because there is not much to say) the latest EC32 update.

 

The high cell over the UK rapidly disappears around the tenth and a very familiar analysis emerges, The Azores high away to the SW and LP Iceland area giving a westerly flow over the UK and about average temps.

 

In a nutshell this scenario prevails until the end of September with the interplay between the low pressure to the NW and the high to the south. There are indications that the HP will perhaps be more influential leading to a reasonable month of pretty dry and average temp weather. The usual caveat that Scotland will be more susceptible to unsettled conditions.

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From the 500mb anomaly perspective the first 15 days look largely blocked at 500mb, some fairly minor differences between the models and GFS with itself. Overall though they keep the upper block as the main ingredient of our weather. Remember they are averages so day to day variability can occur but nothing prolonged at variance with the idea of a lock.

Not that warm especially under clear night skies. Probably below average rainfall and no sign of deep lows. Of course it is hurricane season and if one or a tropical storm make it into the north Atlantic then the anomaly charts will be not a great deal of use.  So watch for any of these being predicted to move into the Atlantic.

links

NOAA last evening

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

ECMWF-GFS this morning

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

Finally there is nothing in the MJO current or predicted output (GFS version) that would suggest any marked difference from what the anomaly charts show. Again the MJO is not a tool to use to try and predict any tropical storm or hurricane development in the Atlantic.

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The Ecm 00z shows high pressure taking a firm grip on our weather from the weekend onwards with increasingly dry and pleasantly warm sunny days with chilly nights and a risk of mist/fog patches with a touch of frost in northern areas. Later next week shows very warm continental SEly winds being drawn nw across the UK with temps soaring well into the 20's celsius as our high migrates further east.

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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 TUESDAY SEP 1ST 2015

 

THE CURRENT GENERAL SITUATION A cool North or NW flow will persist between Low pressure to the East and High pressure to the West of the British Isles.

 


 

MODELS-2 WEEK HEADLINE Cool and showery this week before things warm up from the weekend with a lot of fine and dry weather for many next week.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the recent NE moving flow over the UK now finally exited East of the UK with the flow well away from the UK for most of the rest of the week. A weak arm moves South down the North Sea later in the week and weekend before this too decays as the main thrust of the flow is well to the NW early next week moving NE. It then turns sharply South later next week to the UK or points further South as well as strengthening markedly too and blowing on a West to East course.

 


 

GFS OPERATIONAL The GFS Operational Run today shows a cool Northerly flow blowing down across the UK through the next 4-5 days with showers in places as the pattern of High pressure to the West of the UK and Low to the East persists. With time the High gains supremacy as it moves slowly East across Northern Britain over the weekend and start to next week. This will cut off the cool Northerly flow, veering it towards the East in the South but flat calm in the North. Warmer days are likely with sunny spells but cool and misty nights. Then as the High continues East or NE towards Scandinavia the pattern becomes more complex with various incursions of lower pressure from the South and eventually the West and NW threatening the UK by ending the fine spell with showers then the risk of more windy and wet weather from the NW for all by the end of the run.

 


 


 

THE GFS CONTROL The GFS Control Run today shows a very similar process to the operational run in bringing the High across the Uk from the West by early next week displacing the cool northerly feed with light and variable winds, warmer weather with plenty of sunshine by day and misty nights. Then the passage of the High to the East on this run maintains much more of a ridge across the UK with fine and warmer weather for many with no real major breakdown indicated within the 14 day time frame.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show an estimated 60/40 split in maintaining an influence from High pressure positioned to the South or SW of the UK for most areas away from the far North in 14 days time.

 


 

UKMO UKMO today shows a continuation of the cool North or NW flow across the UK until at least the weekend when the High to the West of Ireland gently moves East to be approaching the western coasts of the UK by early next week. Sunshine and showers chiefly across the East would be the pattern until the weekend when drier and less cool weather encroaches in by day at least.

 


 

THE FAX CHARTS The Fax Charts this morning show a continuation of the rather cool and showery feed of Northerly winds blowing down across the UK for the remainder of the week with less cool air gradually feeding down from the NW towards the weekend perhaps with some rain as a frontal wave slips SE over the UK.. 

 


 

GEM GEM today shows very little change in the current pattern of weather over the next 3-4 days with sunshine and a scattering of showers for all areas in a cool breeze. The pattern is then complicated by a frontal zone moving South at the weekend perhaps with some thick cloud and rain before High pressure finally makes it's move across the UK and on towards Scandinavia next week. This cuts off the cool northerly flow and things are shown to warm up considerably next week as winds freshen from the East and SE dragging warm continental air to all. Pressure falling to the SW at Day 10 would have to be watched over the coming days following Day 10.

 


 

NAVGEM NAVGEM follows a similar theme with little differences to the overall pattern from the other output. Towards the end of the run the High to the West edges closer in with the same theme of the rest of the output suggesting much less cool air eventually affecting the UK under fine conditions.

 


 

ECM ECM this morning shows a cool Northerly flow being maintained across the UK through the remainder of this week. We have to wait for the passage of a trough South across the UK towards the weekend before the High to the West finally makes it's move East across the UK, cutting off the Northerly feed and introducing fine and much warmer conditions. Then through next week the High recedes away to the East over Europe but we have to wait several days before any major signs of breakdown become shown, on this run from the West and SW 

 


 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last night continues to endorse the prospect that the UK could lie under High pressure in 10 days time all part of a theme to drift it across the UK and away to the East from around the 10 day point on.

 


 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models all support High pressure moving East across the UK from the weekend with no strong trends on what happens thereafter.

 

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 96.2 pts followed by UKMO at 96.0 pts and GFS at 95.1 pts. At 5 days UKMO is king at 86.7 pts followed by ECM at 86.2 and GFS at 83.6 pts. Then at 8 Days ECM still leads at 61.6 pts over GFS's 53.3 pts. Finally at Day 10 ECM leads GFS at 40.5 pts to 34.6 pts from GFS.

 


 


 


 


 

MY THOUGHTS The models continue to show the very slow progression towards High pressure crossing into the UK from the West later this coming weekend. In the interim period what we have now looks like sticking for some time to come yet with a cool Northerly flow persistent across all areas. While a reasonable amount of dry weather is likely for many showers are likely too, locally heavy towards the East but with some bright early Autumn sunshine too. Also at the end of this 4-5 day period most models suggest a trough running South early in the weekend which brings a spell of cloud and rain South which in it's wake is the catalyst that prompts the High to the West to move across the UK, cutting off the cool feed and replacing it with little or no wind, warmer sunny spells by days and misty nights. There are various options shown from then on as models differ somewhat on what to do with the High next week. Most output shifts it to the East with some warm and dry weather for much of the UK with sunny spells as winds settle from the East or SE, strongly on GEM. Once the High moves to the East other output suggests that a ridge will be maintained across the UK and dry and very pleasant weather continues for many as a result whereas in the 10-14 day time-frame some suggestion from both ECM and GFS that some ingress of more unsettled weather from either the South, West or NW is knocking on the door at that time. However, there is little common ground between outputs at that range this morning so I will treat these long term evolutions with little confidence at this time. So there you have it, we have 3-4 days more of these chilly and showery northerly winds before warmer and calmer conditions look likely from late in the weekend and much of next week with a hint only of a breakdown at the end of the forecast period. All in all the above indicates typical early Autumn weather especially once the High takes hold from the weekend. This could of course involve some cool morning's of mellow mists and fruitfulness with some fine almost summer-like afternoons. It also suggests that there will be very little in the way of rain across the UK for a while once this week's showers clear out of the way. 

 

Next update from 09:00 Wednesday Sep 2nd 2015

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From the 500mb anomaly perspective the first 15 days look largely blocked at 500mb, some fairly minor differences between the models and GFS with itself. Overall though they keep the upper block as the main ingredient of our weather. Remember they are averages so day to day variability can occur but nothing prolonged at variance with the idea of a lock.

Not that warm especially under clear night skies. Probably below average rainfall and no sign of deep lows. Of course it is hurricane season and if one or a tropical storm make it into the north Atlantic then the anomaly charts will be not a great deal of use.  So watch for any of these being predicted to move into the Atlantic.

links

NOAA last evening

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

ECMWF-GFS this morning

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

Finally there is nothing in the MJO current of predicted output (GFS version) that would suggest any marked difference from what the anomaly charts show. Again the MJO is not a tool to use to try and predict any tropical storm or hurricane development in the Atlantic.

 

Quote from Michael Ventrice.

 

"After a recording setting MJO event back in June & July, the MJO has been no-existent as El Nino forcing took over"

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ECM sends some warm air our way in its latter stages this morning as the high moves east temperatures into the mid 20's if it came off

 

Recm2162.gifRecm2402.gif

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So 00z EPS keener than 00z GEFS to shift the ridge to our west over us than eventually towards Scandi by day 10.

 

Day 10 EPS 500mb

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Day 10 GEFS 500mb 

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Though even GFS has temperatures creep back up into high teens or low 20s next week after an seasonably cool week and probably weekend ahead, though at least we lose the showers towards the end of the week away from eastern coasts.

 

I guess it will depend how quickly to the upper low over Scandi sinks away SE to allow the ridge to build in for any summery warmth to return. Also how the Atlantic trough disrupts to the SW over E Atlantic/Iberia on the edge of the blocking high migrating slowly east. EC day 10 suggest a very warm continental flow across UK by then.

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From the start of next week it's high pressure all the way on the Gfs 6z with cool misty starts giving way to fine days bringing plenty of sunshine with temps close to average but feeling warm in the sunshine. Once the high becomes established over the uk it's really hard to see a breakdown and the latest MO update is for a prolonged largely settled spell through much of September and a suggestion it will become warmer as time goes on which the 6z also shows. It's looking very good beyond the end of this week.

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UKMO shows the high moving over the UK during the weekend this should help temperatures edge up a bit making it pleasantly warm by day but chilly nights and early mornings

 

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The Euro lacks the heat of this morning however it's steadfast in its resolve that pressure will remain high..

 

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GFS has the Atlantic victorious..

 

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The GEFS anomaly tonight is going along with what has been indicated for a couple of days. That is the dropping of the HP cell adjacent or over the UK for weak ridging to the NE and SW giving a band of HP from Scandinavia to the Azores high well to the SW. The precise synoptics will decide the wind flow but one should be looking in a general westerly direction so dry conditions with temps around average. At this stage there would appear to be nothing alarming in the woodshed in the ext period.

http://www.tropicaltidbits.com/

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Nice Ecm 12z from T+144 hours with the Atlantic high ridging eastwards into the uk during the weekend and then the high continues to push further east and becomes centred over the UK before slowly drifting NE into Scandinavia as a blocking high with potential for much warmer continental air to be drawn nw beyond day 10, it's similar to the earlier ecm run but slower in bringing the warmth. Despite the gfs 12z premature breakdown of the fine spell next week I still think we are in for a noteworthy settled spell after this week as per the met office 6-15 / 16-30 day extended outlook.

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Evening folks.! A rather chilly theme for all this week with potent showery weather up until the weekend . High pressure tries to build across the country early next week and this has been put back time after time. The very unreliable timeframe shows high pressure retreating way to the northeast of the uk at T+216......with the Atlantic coming in :cc_confused:

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h850t850eu.png

ecmt850.192.png

 

With little going on in the shorter term, developments a whole week ahead are drawing my interest. What we have here is agreement between GFS (top) and ECM (bottom) for high pressure to be situated over Scandinavia with an easterly flow affecting at least part of the UK (most likely the southern half), this pulling in fairly cool air from the northeast.

 

This could actually work out quite nicely for most or all of us, as the airmass looks to be low in moisture content (so few clouds), winds look fairly light (so not too much trouble on eastern coasts given that the North Sea SSTs are near their annual peak), and temperatures could reach the high teens widely based on the GFS operational output.

 

We just need to hope that where that cooler air meets the warmer air over Europe, there isn't any development of low pressure, as that would be a major spanner in the works as far as fine weather is concerned - for the south in particular.

 

 

Looking further ahead, we see what is arguably a very typical divergence of the two models with respect to that Scandi High; the GFS operational run fires the jet stream through the UK on a NW-SE trajectory, but also maintains enough of a flow going north again to prevent what would otherwise be low pressure 'undercutting' the Scandi High and heading into Europe. Instead, the Atlantic low appears to ride up the western flank of the Scandi High for a time, after which a half-hearted undercut simply opens the door for the jet to power through the UK west to east through much of the 10-16 day period (a very 'flat' pattern - see the first of the two charts below).

 

For a 'classic undercut', we have to turn to ECM, which makes no attempt to take low pressure up the western flank of the Scandi High, instead taking the low toward NW Europe with interesting prospects going forward from day 10 (see the second of the charts below).

 

Now here's the thing - with a near normal SST situation in the North Atlantic, I would tend to favour the undercutting low scenario, but summer this year has shown on many occasions how the anomalously cold region of SSTs in the North Atlantic can promote a stronger jet stream that powers through the UK instead of being held back or at least diverted by blocking areas of high pressure. On the other hand, the latitude at which SSTs drop off fastest as you go north is located quite a way south of the usual position this year, which may increase the odds of the jet powering into Europe and leaving the Scandi High in place. I think it could be quite telling which way it goes at this early stage in the season - a tendency for the jet to dive into Europe can be a neat characteristic to take into the latter stages of November  :wink:

 

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Post above is a good one. Yes will be interesting to note how the jet stream and atlantic trough interplays with the projected movement of heights to a position to our NE. What impact will the cold SST values over NE atlantic, is the jet likely to take a more southerly path aided by the position of the cold/warm boundary which as you say is further south than normal. It could be a sign of how things may play out in the more volatile stormy second half of the autumn...

 

The tendency over the last 4 months has been for the trough to become unstuck to our NW/W dropping SE over the country anchored by a more meridional southerly tracking jet, this has consequently helped to provide warm air advection over southern/central Europe, with the trough dissipating markedly as it advances into the continent.

 

Back to the models, and early September yet again promises to be a slow static affair.. how often has this been the case in recent years, with little change and lots of benign non-descript weather, though today has produced some lively showers. Once again the song title Wake me up when September ends is being uttered..

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I have one question. What evidence is there that cold Atlantic SST anomalies affect the jet stream and how does that work? Make that two questions. So some links to backup this theorising would be appreciated

 

 

I would tend to favour the undercutting low scenario, but summer this year has shown on many occasions how the anomalously cold region of SSTs in the North Atlantic can promote a stronger jet stream that powers through the UK instead of being held back or at least diverted by blocking areas of high pressure

 

Back to tonight. The ecm anomaly moves the HP NE and with a weak trough Iceland, which may briefly impact Scotland, thus creating swathe of high pressure Scandinavia to the Azores high away to the south west. Thus a more or less benign period of weather in the W/SW flow with average temps. This continues in the ext period.

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Post above, not sure of the exact interaction, but the track of low pressure systems can be affected by the position of warm/cold air boundaries, and hence a colder than normal NE atlantic would tend to create a tighter temp gradient further south than usual so we would expect low pressure to track on a more southerly course, but as we know the Jetstream also dictates the path of low pressure systems..

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Post above, not sure of the exact interaction, but the track of low pressure systems can be affected by the position of warm/cold air boundaries, and hence a colder than normal NE atlantic would tend to create a tighter temp gradient further south than usual so we would expect low pressure to track on a more southerly course, but as we know the Jetstream also dictates the path of low pressure systems..

 

I'm not questioning the guidance of low pressure systems by the jet but it seems to me there are a lot of assumptions being made regarding the affect of cold SST anomalies on the northern hemisphere circulation, particularly the jet, so I'm just interested in on what they are based. Indeed some are statements of fact as I quote below. And as you agreed the post was a good one I assume you understand how it works.

 

 

this year has shown on many occasions how the anomalously cold region of SSTs in the North Atlantic can promote a stronger jet stream that powers through the UK

.

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I'm not questioning the guidance of low pressure systems by the jet but it seems to me there are a lot of assumptions being made regarding the affect of cold SST anomalies on the northern hemisphere circulation, particularly the jet, so I'm just interested in on what they are based. Indeed some are statements of fact as I quote below. And as you agreed the post was a good one I assume you understand how it works.

 

.

 

I had this study in my bookmarks and remembered something about changes due to slowing of the AMOC - haven't read the papers mentioned in the snippet that I've screen captured but will search when I get a chance - are we seeing this effect of cooling above warming in action this year?

 

 

OxuigNW.png

 

 

http://www.researchgate.net/publication/265017222_Drivers_of_North_Atlantic_Polar_Front_jet_stream_variability

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Cheers Nouska. Yes I remember reading this when it was discussed in another thread along with, amongst others,

 
For sure it's a complicated and interesting subject but as to what is going on this year who knows.There are so many factors to consider not least El Nino and various other teleconnections and why the upper trough took up residence in the eastern Atlantic along with long term trends that may be attributed to global warming. All a bit above my pay grade I'm afraid.
 
Not only that we will be smacked in a minute for wandering off topic.

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So in an attempt to avoid a yellow card.

 

last nights GEFS upgrade next Weds has the HP cell over the UK with the trough Spain through eastern Europe. Obviously the anomaly doesn't show the detail but it would seem unlikely that the latter will impinge upon the UK. It then proceeds to move the HP NE creating the slack high pressure area stretching from the Azores HP in the SW to Scandinavia, Very similar in fact to the ECM.

Charts courtesy weatherbell

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Looking at the GEFS anomalies this morning and there are disturbing signs of the upper trough making yet another guest appearance. Bit early to say whether this is significant but given the past record the signs aren't good. Need to see how the ecm handles it and maybe give it another couple of days,

http://www.tropicaltidbits.com/

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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 SEP 2ND 2015

 

THE CURRENT GENERAL SITUATION A cool North or NW flow will persist between Low pressure to the East and High pressure to the West of the British Isles.

 


 

MODELS-2 WEEK HEADLINE Cool and showery this week before things warm up from the weekend with a lot of fine and dry weather at least for a time for many next week.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow very slack over and around the UK with the main arm harmlessly away to the North of the UK over the coming days. The flow dives South over the North Sea over the weekend before gradually becoming an undulating pattern in the vicinity of 50-55deg North across and to the West of the UK through the 2nd week.

 


 

GFS OPERATIONAL The GFS Operational Run today shows a cool Northerly flow blowing down across the UK through the next 3-4 days with showers in places as the pattern of High pressure to the West of the UK and Low to the East persists. Then over the weekend the large High to the West of the UK migrates East across Britain delivering fine, sunny and less cool weather. This then persists for several days but then becomes eroded from the NW by Atlantic troughs edging SE. The pattern deepens in Week 2 with Low pressure taking control across all areas with a pattern of rain or showers at times setting up an early Autumn period of blustery winds and average temperatures.

 


 


 

THE GFS CONTROL The theme of the GFS Control Run this morning closely replicates that of the operational with a period of fine and less cool weather at the weekend as High pressure moves East over us. Then as with the operational this declines in favour of a stronger Atlantic Westerly pattern of winds for all areas with rain and showers at times in Week 2 with winds quite strong at times with gales towards the NW.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning have switched much more in favour of a more unsettled period of weather by mid month as Low pressure off the Atlantic takes control most likely positioned to the NW of the UK. This pattern is covered by at least 65% of members while the other 35% show less unsettled conditions at least for the South while the North and NW are almost blanket covered in unsettled conditions by all members in 14 days time.

 


 

UKMO UKMO today shows a continuation of the cool North or NW flow across the UK until at least the weekend when the High to the West of Ireland gently moves East into the UK but as weakening feature. Nevertheless the cool Northerly winds will become a thing of the past by the end of the weekend with fine and less cool weather by day with sunny spells while nights remain calm and come increasingly misty in rural parts.

 


 

THE FAX CHARTS The Fax Charts this morning show a continuation of the rather cool and showery feed of Northerly winds blowing down across the UK for the remainder of the week with less cool air gradually feeding across the UK later in the weekend as troughs clear away to the South. 

 


 

GEM GEM today shows very little change in it's output this morning to that of yesterday morning. After several more days of cool and potentially showery weather a band of cloud and a little rain early in the weekend clears South with High pressure crossing East over the UK with fine and sunny and less cool weather as a result. Through next week the High moves away NE to Scandinavia and a strong but warm SE flow develops with increasingly unsettled weather nudging up from the SW towards the end of the run as pressure falls to the West and SW.

 


 

NAVGEM NAVGEM follows a similar theme in as much as High pressure is shown to move across the UK late in the weekend with less cool and fine weather for all as a result. Then as this pulls away East next week a ridge is maintained across the UK with fine and relatively warm conditions persisting for many areas although the NW may cloud over under a SW wind with a little rain by midweek..

 


 

ECM ECM this morning shows a cool Northerly flow being maintained across the UK through the remainder of this week. We have to wait for the passage of a trough South across the UK towards the weekend before the High to the West finally makes it's move East across the UK, cutting off the Northerly feed and introducing fine and much warmer conditions. Then through next week the High declines to the South or SE and more changeable conditions are introduced ino the North and West though on this run effects in the South are muted with a lot of fine weather persisiting out to the end of the run with rain at times returning only to the North and West. 

 


 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last night shows that the previous day's of High pressure is showing signs of moving slowly away to the East.

 


 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models have changed little in firstly their movement into the UK of High pressure at the weekend and secondly in the confusion and disagreements in where the High migrates or dissolves away to in the period that follows next week and beyond.

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM tieing with UKMO at 96.1 pts at 3 days. At 5 days UKMO is king at 86.5 pts followed by ECM at 86.1 and GFS at 83.5 pts. Then at 8 Days ECM still leads at 61.5 pts over GFS's 53.5 pts. Finally at Day 10 ECM leads GFS at 40.8 pts to 34.5 pts from GFS.

 


 


 


 


 

MY THOUGHTS We still have three or four more days of this stark reminder that we are entering Autumn now with Northerly winds dominant over all of the UK until the end of the weekend with sunshine and showers and jolly cool nights. It looks like a band of cloud and occasional rain will slip South over the UK at the start of the weekend and behind this is when the High to the West of the UK makes it's move into the UK from the West. The main result of this will be to cut off the cool Northerly feed and bring warmer sunny spells by day though cool misty early Autumn nights are still likely. That is as far as any guarantees in the weather that follows goes this morning I'm afraid as all models then show a cocktail of various and very different options as far as what happens next week and beyond. GFS (well supported by the Control and Cluster runs) shows a full blooded change to Atlantic Westerlies and unsettled conditions for all from not long after midweek next week while GEM is still on the track of a strong Scandinavian High, strong SE winds and fronts moving up into the South from the SW. NAVGEM holds High pressure to the East in control as a ridge from it mainatins fine weather over much of the South and Central slice of the UK leaving UKMO and ECM with a much slacker looking High entering Britain at the end of the weekend and start to next week before ECM moves on to maintain fine conditions across the mjority of the South with only the NW seeing any meaningful attack from Atlantic Low pressure. So which is right? That is anyones guess this morning and I don't think it will be resolved until we get the High out West into the UK later this weekend before we can pin down anything that might evolve thereafter. So concentrating for now on what is more or less certain a trend towards less cool, fine and dry weather is likely for all at least for a time commencing this weekend and probably lasting well into next week for some and possibly more. Thereafter, it's a case of more runs needed I'm afraid.

 

Next update from 09:00 Thursday Sep 3rd 2015

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