Model Output Discussion - 1st August 00z---------->

[mushymanrob]

are we looking at the 'best' august in 12 years?... nothing spectacular, true, but pretty decent away from the northwest.

[Polar Maritime]

The GFS continues to show finer more settled weather over the UK than of recent weeks.

Edited August 3, 2015 by Polar Maritime

[mountain shadow]

are we looking at the 'best' august in 12 years?... nothing spectacular, true, but pretty decent away from the northwest.

Away from the Northwest. ...great. :-(

[BlueHedgehog074]

The ECMWF/GFS 6 to 10 day 500mb chart offers similar ideas to the NOAA anomaly charts - troughing dominating to the West or North West of the UK and High Pressure dominating to the East/South-East of the UK giving an impression of a general North-West to South-East split. The GFS version to the right in the chart below would offer the best of the warmest and less unsettled conditions towards the South-East at times where it is a bit more relaxed with the trough to the North-West of the UK and has higher than average heights more influential towards South-Eastern UK. Plus, with the 500mb from the South-West over the UK, could be warm at times. Even Northern areas could perhaps see some less cooler and brighter weather a times between weather systems. The ECMWF version (to left in chart below) looks a bit more unsettled-looking with that trough to the North-West of the UK being more influential. The South-East again perhaps seeing the best of any less unsettled conditions and in the sun, could still be quite warm at times.

One other thing to note about the chart is the GFS version has a big dip in the upper flow to the West of Spain the in Southern Atlantic, which may mean for any Lows that drop further South in the Atlantic, could perhaps lead to more of a warmer Southerly flow towards the UK eventually (although that is sort of guesswork).

Another thing to mention is, interestingly, the 00Z GEM this morning is continuing with a warm plume style setup towards the end of it's run with Low Pressure in the Atlantic dropping to the South-West of the UK and High Pressure getting dragged up to the North-East of the UK towards Scandinavia. This again likely to lead to some thundery breakdowns, especially towards the South and East, as the South-Western UK Low runs into the warm air over the UK.

Unless other models and the anomaly charts start supporting GEM's plume ideas, it would be open for questions for now.

[knocker]

The GEFS anomalies continue on their merry way this morning and if anything reinforcing the position they have been adopting over the last couple of days.

 

Still weakening the upper trough adjacent to the UK by the weekend, but now inserting a ridge, whilst still forming new trough mid Atlantic. This progresses slightly east but only a little way before receding north allowing the Azores HP to strengthen the linkage with the Scandinavian ridge.

 

This analysis would bring settled dry weather, if not particularly hot, to all of the UK apart from a little temporary incursion up north.. It's certainly being persistent with this evolution but so far it's not getting great support as mentioned previously.

http://www.tropicaltidbits.com/

Edited August 3, 2015 by knocker

[ANYWEATHER]

Big,Big differences at the ten day range from ecm and gfs....

[knocker]

Obviously I haven't seen this morning's ECM mean anomalies but I bet a pound to a pasty the reason why it differs so much from the GFS ops is that it brings the mid Atlantic trough east to near the UK instead of the GEFS scenario of weakening it and enhancing the Azores ridge.

Edited August 3, 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 MONDAY AUG 3RD 2015.

 

THE CURRENT GENERAL SITUATION. A deep depression lies to the West of Scotland with a SW flow across the UK, strong in the NW later. A thundery trough will lie close to the SE at times tonight and tomorrow with an Atlantic front moving into the West and North as well.

 

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

 

MODELS-2 WEEK HEADLINE Remaining rather changeable with rain at times especially over the North and West. Some lengthy dry and at times warmer conditions across Southern and Eastern Britain perhaps extending North later.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow troughed over the eastern Atlantic before turning NE across the UK. This pattern then shifts east later in the week with an eastward moving Jet stream across northern Britain by next weekend. Through the second week the trend for the flow to weaken and become less defined is indicated.

 

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

 

GFS OPERATIONAL The GFS Operational Run today shows some changes in it's patterning this morning but not until the second week. As it stands the North/South split in conditions remains through this first week with SW winds and rain at times, chiefly in the North and West. Very warm air will continue to flirt with the SE at times through this period perhaps with a thundery shower. Then through the second week a ridge from the SW stretches across the UK on a more northerly axis than of late eventually allowing all areas to become largely dry and warm with some sunshine as High pressure gradually shifts to the NE of the UK. Pressure will become lower to the South of the UK later with some thundery showers reaching Southern parts late in the run.

 

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

 

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

 

THE GFS CONTROL The GFS Control Run shows a similar theme with the first week as the North/South split in the weather remains intact. Then it too shows a ridge from High pressure to the SW building across the UK through the start of Week 2 with a better and warm spell. for all. The difference being on this run is that greater pressure is put on the ridge from the Atlantic and nudges it South enough to bring the North back into more changeable Atlantic driven weather again later in the second week while the South remains largely dry, bright and warm.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning for 14 days from now closely support the Control Run with a 55% share of members suggesting a ridge from High pressure out to the SW lying across Southern Britain at that point with the North and NW still keeping an Atlantic influence going. The remaining 45% show more Atlantic influence to all areas with rain at times for all while a very small proportion >10% have High pressure across the UK.

 

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 a cool end to the week under a Westerly flow. A trough crossing East at that time will likely bring a spell of rain or showers to all before pressure builds from the SW across Southern areas next weekend with fine and increasingly warm conditions down here while the North stays cooler and breezy with rain at times in the NW as Atlantic westerlies regain supremacy in these areas.

 

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

 

THE FAX CHARTS The Fax Charts this morning show complex synoptics in  a generally West or SW flow. Pressure is never shown to be very low but with a lot of weak troughing within the flow all areas are indicated to have at least a little rain at times between drier and brighter spells.

 

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

 

GEM GEM this morning shows a different path towards a better interlude of weather as the West to SW flow through this week gradually backs to the SE through next weekend as pressure builds from the SE and then East. Warm conditions would likely spread North to many areas for a time though with pressure High to the East it shows the UK open to attack from the West and SW by Low pressure giving a spell of thundery rain and showers as the Atlantic winds try to regain control across the UK by the end of the run.

 

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

 

NAVGEM NAVGEM looks a lot like UKMO this morning at it's Day 6 point with a strong ridge building across Southern Britain and into Denmark. So dry and warm in the South next weekend with some rain still in SW winds for the North. By the end of the run it looks like a GEM solution might be evolving from this run as pressure begins to fall to the West and SW.

 

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

 

ECM ECM this morning is poor if it's a break from this pattern your after as it has virtually nothing of the rise in pressure across the South next weekend mostly due to the stagnating trough that moves through the UK later in the week. It's stagnation instantly attracts more Low pressure down from the NW maintaining rather cool and unsettled weather with rain and showers for all which only slowly lifts out of Southern Britain towards the end of the run.

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last night hasn't changed much for days it seems and although there are ebbs and flows from how much the Low pressure to the NW affects the UK as a whole it is always a pattern that indicates that SE is best for dry and warmth and NW is most likely to see rain and cooler conditions.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS There are a few shreds of evidence of a possible change this morning as several models show High pressure ridging over the South from the weekend and then transiting to the East. However, there remains scepticism from other models including ECM on this theory so pinning hopes on any one evolutionary trend this morning past a week remains futile.

 

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 95.9 pts followed by UKMO at 95.3 pts and GFS at 94.6 pts. At 5 days ECM is stll king at 85.9 pts followed by GFS at 83.1 and UKMO at 82.6 pts. Then at 8 Days ECM still leads at 58.5 pts over GFS's 53.4 pts. Finally at Day 10 ECM leads GFS at 38.0 pts to 33.9 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 There are some small signs of change within the outputs today but it all hinges on events towards the end of this week which may break us out of this synoptic lock down we seem to have had for so long now. For this week there is very little change with Low pressure up to the NW controlling the weather and keeping the warmest and driest conditions towards the SE while most places see at least some rain within drier spells. Things will probably cool down for a time in the SE too late this week as winds turn more westerly and it's from this point that hints of change are shown today. It looks like a ridge will push NE from High pressure to the SW at the weekend which should bring much of England and Wales into fine and increasingly warm weather. The chances for Scotland to join in on this are greatly reduced I'm afraid but there is some suggestion, notably from GFS with some support from GEM that all areas could share in this warmth as the ridge develops a High cell over the UK and eventually to the East and NE. If this was so all areas would become warm in a SE feed of air from Europe and while a thundery breakdown from this pattern is also shown it would at least break us out of this monotonous pattern of a NW/SE split we have seen for so long. The fly in the ointment for me this morning is the ECM model whose verification stats at this range are best and it shows no such build of pressure next week instead throwing more Low pressure down over the UK with rain at times in cool air out to day 10 when it belatedly shows some build of pressure towards the South. So in summary there is some hope for the North this morning while the South continue to enjoy the best weather over the UK in the next week or so. However, before I believe that the North will benefit from any rise of pressure from the SW I would like to see ECM on board, supported by a better 10 day mean chart later. So while improvements and changes are suggested this morning there remains no guarantee of yet but if ECM moves towards some of the other output in future runs for events across the UK beyond this week then we may be in business for a better second half of August.

 

Next update from 09:00 Tuesday Aug 4th 2015

Edited August 3, 2015 by Gibby

[knocker]

As expected the GEFs and ECM anomalies part company post T144 with the ECM moving the trough just west of the UK. This accounts for the ops discrepancies. As the ECM is closer to NOAA common sense dictates that this, or something close to it, is the likely outcome without other indicators.

Charts weatherbell

http://www.tropicaltidbits.com/

[Milhouse]

I must say, signs of high pressure ridging across the southern half of the UK and low pressure retreating back northwards towards Greenland are most encouraging. Despite not looking overly dry, its looking like a vast improvement over the dross of late July. Maybe August can rescue the summer this year?

[BLAST FROM THE PAST]

Most encouraging signs [selfishly] as we look ahead for me with trough activty moving North and HP ridging across the south as I look forward to my Longleat safari and Cornish holiday from next weekend .  I think a N/S divide is going to set in from this weekend onwards for a couple of weeks and above anomalies hint at that.  Unsettled periods this week with the current trough exerting more influence countrywide.

 

BFTP

[Frosty.]

The Gfs 6z shows increasingly anticyclonic conditions from later this week onwards with temperatures rising nicely again from Thursday, becoming very warm at times across the south of the UK and the other thing to like about this run is the gradual improvement in conditions further north / northwest as high pressure becomes more dominant. I'm starting to think there is a summery spell on the way.

[Milhouse]

It will be the first time this summer that we have seen a proper Azores high ridging across the UK if it ends up anything like the 6Z. A deep low passing across Iceland dragging in some very warm uppers from the SW under a very strong ridge of high pressure. Its almost the perfect example of the Azores high ridging across the UK.

 

[summer blizzard]

Euro largely unimpressed by day 7..

 

[Napplewh]

i dont believe that we will get the Azores high this weekend! GFS is very inaccurate model! i dont trust the 06Z. Lets see if it is still there in the 12Z. 

[Yarmy]

i dont believe that we will get the Azores high this weekend! GFS is very inaccurate model! i dont trust the 06Z. Lets see if it is still there in the 12Z. 

 

No it isn't!

 

[stodge]

Afternoon all

 

The 12Z is rolling and all this may change but there is a clear sign of a break in the long negative NAO pattern:

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

 

The return to positivity strongly supportive of rising pressure to the SW, falling heights to the NW and, if the 06Z is any guide, perhaps a week or so of fine and pleasant spell. Warm but not overly hot mercifully and perhaps those on coastal staycations (to use the vernacular) will do particularly well.

 

Hard to know if it will last - I'm inclined to doubt it. The index drops back toward neutrality approaching mid month and signs in low res of 06Z of a cooler and more unsettled theme from mid month onwards.

 

AO very similar at this time:

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

 

I see an improvement and perhaps 7-10 days of decent weather for most but a return to something less settled from or just after mid month.

 

Anyway, 12Z chart rolling and a very nice chart for early next week:

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015080312/gfs-0-198.png?12

[knocker]

An  friend of mine is off to southern Spain today. Rather him than me. Streuth

 

 

[Milhouse]

A ridge building across southern Britan on the UKMO. Close enough to deliver a lot of dry and warm/very warm condtions under 10c 850hps air.

 

[phil nw.]

Just signs of the jet easing north as we go towards the second week of the month from the GFS and UK 12z runs.

The Atlantic trough losing it's sharpness as time goes on as it becomes absorbed by the cooling Arctic heights.

 

We can see this change on the GFS mean run by T180hrs, compared to the current setup

 

the gradual change supported by the UK chart at day 5

 

The Azores high trying to nose in which should bring warmer and sunnier conditions further north.

Early days and we need the ECM to come aboard but encouraging charts for a final chance of Summer- like weather before it's too late.

Edited August 3, 2015 by phil nw.

[Frosty.]

In the last few days the Gfs 6z has been showing a warmer and settled outlook but was then followed by a cooler and more unsettled 12z, I'm pleased to say the latest gfs 12z run shows high pressure building in from the azores towards the end of this week across the south and then gradually, central and northern areas joins in the fine spell through next week, warmest in the south. The last 3 weeks or so have been generally cool and unsettled but there are signs of a fine and warmer spell developing, fingers crossed.

Edited August 3, 2015 by Frosty.

[Methuselah]

Let's all hope so, Frosty...  

[knocker]

The last couple of GFS ops runs are really no surprise as the anomalies have been pointing in this direction for at least a couple of days, And tonight's are continuing with the same upper air evolution. Which is very good news providing the ECM and NOAA come on board or at least move further in that direction.

 

Anyway by Saturday, as previous runs forecast, the trough to the west of the UK absorbed by new trough moving east to mid Atlantic allowing enhanced ridging from the Azores whilst keeping the ridge to the east of Scandinavia. thus allowing for the possibility of connection between the two HP zones. All good for the weekend with just a possibility of ingress of cooler air for the north west.

 

Moving on to day ten and this is where it has parted with the ECM and NOAA the GEFS greatlly reduces the mid Atlantic trough allowing the Azores HP to the SW to become dominant for the whole of the UK bring light W/SW with average temps.

 

It continues this theme to T360 with just a hint of trough disruption for the far north.

 

This scenario brings dry  settled weather to all of the UK for most of the period but the major caveat still applies. The ECM and NOAA are not on board but the GEFS is certainly being persistent.

 

EDIT

Looking at the ECM ops run I'm quietly optimistic it might be moving in the right direction. We shall see.

 

http://www.tropicaltidbits.com/

Edited August 3, 2015 by knocker

[Man With Beard]

Well, well, well, I've been watching the potential for a few days and all of a sudden, a full house for an Azores High ridge at just T144:

The great hope I have is that any lows spanned off the Atlantic will now take a different route, and the trough might fail to make its way back. A hope, yes, but tonight's ECM (and it must be said, quite a few recent GFS runs) agrees - possibly 5 days in the 80sF quite widely for England/Wales and the run finishes in a marvellous position for sun lovers:

Best "seasonal" output of the whole summer?

[ANYWEATHER]

Ecm showed unsettled cooler conditions this morning for the weekend and now it shows an heatwave , gfs  showed a heatwave and now its toned down its output  . A very high level of Shannon Entropy ! You cant make it up!   Theres obviously a lot of confusion in the atmosphere which the computer models cant Bite into....To Be Honest ,I don't believe anything the models are showing by then, lets see what Tuesdays output brings us      Just look at the 12z ecm compared to the 00z This morning,,,,,,

Edited August 3, 2015 by ANYWEATHER