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

[Nick F]

Not a great outlook painted by 00z GFS operational for the start of the school holidays next w/e onwards, I hope it's being too progressive in shifting the upper trough east ... don't want days on end of cool and unsettled northwesterlies in high summer personally!

[Captain Shortwave]

Not a great outlook painted by 00z GFS operational for the start of the school holidays next w/e onwards, I hope it's being too progressive in shifting the upper trough east ... don't want days on end of cool and unsettled northwesterlies in high summer personally!

It seems to depend on where that Arctic cold pool ends up which is currently moving around the Arctic circle.

The cold pool in question being that dartboard-esque feature that moves along the northern Russian coast towards Scandinavia. It's a question of where it ends up to be honest. The GFS stalls it over Scandinavia which isn't great for us in the UK as that pretty much develops a Scandi trough/northerly component to our weather. 

 

Other models though push this further west towards Iceland

UKMO

Not great but I suspect further out a west to south westerly pattern would re-establish.

 

ECM

Mixed certainly but it becomes very warm or potentially hot in the south of the UK as the Euro high strengthens its grip. 

 

All to play for still I feel.

[mushymanrob]

maybe not as good an outlook for this week as many of us would like to see, but its not overly bad, just 'below par' . i reckon those possible (nowts set in stone in this very mobile, unsettled spell) northwesterlies will be quite pleasant in the clear air and strong sun, assuming of course we avoid the cloud.

at least with all the mobility any wetter spells will pass through quickly, as the ridges and troughs play their merry little dance over us, neither 'winning out' . certainly no 07 /12 type long-lasting monsoon drenching.

anomalies are in disagreement, my straw clutching previously is proving to be just that (hopecasting, trying to spot a favourable evolution which is proving to be wrong) ... the bigger question is.... how long will this mobile pattern continue? will it degrade and get worse? or will it break and allow a lasting anticyclonic spell to deliver a hot sunny spell?.... well im not throwing in the towel yet (like i have on other summers to be scorned at, but was actually proven right), i think (based on nothing scientific, just pattern familiarity - so likely to be wrong) that we will get a decent settled spell, but its not looking likely in the next ten days...

maybe august 15 will be the best for 12 years?... it has to happen sometime!

Edited July 12, 2015 by mushymanrob

[Man With Beard]

Morning all

Well, 10 days ago we were still thinking about further plumes, then the scandi trough looked influential, then a mid-atlantic high, then there was no major pattern in the models for a while. A couple of days ago the models went for a plume again. Finally this morning we several dartboard lows over the UK, followed by a couple of north/south splits or a cool northerly depending on the model.

Which reminded me of what an ex-met office told me once - the weather in the north Atlantic is the hardest to predict in the world (his words not mine). It seems to me we are in a particularly difficult period of forecasting. We have an upper trough to our north east which is on the very edge of giving us a cool Arctic influence, but we're also on the edge of a hot contental pattern too. To make matters worse, the state of the Atlantic seems conducive to late-developing lows ( which I wonder if are beyond the measuring of the long-term anomaly charts?). The impact of these late-developing lows on us is guided by tiny differences in the location of the trough to our north, block to the south and indeed the very level of development in these low pressure systems.

So to sum up, the next 10 days appears very volatile for forecasting, and FI may be nearercthan usual - perhaps even T96 or T120. Quite unusual for summer.

One interesting development in both GFS and ECM ens, though, is the weakening of the Arctic heights in the D8 onwards. This could allow a continental influence to spread a bit further north at times as Atlantic troughs will be freer to move north too - though I am speculating in all honesty

[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 SUNDAY JULY 12TH 2015.

 

THE CURRENT GENERAL SITUATION A trailing and weak cold front will slowly edge away SE out of Southern England today. A further warm front will cross NE across the UK tonight and tomorrow in a mild and muggy SW airflow.

 

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

 

MODELS-2 WEEK HEADLINE Somewhat changeable with some rain at times but driest in the South with some short warm spells at times.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow generally moving West to East across the UK at the moment and there is not much movement in this through the coming week. However, towards next weekend it appears to move somewhat South while troughing across the UK. Thereafter, after a period of weak and indecisive positioning it settles to the North of Scotland late in the period strengthening somewhat. 

 

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

 

GFS OPERATIONAL The GFS Operational Run today is quite a complex run it that it is dealing with relatively weak areas of Low and High pressure mostly in the vicinity of the UK through the whole period. In essence the thrust of the forecast is for a weak Westerly flow to continue delivering spells of some rain and showers, mostly in the North while the South sees the best of any dry and brighter weather. However, a somewhat more potent Low develops from the SW next weekend and then away to the NE through Week 2 allowing the pattern to reset with the rain and showers for all next weekend looking likely to become restricted more towards the North again later.

 

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

 

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

 

THE GFS CONTROL The GFS Control Run is very similar in the course of events through the first week with the Low shown at the end of the week on the operational shown here too. However on this run, in Week 2 this Low moving away to the NE is superseded by another one which keeps the weather rather unsettled for longer with all areas seeing some rain well into week 2 before it shows a cooler NW flow down across the UK by the end of it's run

 

THE GFS CLUSTERS(14 Days) The GFS Clusters at 14 days this morning continue the theme of High pressure lying to the SW of the UK in 14 days time with a Westerly airflow across the UK and as usual in these patterns it is likely that the biggest influence of this will be felt across the North where the most rain will fall as Low pressure lies to the North.

 

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

 

UKMO UKMO this morning shows slack pressure gradients across the UK later in the coming week and with a small upper Low moving NE across the UK towards the end of the week some rain or thundery showers are possible. Then as the weekend approaches High pressure ridges in from the SW to dry things up again to conclude what looks to be a fairly benign and otherwise quiet week weather wise.

 

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

 

THE FAX CHARTS The Fax Charts continue to indicate that relatively weak fronts will remain hung up across Southern Britain for several days in  fairly slack pressure gradients across the UK with a little rain in places.

 

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

 

GEM GEM today shows a similarly slack period with troughs hung up across Southern Britain this week with a lot of cloud and a little rain at times. The North looks like being more showery before this run shows more mobility developing later in the run as Low pressure to the NW strengthens a SW flow across Britain with rain at times especially across the North and West.

 

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

 

NAVGEM NAVGEM today keeps things very slack through the coming week with no particular atmospheric feature having overall control across the UK. So a benign week looks likely with a little rain or showers at times but a lot of dry and quiet weather too.

 

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

 

ECM ECM today shows the current SW flow weakening in the coming days as pressure becomes slack across the UK. Then a deepening Low moves NNE across Western areas with an increase of wind, cloud and frontal rain for probably all before the pattern resets to what we have currently to end the run with a SW flow and some rain at times for the North and West in particular.

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last evening shows a trough from Low pressure over Scandinavia lying SW to the West of the UK keeping much of the UK in a somewhat unstable SW flow.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS There is still no definitive trend detected from this morning's output with all models playing around with rather complex and often slack synoptics.

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 96.0 pts followed by UKMO at 95.2 pts and GFS at 94.7 pts. At 5 days ECM is stll king at 85.2 pts followed by GFS at 81.6 and UKMO at 81.3 pts. Then at 8 Days ECM still leads at 53.0 pts over GFS's 49.7 pts. Finally at Day 10 ECM leads GFS at 33.9 pts to 30.5 pts from GFS.

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png 

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.prig

 

MY THOUGHTS The atmosphere around and over the UK is currently quite slack and will remain so for the reliable future. With a lot of relatively weak fronts, Low pressure and High pressure ridges possibly affecting the weather across the UK in the coming week it is very difficult for humans to decipher what particular weather type is going to command dominance in any one place day to day let alone computer models trying to look further ahead. Nevertheless we have what we have and the overall outcome is for there to remain a lot of cloud across the UK under quite weak fronts, delivering some rain and drizzle at times in the coming days. Outside of these zones will be some drier and brighter weather with a few showers. Then later in the week there is still some support for a slightly more coherent Low pressure area at least to move over or to the NW of the UK bringing breezier weather with a more commanding zone of frontal rain over the UK late in the week. Once past the models seem to want to bring us back to square 1 with a SW flow and Low pressure up to the NW bringing rain and showers at times to those regions while the South and East return to drier and warmer phases between very occasional rain bands closest to higher pressure over Europe. So a very difficult pattern for forecasters to predict over the coming period with overall dry conditions probably outweighing wet ones but pinning down local detail could be very difficult and while the weather could be a whole lot better for sun worshippers there is nothing alarmist showing in any output which will trouble outside activities to any great degree for much of the time with temperatures never straying far from average if not rather above in the South at times. 

 

Next update from 08:00 Monday July 13th 2015

[Polar Maritime]

No change from the GFS this morning, With a cooler/unsettled N/W flow from the 14/15th, Thursday next week looks particularly wet for England/Wales...

Edited July 12, 2015 by Polar Maritime

[Summer Sun]

No change from the GFS this morning, With a cooler/unsettled N/W flow from the 14/15th, Thursday next week looks particularly wet for England/Wales...

 

Friday looks a shocker on ECM with a deep low bringing wind and rain though the SE could see temps close to 30c and with the air unstable thunderstorms can't be ruled out

 

 

Thankfully the low pulls away quite quickly so Saturday should become be a bit calmer as the day progresses

 

 

Hopefully with the heat showing no sign of leaving continental Europe any time soon we could tap into it later this month and during August we're well over due a hot August

Edited July 12, 2015 by Summer Sun

[Frosty.]

The Gfs 00z low res is very nice this morning with high pressure becoming dominant, at least across the southern half of the uk and temperatures recovering following the cooler unsettled spell. I will be very happy if the weather improves like this run later in july.

Edited July 12, 2015 by Frosty.

[weatherguru14]

Frosty can you please  post the latest Gfs charts now??  they  got the plume incorrect for  Friday. just the south east now.. and the settled weather for the end of the month as now gone "again".. The gfs long range  models are pointless.

[Frosty.]

Frosty can you please  post the latest Gfs charts now??  they  got the plume incorrect for  Friday. just the south east now.. and the settled weather for the end of the month as now gone "again".. The gfs long range  models are pointless.

Hi weatherguru14, here's the 6z charts for later in the week, I have to say, most of this run is a horror show for the majority of us who want summery weather.

[chapmanslade]

 

It is incorrect to say the GFS models are pointless BUT a useful indicator I find is to look at the point at which the ensembles spread and lose a pattern. It is pretty obvious where this is if you look at the example I have posted from a few years back. You can be fairly sure up to the point of spread but after that it is very unreliable. In addition regarding the plume - a hundred miles or so out with the edge of the plume is a very small variation when you consider the global scale of the model.

Edited July 12, 2015 by chapmanslade

[weatherguru14]

the Gfs have been getting it wrong for at least 2 months..Every 6 hours or when the GFS charts come out. There is a different conclusion every time..they are not realiable.

Edited July 12, 2015 by Polar Maritime
To move discussion on..

[Polar Maritime]

Back to what the Models are showing please, Not members posting styles..

Thanks, PM.

[Tamara]

Ah. So it's all progressing 'as anticipated'?

 

 For what its worth, I think not personally speaking. That is at least if referring to anticipating any protracted cool NW 'erlies.

 

Suggestions have been made a couple of times of late that NWP would be unreliable and not worth taking at indicated face value and analysing too much for details. That is proving to be the case and a good idea not to pick certain individual synoptic model charts as indicators of the likely way ahead either  .

 

A thoughtful and very good post from rjbw earlier I think, that at the very least amounts to well reasoned speculation, and I agree with some important points he expressed there.

 

Overall theme is very much the same as indicated likely the past week - except that the flatter more mobile pattern expected at some distance, is set to produce unsettled conditions to a greater extent across the UK this week than might have seemed apparent previously.

 

But then when making summaries looking at macro trends and likely model output evolutions which are based on looking at wider factors in additions to intra day output, it is never going to be possible for anyone to also provide micro predictions from distance where boundary lines of dividing air masses might lie across a nation as tiny as the UK is in relation to the NH. The professionals like the METO find such detail hard to pin down outside of a day or two. Besides, making suggestions for general patterns to be expected distances ahead at a time does not include and cover, and is not the same as, making detailed predictions for surface conditions regionally IMBY.

 

Its no surprise that such different perceptions and ideas about the weather, and weather model forecasting emerge in a country like this - especially at times when the generally dominating synoptic pattern provides a split division of surface conditions experienced across the UK

 

My previous post the other day gave reasoning as to why heights to the north might begin to show signs of fading with time, and this is becoming apparent in the modelling as rjbw observed in his post.

 

I will try not to bore again with too much unnecessary techno-babble, but will repeat the importance once more that the key to upstream developments to re-amplify the pattern downstream in the Atlantic and slow the jet pattern, further lies with the Global Wind Oscillation path back from Phase 7/8 to de-amplitude Phase 0. And where it heads from there..

 

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

 

These forecasts, like any other model forecast, are never to be wholly relied on - but they have not wavered for days at a time and, much more importantly than that, there is very good underlying factual reason to believe them

 

Phases 7/8 of the GWO typically feature a downstream feeding fast Pacific sub tropical jet stream with a height anomaly to the north and downstream elongated Atlantic trough into Northern Europe and Russia. Pretty much then what it says on the tin currently

 

With the de-amplitude of this phase over the coming 10 days, it makes sense to see the height anomaly fade to the north and also a tendency with time to see upstream jet velocity relax. What is harder to predict (and likely more troublesome to shift) is what happens to the Atlantic/N European trough?

 

Nonetheless, as the Atmospheric pattern, as described in detail in previous posts, starts to turn full circle then despite all the on-going messy synoptics, the expectation, for me, continues to remain the same as before: The pattern across the Pacific will become more conducive to a slower downstream evolution which will mean that secondary phasing of the jet stream in the Atlantic which is providing the 'late arriving' unsettled bands of weather, more especially across the north and west, will start to back west a little and allow greater downstream ridging to occur once more.

 

I think that currently some of the modelling is overplaying the influence and longevity of the Scrussian trough (hence the NW'erlies) and as time moves on, and upstream developments begin to take further shape, the emphasis will turn to the slowing and sharpening of the troughing in the Atlantic once again. 

 

Relaxation of the heights to the north should assist a slower jet stream on a less southerly track, and amplification forcing arriving from the west should force a break in two of the flat elongated troughing, and promote a ridge response ahead of it

 

Precisely to what extent this might influence fortunes in the UK cannot be anticipated just yet. However, it does continue to support the general broad- brush idea of unsettled conditions becoming less widespread following the rain of the first half of this week and  the uncertainties of the problematic low later this week/weekend.

 

Something of a NW/SE split very likely to remain thereafter but less generally unsettled than this week, with a further warming trend always attempting to move up from the south.

 

Anticipating closer detail UK developments in some senses can be much harder to pinpoint than trying to attempt suggestions for longer term trends - even if these cannot be obviously be bullet-proof either.

[Frosty.]

Looking further ahead, there are a fair number of 6z perturbations trending towards a more settled further outlook, the reason I'm posting these is because the met office extended outlook is very promising from week 2 onwards with a good deal of fine and warm / very warm weather, especially further south.

[Frosty.]

Much better Gfs 12z, especially through low res with high pressure building in and intensifying over the uk bringing dry, warm and sunny weather to all parts of the UK. The reliable timeframe looks better too, Thursday looks very warm with sunny spells but then thundery showers developing, Friday turns cooler and fresher but then a nice ridge of high pressure builds north east into next weekend with temperatures starting to rise again. There is some unsettled weather around but most of it misses the southeast and then gradually pressure rises and summery conditions become widespread

Edited July 12, 2015 by Frosty.

[mushymanrob]

Very happy with the gfs 12z, that would deliver a lot of warm sunny weather, not too hot nor too humid, albeit in fi. But a demonstration that the outlook could change for the better quite quickly.

Of course its only one run, itll be interesting to see if the ecm and anomalies start to give support. Heres hoping.

[summer blizzard]

The outlook is certainly not cool but in the next 9 days the 1020mb contour reaches Yorkshire on just 2 days. This suggests it could potentially be wet.

[Frosty.]

The GEFS 12z mean shows there is growing support for a warmer and more settled extended outlook which ties in with the very decent met office longer range update today.

[Summer Sun]

ECM shows things settling down during next weekend

 

 

Though not hot it would be perfectly acceptable providing it was sunny

Edited July 12, 2015 by Summer Sun

[bluearmy]

ECM op may be picking up the pattern that tamara mused about earlier. The building blocks for the stalling Atlantic trough laid early on in the run and the resulting plume reminiscent of what we saw a couple weeks ago.

[Milhouse]

Well this evenings ECM looks increasingly settled and warm from day 7 onwards. No doubt at the absolute warm end of the ensembles though but nice to see nevertheless.

 

[mushymanrob]

Very happy with the gfs 12z, that would deliver a lot of warm sunny weather, not too hot nor too humid, albeit in fi. But a demonstration that the outlook could change for the better quite quickly.

Of course its only one run, itll be interesting to see if the ecm and anomalies start to give support. Heres hoping.

great, the ecm supports high pressure build after this week

A long way to go but promising signs this evening.

[Frosty.]

Well what a cracker the Ecm 12z turned into, another spanish plume event and a buckling jet with high pressure building in the perfect position. I thought the gfs 12z was excellent in low res but this has raised the bar even higher..hope we can tap into the continental heat again soon...lovely stuff.

[ANYWEATHER]

Good Evening Folks. Lots of unsettled weather to get through this week especially for the north. Ecm and Gfs disagree abruptly after this weekend with Gfs the cooler unsettled model, whilst Ecm  is an heatwave lover   I really don't believe any model this far out. but I would hope Ecm is right ,purely for selfish reasons....

Edited July 12, 2015 by ANYWEATHER