Model Output Discussion 31/03/14 onwards.

[ANYWEATHER]

The ecm and gfs look very different at day 10.....[T+240] The gefs ensembles really try to higher the pressure from mid month, but there is lots of scatter...

Edited May 6, 2014 by ANYWEATHER

[knocker]

You can say that in spades. At 12z on Friday the GFS has a depression 999mb to the south west of the UK with high pressure to the NE with the UK in a SE airstream which is quite strong in the south west. No resemblance whatsoever with the ECM. Anyway the GFS anomaly for that day with a trough to the west.

Edited May 6, 2014 by knocker

[Summer Sun]

ECM ensemble slowly coming on board now appears the Op was over cooking the low at t240 with the ensemble clearly going for high pressure rather than low pressure

 

 

[knocker]

Yes it does look a tad nearer the GFS but still clear differences and they haven't got  the upper air sorted. The jet is quite weak.

Edited May 6, 2014 by knocker

[knocker]

After  a quick look at the 00z GFS I might buy a lottery ticket. They certainly haven’t got next week pinned down as yet. This morning’s scenario.

 

Wednesday

Low SW of Iceland with another small low south of that giving a SW airstream over the UK and mainly wet in Ireland and England.

 

Thursday

By now the lows have edged closer to the UK with an area of high pressure centred over the channel. Another wet day with the winds NE in Scotland but mainly calm in England.

 

Friday

Low pressure dominates to the west of the UK. One low north of Iceland and the other around the Bay of Biscay. Giving a broad sweep of SE winds across the UK.

Mainly dry.

 

Saturday

Low pressure now established WSW of Cornwall 991mb giving a strong SE across all of the UK.

 

Sunday

The low still to the SW of Cornwall but further away and high pressure SE of Greenland. An easterly airstream from Scandinavia covers the UK with a frontal system across Wales and Kent.

 

All in all it’s a fairly muddled picture and difficult to suss out any structured evolution. The 500mb anomaly still has trough in mid Atlantic so over to the ECM.

 

 

[Captain Shortwave]

ECM has a much broader Atlantic trough this morning and it teeing up a superb end to its run

 

GFS is slower in it's evolution but gets there in the end and the ensembles still look good into week 2. GEM showing heights building in too but a cooler north easterly flow develops.

GFS

GEM

Edited May 7, 2014 by Captain shortwave

[Polar Maritime]

Yes ECMWF is showing some nice warm seasonal charts this morning from the 15th.. GFS is trying.

 

Edited May 7, 2014 by Polar Maritime

[IDO]

The GFS Control this morning shows what can happen if we get a bit of luck with a plume from the south:

 

   

 

Timing still an issue compared to the ECM, the latter op at T168:   GFS Mean: 

 

So the ECM is 2-3 days more progressive with height rises near the UK. Though the GFS mean at T240 also confident of  a pressure rise: 

 

The GEFS still maintaining this as relatively transitory, with heights continuing towards Scandi so by T300 (mean): 

 

But potential at least for 4-5 days of drier warmer weather for the GFS whilst the ECM suggests HP to stay longer, with a more blocked pattern, lower heights over the Med keeping the HP in situ close to the UK from D8 to D10: 

 

 

No real change from the last few days with regard to synoptics though the GEFS are moving slowly towards an Atlantic trough by D10 increasing the chances of higher pressure over the UK (about 66% support at D10). Only one GEFS member supports ECM UK HP at T168 so low confidence in the recent progressive ECM runs especially as last night's ECM mean only had the HP centered over the UK at D10 (more in line with the GFS):

 

T192 mean from 12z: 

 

Though that is tempered as GEM's op evolution is closer to ECM. That said GEM's ensembles last night at D10 were split 50/50 between UK HP or UK trough.

 

A couple more days model runs probably needed.

 

 

 

[knocker]

There is no comparison whatsover between the GFS and ECM ops runs for the end of next week and that includes the upper air. Well it would. And until that's sorted the surface analysis will remain in a state of flux.

Edited May 7, 2014 by knocker

[Gibby]

HERE IS THE LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM TODAY WEDNESDAY 7TH MAY 2014.

 

THE CURRENT GENERAL SITUATION. A showery SW to West flow cover the UK with embedded showery troughs moving East across Northern Britain. A new Low pressure will move towards the West of the UK tomorrow with attendant troughs moving NE over Southern and Western Britain.

 

GFS GFS maintains unsettled conditions for some while yet as Low pressure from off the Atlantic remains the driving force over the weekend and into next week too. There is a slow transgression into the chance of brighter and drier weather creeping up from the South or SE to affect some places with warmer conditions later. However, it's ensembles and operational is thwart from risks of further Low pressure intervention later which could mean more unsettled weather, perhaps more likely towards the South and West and it could begin to feel rather humid.

 

UKMO UKMO is showing unrelenting Low pressure feeding across the Atlantic into the UK well into next week with rain and showers at times for all in blustery west or SW winds and temperatures little better than average at best.

 

GEM The GEM operational develops better conditions later next week as High pressure slowly builds up from the South bringing drier and brighter conditions generally though with a cool NE breeze across the South later which looking at last night's ensemble data could develop further over the UK with unsettled weather too across the South.

 

NAVGEM NAVGEM shows High pressure building North over the Atlantic towards midweek next week with a chilly Northerly flow over the UK promoting a sunshine and heavy shower mix in rather cool weather outside of the sunshine.

 

ECM is again in Summer mode this morning as it's operational further develops High pressure across the UK later next week As a result with a large 1035mb High across the UK fine and increasingly warm weather would develop with plenty of sunshine away from North Sea coasts. It'e prominence towards this nationwide Summer type needs to be supported by it's ensemble data released later.

 

MY THOUGHTS  This morning's output continues to show rising pressure across the UK later next week following another 5-7 days of very unsettled and breezy weather with rain at times and cool conditions. The improvements then should take place from midweek but the extent and depth of such an improvement is far from clear. We have the ECM operational showing us a full blooded Summer setup by the end of it's run with intense High pressure positioned across the UK while other models including the UKMO shows less inclination to build the ridge leading to this setup early next week. With mixed output from the other models shown it maybe we have to wait several more days before the chance of anything resembling high Summer becomes anymore than a chance with plenty of wind and rain to get through yet before we get there.

[Frank Trough]

The UKMO looks altogether less interested in anything - it doesn't really deepen the low as much and has it much closer to the UK so not really allowing pressure to build north.

 

 

 

 

 

I hope the ECM isn't having another one of its "ridging high pressure" moments. At least the GFS develops more favourably this morning, albeit a little bit slower.

[Frosty.]

Yes ECMWF is showing some nice warm seasonal charts this morning from the 15th.. GFS is trying.

 

 

Yes PM..Let's hope the Ecm has this nailed, would love a warm anticyclonic spell with lots of strong sunshine and light winds, fingers crossed mate.

[johnholmes]

Using the last few days outputs from the 500mb anomaly charts suggests an upper trough somewhere between 20 and 40 west, so a largish variation in position and this would obviously impact on the surface weather pattern. Indications of ridging taking place but again will it be over the UK area or further east. Neither the position of the upper trough or upper ridge is anywhere near fixed for the 6-10 day period let alone any further out, so the actual surface weather is also not yet decided. Will it be unsettled or will it be settled or somewhere between the two-not enough there for me to give a definite answer=sit on fence time.

 

The weather for the next 3-5 days is pretty much determined though, changeable or unsettled with rain or showers at times and only short spells of drier settled weather.

Edited May 7, 2014 by johnholmes

[Summer Sun]

What a stunning run from ECM this morning with high pressure galore from Wednesday week with the 850's becoming increasingly higher as the run progresses

 

 

ECM ensemble continues to show a pressure rise

 

 

So another solid run from ECM from both its Op and Ensemble

 

 

GFS control in FI looking very warm and humid for the time of year for a time

 

Edited May 7, 2014 by Summer Sun

[Frosty.]

Beautiful Ecm 00z op run in the later frames with high pressure building in strongly, very warm air surging northwards with +10 T850 hPa which converts to 25 celsius plus temperatures at the surface, this would be a golden late spring spell if it verifies and I think there is a good chance it will. The end of this week and start of next week is looking cooler and generally unsettled but then things are looking up.

[summer blizzard]

Probably a tad short of 25C if it came off (we're 2 months too early for a 15C lag) but it would certainly be the warmest day of the year so far.

 

Just remember that in May 05 we hit 32C so look out for warmth continuing to build.

 

The dry winter on the continent probably helped as well, low soil moisture means we get more out of any flow.

[knocker]

Not sure it will be as warm as that. Anyway the ECM EPS msl anomaly, 850, 500 mean. Looks good.

 

Sitting on the fence John. Be bold, your not back at work now.

 

[phil nw.]

Just a subjective opinion but when the ECM Op shows a big build of heights like that high in the later frames i become a little wary as it does seem to like a meridonal pattern more than the others.

Until the other models move a little more that way then i remain a little sceptical.

Having said that there does appear to be a growing trend from the ens suites of pressure rising from the south with a gradual movement north of the jet later next week.

Let's hope the ECM is onto something.

[Man With Beard]

Summer chasing mode finally getting engaged! ECM increasingly bullish about a pressure rise end of next week:

Based on this chart, ideas of 25C being reached are totally spot on, in my opinion, so long as the High does not centre itself to the west. Possibly even by next Friday.

 

However, GFS op refusing to go as far - how many times have we seen the following contrast in recent months, ECM ridging further north than GFS? very clear even at T120 (focussing on the blue/green colours 1000 miles west of Ireland):

 

 

The knock-on effect of the GFS will be weaker ridging over the UK in the days following.

 

 

Recent history suggests neither ECM nor GFS will be completely right, so perhaps a sensible forecast for late next week is High Pressure covering the south (with a SW feed) but low pressure/fronts staying closer-by to the north. Could still be good for 20C-23C even so, as the wind source would still be somewhere not far from Iberia. It is mid-May after all, nothing unusual about getting into the 70s now with reasonable synoptics!

[IDO]

The ECM op has little support from it's ensembles. The anomaly 850s at D10:  

 

This shows De Bilt has similar positive anomaly to the UK; so a comparison is fair. It shows temps by D9 and D10 and the op looks to have limited support:

 

 

The control lies closer to the mean, both showing average temps.

 

From the ECM ensembles less than 18% at D10 show max temps above 20c (the op is probably in the 24-26c area):

 

 

So at the moment I still lean towards the GFS 0z op. 

 

FYI the GFS 06z op is showing another possibility, that is also an ens cluster. This is where the trough digs into E.Europe preventing the displaced AH from moving NE and keeping higher pressure to the west of the UK. At D10:

 

 

A cooler scenario with the jet running from the NW to the SE as it digs down into S.Europe. So possibly spells of rain the further north and east you are.

 

So GFS has not nailed Week 2 yet and the ECM op looks to be an outlier in week 2...

Edited May 7, 2014 by i'm dreaming of...

[Man With Beard]

 

From the ECM ensembles less than 18% at D10 show max temps above 20c (the op is probably in the 24-26c area):

 

http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gifvareps_Tx_latest_06260_00.png

 

 

Just one thing, the ECM mean set up by D10 will probably mean a WNW into the Netherlands (i.e. the location of De Bilt) off a coldish North Sea, so I'd add 3C to get approx. maximum temperatures in Eastern England.

[knocker]

Not that I'm saying the ECM analysis is correct by any means but I'm not sure I follow the argument thay the ENS and the 850 temps don't support the ops run although I agree the latter is probably about 4C warmer. I think some of the STs being suggested were way OTT anyway but STs of 18-20 as suggested don't IMO invalidate the ops run. Probably won't verify anyway.

Edited May 7, 2014 by knocker

[IDO]

The ECM London 2m temps also indicating the op is top end of its members and the mean is closer to average for the time of year:

 

 

The op, although unlikely compared to the mean, remains a possibility as the GFS 0z Control (although occurring in a later time frame) also showed the potential for similar high temps.

[Summer Sun]

Given that ECM still has no support for its pressure rise early next week I wouldn't be surprised if it back tracks this evening if it doesn't then it will continue to look very isolated with GFS UKMO and GEM all going against it

 

UKMO wouldn't arrive till later in the week as per today's text update

 

 

GFS FI looking very unsettled with the short spell of warm air moving east

 

Edited May 7, 2014 by Summer Sun

[Captain Shortwave]

I must admit the UKMO is very very poor

The low is aiming straight for southern England, the low moving much quicker and on a more southerly path. Looks like heights would build behind it but again you looking at beyond 7 days.

 

GFS looks a little slowler with the low further north, but still nowhere near the ECM.

Again the Atlantic trough is there behind to try and force heights northwards

 

Hmm, confidence is falling here and frankly the UKMO has fallen off a cliff here now with respect to anything drier and warmer.

 

Edit - GEM coming out, similar to the GFS with the amplified ridge on this mornings run gone

So likely that any possible significant build of pressure will be delayed until the end of next week as I suspect the ECM will be similar to the GFS/GEM solution with the UKMO looking the worst case scenario.

Edited May 7, 2014 by Captain shortwave