Model Output Discussions 12z 03/05/2016

[knocker]

Well I wouldn't have said it was the Euro high dragging in the warm temps anyway. Looking at the 5-10 anomaly the high pressure is becoming less influential as the Atlantic trough edges east. The EPS 850mb chart for Monday has a large area of low pressure to the west dragging warm air from Iberia so possible good convection outlook. This is  the start of the change to more westerly unsettled regime with temps returning to average

Edited May 29, 2016 by knocker

[knocker]

The GFS for the next ten days can be quite quickly summed up. Outbreaks of rain, perhaps thundery moving in from the east overnight tonight that will gradually move west to the Midlands  Tuesday/Weds and gradually dying out in the process.

Thereafter high pressure to the NW tends to dominate affairs with general NE flow over the UK bringing some dry quite pleasant weather although perhaps a bit chilly at Skegy. This more or less persists until Atlantic fronts move in on Monday.

 

 

Edited May 30, 2016 by knocker

[bluearmy]

Post day 10 and the Atlantic trough and associated jet look well displaced south through the uk and n Europe on EC ens.  Gefs a few hundered miles further north which would make a more nw/se split. Tbh, I haven't been following the gefs to see if that's a consistent  picture. 

If EC is  right then flaming June it won't be, throughout the uk! 

[phil nw.]

3 hours ago, bluearmy said:

Post day 10 and the Atlantic trough and associated jet look well displaced south through the uk and n Europe on EC ens.  Gefs a few hundered miles further north which would make a more nw/se split. Tbh, I haven't been following the gefs to see if that's a consistent  picture. 

If EC is  right then flaming June it won't be, throughout the uk! 

YesBA it's noticeable that although the northern high weakens we still see +ve 500hPa anomalies across the Greenland side of the Pole out to day 10.

which means a somewhat different to normal pattern for us going into June.No push of the Azores high from the south west yet and the tendency as you suggest for a weak jet being forced across our latitude.

.

Edited May 30, 2016 by phil nw.

[Summer Sun]

UKMO shows the high lasting for the rest of this week though with the high slowly but surely moving northwards it looks inevitable the low in the Atlantic will win out at some point during the 1st full week of June

[northwestsnow]

I was going to say make the most of the first 6 or 7 days of June but its looking an absolute grot fest for many with cloud spilling in  off the north sea.

After that more concrete signs the trough of despair will be making a visit to our shores , i do hope its not an extended visit!

[MP-R]

I am taking comfort from the fact that the return of the Atlantic is a) in FI and b) rather brief in its return (and c) because I'll be in Italy during the few days it looks unsettled here). Some of the low pressures shown by the GFS look a little too deep considering the very lax temperature gradient in the Atlantic so it'll be interesting to see how the models continue over the next few days. I still don't think a warm/hot spell is out of the question with high pressure having more of an influence. I remember June 2014 was scheduled to turn unsettled after the opening days, only for a mini-plume to take place on the first weekend then strengthening high pressure from the south which put the Atlantic bay for much of the month.

[Summer Sun]

GEM isn't buying the breakdown instead it keeps high pressure with us also becoming very hot for Spain and Portugal from D8

[Matthew.]

Some wonderful looking charts there SS let's hope they become truth before long.

[knocker]

The GEFS anomalies are looking at the transition to an Atlantic regime around the 9th which as it happens coincides with both this evenings GFS and ECM det. runs. Up until then some pretty good weather for most (discounting the next two or three days and thereafter if you are on holiday in Cleethorpes)

[Matthew.]

Maybe it's the turn of the Atlantic to get pushed back and back and back

Edited May 30, 2016 by Matthew Wilson

[Summer Sun]

This evenings ECM ens shows the low slowly winning out through next week temps should remain around or above average for most (eastern coasts possibly remaining fresher)

With some even warmer air close by in northern France the south could see some of the rain / showers turn thundery at times and perhaps feeling humid at times

[northwestsnow]

Yes looking increasingly likely the Atlantic is going to push through our latitude around mid week next week.Too much evidence now weighted in that outcome,not unusual at this time of year really, will be interesting how things transpire post trough,i'd like to see the blocking weaken across Greenland sharpish and the jet lift North,thats purely hope rather then expectation though...

Before then and more especially for all , something useable late this week and the weeekend...

[knocker]

No great disagreement between NOAA and the ecm 6-10 range anomaly but this period rather masks the fact that the transition to the more influential trough occurs late in the period.

 

Edited May 30, 2016 by knocker

[Man With Beard]

10 hours ago, bluearmy said:

Post day 10 and the Atlantic trough and associated jet look well displaced south through the uk and n Europe on EC ens.  Gefs a few hundered miles further north which would make a more nw/se split. Tbh, I haven't been following the gefs to see if that's a consistent  picture. 

If EC is  right then flaming June it won't be, throughout the uk! 

This could be a telling 10 day period. Of course the models seem confident in bringing in an Atlantic trough eventually. Will it be one of those situations where the Azores High throws up a ridge nearer the reliable, like December 2015? Or, on the other hand, will we get into a pattern where weak euro heights in FI are shifted East nearer the time? It seems we are either on the cusp of a good June or a poor June - the pattern up to T192 allows for both, what with the angle of the flow strongly from the SW with potentially a big warm/cool divide close by. My eggs are a little in the more unsettled bag I'm afraid, like you BA.

Edited May 30, 2016 by Man With Beard

[knocker]

A brief look at the EC32 means.

Next Weds see the collapse of the HP to the north and the ridge adjacent to the UK edging SE. This is accompanied by the Atlantic trough tracking in from the west and the beginning of a period of unsettled weather for most but with the south east holding on a little longer.

This Atlantic domination looks set to last about a week until the 15th and then indications are that the Azores HP will become more influential building to some extent in the west/south west.

[Arid Acle]

Can't get that Atlantic back quick enough. Incessant northerly gales, leaden skies and ,last night, torrential rain are not my idea of May/June!

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON TUESDAY MAY 31ST 2016

THE CURRENT GENERAL SITUATION Low pressure over the near continent will push troughs West across England and Wales today and tonight with High pressure remaining centred to the NW of the British Isles with a chilly Northerly breeze in places.

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

CURRENT SNOW FORECAST AND/OR FREEZING LEVEL OVER THE UK The freezing level and snow forecast is now suspended until the beginning of October.

http://www.snow-forecast.com/maps/dynamic/uk

http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif

MODELS-2 WEEK HEADLINE Some thundery rain or showers at times but plenty of dry and fine weather too this especially in the NW at first and the SE later. Occasionally warm.

THE GFS JET STREAM FORECAST The Jet Stream is expected to remain very slack over our part of the Northern hemisphere over the next week as the pattern of Low pressure over Europe and High pressure to the North continues. Then through the second week a steady increase in strength of the flow and patterning of the Jet stream develops with a West to east flow developing either across Southern Britain or to the South late in the period.

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

GFS OPERATIONAL The GFS Operational Run today shows two quite separate weeks in terms of weather with the first week maintaining a theme of Low pressure to the SE and High to the North with an East or NE flow across the UK slowly weakening over next weekend as pressure across the UK becomes even North to South. Then after a period of quiet and settled weather unsettled weather spreads up from the SW across most areas with rain or showers at times and temperatures and winds returning to June averages later as Low pressure lies close by over or to the North of the UK.

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

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

GFS CONTROL RUN The Control Run looks at odds with the Operational in the second week in as much as it prefers to keep High pressure to the North of the UK then with further thundery showers at times easing up from Europe or the Southwest in generally light winds, humid and warm conditions for many.

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=144&mode=0&carte=0

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=384&mode=0&carte=0

GFS ENSEMBLE DAY 14 DATA The clustering today shows a lot of Low pressure weather patterns likely across the UK in two weeks time. The main thrust of this Low pressure shows a centre close to the North with an unstable Westerly or slack flow across the UK. Other scenearios indicate Low pressure in other locations close to 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 The UKMO model this morning shows slack Low pressure to the SE and High pressure towards the North of the UK. Further Low pressure lies across the Atlantic to the WSW of the UK by the end of the week with a very slack airflow expected to be maintained across the UK with thundery showers or rain at times across the South and East.

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

THE FAX CHARTS The Fax Charts maintain the pattern of High pressure to the NW and Low pressure over continental Europe over the next 5 days with troughs of Low pressure crossing England and Wales from the East becoming weaker and slow moving late in the week near Southern England

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

GEM GEM this morning shows a slow reversion back towards a more normal pressure pattern across the UK next week with Low pressure moving up to the NW of the UK and fronts taking a more traditional route NE across the UK by then. In the meantime the status-quo of present persists with Low pressure over Europe sending the risk of thundery rain at times across Southern areas before the South and East become warm for a time before the troughs to the North and West take over later.

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

NAVGEM NAVGEM too shows a slow change towards less in the way of continental Low pressure and swaps it for slack pressure patterns next week with a small pressure gradient across the UK by this time next week. Any rain and thundery showers looks like slowly becoming more restricted towards the far west and NW later as the South and East in-particular becomes warm or possibly very warm.

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

ECM ECM today shows another week or so of either NE winds or slack pressure meaning light winds across the UK as the theme of lower pressure to the SE and higher pressure to the NW is maintained. Then as we move through next week a change in the pressure pattern is accomplished as Atlantic Low pressure is finally able to make it's way up to the NW of the UK and spread more traditional spells of wind and rain North and East across the UK by the end of next week with the driest and warmest weather then likely towards the SE.  

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

ECM 10 DAY MEAN (12z) The 10 Day mean Chart from last night is not a million miles away from that of this morning's operational 10 day chart as Low pressure is shown to be edging into the West of the UK from the Atlantic with winds swinging South with rain or showers at times especially towards Western Britain.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS There seems to be a slow pattern towards a change in the pattern across the UK, probably next week as High pressure to the NW finally begins to give some ground to the Atlantic Low pressure.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.4 pts with UKMO at 99.3 pts and GFS at 99.2 pts.  At 3 days ECM is leading with 97.0 pts to UKMO's 95.6 pts while GFS lags behind at 95.3 pts. At 5 days ECM leads with 87.3 pts to UKMO at 84.5 pts and GFS at 82.2 pts. Then at 8 Days ECM has the leading spot from GFS with 52.2 pts to 46.4 pts. Finally at Day 10 GFS has the lead from ECM with a score of 31.4 pts to 30.1 pts.

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png

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.png

MY THOUGHTS The UK is still locked in this theme of High pressure anchored to the North of the UK and lower pressure over continental Europe. North or NE winds continue to bring the risk of cloud and rain, sometimes thundery in from Europe across the South and East of the UK. Through the remainder of this week it appears that the pressure gradient weakens across the UK by the weekend with slack pressure bringing some thundery showers still especially over the South but quite warm and bright weather as well. Then as we move into next week there seems a growing desire to bring a more traditional pattern across the UK as pressure to the NW falls a little and sufficiently enough to allow Atlantic Low pressure to make it's way slowly NE towards NW Britain finally allowing winds to veer more towards a warm South or SW flow with the emphasis of rain or showers slowly reverting towards the North and West with some warm or very warm weather in the SE. I must stress that this is still not a done deal and there are still some big differences between some of the output on the events of the second week, many of which maintain a lot of Northern High latitude blocking which could in theory result in conditions not dissimilar to those of present and I think it will be well into the second half of this week before the models show any sort of cross model agreement on events beyond next weekend. So in the meantime for many the weather is not too bad with just local nuances revolving around pockets of heavy and thundery rain revolving around Southern Britain and this will continue as long as pressure remains Low over Europe. The NW remains the place to be for the warmest and sunniest conditions for some time yet before we may see the SE claiming that honour next week if the above sequence of events takes place.

Next Update Wednesday Jun 1st 2016 from 09:00

[Summer Sun]

ECM shows the high hanging on till Wednesday before the low moves in at D9 and 10 days 8 and 9 could be quite warm and humid before it gets shifted east at D10

GEM has backtracked overnight unsurprisingly it does however bring some +15 850's to parts of the south and SE but it's a blink and you miss it event

[stodge]

Morning all

A bit of a dog's breakfast among the models this morning in my view with not much for anyone. Those desperate for heat won't find that much to encourage and the question, as it has been for some time, is have the models finally got the erosion of northern blocking correct ?

At various times in the past couple of weeks, we've seen the output offering a return to more traditional Atlantic-based conditions and the promise of everyone's nirvana, the ridging Azores HP and yet the heights remains stubbornly to the north and the Azores HP is stubbornly far away.

ECM tries to bring back the Atlantic AND keep the northern heights but the result is a southerly-tracking jet which does no one any favours. GFS and GEM try to bring in lower pressure as well but all that does is sit over the UK for a couple of days to freshen up the ground for Ascot.

GFS keeps the Greenland heights for longer than other models and, to be honest, they've modelled this better in my view than the ever-progressive ECM.

It does look as though a col of sorts between the pressure systems offers some possibilities for decent conditions but I see little evidence of anything other than transient heat at best in the next couple of weeks but nothing to worry about - plenty of time as summer hasn't officially started (will do so tomorrow).

 

[carinthian]

On ‎27‎/‎05‎/‎2016 at 09:07, carinthian said:

Hope you are right JH with regards to 6-10 days forecast. I have never trusted NEly flows at this time of year. Since I have been in Skipton for 2 weeks,felt  the chill. Played many a game of cricket on the high wolds in mid -summer with 3 sweaters on ! Even BH Monday has great uncertainty at the moment. Could be freezing cold and wet or pleasantly sunny. Furthest west looks best. Skipton sort of  in between, hopefully will see the sun again shortly.

Well the sun shone for most of the Holiday weekend here in Skipton with the rain reserved for the Southeast from early today . Looks like a full spin reversal in fortunes to start this summer season compared with last year with the North West doing well near the high pressure. The  East fairly cold with persistent winds from the North Sea  (sst around 8c brr ) A feature so far is the dominance of the European trough which continues with its vaporous weather to the SE. However, many folk in the NW would like it to stay this way, especially after the horrible dullness and low temps of last summer . Still fascinated to see how the models develop over the coming 10 days. Could be locked in this pattern for a while yet with more unsettled weather to develop this weekend to the south with the added ingredients of heat plumes in development for Southern Iberia and noticeable cold pool into Northern Scandinavia thrown into the equation. Great for forecast watching or trying to predict. As reported earlier ,never trust NEly flows in early summer ,they also provide a surprise to bite back at the forecasters!

 C

[Summer Sun]

The high is putting up a bit more of a fight on the 06z - 00z right

As a result the air is much warmer

Edited May 31, 2016 by Summer Sun

[Singularity]

 

A notable change in the alignment of the Atlantic jet stream (hence trough) on the 06z (right) compared to the 00z (left). It fires more NE than E, helping to throw up more of a ridge to the east of it i.e. through the UK. This in turn discourages continuation of the blocking across Greenland - a win for both the UK and the Arctic sea ice. Intriguingly the changed alignment of the high begins as early as day 5, which means that during the couple of days leading up to the above chart (Sun and Mon), conditions are already a degree or two warmer across the UK than they were on the 00z. It's been quite a turnaround from yesterday's 12z, which was pretty grim, never really establishing the warmer regime prior to the Atlantic trough barging in.

 

Looking further on in the 06z GFS run, and as usual for recent years, the ridge soon sets up more toward Scandinavia and we're left with a 'gently warm' sequence of days. It's quite a lot like the patterns of Jun-Jul 2014, only not quite so unstable on this particular run.

Longer-range signals have recently started moving toward keeping lower heights W of the UK rather than introducing a standard zonal type setup. It will be interesting to see if this new direction is maintained.

[knocker]

The ecm 6-10 anomaly continues to show the trough edging in from the west. in the period thereafter this quickly becomes a more zonal pattern with generally speaking LP to the NW and the Azores HP pushing north to the south west. Ergo continuing to look unsettled for a period and hopes rest to a certain extent on how much influence the Azores HP will have.

Edited May 31, 2016 by knocker

[Man With Beard]

An interesting turn-up in the GEFS 06Z. The mean is fairly reflective:

By D9, the trough is now showing as another staller, allowing warm/hot weather to become established from the south. 15 out of 21 members are variants on this theme.

The trough does make some headway on the mean by D11, but again, 15 members still do not have a trough over the UK by this time and the flatter pattern on the mean chart simply reflects the multitude of options, including troughing splitting and going south. 

I'm really scratching my head over my June CET punt now, hopefully the 12Zs will be more conclusive!