Model Output Discussions 12z 03/05/2016

[davehsug]

Off on the ferry to Spain for a couple of days next week & I was hoping that I might finally catch one of those "Biscay full of storms" events. Looks unlikely now, but it does look a pretty confusing picture overall. As long as it's reasonably calm I'll be happy enough.

[Paul]

There's some uncertainty in the model output but at the moment it does look likely that we're going to see low pressure in the vicinity as it moves off the continent during the early part of the week. Plenty of ensemble runs going for it on the GEFS tonight.

Ensembles keep the low having a reasonable influence into midweek too, even further north on a lot of members. Not many entirely dry options, and even in northern Britain where you'd expect high pressure to be more of a player there's more than enough wetter members. 

  

Looking at the bigger picture, and all looks rosier! The devil is in the detail though.

The ecm sings from a pretty similar hymn sheet - continental low in play for the start of the week, and maybe still in play to one extent or another by the end. Notice the lower heights over northern Britain on Thurs onward too, and a general lowering of the heights as the high to the north loses some of its grip..

   

So yep, can see where the beeb are coming from, but there's still plenty of uncertainty.

[knocker]

Tonight's 6-10 anomalies are all on the same page with the HP centred north of the UK and perhaps quite importantly a negatively tilted trough in the western Atlantic and low pressure SE Europe. So after the still a little uncertain start to the week a more settled period looks very likely. One proviso may be as the the gefs indicates an upper low breaking ranks with the Atlantic trough and tracking east just south of the UK bringing showery outbreaks to the south. Something to keep an eye on maybe.

In the 10-15 day period still looking okay although the EPS differs a fair bit from the GEFS in so much as it doesn't have a HP centre Greenland rather ridging up from Europe through the UK ti Iceland. This would curtail any suggestion tof any perturbations tracking east and affecting the southern half of Britain.

Edited May 25, 2016 by knocker

[stodge]

Evening all

A bit NIMBY-ish as the forecast does look very good for Scotland and much of the north away from the east coast but for the south it looks a long way from some of the rosier prognostications I've been seeing.

Plenty of northern blocking with the centre shifting from Scandinavia to Iceland/Greenland as May ends and June begins bringing in more of a NE flow and little sign even in deep FI of the block relinquishing its grip so the threat of more disturbed conditions affecting the south from the Continent remains as heights remain persistently low over Europe.

 

 

Edited May 25, 2016 by stodge

[Scorcher]

1 hour ago, Summer Sun said:

I've just watched the beebs weekly forecast they are showing low pressure moving right across the UK

I'll give the models another day or 2 to get into full agreement I think

Well it certainly wouldn't be the first time the BBC have put out a pessimistic forecast. I'm struggling to see any charts for next week that show the low slap bang on top of the UK like that, although I am aware that they have extra data that I don't have access to. 

[northwestsnow]

Yes i was very suprised by D Brett, the graphic looked horrendous, lol if that comes off i'll have a wobbler !:D Hopefully it wont look anything like that next week, the trend to build a Greeny high is annoying as i didn;t see a single one in the winter months!

Spoiler

 

 

[knocker]

The latest offerings from the GFS for the weekend.

Not too bad for Saturday and Sunday, just the isolated showers perhaps thundery in some places.

At Monday 00z @the low' with associated inclement weather is over northern Germany. It then proceeds to move west bring the quite wet weather with it to be centred over central England by 1800z. Thereafter it slides it SW over Cornwall where it more or less fills in situ.

The latest fax for midday Monday has the low still northern Germany but probably best wait for the next update

Still looking good in the medium term

 

 

Edited May 26, 2016 by knocker

[knocker]

At 12z Monday the ecm has the general area of low pressure over Germany. In the next 24 hours it tracks the low west and then south over Belgium with the rain belt now lying N/S down the spine of the UK. In the next 24 hours by midday Wednesday the rain belt has swung SW and cleared most of England with the low filling in situ north east France.The obvious difference between this and the GFS is the ecm is not taking the low as far west.

Edited May 26, 2016 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 09:00 ON THURSDAY MAY 26TH 2016

THE CURRENT GENERAL SITUATION  A weakening trough lies East to West across northern Britain moving slowly North and weakening further through the day. A slack airflow lies across Southern Britain with instability developing from the South over the next day or so as warmer continental air filters NW.

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 North. Occasionally warm in the South.

THE GFS JET STREAM FORECAST The Jet Stream is expected to remain South of the UK for much of the next few weeks. It currently is blowing east across Southern Europe in association with lower pressure down there while higher pressure to the North keeps the northern arm well away to the North, also weak. It's not until the final days of the next few weeks that the flow looks like it could move back North towards the UK as pressure finally falls somewhat to the North.

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

GFS OPERATIONAL The GFS Operational Run today shows High pressure maintained to the North of the UK over the next 10 days or so with Low pressure to the South and SE edging up across Southern Britain early next week enhancing a thundery shower risk even more after these become prevalent at times over the weekend. Then through the second week the UK wide Easterly flow veers more Southerly as High pressure slips SE down over Northern and Eastern Britain with Low pressure over the Atlantic edging North with any rain from this restricted to the far West.

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

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

GFS CONTROL RUN The Control Run shows very similar synoptics over the first 10 days with easterly winds and a lot of dry weather for the North while the South lies at risk of thundery showers at times as Low pressure remains close enough by to the South of the UK, Unlike the Operational Run the High pressure at the end of the run remains to the North with Low pressure edging across the UK albeit rather slack with showers or rain at times for many areas then.

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 continues to show quite a mixed pattern with the bias today on higher pressure attracting a 40% cluster lying somewhere near the UK. However, this allows 60% to show a mix of options ranging from UK based Low pressure (10%) to the rest indicating an Atlantic flow from Low pressure further away to the NW.

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 unsettled weather taking us out of the Bank Holiday weekend as Low pressure from Europe drifts West across Southern Britain with rain, heavy at times in the South. With High pressure near Iceland the North would stay drier and brighter and probably warmer than elsewhere.

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

THE FAX CHARTS The Fax Charts show the same theme of the Operational data with the main theme of instability under slack and showery conditions across the South at the weekend with the main talking point next week being the migration west from Europe of Low pressure into the South with cool and unsettled weather likely.

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

GEM The theme of GEM this morning shows the easterly flow between High pressure to the North of the UK and Low pressure to the South and SE remaining the dominant weather pattern for the next 10 days. On this run the early week Low pressure moving into Southern Britain shown by other output stays to the South of the UK so the spread of general rain looks more limited so a lot of dry weather in the North over the next 10 days but a continued risk of thundery showers occurring over Southern Britain in relatively warm and humid weather.

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

NAVGEM NAVGEM too shows a sustained period of east or NE winds between High pressure to the North of the UK and Low pressure to the South and SE with thundery showers at times especially over the South while the best weather remains likely in the far NW.

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

ECM ECM today is maintaining the pattern of High pressure to the North and Low pressure to the South and SE again this morning with the North seeing the brightest and warmest conditions especially towards the Highlands of Scotland. Elsewhere the risk of heavy showers and thunder at times remains a strong possibility as winds remain from an Easterly point with Low pressure near the South feeding instability up into the South of the UK at times.

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

ECM 10 DAY MEAN (12z) The 10 Day mean Chart from last night continues to show a lot of slack pressure over and around the British Isles with the risk of showers remaining in light winds and reasonable temperatures overall.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS There remains no strong desire for the models as a whole to remove Northern blocking High pressure over the next few weeks at least, leading to an East or NE flow being maintained with thundery showers in the South to remain the main theme between the models for some considerable time.  

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.5 pts with UKMO at 99.4 pts and GFS at 99.2 pts.  At 3 days ECM is leading with 97.2 pts to UKMO's 96.0 pts while GFS lags behind at 95.6 pts. At 5 days ECM leads with 89.0 pts to UKMO at 86.3 pts and GFS at 85.0 pts. Then at 8 Days ECM has the leading spot from GFS with 58.4 pts to 52.5 pts. Finally at Day 10 ECM has the lead from GFS with a score of 37.3 pts to 33.7 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 Not much to be said about the models this morning that hasn't been said already in reports from previous days. The main theme is the continuation of High pressure slow moving to the North of the UK while our continental friends continue to import to the South some thundery showers at times, some days more than others. Temperatures will be well up to average or above and it will feel rather humid at times in the South. However, as always in an easterly flow North Sea Coasts will see a lot of cool and sometimes cloudy, misty weather in onshore winds while Western Scotland over the two weeks could see very little rain and maybe some of the highest temperatures in the glens. It should also be mentioned that in the early days of next week a more coherent spell of rain and cool conditions could spill west across Southern and eastern parts before the pattern resets to the North/South split in conditions again later in the week with more dry weather in the North and showers in the South. There are small hints only of a drift towards a more normal SW flow developing late in the period but hint is at far as it looks this morning so overall we have to look forward to a protracted period of warm East winds with humid air especially in the South looking likely to persist for some considerable time with the NW always looking the best place to be for guaranteed dryness and it's not often that can be said in the UK.

Next Update Friday May 27th 2016 from 09:00

[mb018538]

ECM doesn't look bad at all this morning. High pressure dominating from midweek onwards, 850s between 6-8c and generally quite pleasant I would think.

[Snowyowl9]

Good to see the atlantic is dead and lows moving from the east makes a change,love easterlys.

http://weather.unisys.com/gfs/gfs.php?inv=0&plot=850&region=eu&t=l

 

 

[stodge]

Morning all

Just the sense from GFS that the northern blocking is being pushed further north with each output and the possibility of LP coming into the south of the British Isles in particular is there but a very slack pattern and a real possibility of a warm SE'ly picking up later next week as the cooler NE'ly flow previously forecast seems to be receding.

[mb018538]

6z is a peach in the mid term, dragging up some pretty warm air by next weekend as the low stalls out west. Still a lot of variance from run to run, but something along those lines would be great!

[knocker]

Possibilities of a small upper feature emanating from the Atlantic trough tracking towards the European trough across no man's land and bringing showery thundery conditions to the south?

 

[Summer Sun]

UKMO this afternoon shows the low slowly easing away as we move through next week though we are left with a trough over us by Wed's

 

Lets see what ECM comes up with later

Edited May 26, 2016 by Summer Sun

[northwestsnow]

UKMO looks blinkin awful to me , and the trough sat over England at 144, looks wet wet wet, probs just hang around like a limpet  such is our luck.

[knocker]

I see the the GFS has retarded the movement west of the low a tad

[northwestsnow]

4 minutes ago, knocker said:

I see the the GFS has retarded the movement west of the low a tad

It seems the trough of death is causing allsorts of headaches for the models Knocks,i cant get that horrid image of DBrett on TV last night with the trough sat slap bang over us, and lo and behold look at ukmo 144 this evening.

[northwestsnow]

Very nice ECM this evening - certainly saying NO to DBretts wet week next week!!

[Summer Sun]

As above ECM isn't following the beebs thoughts tonight with the high winning out around mid week

[Scorcher]

I wonder if the BBC's rather extreme poor outlook is being influenced by the fact that the Met Office's own model looks considerably worse for Tuesday onwards that any of the other major models. 

Interestingly the 5 day forecasts on the website don't look as bad as the national forecast suggested, certainly not for my neck of the woods.

The ECM certainly looks a lot better- while it wouldn't be particularly hot, it looks good for a very sustained settled spell, especially further west. That low in the Atlantic doesn't look like it's going anywhere fast and should keep high pressure in the vicinity of the UK.

[northwestsnow]

ECM looks to be good to be true- the evolution from 120 - 144 looks very suspect to me though, which would render the rest of the run pointless.

[Summer Sun]

I suspect the fact this low is coming in from the east is causing the models some issues our default arrival for lows is from the west having one from the east is quite rare

Once the track of the low is nailed on the rest of the week should become clearer....hopefully

[DTHFCJ]

At least the temps look above average to well above(some of the runs) that will feel pleasant in any sunshine 

Edited May 26, 2016 by DTHFCJ

[Scorcher]

21 minutes ago, northwestsnow said:

ECM looks to be good to be true- the evolution from 120 - 144 looks very suspect to me though, which would render the rest of the run pointless.

What sort of evolution would you expect then?