Model output discussion - 20th Feb onwards

[Cloud 10]

2 minutes ago, fergieweather said:

Well, at least it's now just down to a 50-50 to contend with further into medium range in 12z EC at T+240....!! 

 

I would bet all my chips on cluster 2.

 

Been posted a few times before,but here is the earth wind map for the stratosphere at 10 hpa which really shows the strength of those reverse easterly winds caused by the ongoing SSW.

http://earth.nullschool.net/#current/wind/isobaric/10hPa/orthographic=-2.93,84.73,512

 

[knocker]

The ecm 6-10 anomaly is precisely as expected so straight on the 10-15. It's now retataining the ridging over the UK and not building heights in the western Atlantic so no longer veering the upper flow but more W/SW thus temps certainly around average and maintaining settled conditions over the UK. Right at the end there is a tendency for the HP over the UK to be replaced by LP edging in from the east and the flow becoming more zonal. Temps becoming a little below average by then but the colder air remains in NE Europe for the moment.

This evening's NOAA charts are not adverse to this scenario.

Still got the barby on standby for Easter.

 

Edited March 7, 2016 by knocker

[Weather Observer]

21 minutes ago, fergieweather said:

Well, at least it's now just down to a 50-50 to contend with further into medium range in 12z EC at T+240....!! 

EDIT but more expansive set of cluster solutions thereafter out to T+360, with (yet again) many opting back to a cyclonic, unsettled/changeable regime by 21-22nd (refer to my post above re that)

Cluster 2 for me two and I suspect a lot of people on here. My confidence that it will prevail comes from a look at the spaghetti. It's all over the place.

[feb1991blizzard]

Cluster 2 the favoured option but I'm not certain at the moment that it would develop into a Northerly, maybe Ian can update us in about an hours time on the EC32 please.

[fergieweather]

1 minute ago, feb1991blizzard said:

Cluster 2 the favoured option but I'm not certain at the moment that it would develop into a Northerly, maybe Ian can update us in about an hours time on the EC32 please.

The later clusters (eg below) illustrate well why the subsequent period is very tricky. Yes, EC Monthly may offer some additional hints. *May*....!

[feb1991blizzard]

1 minute ago, fergieweather said:

The later clusters (eg below) illustrate well why the subsequent period is very tricky. Yes, EC Monthly may offer some additional hints. *May*....!

 

Bloody norah!!!!    I would like the 4th cluster but what variety there!!, it just shows you what effect an SSW has on the models, although not technically an SSW but 2012 feb caused so much debate on here, 2013 Jan and 2009 Jan also. I remember 2012 the met office couldn't judge what was going to happen for a long while, I do believe that any SSW where models are 50/50 between cold / blocked or Atlantic driven and wet that cold is still more likely than mild in mid winter, however because of the resultant temps / weather type from similar synoptics tend to be less weighted in favour of cold (certainly of the snow type) the nearer we get to summer, I would be a little more cautious.

[Captain Shortwave]

Out to day 10 and looking at the ensembles I would back a good 5 day spell at least of mainly dry conditions across most if not all of the UK.

      

That cold plunge looks too far east with us stuck between two deep troughs, one over Russia and the other in the Atlantic, the complication comes when you start to think that the base of the ridge could be eroded from either or both sides. At this point is when I think we will start to see complications, for example the potential for cut off systems and maybe a high developing at higher latitudes with the jet going well south of the UK. At this point I still suspect any change from an anticyclonic regime is beyond the 10 day time frame at the present time.

Fair to say you could get easterlies (Mild or cold), northerlies, or southerlies from this point as well as your underwhelming return of the Atlantic situations.

A lot of dry weather to come beyond the middle of the week in the south and by the weekend in the north, in any sunshine it will feel pleasant and of course will start to dry out areas still impacted by the flooding during the winter just gone.

Edited March 7, 2016 by Captain Shortwave

[knocker]

38 minutes ago, fergieweather said:

The later clusters (eg below) illustrate well why the subsequent period is very tricky. Yes, EC Monthly may offer some additional hints. *May*....!

Cluster 3 would be a humdinger.

[knocker]

There is nothing on the EC32 means that spells cold to me with Easter being a little below average.

Edited March 7, 2016 by knocker

[knocker]

A quick summation of this morning's GFS. Wet and windy in the south tomorrow as a low nips into the channel en route for France. Thereafter it's the story of HP domination until the latter stages of the run when the Atlantic creeps back in. Temperatures generally becoming above average.

No surprises from the woodshed this morning vis the anomalies. The 6-10 is as expected and the 10-15 continues to to introduce zonality with just faint ridging mid Atlantic and thus the temps returning to around average.

Edited March 8, 2016 by knocker

[Paul_1978]

Are the anomalies taking the SSW into account yet @knocker, as unless I'm mistaken even the normal models haven't got a full grip on it yet. 

[knocker]

22 minutes ago, Paul_1978 said:

Are the anomalies taking the SSW into account yet @knocker, as unless I'm mistaken even the normal models haven't got a full grip on it yet. 

That I cannot say with any authority Paul but the EC32 is not dissimilar for the same time period so i would assume to a certain extent. What I;m struggling with regarding the SSW and recently the continued ref to the MJO is that nobody can be certain what the combined affects will be on the dynamics of the trop. in the eastern Atlantic hence rather than speculate I prefer to play safe and stick to the models. I suspect it's after this period when the uncertainty creeps in.

[Tim Bland]

In the immediate term models failed to pick up this front pushing into central Areas From the west mainly falling as snow! 

 

[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 MAR 8TH 2016

THE CURRENT GENERAL SITUATION A weakening trough of Low pressure will move Se across the UK today followed by a vigorous depression moving into Southern Britain later tonight and through tomorrow with complex troughing and gales affecting England and Wales.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK will be a little higher than recently at around 3000-3000ft especially across the South. There will be snowfall over higher ground of Scotland today and perhaps on the highest ground of England and Wales later tonight and tomorrow too as colder uppers are dragged down by heavy precipitation.

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

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

MODELS-2 WEEK HEADLINE  Becoming less cold and mostly dry but perhaps turning rather colder again later with frost at night.

THE GFS JET STREAM FORECAST  The Jet Stream currently moving South over or just to the West of the UK will end soon as pressure rises from the SW from Thursday. This will then divert the flow well to the NW of the UK in a NE direction, probably near Iceland. Through next week this arm of the flow remains well North as well as weakening with a Southern arm strengthening over Spain and Iberia. This arm then becomes the dominant one late in the period gradually edging North but all the while remaining South of the UK.

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

GFS OPERATIONAL The GFS Operational Run today offers a lot of fine weather across the UK in the next few weeks. The period is book-ended though by far from settled conditions at the start with a deep Low tomorrow bringing rain and strong winds to many before High pressure builds NE across the South of the UK in it's wake and then drifts slowly North maintaining fine and sometimes pleasant daytime conditions before temperatures fall back somewhat later next week under an East or SE flow though at this stage fine weather would be maintained. Then towards the end of the period High pressure declines to allow Atlantic Low pressure and fronts to edge across the UK from the SW and West with rain at times and average temperatures.

GFS CONTROL RUN The theme of the Control Run shows similar conditions under High pressure for most of the time from the end of this working week. It's position shuffles around a bit and unlike the Operational Run maintains it's influence across the UK right out to day 14 with mostly fine and settled conditions with some mild days but with a trend to reduce temperatures with time especially by night with frosts in places.

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

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

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 GFS Clusters today show few if any clues as to where we will be in two weeks time. There is an even split between influence from both High and Low pressure near the UK with no firm theme shown today. 

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 High pressure building from the SW behind tomorrows deep, wet and windy Low pressure with the centre looking likely to lie just to the East of the UK with fine and settled conditions gradually developing UK wide. There could be a lot of low grey cloud in places for a while holding back otherwise mild temperatures but rainfall beyond tomorrow should become significantly less. 

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

THE FAX CHARTS The Fax Charts show slow changes across the UK in the coming 5 days. We still have 1 more inclement day to endure tomorrow under the rather cold conditions making Wednesday a very unpleasant wet day across the South in particular and I wouldn't be surprised to see more hill on it's Northern Flank as it clears. Then it's all about how quickly and decisively milder air from the SW engages with the rise of pressure occurs across all parts of the UK towards the weekend and how much influence weak warm fronts moving into the High pressure from the West interact under the High pressure likely to mean a lot of low grey damp cloud.

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

GEM GEM this morning is very High pressure based with fine and settled weather developing later in the week as well as temperatures on the rise to average or maybe a little above in skies brighten. There looks to be little significant change through next week with High pressure always nearby with varying amounts of cloud determining how mild the days become and whether frost is allowed to develop by night in always light winds.

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

NAVGEM NAVGEM looks quite similar to GEM this morning building a belt of High pressure across Southern Britain by the weekend which is then shown to extend slowly North to a previously damper North by late in the weekend and the start of next week.

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

ECM ECM today is a very settled one with High pressure extending across Southern Britain in a few days time and then extending to all of Britain over the weekend and beyond as the High centre drifts towards Scandinavia and then back close to northern Scotland later next week. Some early Spring warmth is possible for a time dependent on cloud amounts though a general cooling breeze from the East is likely to develop across the South of the UK with time. 

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

ECM 10 DAY MEAN The 240hr mean Chart this morning continues to project High pressure lying directly over the UK in 10 days time. This being so the most likely weather would be fine and settled for most if not all of the UK and with any March sunshine it could become quite mild by day at times but still with the risk of frosts should those same cloud breaks occur overnight.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The trend is well set for the weather to become fine, settled and less cold from the latter end of the week with solid cross model support for High pressure to build across or remain close to the UK.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.6 pts with UKMO at 99.5 pts and GFS at 99.4 pts.  At 3 days ECM is leading with 97.6 pts to UKMO's 97.0 pts while GFS lags behind at 96.3 pts. At 5 days ECM leads with 90.9 pts to UKMO at 88.9 pts and GFS at 86.4 pts. Then at 8 Days ECM has the leading spot from GFS with 65.9 pts to 60.6 pts. Finally at Day 10 ECM has regained the lead from GFS with a score of 46.5 pts to 46.4 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  High pressure is soon to become the dominant role player in the UK weather over the next few weeks. I'm sure most people will agree this will be a welcome change to the recent rather cold and changeable weather which has followed on the back of sometimes cloudy and wet but very mild Winter. What type of weather is likely at the surface is all dependent on what the orientation of the High pressure ends up being along with it's positioning but my best guess taken from today's output is that the South will first see the effects of fine if cloudy and milder weather on the lead up to the weekend before this type of weather extends slowly North to a rather damper North as warm fronts there cross NE on the Northern flank of the High for a time. With the High pressure migrating somewhat further North later in the weekend and next week all areas are likely to become or stay dry and probably quite bright with temperatures very respectable especially in any sunnier breaks. Having said that as the High drifts North it opens the door to a flow of air from a chillier continent and it may well be that temperatures fall back somewhat under a chilly breeze and if it stays cloudy it could feel quite raw especially near the East coast. Then as the two week period covered by this morning's output closes the theme is how and if the High pressure declines to a point that Atlantic Low pressure is allowed to return either from the SW or NW and any indicators which way the dice will fall is very unclear from the long term outputs at the moment also endorsed from the long term ensemble and cluster data available too. So recapping a couple of welcome dry and fine weeks of weather seems likely to develop and while no particularly cold weather is likely any mild or Springlike conditions remain totally dependent on whether cloud amounts become favourably small enough to a point that would also accommodate frost by night.

Next Update Wednessday March 9th 2016 from 09:00

[MP-R]

1 hour ago, Tim Bland said:

In the immediate term models failed to pick up this front pushing into central Areas From the west mainly falling as snow! 

 

So is the radar which shows it falling as rain, if reaching the ground at all. Rain started with a temperature of 0.9C here this morning.

[knocker]

The ext EPS 10-15 keeps the HP ridging in the vacinity of the UK all the time weakening it until late in the period when it too resorts to a more zonal flow. The deep trough and the cold air remain over NE Europe.

Edited March 8, 2016 by knocker

[Tim Bland]

39 minutes ago, MP-R said:

So is the radar which shows it falling as rain, if reaching the ground at all. Rain started with a temperature of 0.9C here this morning.

So I must be imagining the snow that is falling and settling in herts right now. Not even a hint of sleet at 90m asl 

[Man With Beard]

Well you can only lol - weeks of snow events disappearing at T24, and today in some southern areas are receiving snow by complete surprise.

Another very localised shock to the system is this unusual developing low for tomorrow morning:

70mph gusts for areas around Somerset, and from a northerly direction - very unusual. The thing that concerns me is that this is a late developing low, so have the models got a handle on it? Could it weaker - or perhaps even stronger?

Mid term - I feel a sense of order this morning, as usual a kind of moderation between the extreme easterly charts and the extreme warm charts - looks like High Pressure will be centred just slightly north of the UK:

This often happens in early spring - a weak easterly element keeping the south/east a bit cloudier and cooler, but western coasts enjoying warmish sunshine (could see 60s F in favoured spots I'd think).

Later on - I think the chart below reflects what I'm expecting; heights over the UK will be perfectly positioned by T168-T216 for a fusing with any increase in heights further towards the Arctic (surely a possibility given the SSW), leading to a northward movement of the UK High and a tentative movement of the very cold Siberian trough towards Scandinavia - looking something like this (with perhaps a touch more lowering of heights towards the Azores)

Edited March 8, 2016 by Man With Beard

[feb1991blizzard]

Cold Knocking on the door of our South West members (pardon the pun)

[Singularity]

This from ECM raises eyebrows as it's about to initiate a cross-polar flow toward the UK. Something which has been notably absent from recent GFS runs which seem to follow the theme of 'omega block or bust'.

There's some crazy stuff going on with the strat. projections though;

 

Just look how fast that vortex remnant is retrogressing across the Atlantic! At this point there is strong support for a blocking high moving from NE to N of the UK, but down in the trop. there are issues with displacing a deep trough to Siberia quickly and cleanly enough to make room for such to occur. Hence the theme of HP over northern UK with a nagging easterly across the south - not a pleasant prospect.

 

Before long we see the remnant making it to the U.S. (as per Cohen's expectations - but faster I think?). GFS lowers heights over Canada in response and on the 00z got very much carried away with that idea. The 06z is more reasonable but I should think it has removed the blocking from N of the UK too quickly - the models often underestimate the persistence of these features. So I am treating an idea of a westerly influence by week 3 of the month as extremely suspect. Perhaps we can get lucky and see the blocking gradually relax back down across the UK for another lengthy spell of dry conditions.

 

Before all of the above shenanigans, we have a little monster to deal with tomorrow;

NetWx-SR:   AROME:   ARPEGE: 

The northward extent remains uncertain, but it does appear that yet again, the added moisture and greater heat input offered by the Channel waters are attracting the core of the system - this being why we so often see 'Channel Lows' in winter/early spring.

 

 

 

 

[feb1991blizzard]

1 minute ago, Singularity said:

 

Just look how fast that vortex remnant is retrogressing across the Atlantic! At this point there is strong support for a blocking high moving from NE to N of the UK, but down in the trop. there are issues with displacing a deep trough to Siberia quickly and cleanly enough to make room for such to occur. Hence the theme of HP over northern UK with a nagging easterly across the south - not a pleasant prospect.

 

 

There is a much more pleasant solution on offer for the South in some GEFS members though, a bitterly cold convective Easterly with heavy snow showers and  a biting wind, what do you think the chances are of anything approaching verification occurring, Strat charts have been brilliant now for a while, so much so that ive  stopped looking at them, its whether it can be replicated now or not, the Strat Vortex looks a complete gonner to me.

[Singularity]

1 hour ago, feb1991blizzard said:

There is a much more pleasant solution on offer for the South in some GEFS members though, a bitterly cold convective Easterly with heavy snow showers and  a biting wind, what do you think the chances are of anything approaching verification occurring, Strat charts have been brilliant now for a while, so much so that ive  stopped looking at them, its whether it can be replicated now or not, the Strat Vortex looks a complete gonner to me.

I think a straight-forward replication of the strat. pattern in the trop. would produce the convective easterly - but as usual there looks to be complications such as how a few peripheral lows interact with the main Siberian trough as it drops south and then possible edges west. An undercut of blocking N/NE of the UK by either that or a secondary low into Scandinavia is needed to import air that is cold enough, and without too much modification of the lower levels by the North Sea. Perhaps a 1 in 4 chance of all the pieces coming together prior to week 3 of March. I have to add that limiter because the longer range is just impossible to fathom at the moment beyond the idea that a standard zonal regime is the least likely outcome.

[Faronstream]

3 hours ago, feb1991blizzard said:

Cold Knocking on the door of our South West members (pardon the pun)

I really hope this chart verifies, more cold is needed now no more spring temperatures

[MP-R]

3 hours ago, Tim Bland said:

So I must be imagining the snow that is falling and settling in herts right now. Not even a hint of sleet at 90m asl 

My reply was adding to the point you were making, not attacking it. Think twice before posting shirty replies please.

[Timmytour]

7 minutes ago, MP-R said:

My reply was adding to the point you were making, not attacking it. Think twice before posting shirty replies please.

Think Tim knows that. Look at the The "shifty" bit of his reply as ironic comment aimed at both the models and the radar projections rather than anything aimed at you. That's how I read it anyway