Model output discussion - 20th Feb onwards

[knocker]

The ecm 5-10 is very similar to the GEFS and in fact this also applies to the 10-15 (can't post) and this would put the surface HP cell over the UK with about average temps. But as mentioned earlier it's far too early for detail but things look promising.

Edited April 10, 2016 by knocker

[Eugene]

Well Done the GEM model which never wanted to turn it warmer and drier next weekend, GFS/UKMO 00Z have come on board to a cool unsettled weekend with slack low pressure and cool uppers, looks like a Northerly Blocking April with slow moving low pressure systems over england and temps slightly below average.

[mb018538]

Big differences this morning.....GFS and UKMO on one side keeping things cool and unsettled with low pressure in charge. ECM builds in high pressure instead - the difference at 144 hours are quite stark. I guess we will have a better idea later on!

[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 MONDAY APR 11TH 2016

THE CURRENT GENERAL SITUATION A large depression lies well to the SW of the UK with an occluded front across Ireland, Wales and Central Southern England. This will swing North across Eastern Britain later to lie East to West over Northern England by tomorrow with a slack airflow across the South promoting thundery showers by day.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The upper air temperatures have risen across the UK over the last 24 hours with the level expected to lie between 5000ft and 6000ft across the South in the coming days with levels a little lower than this at times over the North. Little if any snow is expected to fall across the UK in the coming days.

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

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

MODELS-2 WEEK HEADLINE Rather unsettled with some rain or showers at times. Probably turning drier with time especially across the North and East.

THE GFS JET STREAM FORECAST  All indications are that the Jet Stream will remain steered by Low pressure down to the SW of the UK through this week. It does weaken with time late in the week and become more variable in position as pressure builds across the UK for a time in the middle of the period. Then towards the end of the run Low pressure looks to re-establish across the UK with the Jet Stream pulled South.

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

GFS OPERATIONAL The GFS Operational Run today shows a largely unsettled couple of weeks although having said that of you live across the North and East a lot of dry and none too warm weather looks likely too. Low pressure to the SW takes all week and much of next weekend to finally move across the South of the UK and away to the East taking it's rain and showers with it. Then pressure builds strongly to the North with a SE flow setting up with some rain restricted to the SW. Then as a tongue of cold air is drawn West over the North Sea and engages with Low pressure near the UK deepening Low pressure over us and ending the period with wet and windy conditions for all across the UK.

GFS CONTROL RUN The GFS Control Run is pretty supportive of the theme of the Operational Run so we should expect a similar showery and unsettled period especially across Southern Britain whereas the best of the dry and brighter conditions look likely across the North and in particular the NW.

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 still show a 10% cluster who support High pressure across the UK in 14 days time. However, the vast majority of members continue to project Low pressure more likely to lie somewhere in the vicinity of the UK with rain or showers at times with average temperatures overall.

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 a less encouraging end of the week again this morning as the previously projected ridge of High pressure building down across the UK on yesterday's output is delayed at least as Low pressure holds a foothold across the South of the UK with showers and some more prolonged rain in places but some dry and cool conditions at times in the far North and bright, warmer weather in the far South too between the downpours.

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

THE FAX CHARTS The Fax Charts illustrate a very complex week of weather to come too with the day to day detail very hard to pin down from place to place but in general it would appear that some rain or showers can be expected for many especially across the South where it could feel rather warmer than of late all due to Low pressure and troughs feeding up from the SW at times while the North sees cooler conditions with troughs feeding down from the North towards the weekend.

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

GEM GEM today shows another version of the unsettled theme with it showing Low pressure near or over the UK in the coming week with rain at times along with some cool air too at times especially over the North. Then a brief drier spell looks likely under a brief rise in pressure before further Low pressure off the Atlantic moves SE into the UK later with more rain and showers for most.

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

NAVGEM NAVGEM today shows a Low pressure trough ensconced across the South of the UK through this week with the best of the weather in the far North but heavy showers and outbreaks of rain likely elsewhere on most days before a slow improvement is shown to develop down across the UK from the NW for the weekend albeit a bit on the cool side especially at night by then as a ridge of High pressure builds across.

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

ECM ECM on the other hand follows the theme of yesterday albeit rather slower to develop. The weekdays sees slack Low pressure maintain showery conditions across the South with cool winds and rain at times lodged across the North. Then by and over the weekend High pressure builds down across the UK from the North and then a much more quiet and benign period of weather looks likely in a ESE flow for all with the best and warmest conditions likely to be in the far West and NW with most places staying dry by then.

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

ECM 10 DAY MEAN (12z) The 240hr mean Chart from last night again offers few clues as to where we are in 10 days time with slack pressure not only over the UK but also over the Atlantic and Europe too so though no bad weather is expected whether the weather be dry or showery remains a little unclear.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS Although there is still a fair amount of support for Low pressure based conditions to continue across the UK there are still slightly weaker signs than yesterday that some better weather might develop as High pressure tries to build down across the UK from the North displacing the Low pressure influence from the SW.

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 97.5 pts to UKMO's 97.0 pts while GFS lags behind at 95.9 pts. At 5 days ECM leads with 89.5 pts to UKMO at 87.9 pts and GFS at 84.6 pts. Then at 8 Days ECM has the leading spot from GFS with 64.4 pts to 58.7 pts. Finally at Day 10 ECM has the lead from GFS with a score of 43.8 pts to 39.1 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  A new week and the weather continues to live up to a very normal April standard with plenty of days this week of sunshine and showers, heavy and thundery in places but with some warm sunshine too. In the North skies will be cloudier and as a result cooler with occasional rain here too though the far North could stay dry. All of this remains driven by Low pressure down to the SW which takes at least until the weekend to either fill or move away East allowing the ridge to the NW to sink it's influence down across all of the UK with time. UKMO has separated from it's partner ECM this morning and has reverted to show influence of a tongue of cold uppers to move SW across the North Sea and culminate in another Low pressure zone over or near the UK by next Sunday with GFS also looking less hopeful longer term. However, having said all of the above because the driving pressure systems controlling our weather this week are so slow moving I think we can expect more swings from the models through the coming week as small adjustments to the positioning of troughs, Low and High pressure in the generally expected slack air flows over the UK through the period could mean the patterns and details in conditions place to place will be difficult to predict. However, there looks a good chance of some warmth in the sunshine between the showers across the South and though cold air and the risk of frost remains a possibility over the North this is all standard Spring fayre for the UK and as a result we can continue to watch the pattern of spring growth and wildlife continue unaffected by weather in the coming few weeks.    

Next Update Tuesday April 12th 2016 from 09:00 

[MR EXTREMES]

signs of heights from greenland slipping se into the uk still chilly polar air mid term.

but its what happens after mid term with slow retrogression of heights back nw towards greenland and lows diving down from the arctic into scandi location.

so any warmth would be limited.

but this is fi 240 ecm!

but classic solar minimum weakening el nino and recent strat event type weather.

although id like a nice warm very warm spring and summer now.

this winter has been exhausting and full of dissapointment time to have a nice summer and better next winter bit of something for everyone.

[Summer Sun]

ECM still wants to bring some settled weather from the weekend rather chilly at first before winds shift round to a warmer SE'ly direction

[knocker]

The ecm 5-10 is still looking at HP nudging north over the UK in the latter part of the period. As always the detail will depend on the position of the surface high. At the moment it has it around the north North Sea/ Scotland area which would be fine with temps a little above average. But of course fine margins so subject to change at this range.

The GEFS is not so keen to extend the European high and is slow to move trough to the NE further east although it does do it eventually but leaves the HP to the NW being a temporary main player. This would tend to a NE flow with temps perhaps a little below average. Eventually with the trough to the south west retrogressing the ridge does set up just to the west of the UK where in fact the ecm also ends up.

So the jury is still out on the precise evolution vis days 7-10 regarding the upper air but there doesn't appear to be anything sinister lurking in the woodshed.

So Sidney has gone ahead and booked his spring break for the end of the month

Edited April 11, 2016 by knocker

[stodge]

Morning all

Plenty of comment this morning but it's less about a significant change and more about an option explored, dropped and then picked up again. The 00Z GFS OP has been an option on the table for a number of days with the infiltration of colder air re-invigorating the trough over the British Isles from midweek and delaying the influence of the HP extending from the North.

The 00Z output is very blocked even into FI with HP to the N or NW and LP to the S or SW. As others have said, a slow start to spring isn't atypical of a post-El Nino winter and yesterday in my part of the world was cold. It all depends - a little bit of SE'ly will warm things up nicely but risks setting off some heavy and thundery showers with hail not impossible and local flooding a possibility.

GEM has the HP a little further north than GFS or ECM but all that does is extend the trough across the middle of the country so even the north (which fares well under the GFS/ECM scenario) joins in with unsettled conditions with rain or showers at times.

The 06Z (rolling out now) is slightly better. Basically, it's a race between the HP coming down from the NW and the LP from the far north. The former finishes to the west and the latter to the east of the British Isles so we are left in a slack N'ly. The 00Z had the trough "winning" so we finished up under the LP whereas the output yesterday had the HP setting up to the north of the British isles and pulling in a warmer SE'ly.

The outcome of that "race" to fill the space left by the departing trough and cut off LP will set the scene for the weekend and possibly beyond.

 

[049balt]

This site still has not come on board with the dry outlook.

[Summer Sun]

3 minutes ago, 049balt said:

This site still has not come on board with the dry outlook.

Remember these update twice a day based on GFS anything beyond a week should be taken with extreme caution

[049balt]

23 minutes ago, Summer Sun said:

Remember these update twice a day based on GFS anything beyond a week should be taken with extreme caution

GFS still giving a lot of dry weather over the next 2 weeks but a couple of wet days in the mix.

[TomDav]

Both GFS and ECM 12z runs show south-easterly winds and a brief surge of warm air at day 8

[Guest]

The weekend northerly is looking more potent and widespread on the 18z. Still time for change of course.

[knocker]

A very brief loo at the latest EC32 means update.

A transition to a different pattern underway starting Saturday 16th

On that date the UK is more or less in a col with the upper troughs to the SW/NE and HP NW/SE but by Monday the trough to the NE has moved east and ridging from the European HP NW is now the order of the day.

This HP remains in situ over the UK for the rest of the week with initially the surface high to the north but as the week progresses the upper ridge slips west of the UK. This in turn means that warmer and dry weather initiated at the beginning of the week gradually returns to average by Sunday the 24th.

From thereon the HP rapidly weakens and a zonal flow ensues but as there is no strong signal I'm not going to speculate.

So in a nutshell this week doesn't look too bad in the south but starting at the weekend perhaps a good week to follow with some dry quite warm weather albeit a bit nippy at night.

Be bold, be very bold,

It goes without saying that the GEFS is not in complete agreement with this preferring to keep the HP to the SE with ridging too the east. I think I'll put that on hold as last night's NOAA is more in line with the EC32

 

 

Edited April 12, 2016 by knocker

[knocker]

This morning's ecm ops makes little of the European HP next week and keeps the HP to the W/NW. Ergo a colder northerly flow.

[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 APR 12TH 2016

THE CURRENT GENERAL SITUATION Low pressure remains centred to the SW of the UK with a slack and unstable airflow across the South of the UK ahead of a slow moving trough across Northernmost England and Southern Scotland. Little change in this general setup is likely over the next few days.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The upper air temperatures are now in the range of 5000ft across the UK currently and for the South this looks like the level they remain at for the rest of this week. In the North the level will slowly fall later in the week to around 3500ft

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

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

MODELS-2 WEEK HEADLINE Rather unsettled with some rain or showers at times. Probably turning drier with time especially across the North and East.

THE GFS JET STREAM FORECAST The Jet Stream will be troughed down to the SW of the UK  over the next 5-6 days with only slow changes thereafter with a split flow developing for a time next week, one South and one North of the UK before the Northern arm merges with the one to the South with an indecisive final positioning of the flow looking likely by the end of the two week period. 

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

GFS OPERATIONAL The GFS Operational Run today shows a changeable pattern with all changes being slow and subtle. In the next week it looks like a slow migration of Low pressure currently to the SW moving across Southern England and away to the East over the weekend looks likely with all the time big showers and some more prolonged rainfall between warm sunny intervals the order of each day. High pressure is then shown to build across the Uk early next week with a spell of dry and bright weather with temperatures near average by day but cool at night with some frosts. Then further unsettled and cool conditions moves down from the North later next week with the run ending with a NW flow across the UK with rain at times over the North and East while the best weather develops over the SW in generally rather cool conditions.

GFS CONTROL RUN The GFS Control Run is similar to the operational in theme but day to day differences are of course apparent as we move deeper into the period with the second week offering a mix of rain and showers at times and some days of fine and bright weather as Lows and Highs battle for supremacy over and around the UK in a confused second half of the run.

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 quite strong support for High pressure to lie out to the West of the UK in some shape or form which would lead to the UK lying under a chilly NW or North flow with some showers in places especially over the North and East.

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 there is still a lot of mileage left in the showery theme across the UK currently. The Low pressure to the SW slowly migrates ENE across the South later in the week and that is followed by a ridge of High pressure collapsing SE down the North Sea changing winds towards the SE by the start of next week with showers still a risk in the South and SW.

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

THE FAX CHARTS The Fax Charts illustrate only slow improvements over the North in the next 5 days but none at all in the South as shallow Low pressure continues to lie close to Southern England later in the week with a concoction of troughs ensuring plenty more showers and outbreaks of rain for these areas while colder and drier air from the NE slowly filters down from the North by the end of Day 5

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

GEM GEM today shows Low pressure well in control of the UK weather for a further 4-5 days before a change to higher pressure and a more conventional pressure pattern of High pressure lying over or close to the UK next week brings about a cessation in rain and showers with time to a quiet and more benign period next week with some sunshine and average temperatures by day but possibly chilly nights.

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

NAVGEM NAVGEM today shows pressure patterns only changing very slowly as Low pressure remains slow moving near to Southern England over the weekend and start to next week all the time promoting some heavy showers at times over the South whereas the North may become largely dry of cool from the weekend as a ridge slowly exerts some influence for a time.

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

ECM ECM today while offering no heatwave does promote changes in the pattern from the end of the weekend as High pressure ridges in strongly from the West. How long it lasts look very tentative as the threat of cold air flooding South over the UK looks strong just to the North of the UK on a couple of occasions from the weekend and while certainly a drier prospect looking likely temperatures look suppressed with some unwelcome night frosts feasible especially in the North.

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

ECM 10 DAY MEAN (12z) The 240hr mean Chart from last night is gradually settling into thoughts of High pressure ridging down from the North in 10 days which if evolved would deliver fine and bright weather for many with a chilly North wind in the east and the risk of some night frosts.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The biggest messages from today's output is the slow improvements indicated from Low pressure very slow to lose influence from Southern Britain and the extent of High pressure ridges moving down over the UK next week and how long this theme lasts.

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 97.5 pts to UKMO's 96.9 pts while GFS lags behind at 95.7 pts. At 5 days ECM leads with 89.3 pts to UKMO at 87.6 pts and GFS at 85.1 pts. Then at 8 Days ECM has the leading spot from GFS with 63.2 pts to 58.2 pts. Finally at Day 10 ECM has the lead from GFS with a score of 44.3 pts to 38.4 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 Changes remain slow within the charts this morning with another 5-6 days at least of this Low pressure area to the SW extending influence across Southern England giving rise to sunny spells but big showers, heavy and slow moving at times. In the North colder air will be en-trained and this could be enhanced by the weekend dragging drier air South by the start of next week and with a variety of pressure patterns showing High pressure in some shape or form becoming influential for a while better weather should reach the South too but never overly warm with the risk of night frosts a very real one. then as we look further out into the second week there is no clear cut theme shown but there does at least seem a propensity to keep winds blowing from a chilly North direction with High pressure eventually somewhere out to the west and SW with the best weather developing there while the North and East might see some rain in a chilly NW breeze. It's only UKMO that supports a SE breeze developing next week as it's High pressure slips SE over the North Sea. So as you can tell still a lot of indecision in the models longer term this morning and while nothing particularly unusual is being shown it looks unlikely the magic 21C  70F figure is likely to be breached within the term of the outputs on offer this morning with a greater chance of some night frosts still if skies clear overnight under the higher pressure next week.    

Next Update Wednesday April 13th 2016 from 09:00 

[mb018538]

Looking distinctly cool with a massive Greenland block setting up again on the ECM run today. Disappointing really, a few days ago it was shown as being eroded, now its back as super strength!
Looks like frosty nights and cool days on offer. Not too much rain around, with low pressure centred over Scandinavia instead.

[Singularity]

You can see in the far-southern N. Sea the small low that has caused all the headaches with respect to Friday onward; the scenario in which it tracks across to the east shifts the balane of power in favour of the Scandi trough, suppressing Euro height rises and allowing ridges to the W/NW to flex their muscles. Seeing the -5*C 850 hPa isotherm make it all the way down south in mid-April is not a common sight, though not exceptional in itself.

What is exceptional is the blocking ECM produces in the Arctic by day 10:

 

The resulting mass exports of cold from the Arctic, and imports of relative warmth, won't do the ice much good. Much of the coldest air ends up over open waters beyond the sea ice periphery.

 

GFS is relatively tame, but over the following week it still turns things seriously chilly for the time of year.

This is what you get when you have the residual effects of a mid-March SSW combined with record-low sea ice extent (albeit second factor debatable wrt level of influence). The N. Atlantic Cold Pool may be adding a feedback mechanism too (favours lower heights in positive NAO regime, but may work the other way during neg NAO).

[knocker]

The ecm 6-10 this morning has the HP to the NW thus a N/NE flow so although dry not particularly warm. In the 10-15 period the HP to the NW becomes ridging over Greenland, consolidation of the trough to the east and a slight movement east of the trough in the western Atlantic.  This results in a NW flow and temps still a little depressed.

Assuming for a moment that high pressure does indeed dictate matters next week, as always the detail will very much depend on where the surface high sets up shop. It could be that it will drift west thus moving from above average temps to a little below. On the other hand this might not happen at all.

Edited April 12, 2016 by knocker

[stodge]

Singularity expresses it very well in his previous and the obvious reaction to today's output, so far, is "if only" for coldies. These charts in December/January would have this site in meltdown. The GFS 06Z OP keeps us on the cool side throughout after a brief warmer snap at the weekend. 

THis is the critical moment for the synoptic evolution. The first HP wanders off east and declines but the second establishes to the NW and effectively stays there. The troughs to the south (the remnant of the current trough) and the north (from Iceland) force the HP back to Greenland and leave us in a N or NE'ly airflow.

ECM at 00Z is in a similar place though with the HP more dominant.

For fans of warmth, GEM 00Z offers a much better scenario but the critical thing here is GEM removes the Greenland heights very quickly. If GEM have called this right, kudos to the Canadian model and to be fair they've called this week quite well so far. This would be a huge shift for GFS and ECM but the GEM Ensembles have a majority showing this different evolution.

[Frank Trough]

18 minutes ago, stodge said:

Singularity expresses it very well in his previous and the obvious reaction to today's output, so far, is "if only" for coldies. These charts in December/January would have this site in meltdown. The GFS 06Z OP keeps us on the cool side throughout after a brief warmer snap at the weekend.

THis is the critical moment for the synoptic evolution. The first HP wanders off east and declines but the second establishes to the NW and effectively stays there. The troughs to the south (the remnant of the current trough) and the north (from Iceland) force the HP back to Greenland and leave us in a N or NE'ly airflow.

ECM at 00Z is in a similar place though with the HP more dominant.

For fans of warmth, GEM 00Z offers a much better scenario but the critical thing here is GEM removes the Greenland heights very quickly. If GEM have called this right, kudos to the Canadian model and to be fair they've called this week quite well so far. This would be a huge shift for GFS and ECM but the GEM Ensembles have a majority showing this different evolution.

That is precisely what did happen in the winter wasn't it?! Except the extent of the HLB was massively overdone at range and never got anywhere near verification. I'm thinking that if we don't manage to manage a 20c early next week a la GFS 06z then it might be pretty hard to come by in the remainder of April IF the HLB showing today is anywhere near correct this time around.

 

*edit* the METO update today doesn't seem to favour any kind of N or NE'ly flow in the mid term from what I can see:

"High pressure is then expected to dominate for much of the remaining period, bringing a good deal of dry and settled weather, albeit rather breezy at times. Showery rain may move up from the near continent to affect southern England at times, and the odd shower may develop locally elsewhere. Temperatures generally around average, but with some chilly and potentially frosty nights, especially in the north.

Updated at: 1226 on Tue 12 Apr 2016"

 

Edited April 12, 2016 by Certain kind of fool

[Singularity]

Yes, as if setting out to undermine my assessment this morning, the 06z and 12z GFS runs have added a low west of Iberia which effectively negates the handing over of power to the Scandi trough by the Fri-Sat LP. You see, it helps to build in that ridge from the west, with that old trough sent packing, and doesn't stop there, setting up a SE flow by Tuesday with temperatures trending upward.

Much as the ECM 12z of yesterday showed, this setup has the potential to bring a decent batch of warm air up from the SE for a day or so, which could lift temps into the low-20's. In fact, given that a not quite so effective GFS 06z produced 21*C for the SE, I wouldn't rule out a 24*C in the London area for example.

That is, IF we get that Iberian low developing despite the transfer away from that area of some of the instability on Fri-Sat. Perhaps we have seen a classic struggle of the models when handling the potential development of an unstable region into more than one disturbance.

 

Edit: the 12z GFS doesn't choose to build the warmth; secondary disturbance within the plume changes the alignment of the flow. Another of the numerous outcomes we've seen put forward in the past few days, potentially turning chilly from the NE a few days down the line.

Edited April 12, 2016 by Singularity

[Eugene]

GFS 12Z showing maxs (4C to 6C) widely on Saturday, colder than most max's last December, wouldn't be surprised to see some wintriness on higher ground.

Quite a turn around from the warmth it was showing just a few days ago.

[Cheshire Freeze]

30 minutes ago, Singularity said:

Yes, as if setting out to undermine my assessment this morning, the 06z and 12z GFS runs have added a low west of Iberia which effectively negates the handing over of power to the Scandi trough by the Fri-Sat LP. You see, it helps to build in that ridge from the west, with that old trough sent packing, and doesn't stop there, setting up a SE flow by Tuesday with temperatures trending upward.

Much as the ECM 12z of yesterday showed, this setup has the potential to bring a decent batch of warm air up from the SE for a day or so, which could lift temps into the low-20's. In fact, given that a not quite so effective GFS 06z produced 21*C for the SE, I wouldn't rule out a 24*C in the London area for example.

That is, IF we get that Iberian low developing despite the transfer away from that area of some of the instability on Fri-Sat. Perhaps we have seen a classic struggle of the models when handling the potential development of an unstable region into more than one disturbance.

 

Edit: the 12z GFS doesn't choose to build the warmth; secondary disturbance within the plume changes the alignment of the flow. Another of the numerous outcomes we've seen put forward in the past few days, potentially turning chilly from the NE a few days down the line.

Interestingly the GFS maintains its chilly/cold FI theme

'

Before then, some snow showing to low levels on Saturday with perhaps a keen frost to boot

 

Edited April 12, 2016 by CreweCold

[049balt]

But then..