Model output discussion - 20th Feb onwards

[Allseasons-Si]

Better late than never?

do NOT underestimate cold at this time of the year

Edited March 15, 2016 by Allseasons-si

[Costa Del Fal]

24 minutes ago, Allseasons-si said:

Better late than never?

do NOT underestimate cold at this time of the year

Unless your up in the highlands or Pennines, I can't see -4 to -6 uppers cutting the mustard! More cold rain for most especially at this time of year. Net result is to deliver nothing really of what people want, coldie or mildie! Familiar tale of recent years. The cold to our north around Svalbard just has not been there this winter sadly. Having said that a white easter would be interesting, if not perhaps my personal favourite preference at this time of year (especially hard when we have some of those first sunny warm spring days now!) but some coldish uppers/low heights could at least make things interesting convective wise.

However, a swing round of winds towards the North/NE currently does look a fair shout as the high looks to move west somewhat but not becoming very unsettled as the block looks fairly resolute for a while. Long way to go yet before Easter is decided firmly though warm probably not. White Easter? Possible as with just about anything but some luck in pulling down some really proper cold uppers (sub -8c or even -9c) would be ideal!

Edited March 15, 2016 by Costa Del Fal

[Trom]

Well Costa I'm not sure I totally agree with your comment "Unless your up in the highlands or Pennines, I can't see -4 to -6 uppers cutting the mustard!".  It seems to me that the volatility of the weather has increased over my life time and we seem to see more extremes.  A lot seems to be due to sea temperatures and their effect on global pressure rises and falls which seem to have thrown a lot of theories up in the air.  It's important to remember that this year has been very unusual what with a massive el-nino, a massive SSW break up at the strat level right now and don't forget hurricanes in the atlantic in January!  A -4 to -6 in a NE who knows?  Unlikely to actually happen but I would not totally disregard those synoptics.  Nor would I bet my house on them. 

Edited March 16, 2016 by Trom
I can't spell

[IDO]

9 hours ago, shotski said:

Not true, they do mention colder than average.  

All academic, though it was for "Northern parts with low confidence", as I said yesterday other models had moved away from the ECM setup run by run and now both GFS and GEM have no northerly at all. The GFS D7 and D9 means:

The negative uppers barely touching the east coast on the mean before D10. It was clear a couple of days ago that ECM was wrong and that it was on its wayward D8-10 path, just because it is consistent does not mean it's right, especially when it's mean says no. The GEFS mean is not cold, in fact probably just above average if anything for London:

With those further west probably having milder temps still! The GEM is a corker with what I hope will be closer to the mark, HP in charge till at least D10:

Of course at this time of year some areas will be cooler and cloudier and some will be warmer and sunny, but overall a great setup.

This morning's ECM has, as expected no northerly bar the far NE Scotland and now in line with other models and the continuation of HP through to D10.

[Timmytour]

8 hours ago, Allseasons-si said:

Better late than never?

do NOT underestimate cold at this time of the year

I might have got excited had I not been seeing similar charts for a similar time-frame as least once a week since the end of December
 

[mb018538]

ECM certainly moving well away from that particular option this morning, turning milder again by D9/10, temps towards the low/mid teens...

[mountain shadow]

6 minutes ago, mb018538 said:

ECM certainly moving well away from that particular option this morning, turning milder again by D9/10, temps towards the low/mid teens...

The ECM op really has been a shocker this passed Winter with its constantly over amplification of Atlantic jet.

I have been impressed with the GFS ensembles means which have been rock solid in persisting with the East Canadian PV segment which has been the main driver of our weather.

[Frosty.]

19 minutes ago, mb018538 said:

ECM certainly moving well away from that particular option this morning, turning milder again by D9/10, temps towards the low/mid teens...

Agreed, the Ecm 00z is a generally anticyclonic run, the high just briefly losing some of it's control before another surge from the Azores by day 9 / 10 with a very spring like end to the run across the southern half of the uk.

[Singularity]

 

GFS is really trying for the phase 5 MJO pattern around day 10. We then see more of a phase 6 setup later in the run.

Not sure what ECM is up to, it doesn't tie in with anything really. 

I suppose it does bear a lot of similarity to GFS except for in our part of the world where the jet is further north.

The Greenland height rise with the jet angled further south is the better supported outcome at least in terms of tropical forcing. The SSW* effects seem to have been watered down to obscurity, with MJO activity the main player for trying to keep the Canadian and Siberian vortex lobes apart.

I still see an easterly as a likely feature toward month's end, but that's not to say it has to be chilly.

 

*Arguably this should be considered a 'final warming' with a gradual falling apart of the vortex and little evidence of the dramatic lower-strat. changes in geopotential heights that are associated with a true SSW.

[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 WEDNESDAY MAR 16TH 2016

THE CURRENT GENERAL SITUATION High pressure close to NE Scotland will maintain a chilly NE flow across the South with a very weak front crossing West over England and Wales today.

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK will be highest in the North of the UK over the next few days with levels around 7000ft-8000ft. In the South the levels is falling behind today's weak cold front to around 3000-4000ft for a time. Apart from snow grains over Welsh hills tomorrow morning there will be no snowfall anywhere.

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

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

MODELS-2 WEEK HEADLINE  Mostly dry and bright with some frosts at night. Probably becoming less settled later in the month especially in the North and West.

THE GFS JET STREAM FORECAST  The Jet Stream remains blocked by a large High to the North and NE of the UK. The theme is for the block to persist diverting the flow well North and South of the UK for the next week or so. Thereafter, the flow focuses on a point to the South of the UK as the block collapses somewhat through week 2

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

GFS OPERATIONAL The GFS Operational Run today shows High pressure continuing to control the weather across the UK over the next week or so as it's centre moves West then South just to the West of the UK. The cool and chilly NE flow will slowly back North or NW and decrease with time but this will also allow a lot of cloud from the Atlantic to slip down across the UK next week. Then as the High pressure declines later the Easter period looks like becoming rather cold and unsettled with showers or longer periods of rain for a time with snow on hills. Post Easter then looks staying chilly but drier again especially over the North and East with any rainfall then looking most likely towards the South and West as pressure builds again to the North.  

GFS CONTROL RUN The theme of the Control Run shows a similar theme over the period although the dynamics of the breakdown around the Easter period result from a slightly different pressure distribution. Nevertheless Low pressure looks like spoiling the Easter period with rain at times and perhaps some snow on hills with bluster winds before somewhat drier weather Post Easter as High pressure builds to the NE again.

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 45% of members suggesting a Scandinavian High pressure area holding sway across the UK in two weeks time as a ridge from it extends down across Southern Britain. There is also a mix of options numerically around 55% of members who show Atlantic Low pressure close to the UK with rain or showers at times and average temperatures.

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 situated just to the West of the UK by Day 6 having moved slowly West then South from it's current position just to the NE of the UK. This means that the weather is going to be remaining settled with little in the way of rain but also a lot of cloud at times hence somewhat chilly feeling conditions at times.

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

THE FAX CHARTS The Fax Charts illustrate slow changes over the coming 5 days with cloud amounts the main talking point in an overwhelmingly dry and fine period across the UK as the High responsible shuffles to a position just to the West of the UK by next Sunday. Weak fronts crossing South in the flow will continue to enhance the extent of cloud at times too.

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

GEM GEM this morning looks very settled as High pressure looks like maintaining domination across the UK right out to day 10 which includes the start of the Easter weekend. The centre of High pressure will drift West then South before becoming anchored over or just to the West of Ireland next week with a slack Northerly flow across the UK delivering fine and settled weather but with a lot of cloud at times.

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

NAVGEM NAVGEM shows the same fine weather persisting well into next week as High pressure readjusts it's position to a point to the West of the UK by early next week. Pressure is then shown to decline from the North towards midweek with some rain and fronts heading into the UK from the North and West.

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

ECM ECM this morning shows High pressure moving West then South to the West of the UK early next week with plenty more fine and settled weather if rather cloudy at times for all areas. The keen NE breeze in the South should back Northerly and decrease by the weekend. Then as we move through next week and towards Easter pressure will begin to leak away from the North with the Easter period looking like developing a North/South split in the weather to develops as pressure becomes High over France and Low to the North with Westerly winds for all and rain at times developing across the North and West in particular with average temperatures. 

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

ECM 10 DAY MEAN The 240hr mean Chart shows a Westerly flow across the UK along with the Jet stream. With Low pressure to the North and High pressure more towards a point South and SW of the UK a shift towards some rain at times especially across the North and west is likely over the Easter weekend along with close to average temperatures.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS Things still look unclear as we move towards the Easter period with no real cross model support on any one evolution this morning.

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 97.2 pts while GFS lags behind at 96.3 pts. At 5 days ECM leads with 89.9 pts to UKMO at 89.1 pts and GFS at 85.6 pts. Then at 8 Days ECM has the leading spot from GFS with 63.7 pts to 59.6 pts. Finally at Day 10 ECM has regained the lead from GFS with a score of 45.1 pts to 44.6 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 continues to maintain the focus of attention between the models over the next week or so as it just shuffles around over the next 3-4 days to end up at a point to the West of the UK early next week. All the time this feature stays close to the UK the Atlantic is blocked with the Jet stream diverting bad weather systems well North and South of the UK. A weak northerly flow looks like displacing the cool breeze in the South by the weekend but the NW will become cooler and cloudier by then with all areas seeing a dry and benign weekend with mostly cloudy and cool skies for most. Then next week it's all about how the models try to displace the High to introduce more unsettled conditions as usual towards a Bank Holiday weekend.. However, not to be too much of a pessimist i think there is a 50/50 chance that Easter might turn out OK with no heatwave but nothing alarmist either. GFS is the worst case scenario this morning with rather cold and unsettled Easter weather shown. However, it's Clusters suggest a strong chance of a Scandinavian High affecting the UK while the likes of ECM preferring a Westerly flow across the UK with High pressure close to the South and milder weather with some rain in the North and West it's message. This is strongly endorsed by the 10 day mean Chart this morning too. So my view is that anyone thinking that there will be a wintry period around Easter may be somewhat disappointed as it is becoming less likely as I think ECM has probably got the right handle on this with the most likely result being a Westerly flow of sorts across the UK with rain at times gradually becoming more widespread later in the Easter weekend in temperatures close to the late March average. So while there will be no barbecues or sunshades likely at Easter there shouldn't be any need for snow shovels either and thick thermals either. 

Next Update Thursday March 17th 2016 from 09:00

[Interitus]

2 hours ago, Singularity said:

The Greenland height rise with the jet angled further south is the better supported outcome at least in terms of tropical forcing. The SSW* effects seem to have been watered down to obscurity, with MJO activity the main player for trying to keep the Canadian and Siberian vortex lobes apart.

I still see an easterly as a likely feature toward month's end, but that's not to say it has to be chilly.

 

*Arguably this should be considered a 'final warming' with a gradual falling apart of the vortex and little evidence of the dramatic lower-strat. changes in geopotential heights that are associated with a true SSW.

Disagree - looking at the GFS 240h 10mb pattern shows vortex remnants over Scandinavia/NW Russia and northern US/ southern Canada with anticyclone over Pacific side of Arctic -

This is a fairly good correlation for 500mb anomaly regions at that time -

The charts by Hannah Attard show that at the moment, the strat vortex has only recently split and there is little correspondence between 10mb and 500mb levels, particularly Arctic stratospheric heights are opposite of the troposphere -

But by 180h there is a coherent similarity between stratosphere and troposphere split vortices and Arctic height rises -

For best effect visit the site and animate the charts - http://www.atmos.albany.edu/student/hattard/realtime/dt_500/DT_500.php

Obviously as with all forecasts the strength and duration of this likely coupling is open to question.

Edit to add that it may become a final warming but it isn't at the moment as technically the FW is a radiative process of the stratosphere being warmed by the sun at which point the vortex cannot strengthen and dissipates.

 

 

Edited March 16, 2016 by Interitus

[Frosty.]

The Gfs 6z manages to squeeze out a brief Northerly towards the end of next week with a few wintry showers with snow on hills and night frosts, especially in the north.

[Paul]

Nice blog by Nick on the current high pressure, Omega blocking and how tricky it can be to shift, definitely worth a read!

http://www.netweather.tv/index.cgi?action=news;storyid=7227;sess=

[Frosty.]

Now this looks like a better Northerly next week on the Gfs 12z

[Frosty.]

This is definitely colder than the Gfs 6z with a higher risk of snow for some areas later next week with overnight frosts throughout the Easter period.

[chris55]

Cold GFS 12z !

 

[Frosty.]

I think the Ecm is having a very poor run of form, this is what it was showing for March 24th on the 12z a few days ago and now..it's been the same through the winter too, it raises hopes then dashes them!

[Guest]

MY LATEST REPORT UPDATED WITH MARCH 16TH 2016 INPUT

Please note that most of the charts that I refer to in this post are through “live” links which update periodically. So, if you are reading this a few hours after publication, the charts may already have updated. My comments relate to what the charts showed at the time of this posting.

This is the Last of My “Daily” Updates:

As I said yesterday, I will start winding down the frequency of my reports and will shorten them. I will continue with perhaps 2 reports each week for the next 2 to 3 weeks. If I feel that there is anything more significant to report, I may add a supplementary update. I will post links to, as well as my comments on, Judah Cohen’s next Arctic Oscillation Report due by next Monday evening, March 21st.

I have noticed that some of the models have moved back into rather colder patterns during the last couple of runs, particularly today on the most recent 12z runs. Although there is little sign of any significant or more prolonged cold, there are plenty of transient northerly incursions and several that would appear to be rather longer lasting. I will not post any model charts in this section but the following should not be ignored:

GFS T+132 and again from T+222 right through to T+348 (5 days+); NAVGEM T+162; JMA (March 15th 12z) T+132; GEM particularly from T+174 right through to T+240; UKMO T+144; ECM T+192.

Overall, I would say that there is plenty to interest the coldies. Whilst many of the charts only show a fleeting northerly, several would seem to indicate proper Arctic incursions and perhaps something rather wintry. I noted a couple of posts in the last few days that stated that even if we get a proper Arctic airstream, it will not be cold enough to produce lowland snow just as has been the case all Winter. One poster even mentioned Svalbard as being far too warm! Regular readers of my reports will know that one of my focusses has been looking at Svalbard temperatures, which I do again towards the end of this one. Svalbard is currently experiencing their lowest temperatures of this Winter which look set to last for at least another week (perhaps longer). If we can get one of those northerlies sourced from that part of the high Arctic it should be a good deal more potent than any of the earlier ones. The maximum temperatures there during our January cold snap were between -4c and +2c. Right now the maximums (today and tomorrow) are between -16c and -18c. These readings are actually close to the lowest values recorded there at any time during the last three Winters! Perhaps we might also see a very late recovery in the ice sheet in the Barents Sea region which has been at record lows. Although thin "new" ice would melt again quickly in the summer.

AO Ensemble Charts: 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml

Still a very uncertain outlook. All the ensemble members moved from positive to neutral yesterday and today going slightly negative tomorrow. From there, 4 members go positive again and stay there through to the end on March 26th. Another ends neutral and the other 5 end in negative territory, with 2 of these trending rather lower than the others. The NOAA forecast for some HLB or no HLB is “up in the air” at the moment. Perhaps it is a reflection of some of the forecast transient northerly incursions with temporary HLB ridging to the MLB high pressure close to the UK.

MJO Ensemble charts:

I will be leaving the whole MJO analysis to Singularity after this report. He always does an excellent job and has far greater knowledge and experience than I have. I am posting today’s ensemble charts and even briefer comments below these. Here are today's MJO ensemble charts for the big 4 and Kyle MacRitchie’s for March 16th. 

UKMO:   http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ukme.shtml

ECM:    http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ecmm.shtml

NCEP/GEFS:   http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpe.shtml

JMA: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/jman.shtml

Kyle MacRitchie:   http://www.kylemacritchie.com/real-time-maps/realtime-mjo/

UKMO: Further increase to good amplitude through phase 5 and into phase 6 later next week..

ECM:  No change today - they have better amplitude early on into phase 5 and 6 but quite low amplitude all the way to phase 7 by March 27th/28th and phase 8 by March 30th.

NCEP/GEFS:  Little change.

JMA:  Very little change.

Kyle MacRitchie:  Continues his consistently bullish approach. He shows the MJO progressing through all the phases from 1 right through to 7 by April 5th and on to phase 8 by April 10th. He has once again increased amplitude which is now high to very high as the MJO re-enters the key phases 7, 8 and 1.

Singularity felt that I should continue with Kyle’s analysis. What do other experts like Tamara feel about the validity of Kyle’s research? I could still include his charts in my more occasional reports for the time being.

Current Arctic Surface Temperatures:

GFS – Northern Hemisphere Current Temperatures:

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=9&carte=1

The link to this chart updates 6 hourly with each GFS run. At the time of writing it is showing a chart for 1900 today (16th March***). As this is T0 to T6 hours, it should be pretty accurate. 

In the Arctic, temperatures close to the North Pole are around -24c to -32c (-20c to -28c yesterday). In “our” part of the high Arctic (around the Barents Sea) temperatures remain much lower than recently at around -16c to -20c (-12c to -20c yesterday). Most of Scandinavia having warmed up yesterday is starting to cool off again, mostly around 0c with a little at -4c in the north (0c to +4c yesterday). Much of northern Siberia is slightly less cold again at around -20c to -32c (-28c to -36c yesterday) and no -40c showing. The cold north/south wedge that developed through western Russia during the last 2 to 3 days has warmed up a little to around -8c to -20c ( -20c to -28c yesterday) with north-east Europe now 0c to -4c (0c to -8c).

*** Please note:   At the time of posting this link it was showing 1900 on Monday, March 16th. The charts are automatically updated 4 times a day, so the temperatures shown will be different to those I just mentioned above. We can follow the trends by looking at the latest data at any time from now on. It is vital to note the time of day to take account of daytime/nighttime variations. So for like for like comparisons, for example the 1900 charts for each day should be available to view from the 12z (T+6) updates which are published around 1600 or about 4 hours later. This also applies to some of the other charts I link to in this post.

Svalbard Daily “Maximum” Temperature Forecast for 10 Days:

Here are the links to the 3 Svalbard stations that I am monitoring.

Central Svalbard – Longyearbyen 28 m asl:   

http://www.yr.no/place/Norway/Svalbard/Longyearbyen/forecast.pdf

March 17th  -16c;   March 21st  -12c;    March 25th  -8c.

West Svalbard – Ny-Alesund:                                                            

http://www.yr.no/place/Norway/Svalbard/Ny-%C3%85lesund/forecast.pdf

March 18th  -17c;   March 21st  -16c;    March 25th  -10c.

South Svalbard – Sveagruva:                                          

http://www.yr.no/place/Norway/Svalbard/Sveagruva/forecast.pdf

March 18th  -18c;   March 21st  -20c;    March 25th  -14c.

The general trend is for the “maximum” temperatures (which fell from much higher levels over last few weeks when they often exceeded 0c), to bottom out over this weekend and then only rise very slightly later next week but still maintain pretty low levels.

These links will update automatically at frequent intervals throughout the day. They are the Norway met office’s predictions. We need to be aware that these are only a forecast that is subject to change and I am told that the Arctic surface temperature forecasts are not completely reliable even at short range. 

To put the above figures into context, here is a link to the main Longyearbyen site:  

http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html

This shows monthly means, and actual highest/lowest temperatures recorded during this winter and goes back further. Apart from a couple of days in December, Svalbard is now seeing “maximum” temperatures falling to well below average, for the first time since Winter 2014/15

Next Update:

Probably on Friday, March 18th.

 

Edited March 17, 2016 by Guest
Check that all links work properly, grammar and spelling

[Singularity]

In light of Interitus' well explained post, I guess I was too hasty to call it a final warming based on the rather gradual propagation downward. 

Funnily enough, the 12z GFS features a more even divide between the strength of the separated vortex lobes - i.e. the U.S. vortex is stronger than on previous runs - which possibly helps to 'focus' lower heights over the U.S. with less in the way of cold air and low geopotential heights 'escaping' into the N. Atlantic. In this way, the jet is kept weaker (less of a thermal gradient) and a wedge of high heights over Iceland/Greenland is able to hold its ground from day 9 right through to day 15.

The result is essentially 'nuisance cold' with the chance of some overnight snow across northern parts in particular. In such a scenario I'd be hoping for plenty of clear skies to allow the sun to offset the chill.

 

The 12z ECM nearly gets that wedge of higher heights going as of day 8, but again fails to keep the lower heights over the U.S. from escaping into the N. Atlantic. This could be a reflection of the longer-lived MJO activity (compared to the GEFS outlook) serving to dampen down the meridionality of the jet in our vicinity.

[Frosty.]

4 minutes ago, Singularity said:

 serving to dampen down the meridionality of the jet in our vicinity.

Yes it becomes flatter than a witches t*t

[Man With Beard]

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

Interesting one. Heights rising over Europe slightly, but not exactly a trough over Greenland. Probably westerlies for the UK and warmer, but with just the hint of a northerly influence being a possibility. Odds on the first scenario

[Frosty.]

The Gfs 18z shows gradually milder weather next week with temps into the low to mid teens celsius which would feel quite pleasant. The Northerly from the 12z is gone, on this run it is as dead as Monty pythons parrot as the chart for Good Friday shows.

[bluearmy]

I've not been studying the output too hard but week 2 ops seem to be playing with cut off wedges of higher heights to our nw and southerly tracking systems as a consequence. Potential Winter nirvana 6 weeks too late. Ens means/spreads will not pick up these wedges as they tend not to be made up of particularly high heights. 

[mb018538]

ECM ramps up a northerly this morning, with some quite cold uppers below -5 cutting across the UK. GFS doesn't favour this scenario, with the OP and mean hovering either side of 0, which would just lead to average conditions.

Alex Deakin on BBC mentioned last night that much hinges on the big low that's going to spin up across the states with the warm/cold clash of air masses. The extent of this will determine the position and amplification of the jet. It would appear that ECM favours the more amplified situation, with the low pressure on the side of the block sliding down across the UK more extensively.

[Frosty.]

The Ecm 00z shows a short cold outbreak later next week with wintry showers and potentially snow showers spreading south in a brief Arctic airflow, although it topples quickly, it would bring some sharp frosts for a time and then more unsettled with a potential polar maritime incursion not far beyond T+240, this is more like the Gfs 12z yesterday.