Model Output Discussion - 1st February Onwards 12z--->

[March Blizzard]

Of course the really mild and pleasant weather expected next weekend wont last, before more normal spring/march conditions return... So what! Anything above the norm is welcome by me!

At least you'll be happy mushy, and I will really if it stays clear. Really don't fancy a cloudy high though - they are absolute weather purgatory at this time of year if sourced from a warm place (this one is coming up from the Azores).

Persistent cloud, static temperatures of around 12-16C, no wind, rain or variation is my idea of weather hell. It doesn't float my boat, it outright torpedoes it! But hey-ho, gotta take the rough with the smooth, and all that.

The models seem quite certain of this now, just the exact location of the high and where in goes after early next week still in question.

[bluearmy]

Day 8 on the ECM 00z op is a pretty decent match on the anomoly to the 12z ens. I'd suggest that implies the chances of the surface ridge getting just far enough north to bring an east of south continental flow better than evens. would be higher if we hadn't been through the last few months!

[IDO]

ECM anomaly 850's are impressive:

 

 

 

Other models are not dissimilar in upper air flow but there still remains variations as to how far north the core heights move. ECM as you would expect is the furthest north at D8 compared to the GEM and GFS:

 

 

The GEM looks in the ballpark, as the ECM is probably up to its normal tricks and the GEFS mean is close to the GEM:

 

 

Still the GEFS are uncertain re FI, especially around D11, though a N/S split still favourite according to the mean.

 

D12:   D14: 

 

By D14 the heights in the Atlantic are replace by a negative anomaly and the ensembles suggest the slow erosion of heights across the UK but lots of spread so early days here. London mean temps remain over 10c from around D5 to D16 so average at worse to above average at times especially next weekend where we could get very warm surface temps:

 

Edited March 2, 2015 by IDO

[knocker]

Trying to get a handle on this.

 

Convective mixing in a tropopause fold

 

 

"Mixing between stratospheric and tropospheric air can occur most readily in deep intrusions of stratospheric air into the troposphere, such as tropopause folds (Danielsen 1968). They occur because of the ageostrophic circulation at the jet entrance (Hoskins 1982) and coincide with the frontal zone beneath the jet. Deep folds can extend down to the top of the boundary layer (Browell et al. 1987; Vaughan et al. 1994), while smaller folds, extending only into the upper troposphere, are ubiquitous around the polar jet stream (e.g. Vaughan et al. 2001). They also occur beneath the subtropical jet stream (Gouget et al. 1996), where it has been suggested that mixing between the subtropical fold and tropospheric air promotes the generation of new aerosol particles (Zahn et al. 2000). Turbulence within folds can result from shear instability beneath the jet (Pepler et al. 1998; Hartjenstein 2000) or from convection extending up from the boundary layer (Browning and Reynolds 1994)."

 

http://onlinelibrary.wiley.com/doi/10.1256/qj.03.21/pdf

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS.

THE CURRENT GENERAL SITUATION A cold and showery Westerly airflow will cover the UK through the period with minor troughs swinging East in the flow enhancing spells of rain or showers, wintry in places.

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

MODELS-2 WEEK HEADLINE Steadily becoming more settled and bright with time but some rain still possible along with stronger winds at times in the NW.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble Forecast shows the flow blowing strongly West to East just to the South of the UK for the next few days before it migrates North to a position between Scotland and Iceland on a NE course later this week and further on as a result of rising pressure from the South of the UK.

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

GFS OPERATIONAL The GFS operational today shows the cold westerly flow with wintry showers giving way to fine conditions in a NW wind on Wednesday as a ridge of High pressure moves in from the West. then a milder SW feed of winds accompanies a band of drizzly rain SE later in the week with pressure rising further for many with fine and settled weather affecting all areas for a time with very mild and bright conditions in the South next weekend. Through the remainder of the run High pressure remains close to the South keeping largely fine and bright and mild conditions here while the North and West see pulses of rain from troughs crossing East interrupting the drier periods at times.

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

http://www.wetterzentrale.de/pics/Rtavn3841.gif
 
THE GFS CONTROL The GFS control run is very similar in type through the period although specific day to day details differ from the operational. Nevertheless the theme is one of South being best in West or SW breezes, strong in the North at times but always mild with a lot of dry and sometimes bright weather in the South mixed with some rain at times in the North but with fine and dry spells here as well in between passing fronts.

THE GFS CLUSTERS The GFS Clusters this morning almost without exception show High pressure close to the UK, likely just to the SE or East of the UK bathing the UK in mild SW'lies, light in the South and stronger in the NW where occasional rain looks likely.

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 UKMO this morning shows a North/South split in the weather late this week as High pressure settles just to the South of the UK feeding mild and bright weather across the South while the North sees much windier weather with gales and spells of rain at times, especially in the far NW.

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

THE FAX CHARTS The Fax Charts show a cold and showery start to the week with rising pressure from the South and a ridge of High pressure crossing East followed by milder SW winds and a weak trough making some progress South across the UK but pushed back North again leaving many Southern areas at least in mild and settled conditions in a SW flow.

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

GEM GEM this morning shows a long fetch SW flow developing late this week and next weekend, strong in the North with fronts bringing rain at times while the South becomes dry and bright in more modest strength breezes. High pressure then bilds across the UK for a time before it drifts East and sets up another mild and generally still dry Southerly flow to end the run.

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

NAVGEM NAVGEM too shows pressure building close to the South of the UK with a mild SW flow across the UK, strongest in the North for a time before even here drier and less windy conditions develop later with some pleasant mild temperatures for all.

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

ECM ECM this morning shows a slow build of High pressure across first Southern Britain late this week and then to all areas as a centre shifts from the UK to the east of the UK maintaining a strong ridge across the UK. Temperatures may be a little more uncertain from this evolution with certainly the risk of night frosts and daytime's which could be mild under any sunshine but rather lower if cloud prevails especially under any Continental drift of wind across the South.

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

ECM 10 DAY MEAN The 10 Day Mean Chart shows strong support for a High pressure to lie over the UK in 10 days time with fine and settled weather for all.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend towards drier and more anticyclonic weather later in the period is sustained within this morning's output.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.6 pts followed by UKM at 97.2 pts and GFS at 96.4. At 5 days ECM  continues to lead the field at 90.5 pts over UKMO at 88.6 pts and GFS at 87.2. At 8 days ECM remains the leader with 66.6 pts over GFS's 60.4 pts. Then at Day 10 ECM retains superiority at 49.5 pts over GFS at 42.5.

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.prig
 

MY THOUGHTS There remains the strong likelihood of mild and drier conditions affecting the UK from late this week and more particularly next weekend on. The change may be slower to reach more Northern areas as most output suggests that the milder air will be accompanied by a strong SW feed delivering moist air and occasional rain to Northern and NW areas for some time. In the South the effects of this flow will be much weaker and sufficiently weak enough to allow some cloud breaks to develop in the lee of the hills and temperatures reaching their highest levels so far this year with 15-16C certainly possible. Western coasts though could be dull, drizzly and foggy at times. It also looks as though the North too could join in with High pressure conditions next week as the High pressure belt extends North cutting off the SW feed of moist air. Of course we have to be mindful that it is still just early March and there is every chance that mild conditions could become hampered by cloud amounts or a colder source of air from the East should the centre drift further North than currently anticipated. With the added caveat that quiet and clear skies could also allow frost at night here and there later. Nevertheless, having said all that the weather looks like becoming quite Springlike at times with some decent sunny spells in the South especially and only small if any amounts of rain reaching the South for some considerable time. In the North patience may have to be a virtue before you join in the fine conditions but there is certainly a chance of decent weather up here too at times later. In the far extremities of the output there is no clear signal about where we go as we approach mid March but it maybe that as our High drifts further East more unsettled conditions may begin to encroach down over the UK from the NW but this is far to distant to be given much credence as yet.  

Issued at 09:00 Monday March 2nd 2015

[mushymanrob]

At least you'll be happy mushy, and I will really if it stays clear. Really don't fancy a cloudy high though - they are absolute weather purgatory at this time of year if sourced from a warm place (this one is coming up from the Azores).

Persistent cloud, static temperatures of around 12-16C, no wind, rain or variation is my idea of weather hell. It doesn't float my boat, it outright torpedoes it! But hey-ho, gotta take the rough with the smooth, and all that.

The models seem quite certain of this now, just the exact location of the high and where in goes after early next week still in question.

 

dont care if its cloudy... as long as its reasonably dry and mild. its only early march.

lack of posts says alot this morning.... everythings going according to plan. a few chilly cold days, a few really mild days, then back to around average from next monday and beyond. its really useful outdoor weather, and pleasant enough early spring weather.

[Summer Sun]

Little change on the 00z ens from ECM once this high gets in it could take a lot time till it shifts with some pleasant conditions by day in any sunshine with nights cold and frosty where skies are clear

 

 

GFS again shows temps at the weekend getting into the mid teens for a lot of areas

 

 

Into next week and temperatures in the north return back to around average with the south haning onto the milder temps

 

 

Those lower temps in the north then spread south though with high pressure still over us it would feel very pleasant in any sunshine despit the temperatures lower than those of the weekend

 

[Frosty.]

Lovely charts again this morning with Ecm 0z showing 850's rocketing by the weekend and early next week as a surge of much warmer uppers is set to bathe the uk and high pressure becomes firmly entrenched with very few signs of a breakdown apart from a weakness approaching NW Scotland towards 12th March but it's a nationwide settled spell on the way, too often it's just the south of the UK that has high pressure but this one appears to be a nationwide fine spell with plenty of sunshine, light winds and pleasant temperatures but cold nights where skies are clear.

[stodge]

Morning all

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index.html

 

Very positive AO at the moment and looking set to go even higher - up to +6

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

 

Incredibly strong - record breaking in fact and little surprise given the output being shown with intense HP and very deep LP on offer. Not sustainable and a rapid fall back to something more normal but not yet trending negative.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

 

The NAO trending back toward neutrality and perhaps even going slightly negative which would be unusual for this winter.

 

My conclusions from that is that while the initial HP will be favourable for drawing a mild or very mild airflow, from mid month onward it's much less clear cut and perhaps a re-positioning to a less favourable position for warmth is likely.

 

Unscientifically, I've also observed the route to very cold starts with very mild and it wouldn't be the first spring to see a warm or very warm spell in March followed by a much colder spell in early April so as a coldie still a lot to play for at the start of the new season.

[Frosty.]

GFS 06z shows mild air wafting in by Thursday but the main surge of very mild air arrives from Friday until well into next week, across southern UK it would feel rather warm at times with broken cloud and sunny spells, the best of the sunshine in the south. It should be noted that northern Britain is much less mild for the most part but that is more due to it being cloudy with outbreaks of rain but as time goes on, the 6z shows increasing anticyclonic domination for all of the UK, the main core of the high becoming centred to the east with north western areas joining in the fine, sunny conditions too. This looks like being a prolonged fine spell which lasts beyond mid month.

Edited March 2, 2015 by Frosty.

[summer blizzard]

Glorious output.

 

[Milhouse]

The GFS 12z has a weakening weather front gradually sinking south over the weekend before fizzling out early next week. Ahead of it we are in a run of very mild southwesterlies but cooler air will be coming in behind the front. As the front never really reaches the south coast it should stay mild for longest here.

 

Beyond t+240 it all gets a bit uncertain. The 12z has us under attack from the Atlantic whereas the 6z had a large area of high pressure over the UK.

[JoeShmoe]

Continuing to look very spring like this weekend and early next week, be a lot of folks out in the garden for the first time this year 

[Frosty.]

Lol I threw the towel in yesterday and now the Gfs 12z is tempting me to retrieve it ..haha

[Summer Sun]

GFS ens maintains the high well into FI

 

d10

 

 

Whilst the north does gradually become more prone to some rain the south hangs onto the drier weather the longest

 

Edited March 2, 2015 by Summer Sun

[Captain Shortwave]

ECM placing the high just east of the UK for next week with an Atlantic trough developing.

 

A mild or even warm weekend, in this set up the temperatures would probably not drop too far. Though some eastern coasts may start to feel cooler in a developing on shore breeze.

 

 

GEM for the same time 

Further south but still mainly fine and dry for many, though a Scandi high develops later.

 

GFS

Slightly different again building the next high in the Atlantic quicker.

Edited March 2, 2015 by Captain shortwave

[Summer Sun]

Some very pleasant conditions from ECM over the weekend and well into next week cold by night where skies clear but in any sunshine it will will be very pleasant given the strengthening sunshine

 

 

The weekend sees the 850's peaking ones like below in the summer would send temps into the mid or high 20's but as its early spring we'll be looking at temps peaking around 15c to 17c in favoured spots

 

[Frosty.]

The Ecm 12z ensemble mean shows a gradual transition to anticyclonic domination. For those who are fed up with Atlantic zonal trash, these charts are excellent and they indicate a prolonged spell of pleasant fine conditions. It's been another winter to forget but early spring will bring perfect conditions for farmers, growers and an early chance to get the mower and strimmer out of the shed. :-)

[ANYWEATHER]

Ecm, early spring warmth, Im off down to beautiful Pembrokeshire , may have to go to the beach!

Edited March 2, 2015 by ANYWEATHER

[Biggin]

Trying to get a handle on this.

 

Convective mixing in a tropopause fold

 

 

http://onlinelibrary.wiley.com/doi/10.1256/qj.03.21/pdf

Nope not getting any of that, is it good or bad, what is it?? gonna happen or not and where  

[damianslaw]

A quiet spell of weather ahead with the cloudiest dampest conditions always reserved for the NW once we get past tomorrow which will be another chilly wintry day for many.

 

The weekend promises a NW/SE split, good growing weather in the SE under bright sunny skies and mid teen maxima, further NW a preety cloudy dank affair unfortunately, very poor synoptics for the far NW if you are after dry bright weather.

 

Looking further ahead, all models show a lowering of temps but sustained dry conditions, cold at night where skies are clear.

 

I suspect this thread will go very quiet in the days ahead,  March can like September be a dry high pressure type month with little to discuss..

[reef]

Quite an impressive GFS 0z FI for warm weather with a Bartlett setup bringing in warm south-westerlies.

 

http://max.nwstatic.co.uk/gfsimages/gfs.20150303/00/288/h500slp.png

 

Temperatures reach mid-high teens with 20C just about possible:

 

http://max.nwstatic.co.uk/gfsimages/gfs.20150303/00/300/ukmaxtemp.png

 

Min temps in double figures in places so mean temps would be similar to late-May to early June.

 

http://max.nwstatic.co.uk/gfsimages/gfs.20150303/00/312/ukmintemp.png

 

It would certainly be an exceptional spell of early warmth if it were to come to fruition.

[bluearmy]

EC 32 maintains the pattern with the Azores ridge being a fairly regular visitor throughout. some mobile stuff in weeks 3 and 4 but looks more settled than not, even then. Winter not over for the ne states either.

For the south of England, this sums up the 2 week outlook

[JoeShmoe]

Quite amusing looking at these temp charts for the weekend when there's lying snow outside !

[Penrith Snow]

Quite amusing looking at these temp charts for the weekend when there's lying snow outside !

Yes, could be winter to summer in 3 days!

Andy