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

[Frosty.]

Foehn winds to the Lee of high ground around the middle of next week and for favoured spots in the NE..14 and possibly 15c (57-59f) could be yours with some sunnier gaps as we briefly draw winds from the Azores up across the UK according to the Gfs 00z op. Beyond that, a cold front sweeps through but pressure then rises strongly. In the meantime, current anticyclone lasts until Thursday but then it turns unsettled and breezy from the west with temperatures around average, a brief flat ridge early in the weekend is followed by further unsettled weather off the Atlantic but then we see that change to rather milder weather, especially through the midweek period.

Edited February 10, 2015 by Frosty.

[IDO]

No sign of the NAO or AO going negative:  

 

This ties in with the continued output from the GEFS. No Northern blocking showing with any consistency. The odd member or hi-res run in deep FI give us feint hope but at the moment this is simply not trending. Looking at the NH profile there is not a lot going on, the PV meandering around to the north of the Azores ridge, so the UK caught between the two. If we are lucky it will be more HP than zonal.

 

As a few days ago the MJO is going towards a sleeping phase so no help from here as per the last cold spell:

 

 

As some say it could all change but there needs to be a trigger for that and at the moment there are none in the next 10-15 days. Otherwise we are in a prolonged holding pattern waiting for the pattern to reboot.

 

After D7 the ECM brings more zonal, whilst the GEM and GFS are more settled (especially for the south):

 

  

 

I have always been hopeful of a late cold spell and I am still going for a cold March. Obviously at that time of year we need the variables to be spot on to get some lasting snow but it is possible.

Edited February 10, 2015 by IDO

[johnholmes]

well the link below might give coldies some hope, well the EC version. The trouble is it is on its own, no continuity with itself over the last 3 days let alone with GFS which is nearly as variable. Neither are all that much like the NOAA output. Until the 3 show consistency with one another and themselves then the anomaly charts are no more use than the variable outputs we often see from the synoptic models.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[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 High pressure lying across Southern Britain today will drift away slowly East tomorrow but maintaining a very light Southerly flow over the UK.

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

MODELS-2 WEEK HEADLINE Dry at first and possibly again later with an unsettled period from late this week and into the beginning of next.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble Forecast shows the flow blowing in an Eastward motion to the North of the UK. Later in the week it dips South across the UK in association with a trough and this may be repeated next week before it realigns back to the North of the UK late in the period.

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

GFS OPERATIONAL The GFS operational today shows the current High pressure slipping away East at the end of this week with Low pressure troughs crossing East over the UK at the weekend and early next week with several spells of rain in a blustery breeze and average temperatures. then through the second half of the run High pressure rebuilds from the South to lie over or close to the UK later with mild west winds in the North with further rain in places there while at the very end of the run High pressure located in a colder pool of air could bring widespread frost and cool weather to the UK by Day 15.

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

http://www.wetterzentrale.de/pics/Rtavn3841.gif
 
THE GFS CONTROL The GFS control run shows a very similar sequence of events over the next week as the operational model with all areas seeing some rain for a time. The same build of pressure shown by the operational is shown by the control run too towards the South too late next week before weak troughs bring new interventions of High pressure behind them, positioned such that colder air moves into the UK and as High pressure then moves across to the NE a bitter easterly wind sets up over the South with the risk of snow showers.

THE GFS CLUSTERS The GFS Clusters today continue to indicate that High pressure is likely to be positioned somewhere close to the SW of the UK in two weeks time. There are variations within members that show a different positioning of the High but without too much fundamental difference in weather differences at the surface in what would likely be generally benign and non-descript conditions.

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 Low pressure moving into the SW of the UK late this week with some rain there before the Low is shown to pull away South leaving the UK under 'Col' conditions over England and Wales with a milder SW flow over Scotland by next Monday.

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

THE FAX CHARTS The Fax Charts this morning show High pressure declining away to the East through this week leaving slack winds behind until the end of the week which shows Low pressure and associated troughs edging into the South-West of the UK by the weekend.

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

GEM GEM shows a similar scenario to the majority of the output with an interruption in the fine weather by Low pressure troughs moving over from the West from Friday and into the start of next week. High pressure is then shown to slowly regain authority from the SW sending any rain bearing troughs away to the North where a stronger but mild SW flow will blow before veering towards a cooler WNW flow by 10 days time.

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

NAVGEM NAVGEM shows a much more unsettled period developing in the wake of the trough on Friday as a period of sometimes wet and windy weather moves across all areas at the weekend followed by colder weather with wintry showers in the first half of next week in a strong and cold NW flow.

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

ECM ECM shows the weather becoming much more changeable across the UK from Friday as the model shows the Low on Friday filling but leaving a trough near to the SW and linking to further instability moving in off the Atlantic from the West. This then leads on to a spell of much stronger winds and rain at times as various troughs pass over the UK in the strong flow followed by colder and blustery conditions in NW winds and showers, wintry over Northern hills.

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

ECM 10 DAY MEAN The 10 Day Mean this morning maintains the prospect that pressure is biased lower to the North of the UK and higher to the South and SW. The main belt of High pressure from the Azores will keep the UK in a generally Westerly flow with the biggest chance of the more unsettled and breezy weather likely to the North of the UK.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The long term trend today has show a shift towards less High pressure domination as most output show High pressure held further to the South next week with more risk of a stronger Westerly flow spreading to many areas next week and rain affecting the North at times and possibly to the South too.

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 97.4 pts followed by UKM at 96.9 pts and GFS at 96.2. At 5 days ECM just about leads the field at 89.8 pts over UKMO at 89.2 pts and GFS at 86.9. At 8 days GFS takes over with 62.5 pts over ECM's 62.1 pts. Then at Day 10 ECM regains superiority at 46.3 pts over GFS at 44.5.

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 Todays output has shown a small shift towards the chance of more changeable and breezy conditions to last rather longer than the models were originally programming earlier in the week. The introduction of this weather type is still likely on Friday as a trough moves into the UK from the West bringing some rain at least to the South and East. The models from the States indicate this as a trough crossing East over the UK while the models from this side of the Atlantic show a Low pressure cell close to Southern Britain slipping away South from the UK leading us into a slack no mans land area of atmosphere for a time with quiet and benign weather before all models then come together in bringing a spell of windy and changeable weather with rain at times to start next week. It's then all about how long this changeable theme lasts and how much High pressure still to the South and SW rebuilds sufficiently to shunt rain bearing fronts and Atlantic Westerlies back North to Scotland and return drier and more settled conditions from the South. Some output does indeed build High pressure over the UK later and the GFS Control run then migrates that North to Scandinavia later which would bring a draw of very cold wintry air with origins over Eastern Europe across the South for a time. This has little support though overall and the overwhelming factor is for the UK to lie somewhere between High pressure to the SW and Low pressure to the North with anything between mild SW'lies and colder NW'lies possible later a theme backed up from the ensembles. With regard to temperature there seems little evidence of any return to UK wide Winter anytime soon with temperatures often staying close to average with any wintry precipitation likely to be restricted to the hills of the North in any polar maritime NW'ly interventions of air later in the period.  

Issued at 08:30 Tuesday February 10th 2015

[frosty ground]

Can't post charts but GFS at 240 has HP ridging in again from the Azores, with the Foehn effect giving temps of 15c in NE Scotland

It also has several North Westerly outbreaks that would bring snow to higher ground and at times lower ground (of Scotland).....

The ECM has a rather potent North Westerly outbreak around 168 hours.... Which could give snow to areas of the north west of England with only a slight elevation...... http://www.meteociel.fr/modeles/ecmwf/runs/2015021000/ECM0-168.GIF?10-12

It looks like we have gone full circle with the high pressure domination giving way to the standard for the season of north Westerly outbreaks...... If the pattern is to continue as before we could see a strengthening of these outbreaks, but that's basically pattern matching which is snake oil

Edited February 10, 2015 by frosty ground

[Polar Maritime]

The GFS continues to show a more N/W Pm flow by weeks end, With bands of wind and rain pushing S/E over the UK. And at times the uppers are cold enough for sleet/snow over high ground in the North. Lot's of uncertainty further into the run's,  But the ECMWF seems to keep the cool/cold N/W theme, With a slack Northerly by the 20th for the far N/E..

 

Edited February 10, 2015 by Polar Maritime

[shaky]

One scenario that has gathered some support this morning and hardly anyone has mentioned is the scandi high!! Ecm has not backed down, ukmo showing the same as yesterday's 12z and now the gfs 06z has a stronger high around scandi aswell! ! No one is excited probably cos of the lack of cold 850s!!

[Blake]

What's the GFS up to now? In the semi-reliable too...

 

0h run

 

6h run

 

All eyes on the East...

[Blake]

One scenario that has gathered some support this morning and hardly anyone has mentioned is the scandi high!! Ecm has not backed down, ukmo showing the same as yesterday's 12z and now the gfs 06z has a stronger high around scandi aswell! ! No one is excited probably cos of the lack of cold 850s!!

 

Probably need 3/4 days from when the Scandi forms for the colder air to reach us. If the Scandi is still showing come T240 on this run, should see -6/-8 uppers moving in!

 

EDIT: It's more of an Eastern Europe high, but signs of a change, something to keep an eye on here, couple of tweak in the next couple of days and we could be getting excited again!

Edited February 10, 2015 by GUWeather

[IDO]

The GFS continues to show a more N/W Pm flow by weeks end, With bands of wind and rain pushing S/E over the UK. And at times the uppers are cold enough for sleet/snow over high ground in the North. Lot's of uncertainty further into the run's,  But the ECMWF seems to keep the cool/cold N/W theme, With a slack Northerly by the 20th for the far N/E..

 

 

 

But as with many D8-10 ECM op charts I would treat them as just for fun. The mean is much more like the GEFS:

 

D8:  D10: 

 

Bearing in mind the ECM ensembles still have over 33% (cluster 2) showing a ridge over the south at D5 compared to the op, it is clear that the ECM suite are also struggling with this setup.

 

GEM D10 mean also similar to the GEFS: 

 

In the more reliable (GFS 06z) we have a front crossing the UK on Friday. The front on Sunday looks like dying before it reaches us and it is the Monday cold front that may bring some wintriness to Scotland. From D7 the ridge builds in from the SW again:

 

 

Much like the last 2-3 days GEFS output.

[492]

What's the GFS up to now? In the semi-reliable too...

 

0h run

 

6h run

 

All eyes on the East...

Agreed. UKMO, ECM and GFS have all been entertaining the idea of some sort trough disruption close to the UK over the last few runs with a tendency to build high pressure somewhere to the NE. We could be witnessing an evolving easterly in the medium term.

[Polar Maritime]

A very messy GFS further out in the run... As always a few miles N/S of the High Pressure can make all the difference, It does show a slack S/E flow over the South of the UK bringing cool/cold surface conditions.

 

Edited February 10, 2015 by Polar Maritime

[IDO]

Agreed. UKMO, ECM and GFS have all been entertaining the idea of some sort trough disruption close to the UK over the last few runs with a tendency to build high pressure somewhere to the NE. We could be witnessing an evolving easterly in the medium term.

 

That looks like a surface high with little WAA pumping up the upper ridge, that is until it sinks towards Russia. It will just get pushed aside by either the lower heights or the Azores ridge. We need the Azores ridge to build towards Scandi, and to be fair it has a go after D10, but in a mobile pattern it just continues E/SE:

 

 

Looking at the GEFS over the last few days we have had many different evolutions on this current pattern and none build to a more blocked setup. To me it is a sign that the current synoptics are not viable for any HLB.

[Tamara]

It was expected to be a struggle anyway, but a traditional cold late winter European weak El Nino pattern is not materialising. However, the atmospheric state after mid January showed some reasonable signs this might happen to sustain the increasing interest that had been developing from this time and took us into the opening days of February.

Some sceptics on this thread clearly remain about the influences that the large scale atmospheric state has on the NH pattern, but the GWO has sketched out this -AAM pattern very clearly in the last few months with its repeated low angular phase states - punctuated in the second half of winter with brief incursions to more Nino like amplitude phases.

Whether one likes it or not, or whether one agrees with it (or me) or not, the patterns this winter across the NH have replicated this atmospheric state exactly to what is said on the tin. It just happens to be the case that this type of tropical Pacific led pattern is not favourable for the development of cold blocking our side of the NH, beyond periodic Atlantic amplifications during the winter months. But then this has been repeated more than a few times for quite some time now.

A West Pacific Tropical Cyclone helping to further pump up NH mid latitude anticyclones downstream from the sub tropics and current low amplitude and incoherent extra tropical (GWO) and tropical (MJO) signals are, in the very short term, masking those continuing trends of the whole winter.

However, the eventual destination is the same one as posted last week - with troughing on a NW/SE axis ahead of further amplification in the extended period. The question, as posed towards the end of last week, is when this occurs and not if it will occur

GWO orbit suggestions have remained steadfast on this, only simply delayed by upstream developments. Twin Mountain torques are in the process of occurring (EAMT already has occurred) which are set to provide vertical wave activity both sides of the pole and will serve in the extended period to pinch the vortex, much as they did in late January.

This process will serve to send vorticity energy across the pole and the weather become increasingly more mobile into the medium term. Timing is hard to be precise, but towards the 15 day period we are looking towards a next incoming amplification phase feeding downstream from the Pacific - and whilst it is difficult to know the extent of any possible colder conditions this might provide, it fits precisely with the cyclical pattern seen this winter.

GWO set to increase amplitude into Phase 1/2 in the extended period. This is only forecasted at this stage, but it is logically underpinned as twin torques re-initiate low AAM tendency - which subsequently drives the GWO orbit on to these phases.

Much as it has done at least three or four times since December

Phase 1/2 signals that next Pacific retrogression - which will serve to draw the Azores High further west much as it has done periodically during this winter to give the colder spells we have seen. These low AAM phases in (probably) late February teleconnect well to a NW European trough and NE Atlantic ridge.

The trend as we head to winters end and into March is to see the retrogressive signal increase - the shortening wave lengths under this -AAM regime (the reasonable assumption here is this entrenched atmospheric state will continue for a while yet) are supportive of a below average start to Spring as cold air expelled from the Arctic becomes more and more likely.

That might not fit with the changing wave lengths of the audience in this thread, with increasing numbers wanting to put on their sunshades instead of snow goggles - but again, whether one likes it or not a typical amplified change of season mix seems in line with prospects - as I see things anyway at this stage.

As one who prefers deep winter cold, but still receptive to late wintry surprises (and likes to continue to watch weather patterns unfold throughout the year anyway) I am looking forward to seeing how things progress as always

http://www.atmos.albany.edu/student/nschiral/research/gwo/gfsgwo_1.png

Edited February 10, 2015 by DiagonalRedLine
Image version of chart added to post as well.

[knocker]

Looking briefly at yesterdays EC32. No sign of any extended cold.

 

By the 23rd LP Canada/Pole with trough orientated south to the UK. HP mid Atlantic.

 

By the 3rd the LP weaker (to be expected given the time frame) and Atlantic HP further east with a suggestion of Scandinavian height build up.

 

By the 13th not a huge amount of change.

 

Temps going from below average to slightly above.

[nick sussex]

This morning is a case of an acorn growing into a sapling but still meeting an untimely end! which is better than yesterday with no acorn!

 

The overall NH pattern is still poor for any proper cold into the UK but the weekend and early next week remains the subject of some uncertainty.

 

The models by and large have made a pigs ear of trough disruption near the UK and the ensembles have been even worse, their lower resolution is having a hard time picking up on that trough disruption.

 

The GFS in particular is showing a lot of mood swings but its 06hrs output has edged towards the ECM solution, whats interesting is that the outputs develop some cold pooling in southern Norway and the GFS now wants to disrupt energy from the next upstream low.

 

Sometimes small early changes can incrementally start altering that important more local detail further on, the PV is in no mood to back down but its the angle of attack from the next upstream low that could be effected by these early changes.

 

I wonder whether we're seeing some response to the MJO, even though this is weak it could be with the timelag that the models are picking up on this, not enough for some major NH change but effecting the weekend and early next week for western Europe.

 

I don't see a miracle happening, its likely the Azores high will move in again but its the changeover period that could become a bit more messy and a little bit more wintry.

 

We'll see tonight whether we can squeeze a bit more out of a possible Scandi high but its crucial that the favourable trough disruption allows that to happen in the first place.

Edited February 10, 2015 by nick sussex

[legritter]

This morning is a case of an acorn growing into a sapling but still meeting an untimely end! which is better than yesterday with no acorn!

 

The overall NH pattern is still poor for any proper cold into the UK but the weekend and early next week remains the subject of some uncertainty.

 

The models by and large have made a pigs ear of trough disruption near the UK and the ensembles have been even worse, their lower resolution is having a hard time picking up on that trough disruption.

 

The GFS in particular is showing a lot of mood swings but its 06hrs output has edged towards the ECM solution, whats interesting is that the outputs develop some cold pooling in southern Norway and the GFS now wants to disrupt energy from the next upstream low.

 

Sometimes small early changes can incrementally start altering that important more local detail further on, the PV is in no mood to back down but its the angle of attack from the next upstream low that could be effected by these early changes.

 

I wonder whether we're seeing some response to the MJO, even though this is weak it could be with the timelag that the models are picking up on this, not enough for some major NH change but effecting the weekend and early next week for western Europe.

 

I don't see a miracle happening, its likely the Azores high will move in again but its the changeover period that could become a bit more messy and a little bit more wintry.

 

We'll see tonight whether we can squeeze a bit more out of a possible Scandi high but its crucial that the favourable trough disruption allows that to happen in the first place.

yes certainly some interesting Possibilitys on the table at the moment ,i wonder where our azores high will be in the proceedings ,will we see some possible Lows pushing further south out of north America ,combining with a possible hight rise to our n /east but the one to watch is azores i feel ,if as my straw clutch comes off we would see a final good bye  to high pressure to the s/west we could get down to some good cold snowy Hunting .Well it looked not that long ago that high pressure would be totally in control so ten days from now could be a new chapter ,i,m certainly keeping the Lamps burning for some wintry fun as today is 10th february ,cheers all   

[mushymanrob]

One scenario that has gathered some support this morning and hardly anyone has mentioned is the scandi high!! Ecm has not backed down, ukmo showing the same as yesterday's 12z and now the gfs 06z has a stronger high around scandi aswell! ! No one is excited probably cos of the lack of cold 850s!!

 

youre right, there is potential for a scandi high /easterly. the fax @ 120 suggests the expected trough undercutting and joining the other in the med.  omly low potential though but with gathering uncertainty it must be plausible.

Edited February 10, 2015 by mushymanrob

[Jason M]

One scenario that has gathered some support this morning and hardly anyone has mentioned is the scandi high!! Ecm has not backed down, ukmo showing the same as yesterday's 12z and now the gfs 06z has a stronger high around scandi aswell! ! No one is excited probably cos of the lack of cold 850s!!

 

Yep, its those 850s yet again.

 

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=120&mode=1

 

Although the models have played around with this scenario there is nothing in the output that currently suggests it amounting to anything. The GEFS are supportive at day 5, but they almost all go onto show the azures high ridging back in by 192 hours with a push of SW winds and associated TM air mass.

 

With the jet far to our north a full blown easterly looks improbable at this point.

[winterof79]

Hello Carinthian

 

 

[johnholmes]

As it is very quiet in here I thought I would place a pdf file about another case of a cold spell being well predicted by the 500mb anomaly charts, those who do not want to do not have to read it to get to the next post.

Over and just after Christmas 2014.

 

 

john-h 10 feb 2015.pdf

 

if only it was as simple as that, the whole period up to the actual snow in this area was a nightmare to try and get correct. The anomaly charts which seemed to be fairly sure with the arrival of colder air then started to backtrack, wobble around, along with the synoptic outputs and overall guidance, so the actual snowfall for some low lying areas was not correctly predicted even 6-12 hours ahead of it accumulating.

Fun being a weather forecaster providing you have or develop a thick skin!

Edited February 10, 2015 by johnholmes

[seaside 60]

There are some seriously long south westerlies ish, starting from the bottom left (mid south west  Atlantic) of the charts and riding over our high to the north west/north of us and still going of the top right of the charts, more westerly, being shown from many charts in 7/14 days.

I have notice several of these showing up, however it well away from us as we talk now.

[shaky]

Big changes on the 12z already! ! Low pressure just about makes it to south west england before sliding south of the uk!! 06z had it centre of the uk!! This only at 78 hours!! Scandi high maybe about to gather pace!!

[Captain Shortwave]

The model output doesn't seem to be trending anywhere to be honest, just the models picking out a different 4-6 day range solution everytime.

GFS further west with that low

UKMO pushes it further east compared to the 00z which had a similar track to the current GFS output

 

Scandi high? I can't see it being sustained, it will likely topple towards western Russia with any continental feed being transient. The main issue here will likely be high rainfall totals as active fronts stall over the UK.

Edited February 10, 2015 by Captain shortwave

[frosty ground]

A Temp flow from the East?