Model Output Discussions 18z 31/01/2016

[Mildcarlisle]

And the 'Sunday snow for Scotland' possibility is now melting away south as the chart below shows the frontal boundary much further south.

[fergieweather]

21 minutes ago, nick sussex said:

The UKMO for the second night in a row have modified their raw output and the fax charts look more like the ECM. Obviously they think their operational run is an outlier solution.

 

Yes. 00z was considered outlier and ignored past Sunday (ditto downstream products like E4). However, replication of some aspects in 12z run, plus in some EC-ENS, now adds a doubt factor of 20% (in favour of raw UKMO-GM). Hopefully 00z suites will offer better sense of direction.

[Man With Beard]

UKMO not too far off last night's - probably not enough of a block to prevent the Atlantic gaining control this time by T168

[IDO]

Still no clear sign of any kind of blocked pattern in the UK sector by 6th March from the GFS. The most telling chart is the D16 uppers mean:

The continued modelling of the two cold upper cores in W. Asia and E. US. Without some disruption to this pattern the best we will get is some PM air heavily modified as it journeys from the NW. The GEFS at D16 are in a state of flux at the moment with no clear signal as to where we will be from around D10, but they all have this axis of cold suggesting even if we get some sort of block it may take a while before that cold can feed to the UK.

Though it is hard to ignore the prospect of a cool (at least) March with lots of cold rain for the south.

As for the prospects of something wintry on Sunday, ignore the woeful snow GFS charts, the two hi-res models make nothing of that band sinking south:

According to the GFS Feb will go out with a whimper, good riddance to this Winter. I suspect March will be cooler than any of the three winter months and may even get a negative CET anomaly! No clear signal from this morning's GFS as to March's direction, though a pattern change seems likely as the PV wanes and the MJO moves into more amplified phases, but without the cold orientated better, wintriness may remain elusive.

Edited February 19, 2016 by IDO

[Johnp]

14 minutes ago, IDO said:

Still no clear sign of any kind of blocked pattern in the UK sector by 6th March from the GFS. The most telling chart is the D16 uppers mean:

The continued modelling of the two cold upper cores in W. Asia and E. US. Without some disruption to this pattern the best we will get is some PM air heavily modified as it journeys from the NW. The GEFS at D16 are in a state of flux at the moment with no clear signal as to where we will be from around D10, but they all have this axis of cold suggesting even if we get some sort of block it may take a while before that cold can feed to the UK.

Though it is hard to ignore the prospect of a cool (at least) March with lots of cold rain for the south.

As for the prospects of something wintry on Sunday, ignore the woeful snow GFS charts, the two hi-res models make nothing of that band sinking south:

According to the GFS Feb will go out with a whimper, good riddance to this Winter. I suspect March will be cooler than any of the three winter months and may even get a negative CET anomaly! No clear signal from this morning's GFS as to March's direction, though a pattern change seems likely as the PV wanes and the MJO moves into more amplified phases, but without the cold orientated better, wintriness may remain elusive.

Is there a reason you've neglected to mention the euro models, other than the fact they both show cold and blocked conditions?

You've also gone the entire winter without taking on board the entire community's advice that day 16 mean charts are as useless as a chocolate frying pan.

[terrier]

So the ecm and ukmo show colder conditions moving in again next week. Looking like march will be a cold month listening to the experts. But to be honest cold and damp as Spring starts doesn't really sound great. 

[IDO]

5 minutes ago, Johnp said:

Is there a reason you've neglected to mention the euro models, other than the fact they both show cold and blocked conditions?

You've also gone the entire winter without taking on board the entire community's advice that day 16 mean charts are as useless as a chocolate frying pan.

Hi

I don't see any blocked patterns on the Euro's, please post a chart.

The ECM over does the uppers time after time at D5 plus. This current cold spell was predicted to be bitter but down south the days have been close to average. The GEFS mean for 2m temp does not show "cold" for London for the next 16 days:

Of course ECM T850's may not get moderated as they have all Winter but the percentage call is they will. 

It is best not to take the models at face value especially when they have their own known bias, and although you cannot ignore them, it is best to treat them with a wary eye until we get some continuity, cross and inter model. GEM at D7 for instance:

 

[Frosty.]

9 hours ago, fergieweather said:

This fits well with UKMO suspicion re colder start to spring.

Something afoot..

Lovely T+144 chart from ukmo 00z..nice way to start the day!

[Severe Siberian icy blast]

59 minutes ago, IDO said:

Hi

I don't see any blocked patterns on the Euro's, please post a chart.

The ECM over does the uppers time after time at D5 plus. This current cold spell was predicted to be bitter but down south the days have been close to average. The GEFS mean for 2m temp does not show "cold" for London for the next 16 days:

Of course ECM T850's may not get moderated as they have all Winter but the percentage call is they will. 

It is best not to take the models at face value especially when they have their own known bias, and although you cannot ignore them, it is best to treat them with a wary eye until we get some continuity, cross and inter model. GEM at D7 for instance:

 

IDO you seriously can't see any blocked charts ? You must be blind sorry . 

Even if they don't have a direct effect on the uk although many of them do , nobody can deny that northern blocking is taking a foothold on the northern hemisphere , we don't have to look post t168 for it as it's all within the more reliable timeframe , what happens after this is up for debate but models historically underestimate blocking situations , so be wary of any models blowing them out the way for fun . 

The last few winters have been mainly zonal so your assessments relying on day 16 mean charts have not been too bad but you really should no by now/recognise that mean charts for over 2 weeks out are pointless and misleading. But I personally would rather try to use discretion and look at signs and what 'may' happen , because 1 , it's more fun , and 2 , I learn more .

But like I say , each to there own I suppose

Edited February 19, 2016 by Polar Maritime
To move discussion on..

[Polar Maritime]

A few post have been edited/hidden, Can we please continue with friendly model output discussion and not members personal posting styles.

Many Thanks, PM

[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 FRIDAY FEB 19TH 2016

THE CURRENT GENERAL SITUATION   A milder and stronger Westerly flow will develop behind a trough of Low pressure moving East over the UK today clearing all but Southern England tonight and returning North as a waving feature across the Southern half of the UK in the coming days.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across much of the UK is on the rise for many today as fronts move East introducing tropical air across the far South through the weekend and rising the freezing level to as high as 10,000ft come Sunday while North of the front in Scotland freezing levels will be around 2000ft meaning a big contrast across the UK.. Snowfall will remain restricted to Scottish mountains through this weekend.

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

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

MODELS-2 WEEK HEADLINE  Some rain or showers at times with snow over hills. Temperatures mostly near or somewhat below average though with a few short milder interludes in the South.

THE GFS JET STREAM FORECAST  The Jet Stream strengthens over the coming days blowing in a West to East direction across the UK for some time before slipping further South later next week as a UK trough develops. Thereafter the flow appears to realign SW to NE across Scotland at the end of the period.

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

GFS OPERATIONAL The GFS Operational Run today maintains it's changeable theme with some colder periods especially over the first week with wintry showers and with equally milder periods too across the South with cloudy and occasionally rainier times. Little changes within Week 2 though with higher pressure due to closer proximity to High pressure to the South and SW at times there may be less in the way of rain in the South longer term and temperatures never look like being particularly cold in the South either by then with wintry showers in polar maritime incursions restricted to the North.

GFS CONTROL RUN The Control Run today shows a changeable and sometimes rather cold theme going for all areas throughout the two week period as successive Low pressure areas crossing the UK and exiting the East swings winds into a cold NW flow at times with wintry showers at times before less cold and milder Atlantic air returns.

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 70% of members clustering around a solution that would maintain Atlantic Westerly breezes with rain at times with some colder NW winds shown by 35% of members within this group. There is a remaining 30% of members who place High pressure over or close to the UK with fine and dry weather more likely with frost and fog patches by night in light anticyclonic winds.

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 Low pressure up to the NE of the UK early next week with another centre out in the Atlantic preventing the cold NW feed shown by other output from reaching the South where it will probably stay mild until midweek whereas the North sees colder conditions with wintry showers. Then as the Low in the Atlantic shifts across the UK and away to the East the door then opens more for colder air with wintry showers to reach the South too.

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

THE FAX CHARTS The Fax Charts today go against there raw data and push the colder NW flow down across the UK early next week with a subsequent ridge drying things out midweek before signs of further Low pressure entering the West by Day 5 from the West.

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

GEM GEM today shows a Westerly component to the winds across the UK throughout the next 10 days. Next week shows a lot of NW winds and wintry showers across the North whereas the milder South becomes somewhat chillier over Monday. Then after the chilly theme of next week signs of a split in conditions between a milder SW and a colder at times North and East where further rain and showers, wintry on hills look feasible in stronger NW winds.

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

NAVGEM NAVGEM is somewhat different evaporating the milder West winds over the South this weekend and replacing it with a complex slack pattern of Low pressure across the UK later next week with rain at times, falling as sleet or snow over the hills.

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

ECM ECM this morning shows a lot of SE moving Low pressure next week as the mild Westerly flow at the weekend is pushed away by chilly NW winds and showers, wintry on Northern hills from Monday. A small disturbance near the far South midweek could prove problematical in detail for a time where some rain and hill snow is possible before all areas become rather cold and unsettled as Low pressure slips SE across all areas late next week and becomes slow to clear from the South in a wrap around Easterly flow with rain and sleet. High pressure then straddling the North of the UK from both the SW and NE ensure cold and drier weather here to end the period.

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

ECM 10 DAY MEAN The 10 day mean chart today shows the Jet stream a long way South in 10 days with a NW feed of air most likely across the UK  with Low pressure close to the NE stretching up to the NW. Rain at times look the most likely pattern with a lot of the rain showery in nature and under a NW flow some colder air at times would likely bring some snow at times to the hills.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS There are again many differences in evolution shown this morning of a broad Westerly based weather pattern between the outputs this morning with little specific cohesion between outcomes  from quite early next week.

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 97.7 pts to UKMO's 97.2 pts while GFS lags behind at 96.6 pts. At 5 days ECM leads with 92.0 pts to UKMO at 89.9 pts and GFS at 88.6 pts. Then at 8 Days ECM has the leading spot from GFS with 70.9 pts to 66.7 pts. Finally at Day 10 ECM leads today at 51.7 pts to GFS's 51.5 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   Not a lot of clarification in future events shown from the models this morning. The weekend is well agreed upon though with most areas facing yet another weekend of largely cloudy skies with rain at times in a blustery but mild Westerly flow. Central areas could see the most rainfall while Scotland and parts of Northern Ireland see colder and more showery weather and this is then shown to push SE across the UK early next week. It's then that the models diverge mostly surrounding the way in which a shallow Low in the Atlantic integrates with the pattern across the UK with some output showing this becoming a major system with gales and rain for a time others show it as a filling and weak feature with just patchy rain in the South. The pattern then becomes no clearer as from some runs we have High pressure to the South and SW becoming more influential with time and supporting a Jet Stream further North whereas the likes of ECM prefer keeping the Jet Stream well South of the UK and maintaining a NW feed of rain and showers falling as sleet and snow in rather cold air at times as Low pressure areas are shown to continue to slip SE down the North Sea. So as we approach the weekend the models need to handle the pattern next week better before any guarantees of any particular weather type looks likely. The one thing I can say is that nothing alarmist is shown in any output this morning with pretty bog standard Winter fare weather shown for many in the next few weeks. I'll be back on Sunday morning for a further update.         

Next Update Sunday February 21st 2016 from 09:00

[IDO]

25 minutes ago, Severe Siberian icy blast said:

IDO you seriously can't see any blocked charts ? You must be blind sorry . 

 

Even if they don't have a direct effect on the uk although many of them do , nobody can deny that northern blocking is taking a foothold on the northern hemisphere , we don't have to look post t168 for it as it's all within the more reliable timeframe , what happens after this is up for debate but models historically underestimate blocking situations , so be wary of any models blowing them out the way for fun . 

The last few winters have been mainly zonal so your assessments relying on day 16 mean charts have not been too bad but you really should no by now/recognise that mean charts for over 2 weeks out are pointless and misleading. But I personally would rather try to use discretion and look at signs and what 'may' happen , because 1 , it's more fun , and 2 , I learn more .

But like I say , each to there own I suppose

My quote: "Still no clear sign of any kind of blocked pattern in the UK sector by 6th March "

And you posting one chart out of context suggesting the pattern is blocked is misleading. We are in a relatively mobile pattern, not a zonal onslaught, so the Azores will push some wedges of heights into the mix every 5-7 days, but that is not a block, that is just a moment in time and in 48 hours it is gone. 

I cannot for the life of me see a sustainable blocked pattern in our region on the GFS op, and neither GEM or ECM are showing that either. Yes we have the omnipresent Russian high, tick that is a block, and the EPO Ridge, that is a block, but they are far away from the Atlantic sector IMO. I have never defined a toppler or a transient wedge of heights a block.

Sorry if we see things differently.

[Captain Shortwave]

There have been some shorter term changes this morning, for the most part suggesting that the UKMO runs over the past day or so were not as outlandish as we first thought.

GFS/UKMO/ECM at day 5

          

The GFS less keen but in fact looks the outside solution with the GEM going for something similar to the UKMO solution. The ECM is in between but drops low heights through the ridge and pushes this through the channel.

Longer term, no real change with low heights forecast to move south east into Europe maintain a Euro trough with above normal heights present throughout.

GEFs

      

ECM ens

      

The ECM ens not particularly supportive of cutting the trough off with an easterly developing, so the story continues of cool and mixed though it wouldn't take too much to develop a much colder pattern from where we are. In fact it is more likely to turn cold than mild given the present synoptics (This weekend being the exception).

[Costa Del Fal]

2 hours ago, IDO said:

Still no clear sign of any kind of blocked pattern in the UK sector by 6th March from the GFS. The most telling chart is the D16 uppers mean:

The continued modelling of the two cold upper cores in W. Asia and E. US. Without some disruption to this pattern the best we will get is some PM air heavily modified as it journeys from the NW. The GEFS at D16 are in a state of flux at the moment with no clear signal as to where we will be from around D10, but they all have this axis of cold suggesting even if we get some sort of block it may take a while before that cold can feed to the UK.

Though it is hard to ignore the prospect of a cool (at least) March with lots of cold rain for the south.

I know it has been said many times but what real use to day 16 mean charts have? It's got to be so watered down that unless a very significant majority pointed to something, which lets be honest rarely happens around the uk. anomalies/spaghetti plots are always showing the locale from uk to Iceland as one of the most uncertain areas for prediction in the northern hemisphere. 

Hence finer details are easily lost. Looking at the broad long wave pattern I would take encouragement at the fact for foodies that there the sub 0c/-4c 850hpa lines sink a good deal south into Europe, embodying the uk within this mostly too. As a hemispheric view, it is clear our pet of Europe on that chart is where colder air is trying to sinking the most south in the northern hemisphere. Yes the core of that cold sinking south is more over Central Europe but certainly not without potential for the uk too and far from a poor outlook imo. In fact at the worst cold air around western/Central Europe and less over us to me at least indicates potential for battleground scenarios.

So, as much as I don't support the use of  means at such a range, the chart you use above would actually be quite good for those after cold imo. Just my opinion though.  Happy to discuss further.

Edited February 19, 2016 by Costa Del Fal

[Polar Maritime]

Some pretty heavy and possibly disruptive snow for the the North over the weekend as some cold -7 850's push in over the Northern half of the UK from the N/W, Giving blizzard conditions at times for parts of the Highlands.

Edited February 19, 2016 by Polar Maritime

[Singularity]

Well, I'm a bit miffed at the lack of proper HLB from ECM this morning - where's the Arctic High gone? - but next week could start to look more interesting if the trend toward better trough disruption continues.

The UKMO run seems rather strange in the way that all of the potential instability ends up with the low moving directly east to the UK days 3-5 rather than being split between that feature and the upstream trough as per ECM. In this way UKMO is now able to over-develop the low and lead to at best a back-end snow event.

Then we see the trough disruption being indicated but again with the issue that the air exiting the U.S./Canada is so very cold that there is greater instability than usual, threatening to make these lows too strong in the mid-Atlantic. The SST profile in the N. Atlantic only serves to enhance this problem.

 

What's really puzzling longer term is that we have a decent displacement of the lower-stratospheric vortex toward Eurasia being indicated by GEFS in the 8-12 day range (and possible split but this not well supported this morning) and the MJO moving through 7 toward 8 at decent amplitude, while the upstream ENSO forcing is moving steadily away from the classical El Nino setup, and these all point toward a lot of added amplification across the U.S. and Atlantic sectors and a build of HLB... yet the efforts made by ECM and to a greater extent GFS this morning are rather lackluster. ECM could be salvaged soon after day 10 but only if the low west of Iceland cleared E/SE quickly so as to avoid interaction with the next trough off the U.S./Canada.

 

There does look to be a key period +144 to +192 in which added amplification upstream could make a big difference and allow the mid-Atlantic ridge to gain a foothold NW of the UK so that's worth watching.

I have done a comparison of where the model projections of 16th Feb had the MJO by the 18th with where it actually is, but the share function from dropbox seems to be down this morning. So I'll describe it for now; ECM is the only model to have progressed it to phase 7 quickly enough, while in terms of amplification all of the models were short by about 0.5 on the RMM2 scale. That's a significant difference and even larger errors were evident for the 17th - which means such a disparity may well continue as the MJO moves into phase 7. 

If so, the impacts will be significant; the latest projections haven't adjusted to account for the observation being so much more amplified and so are going for a sudden drop of more than 0.5 on the RMM2 scale and with much less progression east than has been seen in recent days. 

If the MJO instead just saunters on into phase 7 without much loss of amplification nor slowing down as much as predicted... well, phase 8 could be with us a whole lot sooner than is currently being factored into the model output.

My gut feeling is that we will see the slowdown and climb about 2/3 way toward phase 8, with the decay occurring 7-10 days later close to phase 1. This is based on the past couple of times that the MJO has been moving into phase 7; progression was underestimated in both cases, by around 1 phase worth of eastward movement.

[nick sussex]

Oh dear what on earth is going on with the UKMO output. The differences with the earlier GFS 00hrs run started within T24hrs over the ne USA. The UKMO have now had to modify their T72 and T84hrs fax charts. Bizarre to see this marked difference still after two days.

I think the more likelier solution is something closer to the ECM which is midway between the GFS and UKMO.

Looking at the ECM postage stamps there is still a mix of solutions at T120hrs. Of interest to snow lovers is that many are likely to bring some snow on the northern flank, the ones with a shallow feature and also the op and control run. Compared to the PM undercut damp squib of a few days ago the air is sourced more north rather than nw and has had more chance to build up to the north and undercutting the precip. At this range though getting the track correct is difficult.

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2016021900!!/

Edited February 19, 2016 by nick sussex

[Frosty.]

Quite a stark temperature contrast from north to south this weekend from the Gfs 6z but it's been a similar story for most of this winter. In terms of weather, wintry showers blasting across more northern parts of the uk with colder north Atlantic / polar maritime airmass, outbreaks of rain across the central swathe and some rain at times in the south but with drier and brighter spells too in a Tropical maritime airflow but becoming colder from the NW early next week.

Edited February 19, 2016 by Karl.

[karyo]

6z GFS only out till 72 hours for me on net weather. Anybody else has the same problem?

[Paul]

1 minute ago, karyo said:

6z GFS only out till 72 hours for me on net weather. Anybody else has the same problem?

The NCEP server is very slow in terms of downloading the files this morning, we're switching to a backup now, so it should speed back up again shortly. 

[Polar Maritime]

The GFS 6z shows unsettled cool/cold conditions as we head into the last week of the Month and into the start of Spring. With temps generally below average from a N/W Pm flow, Turning Northerly at times giving plenty of opportunity's for snowfall for the North (but not exclusively) as the Jet drops further South at times.

So a 'Seasonal' end to Winter and a cold start to Spring looks to be on the cards, With plenty of interest in the Models over the coming days.

Edited February 19, 2016 by Polar Maritime

[SMU]

Anyone belittling the UKMO today should review the GFS 12z at T72

A 100% swing to the UKMO 00z.

[IDO]

6 minutes ago, Steve Murr said:

Anyone belittling the UKMO today should review the GFS 12z at T72

A 100% swing to the UKMO 00z.

Not really, more of a move towards the ECM as Nick suggested earlier:

UK:   ECM:   GFS: 

 

[Man With Beard]

UKMO T144 could lead to a very cold NEly by T192 - air all the way from above Norway will get on the top flank of the Atlantic low, which itself looks set to drop over us in later frames

[Cloud 10]

Does look as though the GFS has swung towards the UKMO this evening by taking that LP under the block rather than through it at just 72 hrs.

 

We seem to be sneaking into an ever colder pattern at the moment.

 

yesterday..today..