Jump to content
Sign in to follow this  
Paul

Model output discussion - into 2018

Recommended Posts

4 minutes ago, CreweCold said:

Yes and there has been. Just because I can't pull dates out of my sleeve it does not make it factually incorrect what I said. From experience, and others I'm sure can back me up here, we have gone to bed on a bad 18z only to wake up to find the other models have followed suit

Like I said, I'm not for one second saying that will be the case this time, but to dismiss a model run because it isn't desirable is lunacy.

Yes although one good thing - this time last year we had a crap 18z where any chance of blocking had gone and they were as flat as a pancake but woke up to some decent PM on the 0z suite, bet we have a massive change overnight - either for better or worse - lack of data.

Share this post


Link to post
Share on other sites
3 minutes ago, ShortWaveHell said:

I merely wondered if you could show me any specific instances , never mind 

Well funnily enough, I don't keep a mental log of specific dates and times that specific model runs and their associated displayed synoptic forecasts were run.

Anyway, moving on...we want to see the ECM maintain its 12z output but of greater importance would be an improved 0z UKMO and GFS. Get those two on board and I will raise an eyebrow!

Share this post


Link to post
Share on other sites

Whatever your weather prefences may you all have a healthy happy new year! (Cant post a chart as on my mobile ;) )

Share this post


Link to post
Share on other sites

Happy new year to all!

SHOULD ALL THE BAD RUNS BE FORGOT AND NEVER BROUGHT TO MIND!

SHOULD ALL THE BAD RUNS BE FORGOT AND NEVER BROUGHT TO MIND!

Share this post


Link to post
Share on other sites
2 minutes ago, ShortWaveHell said:

I’ll sleep better knowing that 

My pleasure :)

Happy New Year

Edited by CreweCold

Share this post


Link to post
Share on other sites
5 minutes ago, Mokidugway said:

Merry new year , I'm shure Shannon entropy will steer the year :cc_confused:

Isn't that a dutch supermodel?

Share this post


Link to post
Share on other sites
9 minutes ago, Ice Man 85 said:

Isn't that a dutch supermodel?

No, that' Shannon N. Trophy.

Share this post


Link to post
Share on other sites
10 minutes ago, northwestsnow said:

Happy new year brothers and sisters on NW!!

PS Im not drunk but GFS is...

The king has spoken(EC)- its all going to look amazing on the 00z runs (well maybe 6z or 12z in gfs case)..

18Z GFS.......too much (hic)

giphy.gif

 

Share this post


Link to post
Share on other sites

Not model related,but happy new year to the best bunch of weather people anywhere

Share this post


Link to post
Share on other sites
1 hour ago, Dancerwithwings said:

Happy new year to all at Net Weather and to lassi & Moki, I'm sure your posts will stay just this once as it's party time and all that :drunk-emoji:

Let hope it's party time for us coldies in 2018 :drunk-emoji:

I'm shure I can generate endless irrelevant posts for your entertainment ☠️👌

Share this post


Link to post
Share on other sites
10 minutes ago, Dancerwithwings said:

18Z GFS.......too much (hic)

giphy.gif

 

Shure that's crew cold :oops:

Share this post


Link to post
Share on other sites

HNY everyone. If January and February are even half as interesting as December has just been, then there will be plenty to discuss and look forward to... especially if the US can stop stealing all the intense arctic cold... |-[

Share this post


Link to post
Share on other sites

Happy New Year everyone, I have followed this discussion for a few years now 24/7/365 and still don’t know what your all talking about but I love it!! :)

Share this post


Link to post
Share on other sites
Guest

EURASIAN TEMPERATURE AND SNOW COVER ANALYSIS

Firstly, although I’ve been working on this post on and off all day, I realise that it will not go live until the small hours of tomorrow. So, let me wish all of you a very happy New Year and may all your weather dreams come true during 2018. For many of us, that might mean much of the UK being snowed in but with a few isolated warm pockets such as a curious winter heatwave in the Camborne area for you know who!

It’s 3 weeks since I last produced one of these reports. With all the excitement surrounding a possible and “perhaps” only brief easterly in about a week from now, it’s time for an update. Earlier today I did a thorough cross-model analysis focusing on day 7 output.  I wanted to see whether any easterly, if it did verify, would be transient or might turn into a longer cold spell. The evidence was inconclusive. The models have only recently latched on to this changing set up and they could easily drop this signal or develop the evolution in various different ways (Update: I see that the GFS 18z has just come out and has found one of the very few less cold solutions shown for a week's time from any of the 12z GEFS ensemble members; is this a one off swing away from an easterly evolution or a new trend? Further update: better news with the 18z GEFS ensemble suite not looking too bad).

In any event, even if the easterly is brushed away quickly, there are still so many uncertainties going forward, that there is still plenty of time for the building blocks to fall into place for a longer cold spell later in January. There has been some unusually warm weather in eastern Europe and western Russia for quite a while and I’ll take a closer look at this. How cold might it be if we do manage the right synoptic patterns?

Quite a few of my posts so far this winter have looked into the different type of easterlies and I drew on my 55 years of following the weather patterns and maintaining written records to look at some of the examples from the 1960s to 1980s when they were much more common visitors. If anyone missed those posts and wants to be directed to where they are on the earlier model threads, please PM me and I will respond promptly. 

British Sea Surface Temperatures:

  Anomalies - Dec 30th 2017            Temps Dec 29th 2017                 Temps Dec 10th 2017                Temps Dec 30th 2016              Temps Dec 30th  2015   

 sst_anom.gif  2017-12-29uk.gif   2017-12-10uk.gif   2016-12-29uk.gif  2015-12-29uk.gif     

       Source: NetWeather                       Source: Meteoceil

The first chart shows the anomalies compared to the 1971 to 2000 30 year mean. Southern parts of the North Sea are up to 2c below the mean. This is significant and would cause slightly less modification to an easterly air stream compared to what would be more typical for this stage of the winter. The recent frequent northerlies and the cold spell have helped to lower the sea surface temperatures around the UK from above average in October to around average in the south and west and slightly below average  in the north and east right now. They are generally 1c to 1.5c degrees lower since my Dec 10th report. This is also partly due to the lack of strong south-westerlies as well as the normal decrease from the summer to the winter months. I also show the charts for the same dates for the last two winters. Remember the second half of November and early December last winter was also colder than average but early winter 2015 saw very mild south-westerlies following a rather cold and anticyclonic spell in October. Compared to the last two winters at the same stage, this winter has seen slightly lower sea temperatures around our shores overall and up to 2c to 3c lower in the southern North Sea.

European 2m Surface Temperatures:

             Dec 31st 1450                              Dec 21st 1450                            Dec 11th 1450                             Dec 1st 1450      

 temp_eur2-14.png      temp_eur2-14.png     temp_eur2-14.png     temp_eur2-14.png

             Dec 31st 0650                              Dec 21st 0650                            Dec 11th 0650                             Dec 1st 0650      

 temp_eur2-06.png      temp_eur2-06.png     temp_eur2-06.png     temp_eur2-06.png 

Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1450s are usually close to maximums when other conditions remain similar.  I selected 10 day intervals throughout December. Apart from brief colder interludes elsewhere in Europe it has often been milder than the UK. Scandinavia has been more consistently colder and north-west Russia was a lot colder in the first half of December (the purple colours) than it has been since. This only tells part of the story and so I move onto to the northern hemisphere charts.

Northern Hemisphere 2m Surface Temperature Charts (from GFS 6z output for T+6):  

              Dec 31st 1300                              Dec 21st 1300                            Dec 11th 1300                             Dec 1st 1300  

   gfsnh-9-6.png?6      gfsnh-9-6.png?6    gfsnh-9-6.png?6     gfsnh-9-6.png?6

I have selected current and archived charts for 1300 as this would normally be closer to the maximum temperature in normal weather conditions, although remember that the Arctic has pretty much 24 hours of darkness at this time of the year. The first chart shows the current position and shows how little cold there is in western Russia and much of Europe with only Scandinavia seeing temperatures substantially below freezing. Only the far north of Russia and Siberia have temperatures closer to their average. The white area of sub -32s is usually more extensive in early January. Looking at the earlier charts, Russia and northern Asia were a lot colder in the first half of December. Meanwhile the position is reversed in North America. Much of the lowest temperatures are now over there with some local minimum records being hit. It was much warmer there in early December. Now let's compare these charts to a sample of those modelled for a week from now - these are all for 1300 on January 7th:

                  GFS 12z  T+168                        NAVGEM 12z  T+168                    GEM    12z  T+168                       GEFS 18z  T+162 Ens  

   gfsnh-9-168.png?12      navgemnh-8-168.png?31-19      gemnh-9-168.png       gens_panel_ulm1.png                                                                        I have selected these models as they are the only ones on Meteoceil showing 2m temperatures. On the GFS, most of Europe and the UK are above zero, typically around 4c in central and northern Europe, higher in southern Europe and closer to 0c to 2c in north-east Europe. Only Scandinavia is substantially below zero. Further afield, there is a lobe of sub -20s pushing south-westwards from southern Siberia through central Russia while north-eastern Russia and northern Siberia are much colder with sub -32s to -36s quite widespread. Much of the cold in the USA and western Canada has eased with a shift back towards the Asian side - this might help a little later on. Both the NAVGEM and GEM use a black shade for sub -28s but so not show lower temperatures despite it looking quite sinister! The NAVGEM has lower temperatures over the UK and parts of Europe compared to the GFS, with some 0s showing up. Elsewhere it's more comparable to the GFS.  I'll leave it up to other posters to show and comment on the finer detail with more local charts. The GEM has more extensive 0s in central and eastern Europe but still closer to 4c over the UK and 8c to 12c over France. Archived charts are not available for the GEFS output on Meteoceil. So I show the 18z panel with the ensemble suite for T+162. This is partial northern hemisphere/Europe view. For the UK, only 1 member has temperatures close to average around 8c and 2 members have 4c to 8c, 9 are in the 0c to 4c band and 8 have -4c to +4c.                

Northern Hemisphere 850 Temperature Charts (from GFS 6z output for T+6):  

              Dec 31st 1300                              Dec 21st 1300                            Dec 11th 1300                             Dec 1st 1300  

    gfsnh-1-6.png?6       gfsnh-1-6.png?6       gfsnh-1-6.png?6      gfsnh-1-6.png?6  

Current 850s are around or just above the mean over the UK and just as with the surface temperatures North America has some very low values, again at the expense of much of Eurasia. The earlier December charts again reverse the position with the highest value in the USA and the lowest over Siberia and north-east Russia. Now let's compare these charts to a sample of those modelled for a week from now - these are all for 1300 on January 7th:

                  GFS 12z  T+168                          ECM 12z  T+168                          GEM    12z  T+168                     GEFS 18z  T+162 Ens  

    gfsnh-1-168.png?12?12        ECH0-168.GIF       gemnh-1-168.png      gens_panel_ctw3.png

GFS does have a small pool of sub 16c 850s over eastern Scandinavia and north-west Russia but with the UK only under -2s. As with the surface temperatures, the very low 850s over North America right now are weakening considerably during the next few days and the lower values are shifting back towards the Asian side. Again, this is a good sign for us after next weekend, if we can possibly hold onto the easterly or see a renewed attempt later in January. The ECM, on the other hand, shows a much more even distribution of 850s across both continents. It does show some -6s to -8s over the UK with -12s over Scandinavia and a lobe of sub -20s and -24s surprisingly close to us in the Norwegian Sea. If we can get those extremely low uppers into northern Europe, that would give us the chance to tap into some very cold air indeed. In fact anything halfway down to those values (with sub -8s and -10s) would be low enough for convective easterlies given the right synoptic pattern. The GEM has us under sub -4s to -8s with a pool of sub -10s to -12s close to our east, ready to tap into. So the latter two models are much more promising. The GEFS 18z ensemble panel for T+162 has many colder members and certainly show that the operational run was a far less cold outlier with most of the UK under 0s to -2s with a few small pockets closer to -4c. The control shows mostly sub -4s. Only 3 members are in the 0c to -4c cluster. 10 are in the -4c to -8c cluster and the other 7 are all sub -8s. I feel that all these lower values are about the best we can hope for given the current warmth. Things do look at lo better moving further forward and we may not see the same problem in the second half of this winter - with low enough 850s and surface cold to tap into from mid January given the right synoptics. We may even be able to establish a cold pool over Europe. In December and January with the sun so low in the sky, these pools can stagnate and expand with some entrenched home-grown cold in relatively benign conditions - so the jet needs to weaken and or dip well away from us, ideally much further south of us.   

Asian and European Snow Cover:

I show animations for snow cover and sea ice changes. These are produced by the National Ocean and Atmospheric Administration (NOAA).  When you go to their site you can change the date range and go back over 10 years. You can change the speed and pause on any particular day. You can also switch to a northern hemisphere view. These are brilliant, very informative charts and great to play around with. I’ve re-set the link below to show the period  from December 1st to December 31st but you can change the dates on the site and choose your own options.

Animated Europe and Asia Day Snow Cover  (updated by NOAA December 31st):

https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/ea/20171201-20171231

         December 31st chart                             December 1st chart

   ims2017365_asiaeurope.gif           ims2017335_asiaeurope.gif

North Asian snow cover has been well above average since mid-October. During the last few days, the widespread snow cover there has extended further south and south-eastwards. Scandinavia had a complete snow cover but much of the far south is currently fairly snow-free. With all the less cold weather the snow cover in Europe has come and gone with hardly any in lowland areas now. Nice to see some snow cover in Scotland - they're having a decent skiing season except when they're stormbound! 

In Conclusion:

The ECM and several other models are showing that it's still possible to conjure up cold enough uppers almost out of nowhere. It does look like both surface temperatures and uppers will recover strongly on the Eurasia continent with North America giving up its monopoly on the cold during the next couple of weeks. Overall, things were not as bad as I had expected - still a little way to go. So, all we require are the right synoptics to deliver the cold patterns.

It's 0150 and a whole year has ticked by while I was writing this report! 

Edited by Guest
Correct typos and check charts & links

Share this post


Link to post
Share on other sites

@Bring Back1962-63  

Another awesome update as always and its always a pleasure reading through your very informative posts.  One of the few posters on here who always makes their posts nice and easy to explain for new kids like myself (who have no idea what all the weather charts mean, but slowly learning)

Just wanted to take the opportunity to thank yourself for the efforts you bring to the forum (along with others) and wish you all the best for 2018.

Share this post


Link to post
Share on other sites

Sorry mods but I just want to thank everyone for all the fantastic input on this amazing thread, I've been glued for years and it gives a release from everyday life! Happy new year people, let's make it snow :cold:

 

Edited by Tim Goffer

Share this post


Link to post
Share on other sites
Guest
2 hours ago, feb1991blizzard said:

Yes I was debating whether to post them, the London ensemble graph shows another dip right at the end but nothing to write home about, ive got a feeling that 2017/18 is going to be year of the slider.

EDIT : mind you those graphs are apparantely for isle of wight or somewhere like that- a bit misleading, its like me saying - look at these Saddleworth ensembles!!!!

graphe3_1000___-19.9781227112_87.84375_.

Hi Feb, Happy New Year to you.

Did you post this chart as a joke or have you been out celebrating a little too enthusiastically? As I think it has been produced for just that purpose. The location 87.8 N and 20 W is on the Polar ice cap!!! The 850 temps of sub -25c are about right for that location. Big chances of snow on every day. Yes, the temps certainly show a dip and the whole graph is a real slider!

Edited by Guest
Correct typos

Share this post


Link to post
Share on other sites

Hello Folks

Happy New Year to all on Netweather... posters and lurkers alike.

I love the weather, in fact, everything about the weath:yahoo:er 

It provides me a wee release from the pressures of everyday life.

At this time of year especially, please enjoy and appreciate the more important things in life ... those that are important to you...

the weather will always be there no matter what.

Best Wishes Folks

And HNY

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  

×
×
  • Create New...