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Hunt For Cold: Model Discussion - Heading Into Christmas

Paul

If you're hunting for cold potential in the model output, this thread is for you. But if you'd like to look more widely at the models, please head over to the general model discussion thread.

This is a model related thread, so a general, frequent theme of the model output is a given, but it will not be strictly enforced:

  • Some topic drift, humorous responses etc are fine
  • Posts likely to lead the thread off on an entirely off topic tangent are not ok. For example (but not solely limited to): Posts entirely or mainly about Met Office, BBC or media forecasts with little or no model context, and posts solely asking for a weather forecast in a specific location.
  • Posts which start with something like 'I know this is off topic but ...' are not ok.
  • Posts which break the forum guidelines are not ok (eg trolling, troll-hunting, weather guilt tripping, overly defensive/aggressive, abusive, disrespectful to others)

Message added by Paul

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Call it weather enthusiast intuition, but I don’t think the GFS has a scooby doo!

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12 minutes ago, northwestsnow said:

Is EC going to get that high north enough at 240?

I'll tell you one thing NWS when it does move it can be very quick. Some of our classic spells have seen euro slugs morph into Greeny or Scandi highs in two/three days and at short notice too.

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6 minutes ago, karlos1983 said:

Call it weather enthusiast intuition, but I don’t think the GFS has a scooby doo!

I doubt it'll surprise anyone, if I say that I prefer the FV3's evolution to that of the old version...a twelve-hour-long winter is better than no winter at all?:santa-emoji:

IMO, the models are not alone in their all being pretty clueless just now...?:help:

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12 minutes ago, feb1991blizzard said:

Got a feeling that the ECM 240 might show a bigger split PV at 10mb

It’s much of a muchness - no bigger .... lower down there are some changes as the vortex splits and bends around towards the East Asian vortice ..... less energy pushing into e Europe .... I wonder if the extended eps are going to show a relaxation of the low heights to our ne later on 

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I kind of think although there are multiple model runs every day, It`s probably best to just observe them and not even bother to comment until New Year (me included)

Festive time,  we pretty much know the near future, not worth picking holes. Tricky period for me so see you in a while guys.

Enjoy.

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On balance, I think the last 24 hours output is slightly negative.  ECM T240 leaves a situation that could promote blocking when the SSW does it's stuff, so that's OK, T240:

image.thumb.jpg.1df1746b432a82183aefc3de75da9a83.jpg

ECM strat has reversal at T192 now at 10mb, but re reversal by T240 at 1 mb:

image.thumb.jpg.c1d86a7e6bb797e1f10dfb912758b644.jpgimage.thumb.jpg.da643cfb53ded59630c4e1bd763e5f18.jpg

GEFS also less keen to take the reverse zonal winds negative for very long, as posted earlier.

Starting to think outcome might be very similar to Jan 2013, very cold and snowy week mid month, but that might be about it.  Hope I'm wrong, and it is a more significant cold spell than that, but have to tell it as I see it.

And of course should note that is based on a snapshot of runs over 24 hours and could, and probably will, change tomorrow in a very volatile situation!

 

Edited by Mike Poole

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7 minutes ago, Roger J Smith said:

One example of how a high to the south of the UK can rebuild north to set up a cold spell would be Jan 1-7, 1881, followed by several weeks of epic cold and snow. (check maps on wetterzentrale archives, select 20th century NOAA and input dates). The high eventually got absorbed into a Greenland high and the flow became increasingly northeast over the period. In this low-energy environment, with a southerly flow into Greenland, this seems like a possible outcome and it might be a few days before models catch on to it. 

Indeed Roger. A classic. Mainly because Dorset and the Isle of Wight had level snow a metre deep, that's where it wasnt drifted to 8 metres deep of course. 😀

PS:Worth checking out Mr Murr,s post in strat thread.

Edited by Broadmayne blizzard

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6 minutes ago, feb1991blizzard said:

archivesnh-1881-1-1-0-0.png?archivesnh-1881-1-5-0-0.png?archivesnh-1881-1-6-12-0.png?archivesnh-1881-1-8-12-0.png?archivesnh-1881-1-9-12-0.png?archivesnh-1881-1-10-12-0.png?archivesnh-1881-1-12-0-0.png?archivesnh-1881-1-13-12-0.png?archivesnh-1881-1-14-12-0.png?archives-1881-1-20-12-2.png?archivesnh-1881-1-19-12-0.png?

What an insane set of charts, have to question how accurate that is though how did they get these charts from a time with little technology available at the time? Is it plotted based on weather observations at the time alone?

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1 minute ago, Weathizard said:

What an insane set of charts, have to question how accurate that is though how did they get these charts from a time with little technology available at the time? Is it plotted based on weather observations at the time alone?

No, it will have been based on putting whatever observations that were available at the time through one of the modern weather models to get this, probably GFS or one of it's earlier variants, I think.

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2 minutes ago, Weathizard said:

What an insane set of charts, have to question how accurate that is though how did they get these charts from a time with little technology available at the time? Is it plotted based on weather observations at the time alone?

Not sure, but there will have been reports like Broadmayne blizzard posted, so it might not be 100% accurate but there's no way it will be complete bullshi, 

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9 minutes ago, Weathizard said:

What an insane set of charts, have to question how accurate that is though how did they get these charts from a time with little technology available at the time? Is it plotted based on weather observations at the time alone?

Article I wrote on this 12 years ago on UKWeatherworld. I wrote an article on this on this site same time but the links have been broken

http://www.ukweatherworld.co.uk/forum/index.php?/topic/49788-the-times-the-great-blizzard-of-january-1881/

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24 minutes ago, Weather-history said:

Article I wrote on this 12 years ago on UKWeatherworld. I wrote an article on this on this site same time but the links have been broken

http://www.ukweatherworld.co.uk/forum/index.php?/topic/49788-the-times-the-great-blizzard-of-january-1881/

Thanks WH, Amazing minima across the entire UK.....-30 at Blackadder, wherever that is, but widely -15 to -20....even the northern lights was seen across all of the UK.....just heavenly 👌

Edited by Dancerwithwings

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4 minutes ago, Dancerwithwings said:

Thanks WH, Amazing minima across the entire UK.....-30 at Blackadder, where ever that is, but widely -15 to -20....even the northern lights was seen across all of the UK.....just heavenly 👌

Also worth reading Phillip Eden's superb in-depth case study of this event in his book. Great British weather disasters 

Worth buying the book for that chapter alone.

Edited by Broadmayne blizzard

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Evening ! As some have mused a lot of settled weather over Christmas but how far north can high pressure build after Christmas? Both gfs and ecm show a build of pressure after Christmas , to the north of the uk , Interesting Christmas Eve viewing, well better than watching the TV!!!

creatures.png

creaturesx.png

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44 minutes ago, Weathizard said:

What an insane set of charts, have to question how accurate that is though how did they get these charts from a time with little technology available at the time? Is it plotted based on weather observations at the time alone?

Those re-analysis charts are much more accurate than you might realise - especially for the MSLP, perhaps slightly less so for the 850s. Remember that we had many more ships at sea in those days and they all kept meticulous logs.  We had daily weather reports from many sources (met offices, official observers, local authorities, waterworks etc) and one can check many archive records which are now online back to well before 1871 when the reconstruction period starts. We might have satellites and computers these days but don't assume that observations were any less reliable or plentiful, particularly in the Northern Hemisphere for Europe, the Atlantic (right up to Arctic ice sheet (many ice breakers and fishing trawlers up there) and the eastern US and Canada.

Many of our severe cold spells have started with HP building from the south. Check out Dec 1962, Jan 1947 amongst many others. For those wishing to check earlier re-analysis records, here's the link: 

http://www.meteociel.fr/modeles/archives/archives.php?mode=2&month=12&day=20&year=1962&map=4&type=ncep

You can fiddle around for hours on that site.  I set the link to Dec 20th 1962 - just run through that week to see how rapidly a pattern change can take effect. 

I'm more bullish about this upcoming cold spell than I've been for many years for all the reasons that I given in my last few posts. The changes in the background signals are even more strongly pointing towards this.  The model output will change dramatically once they start to factor in the huge pattern reset that is already underway before we actually see impacts from the SSW. The troposphere is looking really responsive and both the NAO next week and later the AO will turn increasingly -ve.  No more time now,  David 🙂 

EDIT:  Ah @Broadmayne blizzard, my late friend Philip Eden - we teamed up to research frost hollows back in the 1980s and 1990s and I set up and used to run the weather station in the Rickmansworth frost hollow. Philip kept some amazing weather records and wrote a number of superb "easy read" books.

Edited by Guest
correct typos and add comment

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A more promising GFS parallel 100/500 hPa run compared to the GFS current model.

Compare the 2 at T264hrs at 100 hPa and 500 hPa levels-the old GFS first


873629378_old1.thumb.png.29a88def71bb47ac29fbafbf5a41ec54.png1265381244_old2.thumb.png.2534d808f4555af494a6cd0bb6b73270.png



new 2.png2074038079_new2.thumb.png.1b9b73aa92ca4d0026f4cdddf377ce36.png

A better split modeled down through the levels resulting in a more amplified high heading for an easterly later.

Not quite the expected pattern but evidence that GFS modeling has still to pin this down beyond the next 6/7 days as the downwelling progresses.

 

 

 

Edited by phil nw.

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Few of the 12z GEFS suite that look interesting, here T300:

image.thumb.jpg.6c99f14236d7d21a2302299513307d61.jpgimage.thumb.jpg.a4ac0dfc20c3f30651a7209396d89387.jpgimage.thumb.jpg.56ef260c94aa924de9e9f75d5e06ffd6.jpg

No idea if these have got wind of SSW, probably, more an indication of the possibilities on offer on the two week timeframe. 

 

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FV3 strat at end of run still not anywhere near the expected split:

image.thumb.jpg.2f3546552aa9f5013861e2e9608058b1.jpg

Think this one is dunk your hobnobs rather than smell the coffee...

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2 hours ago, Quicksilver1989 said:

Shouldn't people be allowed to post what they like provided they have backing? If not then perhaps the thread should be renamed 'post cold charts and speculate thread'. I presume the majority of people are hunting for cold on here and are simply posting a chart to say what's going on.

I don't believe there is anything wrong with that and many people viewing this thread will be looking to find out what the models are showing as well as looking for signs of cold.

It’s the schadenfreude that accompanies posts from the same old suspects who incidentally, also do their best to be first to post gloating posts indicating mild weather as earlier as possible in the morning 

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