Strange winter weather looks set to continue

Posted: February 17, 2013 by tchannon in weather

Image

I hope Wetterzentrale will accept a link in return for showing a chart here. Click image for access to the whole series.

500 hPa level for 23rd Feb 2013

Wejkoff bridge as mention by Michele Casati recently in a Talkshop comment here, where this winter these conditions repeatedly threaten, so maybe it is a matter of when.

The UK has been under cool conditions for some time, with a brief warming at the end of the past week, at the weekend it is settling into little wind under high pressure.

We seem to have solid blocking conditions keeping an Atlantic flow at bay, bouncing off to the south and north.

The longer conventional forecasts are showing a sustained separation through almost to March but that is too far ahead given these kinds of condition are notoriously difficult to model.

Winds are from the east, cold winds, moderated a little by the North Sea.

Out a moderate way ahead Nautica show the separation of pressure quite clearly http://www.eurometeo.com/english/chart/id_mslp4029, explore the dates (controls to the left).

netweather agree out to 27th Feb, you’ll have to select content
http://www.netweather.tv/index.cgi?action=nwdc;sess=

GFS model is showing snow over Germany, Scandinavia far out and suggests some scattered snow east coast of UK, typical of winter blocking, although this is getting late in the season for really cold.

metview produced by a New Zealander gives a useful overview of how things are forecast to develop
http://www.metvuw.com/forecast/forecast.php?type=rain&region=uk

Foregoing is my personal view, paraphrasing Murray Walker ‘… anything can go wrong. And probably will.”

Having endured a lousy last year, water wings and no light, now we get chilly. We want some sunshine and warm, but that will just feed the hotheads.

Post by Tim Channon

Comments
  1. tallbloke says:

    It’s just winter weather, about as predictable as it ever was. :)

  2. oldbrew says:

    Netweather also do a good jetstream animation for about 12 days ahead.

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

  3. Stephen Richards says:

    Joe Bastardi forecast this spell at the beginning of autumn last year.

    “last two weeks of feb will be very cold”

  4. tchannon says:

    You might find this historic generalisation illuminating

    “Singularities developed for the British Isles”

    “1. CEP Brooks
    2. HH Lamb
    3. Alexander Buchan
    4. Barry and Perry (after Lamb as above)”

    http://weatherfaqs.org.uk/node/179

  5. Craig M says:

    Going on 1882/3 which has been a fair guide:

    cold March possibly top ten past 100yrs, drought conditions* in spring affecting crops and a heatwave focused on S/SE in July temps high 90s (clear not cloudy as we saw last year). This could well be the late Elizabethan Dry Phase (like the late Victorian one). Warmists will no doubt jump on any drought but it tends to follow these wet phases in meridional periods.

    I’d rate my forecast better the MetO l/t as it applies common sense – like knowing the drought early last year, especially the dry warm period late March, is inevitably followed by deluge and it was. Life taught me that one and I later found there was some support for it (Philip Eden).

    Philip Eden noted Jan was dull, probably why no real deep cold like in Dec. Been nice to see the Sun and sky this past week

    Speaking of cloud I missed DA2012 (plus transit and various eclipses). Any good databases for cloud cover?

  6. Craig M says:

    *If I get it right will Sligo employ me? ;-)

  7. tchannon says:

    Hubert Lamb, founder and first director of CRU

    http://www.cru.uea.ac.uk/cru/people/lamb/

    Some data on Lamb Weather Types at CRU

    http://www.cru.uea.ac.uk/cru/data/lwt/

  8. tchannon says:

    Update on the Lamb weather, this looks a nice web page explaining what is going on, matches the above data.

    http://www.weathertypes.info/

  9. Stephen Wilde says:

    Is anyone still in doubt that we see more of this when the sun is quiet ?

    Or that it is a global phenomenon centred on both poles ?

    Or that the shift in synoptics represents a change in the global temperature trend ?

  10. Ulric Lyons says:

    Craig M says:

    “Going on 1882/3 which has been a fair guide:”

    It misses the cold shot in Feb 2012 completely. Simple analogues, even if they are based on beats of the Hale cycle and lunar periods will inevitably miss such events.

  11. oldbrew says:

    @ Craig M

    Cloud cover data: ‘These maps show what fraction of an area was cloudy on average each month’ – it says on the website (small download).

    http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MODAL2_M_CLD_FR

  12. Craig M says:

    Ulric – agreed I know it often misses but only using as a rough guide then looking at other factors i.e. Qbo etc. I originally started on that period for non hale reasons but noticed similarities and transit of venus. Missed Late May warmth too. Main thrust for me is similarity of prcp which has not been a bad guide but mostly common sense – predated EWP records mind so only broad based. A long work in progress ;-)

    Oldbrew – thanks! More fun to play with!
    :-)

  13. Ulric Lyons says:

    Craig – that is an odd Venus transit interval (Dec 6 1882 to Jun 6 2012). It has a 6 month offset.

  14. tchannon says:

    Forecast is now showing blocking continuing into March, frost night after night.

    Continental Europe is shown as having things much worse, Spain too frost after frost. Snow in many areas.

    Lets hope the weather models are wrong. It’s not nice.

  15. tchannon says:

    A glimmer of better, weather might break 5th March but if the weather GCM are right this far out they are doing very well indeed.

  16. Ulaaa.laaaa…. :smile:

  17. Ulric Lyons says:

    My solar based forecast gave a stronger cold period from 4th to 23rd March, it is arriving some ~5 days later than forecast.

  18. tallbloke says:

    We’ve had freezing mists here in Yorks for the last three days. Good call Ulric!