On Dec 18, 9:44*pm, John Hall wrote:
In article
,

*Dawlish writes:
On a different note and back to the purpose of this newsgroup, which
it ridicules with every post, the 00z ensembles don't give too much of
a clue to the weather at 10 days, with the ECM being a warm outlier
and the gfs being a colder run - and there is one hell of a spread
after only a few days. It will be interesting to see the 12z
ensembles.

I find this a useful tool for getting a feel of what the latest GFS
ensemble is saying:

http://www.wzkarten3.de/pics/MT8_London_ens.png

(Of course that graph has its limitations. For example in an easterly
the 850mb temp can be quite high when there's cold air at the surface.)

There's reasonable agreement in the 12Z 850mb temperatures up to
Christmas Day (though 2 members turn it much warmer for the 23rd and
24th). After that, the lines spread out, though the consensus is that
850mb temps will return to close to the average for this time of year.
The operational run is a mild outlier from the 27th onwards. Prior to
Christmas Tuesday looks like being the wettest and least cold day, at
least in the SE. (The 12Z ECM ensemble 850mb "mittel" chart suggests the
same thing but extends it into Wednesday.) Looks from the GFS graph like
it could be pretty unsettled from about the 26th-31st, after which it
might settle down (but that's a long way out).
--
John Hall
* * * * * * * *"I look upon it, that he who does not mind his belly,
* * * * * * * * will hardly mind anything else."
* * * * * * * * * * * * * * * * * * * * * *Dr Samuel Johnson (1709-84)

Agreed. They're the gfs ensembles. Past the 28th anything could happen
and it *could* be a very zonal set-up into the new year, with a
European high encroaching into southern England. 70F in an English
winter, for the first time, later in the winter anyone? *))