On Dec 24, 8:13*am, Dawlish wrote:
On Dec 23, 7:47*pm, John Hall wrote:
In article
,
*Dawlish writes:
On Dec 23, 6:44 pm, John Hall wrote:
In article
,
Scott W writes:
On 23 Dec, 07:51, Nick wrote:
There seems to be some suggestion (from Darren's latest model
interpretation) that the cold spell around Wednesday/Thursday next
week will only be temporary, with predictable January zonality setting
in after that. What are people's feelings on this? Are we now looking
at yet another of these winters which start promising, only to descend
into mildness once Christmas is over?
Oh well, at least the nights will be drawing out by then.
Nick
I was under the impression that the next cold plunge the first week of
January will be the real deal - and make this last cold spell look
like a tea party...
Judging by the GFS 12Z ensemble, it looks like it will be comparable in
intensity to this one.
Judging by the 12z ECM, it may well not happen!
snip interesting analysis
Yes. The 12Z ECM run wasn't available when I made my comment. The ECM
operational run puts the High much further south on the 31st than does
the GFS, giving a milder NWerly. However by the last day of the
operational run, on the 2nd, the high has shifted north to Greenland,
and things are looking "better" if you like cold.
The mean pressure chart for the ensemble looks better for the 31st than
the operational run, showing a Northerly, but after that everything
quickly starts to look very "flabby" and ill-defined, presumably a sign
that from the 1st onwards the ensemble members are coming up with a wide
range of solutions.
The 12Z UKMO run doesn't go out far enough to help too much, but out to
the 29th it keeps pressure high over Greenland and by then low pressure
looks to be sinking south again, with the possibility of a NEerly being
introduced by the end of the month.
I think the odds favour the re-establishment of cold conditions -
probably via a Northerly - just before or around the New Year, but it's
far from certain, and it's even more uncertain how long it will last.
But as we're looking 9-16 days out, that's unsurprising.
--
John Hall *"[It was] so steep that at intervals the street broke into steps,
* * * * * * like a person breaking into giggles or hiccups, and then resumed
* * * * * * its sober climb, until it had another fit of steps."
* * * * * * * * * * * * * * * * * * * Ursula K Le Guin "The Beginning Place"- Hide quoted text -
- Show quoted text -
There's your northerly on both models this morning John!- Hide quoted text -
- Show quoted text -
gfs 00z ens show the big change in this winter (so far) compared to
many recently; the milder interludes are short and the colder weather
is dominating. Today's charts show that colder is certainly more
likely at 10 days than warmer. It still doesn't quite fit my 10-day
75% chance of occurrence, forecasting criteria, though again it is
close..
http://www.jp2webdesign.co.uk/two/ensembles/