"Will Hand" wrote in message news:...

"Will Hand" wrote in message news:...

"Jon O'Rourke" wrote in message
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"Will Hand" wrote in message
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GFS DT12Z 4/12/09

Shows battle lines drawn by as early as next Saturday. As suggested by
the ensembles earlier this week
a deep Atlantic low throws up a ridge over Britain on Thursday and then
this merges with the Russian high containing extremely deep cold air
and the density easterly current surges westwards as I expected
yesterday.
Britain could be in a very wintry setup as early as next weekend. As
this is backed up by previous ensemble runs and consistent dynamics I'm
getting more confident. Expect a few more flip-flops of course and the
cold may yet stay just to the east of us but we will be entering a
different weather regime after less than a week from now.



Looks that way, Will. By next Friday EC's 12Z operational run has
developed a strong upper block over western Europe. Even if there's not
cold air in depth by then the low level flow into the UK could be quite
chilly. Will be interesting to see how this fits with the midday
ensemble data.

Jon.

12Z ensembles are rocking and rolling Jon. Party on!


No real change today. As Darren says a change in the weather later next
week is practically certain. What interests me is the consistent and
strong development of a northern block, predicted by some models last
month. This is feeding sub 492 DAM air into Russia which will filter west
as a density current and could take many by surprise. Even next weekend we
are looking at below normal temperatures in the UK with night frost.
Ensembles still suggest that a cold or even very cold spell is on the
cards. Even at T+240 the Spaghetti plots are more confident than normal
showing an upper high over Britain with a very cold trough over Russia.
The ensemble mean is now beginning to show a developing low pressure
region over Poland which will strengthen more any very cold easterly. Next
week is going to be most interesting watching how this is all going to pan
out.

Will
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DT 12Z ECM 5th is showing an omega block developing centred over Britain
extending into the Arctic next Sunday/Monday with bitterly cold air (sub 492
DAM) to the east. That model is consistent with 12Z GFS ensembles and with
itself in a time-lagged sense. Weather regime change is on the way!

Will
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