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Old September 17th 12, 01:52 PM posted to uk.sci.weather
Dartmoor Will Dartmoor Will is offline
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Default UK GloSea4 indications for Winter etc.


"Martin Rowley" wrote in message
...
http://www.metoffice.gov.uk/research...l/gpc-outlooks

Not sure what stage we're in with these ... I assume that the last couple
of iterations at least (issues August & September) have the benefit of the
'high-top', i.e., enhanced stratospheric modelling, and thus the output
indicated is most interesting.

Both August and September issues have fairly strong signals for
below-average temperatures over the 3-month periods NDJ & DJF (where
available from August run): looking at the ensemble mean output, the
indication are for departures from the mean of at least -0.5degC/-1.0degC,
and 'fringing' the SW (i.e., across the SW Approaches & western Ireland)
and also in the broad area Iceland - Faeroes - Viking, the departure is
circa -1.5degC. [Not sure what the climatology period is ... might be
'model' climatology, i.e., based on hindcast runs from 1989 - 2002 rather
than a 'standard' dataset].

The usual caveats apply of course - high probabilities doesn't mean it's
going to happen - but two consecutive runs with a similar (and reasonably
strong) signal, and with the assimilitation of the consistently anomalous
SSTAs that we've seen as commented upon elsewhere, these products are
either going to be wildly wrong and risible, or are in fact offering us a
good steer on the season to come.

Martin.


The output charts to me would suggest Atlantic blocking or even Greenland
blocking with a lot of northerlies. Could be interesting in Copley! :-)

Will
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