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.



--
Martin Rowley
West Moors/East Dorset UK