Thank you Philip.
So have they made a forecast of what it will be for February? Since it was
possible to make a forecast for winter, early on, one would presume they can
make one for Febraury - hopefully with greater accuracy.

Dave
"Philip Eden" philipATweatherHYPHENukDOTcom wrote in message
...
Amongst all the discussion of the MO's winter forecast, one very
important point has been missed. Unfortunately, the original
forecast seems no longer to be available, but the updated version,
issued on 22 Dec, says:

QUOTE
The forecast is based on our prediction that the North Atlantic
Oscillation (NAO) will be negative this winter.
UNQUOTE

Note the use of the word "will", and the absence of any
percentage probability. Unlike other parts of the forecast which
are given probabilities, this statement will be able to be judged
come the end of February.

No judgment should, of course, be made at this stage, but
these figures indicate what sort of February may be required for
the statement to verify:

Month.....Iceland/Azores....1961-90 norm......NAO-index
Dec 2005 ...... 18.1 .................17.0 ..................+1.1
Jan 2006 ....... 28.7 ................. 17.4 .................+11.3
required
Feb 2006 ........ 2.2 ................. 14.7 ................. -12.5

I have used mean sea-level pressure at grid-points 65N25W
and 40N 30W to represent Iceland and the Azores, because
these are easily available to me, and I have used 1961-90 as
it is believed that this is probably the standard period used in
developing the method, although I cannot find in the documents
covering methodology (or the forecast itself) on the MO
website any specification of the period. The only quoted
period I have found is 1950-1998 for the hindcast study itself.
In that hindcast study it is said that the NAO index used there
is based on data at the 500mbar level, but it also insists that there is
little difference between that index and the surface NAO index.

Out of interest, the coldest Februarys of the last 130 years
had the following NAO indexes[sic]:
1986 -17.7
1963 -11.2
1956 -12.7
1947 -32.7
1895 -32.2
....so it is possible ....

Philip Eden