In article ,
TT writes:
there seems to rumors that these are compiled from ouput that is 24hrs old?


They are released around noon, which suggests that they will be using
output from the ECM and UKMO 00Z runs, which would become available
sometime around 7am. For the GFS, the 06Z run doesn't complete until
about 10:30, which suggests that there might be time for a quick look at
that. Remember that they'll be looking at the ensembles as well as the
operational runs. (Is there a UKMO ensemble, which we don't get to see,
or just the operational run?)

They may give less weight to the GFS than to the other two models, since
the UKMO isn't a stakeholder in it.


UK Outlook for Monday 1 Feb 2010 to Wednesday 10 Feb 2010:
Cold with overnight frost and ice throughout, but a good deal of dry
and bright weather for many parts of the UK by day. However, wintry
showers are likely for exposed northeastern parts throughout the
period, with a risk of more persistent sleet or snow for some eastern
areas at times on Monday. Rain, maybe hill snow, might reach the
northwest on Tuesday. Wintry showers may spread further inland towards
the end of the week as winds become more northeasterly. The mainly dry
weather with frost, ice and possibly fog, is likely to continue for
much of the rest of the period, with temperatures mostly below normal.
However, wintry showers or more persistent snow could affect eastern
and southern areas towards the end of the period.

Updated: 1141 on Wed 27 Jan 2010

That doesn't seem unreasonable to me, based on the 00Z/06Z runs (or even
going by the subsequent 12Z runs come to that, which haven't greatly
changed things).
--
John Hall
"Acting is merely the art of keeping a large group of people
from coughing."
Sir Ralph Richardson (1902-83)