It's over 4 weeks old according to the meterological definition (which, as this is a weather site, is the one most of us will be using).
Interesting to see the 6z GFS has a go at inflating a Scandinavian High at the end of the run. Oddly the 6z on Christmas Day did the same thing at the same time range, but it soon vanished in the 12z output. Wonder if this one will do the same...
Originally Posted by: Retron