The NCEP Climate Forecast System version 2 (CFSv2) became operational in March 2011. In raw form, it is run as a 4-member ensemble 4 times per day. Typically, this is turned into a time-lagged 16-member ensemble, i.e. today’s 00Z initialisations are combined with the 06, 12, and 18Z initialisations from yesterday.
Following the style used in the S2S database, the subseasonal stratosphere forecasts shown here run out to 44 days. The 4-weekly 500 hPa anomalies use a 16-member ensemble (1 day, 4 runs of 4 members), while the 6-monthly 700 hPa anomalies use a 40-member ensemble (10 days of 4 members).