Pardon if this is well-covered territory:

I've noticed that the RUC2 files (from ftp site 140.90.88.142 in
/ncepe/p211grib/ruc2a.*) go stale at the 23Z 3-hour forecast file for
about 5 or 6 hours and then that directory is completely empty for an hour or
two (when checked at 22:30 and 23:30 Pacific Time). Anyone know why
this happens?

Thanks for any help!