His GFS models are 120 hours (5 days) out, and his NAM models are 84 hours (3.5 days) out.
The GFS actually goes out 16 days (384 hours) so there are a couple other places you can grab model predictions past that.
Here is one site, although it is not put into nice maps like the Earl Barker site:
Bufkit and Cobb Precipitation Type Data Available from NWS Des Moines
If you scroll down on that page you will find two tables. "Cobb Precipitation Type (ver 5.7) Output (NAM)" and one below that for GFS.
For Des Moines click on "KDSM" in the current run column. Again, this will be uglier than what you see on the Earl pages, but it will take you out 180 hours.
"TotSN" column is the one you want to track.
Also, instead of KDSM you can select a few other sites, or click "-1" "-2" etc to look back at previous runs of the GFS model to see how consistent it has been.