I misspoke. Actually it's two gauges: Gunnison River @ Grand Junction and Gunnison River @ Delta. IF the difference between the two is > 800 cfs it is possibly running low to medium. This is a very inexact science since the difference you get can vary by as much as 200 cfs per the time of day you check. We were headed over there today if it was 600+, but it was between 300 and 500. Keep in mind that it's a reasonable distance to GJ from Delta with more than one tributary in that distance. That's why everyone is waiting for someone to post a trip report (notice the number of views vs. replies).
Having said that, it's probably nukin'. Go get some.... and then post a trip report!