How to read NOAA NWS hourly chart

I failed to find a key or directions on the weather.gov site but I'm struggling to understand exactly what the accumulation numbers mean in the hourly forecast chart. I've noted the numbers with a sloppy red marker. Do they mean that amount of accumulation per hour, or for the width of the band containing the number? Or something else? Any help is much appreciated. Thanks!

https://preview.redd.it/w3t7krn6gn4g1.png?width=787&format=png&auto=webp&s=81382268ffe3ec69f5c23320d84bb1c23305ee1f