Weather forecast for specific time/day

I couldn't find this question anywhere so I thought I'd ask here.

I'm using as my weather provider, and in their own widget they have a M-F forecast, that I would like to reproduce. I can't figure out however, how to get forecast data for a specific time (say "this week Sunday", or "today between 12-18") and not just an off-set of current time which changes. I need something that's static until the beginning of the following week and then updates. Is that even possible to do with KWGT?

Thanks in advance for any advice!