Seems like the heaviest part of this rain storm followed the same path as the heavy part of the snow from last week, which of course led to all sorts of issues with flooding, and even an avalanche at a ski area in the Catskills - the ski trails aren't supposed to go THROUGH the lodge .
Would shading it help? Like having one of those cheap blue tarps hung above the tent itself (let that tarp take the UV, since it's far cheaper than most tents).