I have a similar but thing bit better set up on my stable table. I have a waxed tarp covering the plastic table top, makes it less slippery. then a bench rest tripod and and owl ear rear bag. To cover those two pieces I found an oblong washtub, not quite the length of the table. Then over that I got a large waterproof fabric grill cover. Everything stays dry. WHen I am ready to shoot, pop the grill cover and set the washtub aside. The grill cover goes almost to the ground and covers most of the table legs, not quite all. Mine is on a back patio no cover so completely exposed to the weather.
64F here today, light rain about 3/4", humid and chilly feeling. Temps are supposed to be about the same for the next week to ten days. I wish we could get some colder weather. Growing up in NE Louisiana 65-70 years ago I remember it getting cold and staying that way, not like the northern states or Canada, but nightly freezes were very regular this time of year, now almost non occuring.