Fresh water flooding is likely to be the greatest threat of all out of Dolly.. and this will apply to her sphere of influence all the way around, and not just on any one side.

To her left and inland (likely will be to her southwest at landfall and then south as she progresses inland) are the formidable Sierra Madre Orientals. Dolly could easily wring out 10-30++ inches of rain over large areas in these, considering her slowing forward speed, and ultimately, her expected demise over these very mountains

In the Rio Grande Valley, Dolly is expected to produce widespread 3 to 8 inch rainfall totals, with locally higher amounts of 15 inches or more.. largely dependent on her forward speed, assuming she makes landfall within about 40 miles either side of Brownsville. On Abrams & Bettes tonight (TWC) Mike Bettes was reporting from lines of cars and trucks blocks long.. people waiting in them for up to two and a half hours for their maximum allotment of eight sand bags.

Of course, as with all landfalling tropical cyclones, tornadoes and waterspouts will probably become a risk, and Texas tends to get them good from TCs. SPC has been hinting around that watches will be going up for much of extreme south Texas - along the coast initially, and then progressing inland. (As Random points out, they were in fact issuing Watch #732 as I was typing - It covers deep south Texas and adjacent coastal waters until 10AM Wednesday - A very long duration, but also an ever-slower moving hurricane).

All-in-all, those 80MPH winds are in a really small portion of the cyclone. Considering how small a sliver within the eyewall the HF winds are, Brownsville may never experience them at all. Of course, for whoever does, it's going to feel like an EF1 tornado that just goes on and on and on. Prudent course of action is to not play by un-boarded windows.