Because the digging trough is what will eventually turn Wilma to the NE, it will not be able to escape the SW shear ahead of the trough. In October, it is common for intense hurricanes in the western Caribbean to weaken ahead of troughs as they turn northeast in the GOM. Granted, this weakening may not be drastic, but it should keep landfall intensity at Cat 2--and less likely a low-end 3--regardless of how intense Wilma becomes in the Caribbean. This is what happened in the October 1921 hurricane that struck Tampa: http://weather.unisys.com/hurricane/atlantic/1921/6/track.gif. Looks like this system will come in farther south because of its current slow movement.