After having lived on Galveston Bay for 30 years and weathering 12 hurricanes, I can tell you this tide phenomena is normal, especially if you are on the dry side of the storm as you are JW. I've been able to walk 1/4 mile out on East Galveston Bay after a storm sucked out the water like that. Found all kinds of weird stuff and lots of lures, and the seagulls had a field day.
The water will come back after the barometric effects of the storm is gone, usually within 6 hours. Hope you guys in 'Bama get thru it without any damage. You'll have excellent fishing the week after the storm has rolled through.