Hi grdn,
You are a wise and conscientious dahlia tender to be bracing for the storm. If we are going to have wind and wet, what I consider the biggest enemies to the dahlia aside from frost, I always cut what flowers I can't bear to lose that are close to fully open. Saves those blooms and lightens the weight on the plant branches for better wind resistance.

I make sure stakes are in very firmly, add taller ones immediately adjacent to existing stakes if needed, and cinch up all ties and add more if needed fairly high on the plant. Not so tight to strangle them or bend stalks/stems, but snugged up so they aren't susceptible to breakage by lashing winds and rains. This is where the inexpensive 1/2" plastic tape ties come in real handy.

Thankfully, we don't have such weather very often at all, but when it's expected, I'm out there tying like mad. Good luck and please let us know how you fare. I'll cross my fingers that Bill goes far out to sea to miss the entire east coast of North America.

Thanks!
I have been staking like mad and putting potted plants in the shed. Again, a shame to have to cut the blooms, but it sounds like good advice to remove them.
Thanks again and keep your fingers crossed for us!
G