After the middle of November, nearly all of my flounder, especially the larger ones have been caught on small lures.
If you are seeing a lot of flounder striking the surface and “rolling” as I like to call it but cannot get them to hit, switch to tiny shad imitations. I caught around 85 of the 102 flounder I did in the four day Fall Flounder Run last fall using the 2.5-inch Sassy Shad by Mr. Twister on an 1/8 jighead and tipped with shrimp. This is an absolutely killer lure and has been the ticket for me not only when the bite gets weird but in general.
All of the four pound plus fish caught by my Dad and I in the last two years from Nov. 15 through Christmas came on these types of small lures.