First, australia is not really good location to start generalization about local tidal information in florida.
For example, rain trap pattern, snow, somewhat trapped gulf of mexico.
Second, I am offering THEORETICAL possibility without regard to actual magnitude of contribution.
Mississippi...
Since you did not specify accurate dates I assume you did not take sun's tidal affect.
"El niño like effects on sea level? " might have some sort of thermal expansion of water; different current; or winds.
One other thing is moisture in air and where it rains might have some impact. For example...