From the NHC 5 pm advisory discussion, large Cat 3 Helene's east-loaded surge may pose the greatest threat to life and property:

Warm sea surface temperatures, decreasing shear, and strong upper-level divergence are likely to foster Helene's strengthening
while it moves across the northwestern Caribbean Sea and eastern Gulf of Mexico. The statistical-dynamical SHIPS/LGEM models, as
well as the regional hurricane models, continue to show Helene reaching major hurricane intensity while over the eastern Gulf of
Mexico, and that continues to be shown in the NHC forecast. Helene could maintain that level of intensity until it reaches the Gulf
coast of Florida.

Of equal importance to the forecast intensity is Helene's forecast size. Helene's forecast radii are at the 90th percentile of major hurricane size at similar latitudes, and therefore storm surge, wind, and rainfall impacts will likely extend well away from the center and outside the forecast cone, particularly on the east side. In addition, the fast forward speed while it crosses the coast will likely result in farther inland penetration of strong
winds over parts of the southeastern United States after landfall.

In many decades of following tropical weather surrounding the Florida peninsula, I don't recall ever seeing a storm surge warning for this much length for the west coast of the state.