The term "Full Sabrina" predates the telly by a few hundred years.
Sabrina is the latin spelling of the English Severn. The river Severn is geographically laid out in such a manner that it gets tremendous tidal bores. With moon, sun and tides just right, one can surf the bore UP the river for quite a ways. Needless to say, tis a bit rough on small boats, floathouses etc.
"Full Sabrina" is when the assorted variables come together to make an unusually strong bore......and fill the river with wrong way water.
Quiz at eight.