There's not much you can do. Anyone you call or speak to at a physical location will not have much more information than you already have access to via your tracking number. The only thing they might be able to do is clarify the shipping process and logistics chain (i.e. "if it was last in Memphis, it still needs to fly to RDU, be transferred to the regional sort facility, transferred to the local express facility, loaded onto a delivery truck and then delivered to you). This can give you an idea of when you might be able to expect it, but they can't really speed it up and intercepting it is borderline impossible (don't try via the website if the shipment is already in progress as it will only delay the shipping further).
FWIW, if you live anywhere near an airport with a FedEx freight hub (like RDU), they usually have a ship center on-site. If you want to minimize delayed shipping risk, have it shipped to the airport hub. It eliminates several transfer steps (airport > regional sort facility > local warehouse > delivery by truck - all of which are potential delay points) since it basically gets pulled directly from the plane. I'm within walking distance to our airport hub and I can almost always get my FedEx overnight packages by 9am the following day, even when they're "experiencing delays." As long as the plane makes it in, you'll get it.
If it's just an extra day, there's a chance your shrimp might make it (though hopefully the package isn't in too hot a spot). Fingers crossed.
