STORM2K

I hope I got this right.

Numbering
1-40=Full grown storm
50-59=Storms that form in unusual areas, like South Atlantic Ocean
80-89=Test Run by NRL
90-99=Potential storms

Lettering
A=Arabian Sea
B=Bay of Bengal
C=Central Pacific
E=East Pacific
F=South Pacific
L=Atlantic
R=Southwest Indian Ocean
S=Australian Region
W=West Pacific

Feel free to add and correct me.

F and R are official designations by the RSMCs of the two areas (like how L, E and C are official designations by NHC/CPHC). The NRL/JTWC uses S for all storms west of 125°E and P for east of 125°E in the southern hemisphere. This splits Australia in the Gulf of Carpentaria.

The NRL letters are A, B, C, E, L, P, (Q), S, W, with Q being used at least once for a South Atlantic system.

F and R are not used by NRL.