For Severe Wx, find the NOAA frequency for your area and program it in. Have you checked your scanner for Wx operation being built in? A lot of newer scanners have a preprogrammed Wx search, and some even give you the ability to program in SAME/FIPS codes, so you only get the alerts for your area.
As for programming your 10 banks, I usually group stuff together into each bank. I will put all "emergency" related (police, fire, EMS) into one bank. Then some mil-air into another bank. Then some HAM freqs. into another... etc. What scanner do you have? It would be more helpful to know what you have and what your interests are.
Roger