Unless you're running a Ice-based team, Hail and Blizzard aren't really fit moves. Even then you could just use Abomasnow (he is a must in every hail team) and retain an extra move.
First off, I will assume that you know about EVs, IVs, and all that in competitive play. Here's a moveset I constructed off the top of my head, but it probably's from Smogon or something:
Jynx:
Item: Focus Sash
EVS: 6 HP 252 Special Attack 252 Speed
Ability: Either but Forewarn is generally more useful
Moves:
Ice Beam
Psychic
Lovely Kiss
Focus Blast
Lovely Kiss is a sleep inducing move, other moves are STAB and Focus Blast provides type coverage. Now, there are various other options such as Calm Mind+Substitute+Leftovers, but in my opinion, this is a good set because it guarantees sleep unless stealth rock, spikes, etc. are in play. So it would be a good idea to have a rapid spinner on your team.