I am have a hard time getting a sand storm in the Dalmasca Westersand in order to beat the hunt there. Does anyone know how to get a sand storm?

The hunt is " for whom the wyrm tolls".
Thanks Karen

I hope this helps!

This again is from the walkthrough by Berserker (on a different gaming site)

07 - For Whom the Wyrm Tolls
Rank: III
Mark: Ring Wyrm
Requirements: Meet the Garif-chief in Jahara.
Petitioner: Balzac (Rabanastre)
Mark Location: Dalmasca Westersand/Windtrace Dunes (During a sandstorm)
Bounty: 200 gil, Moon Ring, Icebrand

Go to the Lowtown area of Rabanastre. Facing away from the north item merchant, Balzac is in the southwest big area. This is the same guy that you talked to when you first brought Basch back to Rabanastre. The Ring Wyrm will only show up in the south portion of the Windtrace Dunes during a sandstorm. If the skies are dark in the Westerland then there will be a sandstorm when the Windtrace Dunes is entered. If there is not a sandstorm there then you need to enter and exit from the Zertinan Caverns entrance of the Shimmering Horizones until the sky is full of dark clouds. This zoning should also work from Rabanastre, the Westersand, and Giza Plains, but it seems to work better with the Zertinan Caverns for me.

Lv. 32 Ring Wyrm
HP: 128648
Weak: Fire
Absorb: Water
Exp: 0
Steal: Phoenix Down, Hi-Potion, Water Magicite
LP: 16
Recommended Level: 29 - 3
Recommended Gambits:
Ally: any (>) Raise
Ally: HP < 50% (>) Curaga
Self (>) Protect
Foe: party leader's target (>) Attack

Equip all three party members with some Jackboots to avoid the Ring Wyrm's Immobilizaga. He will constantly perform this move nearly every other turn. Set up a gambit for Esuna if you don't have enough Jackboots for everyone. At the start of the battle begin casting Blind on the Ring Wyrm as much as you can until he is blinded - it will take a few castings but it will affect him eventually. The Ring Wyrm will mainly try to hit your party physically and use his Breath command to breathe fire on the whole party. His Breath will randomly inflict Sap so cast Regen or let an Esuna gambit handle it. Have some Curaga gambits setup and manually cast Cura when all party members start to get low in life. It's good to have Shielded Armors for this fight and if you still have Larsa then he will help out a bunch in the curing department as usual.

The Ring Wyrm's extreme amount of HP will make the battle last quite long and he will even use Restore to give himself another HP boost. He will only use Restore once. He's weak against fire, so you can cast Fire spells or summon Belias. Belias will constantly use Painflare for about 2000 HP damage and Ring Wyrm's Breath will actually heal Belias! I would recommend saving most of your MP for healing, but two Belias summons would definitely help out in this battle. Equip Wyrmfire Shot with your guns or Flametounge and to take off some extra elemental damage from the Ring Wrym. Haste can also speed up the battle a bit. Cast Haste on Belias to help him out a bit!

Another tip that I have heard is that you can equip a long-range weapon to a character while you have that one character in your party (no one else) and run around one of the big cacti while shooting at the Ring Wyrm. Equip some Jackboots to stop his Immobilizing and he will not be able to catch up with you for any serious attacks, except for maybe his fire attack.