Obvious reason would be that hurricanes are large. Like 100km large. Force exerted by blast follows inverse-square law and it's quite negligible in 30km for the

Obvious reason would be that hurricanes are large. Like 100km large. Force exerted by blast follows inverse-square law and it's quite negligible in 30km for thermonuclear bombs. 30km diameter disruption of wind affects only 9% of 100km diameter cyclone. It's quite unlikely that it would disrupt cyclone, but someone with better fluid mechanics knowledge can probably do such calculation.