Synchro Cyclone is a synergy ability in Final Fantasy VII Rebirth, used by Tifa Lockhart with Cloud Strife as a synergy partner. It costs three synergy charges each, performs physical damage to a target, and grants them temporarily unlimited MP for a duration.
In the ability's animation, Tifa and Cloud pose together, before both grabbing onto Cloud's broadsword. They then leap toward a foe and swing it up in the air at the target, before both backflipping together.
Obtained[]
Synchro Cyclone is unlocked on Tifa's folio, and costs 5 SP. It is available at party level 1.
Use[]
Synchro Cyclone costs three synergy charges each on first use, and four on subsequent uses, and will grant Cloud and Tifa unlimited MP for a duration. This allows them to freely use spells, limited only by ATB charges and not by their MP, and by the spells they have in their equipped 
Magic Materia. Cloud has a strong 
Magic Attack pool and good MP, but Tifa's magic attack and MP are normally limited.
Synchro Cyclone is Tifa's only synergy ability that grants her unlimited MP, meaning if she wants this effect, she will need to be in a party with Cloud. Cloud can also use Curiosity's End with Cait Sith to achieve the same effect.
The usefulness of this synergy ability will depend on the materia equipped. For example, if Cloud has Healing Materia and 
Magnify Materia (a viable setup given Cloud is often the leader of most parties), he can freely cast 
Curaga on all while MP is unlimited. Though Tifa's magic attack is typically low, there are still spells not dependent on her magic stats that can make use of; for example, she benefits greatly from Time Materia, and can use Synchro Cyclone to cast Stop for free. Tifa and Cloud also both benefit from pairing an elemental magic materia with Elemental Materia for their attacks, and Synchro Cyclone can unlock their ability to use spells from them freely.
Normally, Tifa and Cloud are less likely to be used as offensive spellcasters, making Synchro Cyclone less useful on them than other synergy ability options outside of some defensive use cases. However, if they are built toward weapons boosting their magic stats, such as with Tifa's 
Crystal Gloves or Cloud's 
Rune Blade, they can find more use for it.
In Hard Mode, gaining unlimited MP can be more crucial as means to restore MP are more limited. The player may also have the rare and expensive Reraise spell available, perfect to be cast during any MP-free period.