Do Steel Wind Strike's attacks have advantage or disadvantage against distant prone targets?

Question

Any attack against a prone target either has advantage if within 5 feet or disadvantage otherwise. Suppose I cast steel wind strike (XGtE, p. 166) and one of the targets is prone and not within 5 feet of my current position. An ordinary attack against this target from my current position would have disadvantage. Steel wind strike says:

You [...] vanish to strike like the wind. Choose up to five creatures you can see within range. Make a melee spell attack against each target. [...]

You can then teleport to an unoccupied space you can see within 5 feet of one of the targets you hit or missed.

Clearly, the "flavor" of this spell is that you are rapidly teleporting next to each target and attacking them (confirmed by Jeremy Crawford in this tweet). However, there is no explicit mention of movement or teleportation until after all the attacks are finished, though it is arguably implied by the phrase "vanish to strike like the wind".

Mechanically, when I make my attacks with steel wind strike, am I considered to be within 5 feet of each target, giving me advantage on the attack against a prone target? Or do I have disadvantage since the prone target is more than 5 ft from where I cast the spell?

Answer 1

No, you are not within 5ft and so do not have advantage

The spell states you 'vanish' (whatever that means mechanically), make the attacks, and then after all the attacks are done you can teleport to various spaces. Nothing says you teleport to each target to make the attack. Likewise, you would have disadvantage to hit prone targets.

I agree the flavor of the spell is that you are moving so fast you can run up and hit all the targets, but that is not what the spell says it does. This is similar to how you don't actually use the weapon you are holding to make the attacks. Additionally, don't let the fact that you are making melee spell attacks throw you. You can make the 'melee' attack because the spell says you can, regardless of distance, and even a regular melee attack wouldn't necessarily have advantage vs a prone target (if you were using a reach weapon for instance).

Answer 2

Straight roll.

You would have neither advantage nor disadvantage on all of the attacks.

First, we understand that there is no flavor text in spell descriptions.

That said, the following sentence is rules, not flavor:

You flourish the weapon used in the casting and then vanish to strike like the wind.

You vanish. If you vanish, you are unseen. If you are unseen, then:

When a creature can't see you, you have advantage on attack rolls against it.

You are an unseen attacker for each attack of steel wind strike, so they would be made with advantage.

Now, since the targets are prone, and we are making an attack against them from more than five feet away, this gives us disadvantage. The advantage and disadvantage cancel out to a straight roll.