Question

If at a given instant the magnetic field for one section of the wave points south, in which direction does the electric field for that section point at that instant?

Answer 1

The electric and magnetic fields of a traveling electromagnetic wave
are always perpendicular.

If the magnetic field points south, then the electric field at the same
place can point east, west, or any direction along a radius of a vertical
circle at that place.

In order to narrow it down further, we'd need to know which direction
the wave is traveling.