[aerohead]

Major flares are no predictor of magnetic storms, as no one can say how impinging fields will be oriented.
While a solar 'day' is 26-Earth days long, the Sun's surface rotates with a variable-periodicity of 23-32-Earth days in length. A nine-day variability, depending on solar latitude.
Aurorae, produced by magnetic 'storms' occur from 42-to- 192 miles 'above' Earth's atmosphere.
Any solar surface, or solar atmospheric temperature of 1-million degrees Kelvin or above produces X-rays.
X-rays are completely filtered by Earth's atmosphere. They pose no threat.