Seed the clouds with radio reflective particles the size of dust motes, the water in the clouds condenses around them to make rain, so the whole cloud system can be steered by pulses of RF beams. Spin them round to make them stronger and steer them to wherever you want. It take a lot of infrastructure to do this, expensive infrastructure.
Making cyclones is a proven science.
Seed the clouds with radio reflective particles the size of dust motes, the water in the clouds condenses around them to make rain, so the whole cloud system can be steered by pulses of RF beams. Spin them round to make them stronger and steer them to wherever you want. It take a lot of infrastructure to do this, expensive infrastructure.