Here's instructions for changing the config in-game. I'm assuming you have OP for your server or it's singleplayer:
- Hit Esc.
- Click on "Weather2 Config (unpauses game)" (top of screen).
- Click "Advanced" (bottom right).
- Use the arrows (top right) to go to the "Config for: weather2Misc" (says this top left).
- Scroll down to midway in the config.
- Continue down until you find "Storm_OddsTo1OfLandBasedStorm". This is likely set to 0.
- Change it to the same as Storm_OddsTo1OfOceanBasedStorm (mine was 300).
- Click "Save" (bottom).