日雷
Meanings
1
thunder on a clear day; thunder from a blue sky
Refers to thunder occurring when the sky is otherwise clear, often considered an unusual or ominous phenomenon. Typically written as 日雷.
Today, even though it's sunny, there was thunder from a clear sky.
2
lightning that starts a fire; fire-causing lightning
Lightning strike that ignites a fire. Often written as 火雷 or 火神鳴り. Related to 水雷 (みずがみなり, lightning accompanied by heavy rain).
See also: 水雷 (みずがみなり)
Fire-causing lightning struck and started a forest fire.