Thunderstorm
noun
A thunder rain is a rain that's coming with thunder. For all intents and purposes, if you see this, you'll think thunderstorm.
The reading is the on'yomi readings. For 雨, you haven't seen the on'yomi reading, which is う. To remember this, just think about how in a thunderstorm, it rains uni (sea urchin). You go outside, dodging the thunder, to collect these uni.
今朝の強烈な雷雨で停電になったので、今はインターネットが使えません。
The severe thunderstorm this morning caused a power outage, so I can’t use the internet right now.