Possible Clues:

• Weather event where you'd hear the starts of 20-, 33- and 41-Across
• Modern truths about violent weather
• Brontophobe's torment
• Hard time coming back down south to Reading and Maidenhead in a cloudburst
• Bit of bad weather
• Disturbance in elements of various modern truths
• In which Thor must rend ground?
• Cumulonimbus weather
• Loud ruckus outside makes half of them go below to the store, briefly, with military leader
• Modern truths about violent weather event