Related Clues:

• Far from flustered
• Imperturbable
• Sedated
• Agree out of court
• Not nervous
• Resolve, as a dispute
• It may precede a storm
• Halcyon
• Reach an accord
• Alight
• Pre-storm status
• Storm preceder, it's said
• End a suit
• Storm preceder, supposedly
• Serenity found in 17-, 26-, 42- and 54-Across