Related Clues:

• Weather-page stats
• Helps enough to keep going, with ''over''
• Sea movements
• Sea motion
• Phenomenon measured by a marigraph
• It's high part of the time
• Geophysics topic
• Subject of some tables
• They rise and fall periodically
• ''High'' or ''low'' water
• Sand castle's undoing
• It can get high every day
• Sailors' concerns
• They have highs and lows
• It gets turned in a comeback