Here are a few ways to rewrite the title, emphasizing different aspects:

Focusing on the Urgency and Live Broadcast:

• On-Air Tornado Warning: Wisconsin Meteorologist Alerts Mom Live
• Live TV Alert: Wisconsin Meteorologist Warns Mom of Impending Tornado
• Urgent Warning Live: Wisconsin Meteorologist Alerts Mother to Approaching Tornado

Focusing on the Specific Relationship:

• Wisconsin Meteorologist Issues Tornado Warning to His Mom on Live TV
• Family First: Meteorologist Warns His Mother About Tornado During Broadcast in Wisconsin

More Concise Options:

• Wisconsin Meteorologist Warns Mom of Tornado Live
• Meteorologist Alerts Mother to Tornado During Wisconsin Broadcast

The best option depends on the desired tone and the context of where the title will be used.