The correct option is Faster than the warm front..
Explanation
Extra-tropical cyclones (also known as temperate or wave cyclones) are low-pressure systems that form in the mid-latitudes at the boundary between warm and cold air masses. Their structure typically includes a warm front and a cold front rotating around a central low.
Dynamics of Frontal Movement:
- Cold Front: This is the leading edge of a cold air mass displacing a warmer air mass. Cold air is dense and heavy; it advances by wedging itself aggressively under the lighter warm air. This dynamic allows the cold front to move rapidly across the surface.
- Warm Front: This is the leading edge of a warm air mass replacing a cold air mass. Since warm air is less dense, it cannot easily push the heavy cold air aside. Instead, it slides gradually over the cold air in a process known as overrunning. Consequently, warm fronts move more slowly due to the resistance of the cold air and surface friction.
- Result (Occlusion): Because the cold front travels faster than the warm front, it eventually catches up to and overtakes the warm front. This process lifts the warm air sector off the ground, forming an occluded front, which marks the mature and dissipating stages of the cyclone.
Key Takeaway: In the life cycle of an extra-tropical cyclone, the cold front moves faster than the warm front, eventually leading to the formation of an occluded front.