What primary information does reconnaissance provide for fire support operations?

Reconnaissance plays a crucial role in informing fire support operations by providing detailed information about enemy positions and the surrounding terrain. This information is vital as it allows commanders to understand where to engage the enemy most effectively while considering factors like range and line of sight. Knowing the enemy's exact location enables fire support units to plan and execute accurate strikes. Additionally, understanding the terrain helps in assessing how obstacles and natural features will affect the trajectory and effectiveness of the fire support.

The other options, while they may play a role in operational planning, do not represent the primary focus of reconnaissance in the context of fire support. Knowledge about artillery unit placement is typically a separate planning consideration that comes after reconnaissance has informed the overall strategy. Weather patterns are important for overall mission planning but do not provide the direct tactical intelligence that reconnaissance offers regarding enemy positions. On the logistical side, knowing support availability does not directly relate to the immediate needs for targeting and engaging enemy forces, which is the primary purpose of reconnaissance in fire support operations.