What weather service provides information about actual weather and thunderstorm activity along a proposed flight route?

The choice regarding Flight Watch is supported by its specific role in providing real-time weather information, including updates on conditions and any thunderstorm activity along a proposed flight route. Flight Watch is designed to assist pilots during flight by disseminating essential weather data, allowing for informed decisions to be made en route. This service provides timely updates which are crucial for ensuring flight safety and operations, especially in the dynamic context of changing weather patterns.

In contrast, Flight Service Stations primarily relate to pre-flight planning and filing flight plans, rather than supplying in-flight weather updates. Air Traffic Control focuses more on managing traffic in controlled airspace and ensuring safe separation between aircraft, without providing detailed weather information. The National Weather Service, while responsible for forecasting and reporting larger-scale weather phenomena, does not typically provide the kind of immediate, flight-specific weather observations that Flight Watch does. Thus, when considering the need for timely and relevant weather information during flight, Flight Watch is the most appropriate service.