Final answer:
Based on the sudden drop in temperature, the best weather prediction for Fey to make would be that a cold front is approaching.
Step-by-step explanation:
Based on the given information, Fey measures wind speed every 15 minutes for one hour in her backyard. However, right after she takes her last measurement, she notices a sudden drop in temperature. This sudden drop in temperature could indicate the arrival of a cold front.
A cold front is a boundary between a mass of cold air and a mass of warmer air. As the cold front moves in, it displaces the warmer air and causes a sudden drop in temperature. This is often accompanied by changes in weather conditions such as strong winds, thunderstorms, and precipitation.
Therefore, the best weather prediction for Fey to make based on the sudden drop in temperature is that a cold front is approaching, which may bring changes in wind speed and other weather conditions.