Only two official weather-related terms begin with the letter Q: quasi-stationary front and quantitative precipitation forecast. Some less technical words beginning with Q can apply to weather as well; for example, a storm can move quickly, and scientists can measure quantities of rain or snow.
A weather front is the zone separating two masses of air that have different densities or temperatures, such as a cold mass of air and a hot one. A quasi-stationary zone moves around only a tiny bit or stays mostly in the same place.
A quantitative precipitation forecast, often abbreviated to QPF, is a prediction of how much rain or snow will fall within a certain amount of time. The Weather Prediction Center puts out several QPFs every day, predicting how much rain or snow will fall in the next 6 to 24 hours.