QUALITATIVE ANALYSIS — (Data Analysis) The examination or analysis of a phenomenon to determine its qualitative characteristics versus its quantitative characteristics, i.e., characteristics for which precise numerical identification are not appropriate.

QUANTITATIVE ANALYSIS — (Data Analysis) The examination of phenomena using actual observed data with an intention to explain historical behavior and/or predict the future behavior of some phenomenon.

QUANTITATIVE PRECIPITATION FORECAST (QPF) — A forecast of the amount of precipitation which will fall during a specific time period. These precipitation amount forecast values can then be used as inputs to hydrologic models for river forecasting purposes.

QUENCH — (1) To slake one's thirst. (2) To cool (hot metal) by thrusting into water or other liquid.

QUENCH TANK — A water-filled tank used to cool incinerator residues or hot materials during industrial processing.

QUICKSAND — Sand that is unstable due to the upward pressure of water.