With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: The Challenge aired on television.
text_B: The Quantitative Precipitation Forecast -LRB- abbreviated QPF -RRB- is the expected amount of melted precipitation accumulated over a specified time period over a specified area .. precipitation. precipitation ( meteorology ). A QPF will be created when precipitation amounts reaching a minimum threshold are expected during the forecast 's valid period .. precipitation. precipitation ( meteorology ). Valid periods of precipitation forecasts are normally synoptic hours such as 0000 , 0600 , 1200 and 1800 GMT .. precipitation. precipitation ( meteorology ). GMT. GMT. Terrain is considered in QPFs by use of topography or based upon climatological precipitation patterns from observations with fine detail .. precipitation. precipitation ( meteorology ). Starting in the mid-to-late 1990s , QPFs were used within hydrologic forecast models to simulate impact to rivers throughout the United States .. Forecast models show significant sensitivity to humidity levels within the planetary boundary layer , or in the lowest levels of the atmosphere , which decreases with height .. Forecast models. Numerical weather prediction. planetary boundary layer. planetary boundary layer. QPF can be generated on a quantitative , forecasting amounts , or a qualitative , forecasting the probability of a specific amount , basis .. Radar imagery forecasting techniques show higher skill than model forecasts within 6 to 7 hours of the time of the radar image .. The forecasts can be verified through use of rain gauge measurements , weather radar estimates , or a combination of both .. rain gauge. rain gauge. weather radar. weather radar. Various skill scores can be determined to measure the value of the rainfall forecast .
not_related.