warm and humid air masses are usually unstable
unstable_angina is not acute_coronary_syndrome. hot_air is not lighter_than_cool_air. humidity is wet_air. hot_air is not lighter_than_cold_air. humidity is not wetness. humidity is not weather_quantity. white_heat is not hotness. humidity is not wet_air. hot_air is lighter_than_cold_air. humidity is wetness.