An Affect is a term that encompasses a broad range of feelings that people can experience. It embodies both emotions and moods.
An Emotion is an intense feeling that is short-term and is typically directed at a source. Emotions can often have indicative facial expressions and body language as well.
A Mood is a state of mind that tends to be less intense than an emotion, and does not necessarily need a contextual stimulus. Moods last longer than emotions, from hours to days.
Emotions have the ability to turn into a mood state when unattended to. If a precipitating event is ignored or lost focus of, the emotion of said event could transform into a new mood state. Also, moods can effect a person’s emotion and emotional intensity of new situations that follow as well. Emotions and moods influence one another.