Structure and Composition
High and Low Pressure (Thanks ID for sharing this link!)
Air Masses and Fronts
La Nina/El Nino & Air Masses and Fronts by EIU– I really like how this site has pictures of weather maps alongside pictures explaining how different air masses form each kind of front. Scroll down to see this.
Why does wind get deflected RIGHT in the Northern hemisphere and storms spin COUNTER-CLOCKWISE in the Northern hemisphere? This video explains why.