Weather patterns are determined by the movement and interaction of air masses and pressure systems. Air masses develop over land or water and bring characteristic properties. Low pressure systems see the collision of differing air masses which can lead to stormy conditions as warmer air is forced aloft. Specific severe weather events like thunderstorms and tornadoes occur from atmospheric conditions like wind shear and differences in pressure that allow warm moist air to rapidly rise.

1. Weather Patterns

6. Pressure Systems