Cyclones

Starts with a polar front or a stationary front

Large temperature contrast --> large wind shear

--> unstable for small perturbation

--> produce a wave in upper level and high and low on surface

The structure of a developing cyclone

Warm in east and cold in west --> low tilt toward the west

Upper level PVA and low level warm advection may coincide

--> cyclone development

After occlusion, no east-west temperature contrast

--> no tilting of the low

Cold low --> upper level low over surface low,

low intensifies with height

no steering flow to move the surface low

Warm low --> low weakens with height and may becomes a high

High pressure center

Cold high --> high weakens with height and may becomes a low

Warm high --> high intensifies with height

may create a blocking pattern