Norwegian cyclone model

In this theory, cyclones develop as they move up and along a frontal boundary, eventually occluding and reaching a barotropically cold environment.

Polar front theory is attributed to Jacob Bjerknes, derived from a coastal network of observation sites in Norway during World War I.

Precipitation will begin to form ahead of the surface low, within the cold sector of the cyclone poleward of the warm front.

The frontal boundary becomes weaker and surrounds the equatorward portion of the cyclone, waiting for the next upper level disturbance to form a new low pressure area.

However, the western portion of this belt wraps around the northwest (southwest in the Southern Hemisphere) side of the cyclone, which can contain moderate to heavy precipitation.