Anabatic and Katabatic Cold Fronts (Summary):

 

Anabatic Cold Front:

 

An ana front has a smoothed but structured cloud band. There are convective regions of cloudiness and enclosed by a jet intensification. A curvature or wave development along the cloud front is usually present. Both the jet maximum (high positive vorticity advection region) and wave development have a bright region on the IR satellite imagery.

            Cold air moves rapidly towards the warmer air causing convergence and warm and moist air to rise over the colder air mass.  Most precipitation occurs behind the surface cold front and the cloud mass is inclined backward to the direction that the cold front is travelling. High cloud is transported downstream by strong upper level winds.  Precipitation and the cloud band are as a result of warm conveyor belt ascent. The potential temperature is constant along the line of the front.

            A narrow band of intense precipitation is usually present due to strong upward motion directly ahead of the cold front, called “line convection”. There is also an enhance region of precipitation directly behind the front line. Gusty winds, hail and thunder often occur.

            Dry cold air extends from the top of the cold front downwards, whereas warm moist air in the warm sector with a backward inclination from the surface to the top of the troposphere.

 

Katabatic Cold Font:

 

            Rising of air is restricted by the descent of cooler dryer air from aloft behind the surface front. This effect reduces the cloud amount at higher levels. The main band of cloud and precipitation therefore appears directly in front of the cold front. The ascending warm conveyor belt is overrun by dryer air originating from the dry intrusion. The dry air originates from the top of the troposphere or lower stratosphere.  In the region of sinking air the clouds are warmer (lower) than in an anabatic cold front. There is usually a region of conditionally unstable air at the leading edge of the frontal cloud band.