Precipitation Along a Cold Front :

 Animation :

The animation below depicts the development of precipitation ahead of and along a cold front .This picture is vertical cross section across a cold front .The surging blue region represents the cold front mass behind the cold front (solid blue line ) and the yellow areas indicate the warm moist air mass ahead of the cold front .The red arrows represent the lifted air flow .

Use this animation for reference 

As the cold air mass propagates ,it lifts the lighter and less dense warm moist air ahead of it .The moisture in the rising air cools and condenses producing cloud droplets, which in turn lead to the development of the clouds and precipitation ahead of and along the cold front .

In contrast to lifting along a warm front ,lifting along a cold front is much more vigorous, leading to the development of deeper clouds and intense bands of showers and thunderstorms . However, these bands of clouds and precipitation are often times quite narrow and move rapidly just ahead of the cold front .

A Closer Examination of the Animation:
Initially, the cold air mass wedges into the warmer air mass ahead of it, (separated from each other by the cold front). The lighter warm air is lifted upwards by the denser cold air and if enough water vapor condenses, clouds develop.

If condensation of water vapor persists, precipitation may develop, typically in a narrow band just ahead of the cold front.

Due to the steep slope of a cold front, vigorous rising motion is often produced, leading to the development of showers and occasionally severe thunderstorms.