Illustration of cold and warm fronts in weather systems.

Problem Description:

The image provided illustrates weather fronts, specifically a warm front and a cold front, along with their associated weather conditions. The task is to identify the weather patterns and phenomena that occur at different stages of these fronts.

Key Elements in the Image:

1. Warm Front:
- Warm air mass moving over a cold air mass.
- Clouds form as warm air rises over the cold air.
- Precipitation occurs before the front passes.
- After the front passes, the weather becomes warm and clear.

2. Cold Front:
- Cold air mass moving under a warm air mass.
- Rapid lifting of warm air leads to intense cloud formation and precipitation.
- After the front passes, the weather becomes cooler and clearer.

Solution Explanation:

#### Warm Front (Bottom Section of the Image):
1. Stage 1 (Before the Front Passes):
- As the warm air mass moves over the cold air mass, it gradually lifts the colder air.
- This lifting causes condensation and cloud formation, leading to precipitation.
- The clouds are typically stratiform (layered) and spread out over a large area.
- The weather is characterized by steady rain or drizzle before the front passes.

2. Stage 2 (After the Front Passes):
- Once the warm air mass completely overtakes the cold air mass, the weather clears up.
- The warm air mass brings warmer temperatures and higher humidity.
- The sky becomes mostly clear, and the weather is generally calm and stable.

#### Cold Front (Top Section of the Image):
1. Stage 1 (Before the Front Passes):
- The cold air mass rapidly pushes under the warm air mass.
- The warm air is forced to rise quickly, leading to the formation of cumulus or cumulonimbus clouds.
- These clouds can produce intense precipitation, including heavy rain, thunderstorms, or even tornadoes.
- The weather is often turbulent and unstable before the front passes.

2. Stage 2 (After the Front Passes):
- Once the cold air mass has moved through, it displaces the warm air completely.
- The cold air mass brings cooler temperatures and lower humidity.
- The weather becomes clearer and more stable after the front passes.

Final Answer:

- Warm Front:
- Before the front: Steady rain or drizzle, cloudy skies.
- After the front: Warm and clear weather.

- Cold Front:
- Before the front: Intense precipitation, stormy weather.
- After the front: Cooler and clear weather.

$$
\boxed{\text{Warm Front: Before - Rainy, After - Warm and Clear; Cold Front: Before - Stormy, After - Cool and Clear}}
$$