Stationary front, occluded front and trough are presented in weather forecast maps.

Stationary Front    

Stationary Front is a type of weather front where two air masses meet, but neither is strong enough to replace the other. As a result, the boundary between the warm and cold air masses stays in roughly the same place for an extended period. Weather associated with stationary fronts often includes prolonged periods of clouds and precipitation, as the air masses are not moving to push the weather systems away.

Weather Effects:

• Prolonged Precipitation: Since a stationary front represents a boundary where two air masses are not moving relative to each other, the weather can remain unsettled for an extended period. This often results in prolonged periods of rain, drizzle, or light precipitation.
• Extended Cloudiness: Cloud cover can be extensive and persistent, leading to overcast skies.
• Temperature Variation: Temperature differences across the front can be noticeable, but because the front isn’t moving, temperatures might not change significantly over short periods.

Impact:

• Flooding Risk: Continuous precipitation over the same area can lead to localized flooding, especially if the rain is heavy.
• Dreary Conditions: The prolonged cloud cover and precipitation can lead to prolonged periods of dreary or gloomy weather.

Visualization: It is shown on weather maps as alternating red semicircles and blue triangles pointing in opposite directions.

Occluded Front    

An occluded front occurs when a cold front overtakes a warm front. This typically happens in a mature low-pressure system. The warm air mass is lifted off the ground as the cold air masses from both the cold front and the cool air behind the warm front converge. Occluded fronts often bring complex weather patterns, including a mix of rain, snow, and changes in temperature.

Weather Effects:

• Complex Weather Patterns: Occluded fronts can lead to a variety of weather conditions, including rain, snow, or mixed precipitation, depending on the temperature profile of the area.
• Weather Transitions: The passage of an occluded front often brings a transition from one type of weather to another, such as from rain to snow or from overcast skies to clearing.
• Variable Intensity: The intensity and type of precipitation can vary, and weather can be more dynamic and changeable as the front moves through.

Impact:

• Storms: Occluded fronts are often associated with mid-latitude cyclones and can contribute to stormy conditions, including thunderstorms.
• Temperature Changes: The occlusion can bring significant shifts in temperature and weather patterns.

Visualization: It is shown on weather maps as alternating blue triangles and semicircles pointing in the directions of the movement.

Trough    

Trough is an elongated area of relatively low pressure. It is often associated with cooler temperatures and unsettled weather. A trough can be found in various weather patterns, including within low-pressure systems or as part of a larger atmospheric wave. It can lead to increased cloudiness and precipitation as air converges and rises in the trough.

Weather Effects:

• Increased Cloudiness: A trough typically brings increased cloudiness as it creates an area of low pressure that encourages the upward movement of air, leading to cloud formation.
• Precipitation: The rising air in a trough can lead to convection and precipitation, ranging from light showers to more intense storms, depending on the trough’s strength and moisture content.
• Storm Development: Troughs can be associated with the development of thunderstorms, particularly if they are accompanied by significant moisture and instability.

Impact:

• Unsettled Weather: Troughs often lead to unsettled weather, including rain or thunderstorms, and can influence the development and movement of other weather systems.
• Temperature Fluctuations: The trough can lead to shifts in temperature as it modifies the local pressure patterns and airflow.

Visualization: It is shown on weather maps as brown dashed lines.