Nimbostratus clouds are characterized by continuous precipitation. They are low-level clouds that are typically thick and gray in appearance. These clouds form at altitudes below 6,500 feet (2,000 meters) and are associated with steady, prolonged rain or snowfall.

Here is a detailed explanation of why nimbostratus clouds are characterized by continuous precipitation:

Formation of Nimbostratus Clouds:
Nimbostratus clouds form when warm, moist air is forced to rise over a layer of colder air. As the warm air rises, it cools and condenses into a thick, uniform layer of cloud. This process occurs when a warm front or a stationary front approaches an area, causing a prolonged period of precipitation.

Characteristics of Nimbostratus Clouds:
1. Appearance: Nimbostratus clouds appear as a thick, gray layer that often covers the entire sky. They have a featureless and uniform appearance, which distinguishes them from other cloud types.
2. Thickness: These clouds are typically thick and extend over a large area.
3. Precipitation: Nimbostratus clouds are associated with continuous and steady precipitation, which can be in the form of rain, snow, or drizzle. The precipitation from nimbostratus clouds is often light to moderate but can last for an extended period.
4. Lack of distinct cloud features: Unlike other cloud types, nimbostratus clouds do not have well-defined edges or individual cloud elements. They have a smooth and featureless appearance.

Factors contributing to continuous precipitation:
1. Vertical extent: Nimbostratus clouds have a significant vertical extent, which allows for the continuous production of precipitation over a large area.
2. Long-lasting conditions: Nimbostratus clouds are often associated with slow-moving weather systems, such as warm fronts or stationary fronts. These systems can linger over an area for an extended period, resulting in continuous precipitation.
3. Uniformity: The uniform and featureless nature of nimbostratus clouds indicates a stable and widespread cloud layer. This stability allows for the continuous production of precipitation without significant breaks or interruptions.

Conclusion:
Nimbostratus clouds are characterized by continuous precipitation due to their thick, uniform, and stable nature. These clouds often form in association with warm fronts or stationary fronts, resulting in prolonged periods of rain or snowfall.