Aviation Weather – Cloud Types

A Better Understanding of Aviation Weather

Clouds play an important role in aviation weather and serve as vital indicators to pilots. It’s imperative to be familiar with the different cloud types and more specifically, what each type reveals in terms of weather.

Types of Clouds

There are three basic types of clouds: cirrus, stratus and cumulus.

1. Cirrus clouds: found at higher altitudes, generally above 20,000; characterized by their wispy almost hair like appearance and generally appear white or light grey in color
2. Stratus clouds: layered, horizontal clouds with a wide range of shading, from white to dark grey
3. Cumulus clouds: easily recognized by their fluffy appearance on a flat base; may appear as a single cloud but can often be found in clusters or lines

Utilizing Clouds in Forecasting

Clouds speak to the state and stability of the atmospheric environment and can provide useful insights when it comes to weather forecasting. While isolated cirrus formations may be relatively benign, other cirrus types, such as cirrus castellanus, can signify atmospheric instability. In fact, this type is commonly associated with the movement of a weather front. So, pilots can use it as an early sign of pending storms.

Stratus clouds can form from an inversion pushing and spreading out a stratocumulus cloud. This means that they are oftentimes indicative of longer lasting, gloomy, cloudy weather. Stratocumulus clouds form through convection, so their presence is a sure sign convective activity.

Cumulus clouds are usually the most foreboding in terms of aviation weather (with the exception of cumulis humilis, although pilots can usually be assured of no turbulence above cumulus humilis). Cumulonimbus clouds have the capacity to produce severe thunderstorms including lightening, hail, heavy rain and fierce winds. They are also associated with the phenomenon referred to as “cloud suck”, strong rising thermals that may appear to suck small aircraft or gliders into the sky, most pronounced in low pressure, humid conditions.

Regardless of the predicted weather it can be extremely beneficial and even lifesaving for pilots to have knowledge surrounding cloud types and their associated weather behaviors. Forecasts are notoriously flawed and, while accuracy surrounding weather forecasting continues to improve, the reality is that even in the best cases weather is often rapidly moving and erratic. While this offers a brief refresher of cloud types and characteristics it is vital for pilots to study and continue to gain knowledge on all matters of aviation weather.