Figure 2-25 Atmospheric Stability and Flight Conditions

AVIATION WEATHER

CHAPTER TWO

Figure 2-24 Clouds in Stable and Unstable Air

There are a significant number of flight conditions associated with atmospheric stability, as

depicted in Figure 2-25. If one or more of these conditions is encountered, the stability of the

atmosphere can be easily determined, and other flight conditions can be predicted. Thus,

understanding the relationships among stability and flight conditions provides aircrew with a key

that unlocks many of the mysteries of weather phenomena.

Flight Conditions

Stable Atmosphere

Unstable Atmosphere

Cloud type

Stratus

Turbulence

Smooth

Rough

Visibility

Poor

Good (outside clouds)

Winds

Steady

Gusty

Steady

Showery

Icing

Rime

Clear

Air mass

Warm

Cold

Front

Warm

Cold

Figure 2-25 Atmospheric Stability and Flight Conditions

Being able to recognize the stability of the air while flying will help prepare you for the various

flight conditions you are experiencing. When encountering a change in weather conditionsapart

from what was briefedthe relationships in Figure 2-25 can also be a guide to understanding the

different options available and to making better decisions for avoiding weather hazards. Here

are some additional "signs in the sky" that indicate stable air: temperature inversions, low fog

and stratus, and rising air temperature while climbing. Thunderstorms, showers, towering

clouds, dust devils, and rapidly decreasing air temperature while climbing all indicate unstable

atmospheric conditions.

Atmospheric Mechanics of Winds, Clouds and Moisture, and Atmospheric Stability

2-23