Weather

An introduction to

Objective

Purpose

To ensure the applicant learns the purpose of and and can exhibit a clear understanding of basic weather theory and how it affects aviation

​

When flying, pilots need to understand how different atmospheric conditions affect flight. This lesson in weather theory will introduce pilots to weather and many other important concepts that are fundamental to other aspects of flying.

​

​

What is Weather?

The state of the atmosphere at a given time and place

​

Includes:

Temperature

Moisture

Wind

Visibility

Barometric Pressure

Atmosphere

4 Layers

​

• Troposphere
• Extends up to 48000 Feet
• Contains most weather
• Standard Lapse Rate
• Tropopause
• Stratosphere
• Mesosphere
• Thermosphere

Atmospheric Pressure

• Air has weight

​

• More air above you = More Weight

​

Measuring Atmospheric Pressure

Old School

​

​

New School

​

​

Standard Conditions

• Sea Level

​

• 29.92” Hg or 1,013.2mb

​

• 15°C (59°F)

​

Atmospheric Circulation

• Driven by the uneven heating of the Earth's surface

​

• Warm air rises

​

• Cool air sinks

​

Coriolis Forces

• Caused by rotation of the earth

​

• More perceptible over long distances

​

• Deflects moving air to the right in the northern hemisphere
• Greater effect at the Poles

​

• Causes 3 distinct wind patterns

​

Wind Patterns

• High Pressure
• Clockwise rotation
• Downward flowing
• Dry conditions

​

• Low pressure
• Counter-clockwise rotation
• Upward flowing
• Wet conditions

​

Convective Currents

• Up and down movement of air

​

• Different materials heat/cool at different rates
• Heating air creates bumps and updrafts
• Cooling air creates downdrafts

​

Effects of Obstructions on wind

• Can change wind speed/direction

​

• Can affect flight

Wind Shear

• Sudden change in wind direction/speed

​

• Effects aircraft performance

​

• Dangerous close to ground