Definition
A vertical air current produced by the uneven heating of the Earth's surface. Warm air over a heated surface expands, becomes less dense, and rises; cooler, denser air flows in to replace it, creating a circulating flow of air.
Plain English
Air rising from a warm patch of ground while cooler air sinks down nearby to take its place. It's the reason the air over a parking lot feels different from the air over a grassy field on a sunny day.
Context Anchor
Seen in aviation weather discussions about rising air, turbulence, cloud formation, and afternoon heating over land.
Derivation
From Latin convehere, meaning 'to carry together.' The word captures the idea of heat being carried upward by moving air rather than passing through still air.
Why Pilots Care
These currents create updrafts and downdrafts that affect climb performance, descent rates, and can produce turbulence.
Analogy
Like the rising bubbles in a pot of water just before it boils — warm parcels rise, cooler ones sink, and the whole pot keeps circulating as long as the heat is on.
Grounding Statement
On a sunny afternoon, dark pavement can heat the air above it, causing that air to rise while nearby cooler air moves in to replace it.
Intuition Check
A convection current is not an electrical current, and it is not simply wind blowing across the ground. Here, current means a flow of air, usually rising and sinking because of heating.
Example Sentence 1
On the hot summer afternoon, convection currents over the asphalt runway caused the aircraft to balloon just before touchdown.
Example Sentence 2
Strong convection currents near the airport made the final approach bumpy for the arriving traffic.