Definition
A weather front formed when a faster-moving cold front overtakes a slower-moving warm front, lifting the warm air mass off the surface so it no longer touches the ground. The result is two cold (or cool) air masses meeting at the surface with the displaced warm air aloft. Occluded fronts typically bring a mix of weather associated with both cold and warm fronts, including widespread cloud cover, precipitation, and sometimes embedded thunderstorms.
Plain English
When a fast cold front catches up to a slow warm front, it shoves the warm air upward off the ground. What's left at the surface is two cool air masses meeting, with the warm air trapped above them. Pilots often see a stretch of cloudy, wet, sometimes bumpy weather as this passes through.
Context Anchor
Seen in aviation weather reports, forecasts, surface analysis charts, and flight planning discussions about fronts.
Derivation
From the Latin occludere, meaning 'to close up' or 'shut off.' The warm air is effectively closed off from the surface — squeezed upward and out of contact with the ground.
Why Pilots Care
These fronts can produce layered clouds, steady precipitation, turbulence, and icing that affect route selection and flight safety.
Grounding Statement
Picture a mass of cold air catching a mass of warm air from behind and lifting the warm air off the ground, spreading active weather around the joined boundary.
Intuition Check
Do not read “occluded” as simply “hidden” or “blocked.” In weather, an occluded front specifically means a cold front has caught a warm front and lifted the warm air away from the surface.
Example Sentence 1
The briefer pointed out an occluded front moving through the route and warned of low ceilings and possible icing in the clouds.
Example Sentence 2
Preflight planning included extra fuel because the occluded front was expected to bring widespread low ceilings.