Definition
A large-scale region of high atmospheric pressure where air flows outward from the center. In the Northern Hemisphere, the air circulates clockwise around the high; in the Southern Hemisphere, it circulates counterclockwise. Anticyclones are typically associated with descending air, light winds near the center, and generally fair, stable weather.
Plain English
A high-pressure area where air spreads outward and sinks. The sinking air dries out and warms slightly, which usually means clear skies and calm conditions.
Context Anchor
You may see this term in weather briefings, surface weather charts, and aviation weather discussions when a high-pressure system is affecting a route or airport.
Derivation
From Greek 'anti-' (against, opposite) and 'cyclone' (a rotating storm system). Literally 'opposite of a cyclone.' A cyclone is a low-pressure system with inflowing, rising air; an anticyclone is its opposite -- a high with outflowing, sinking air.
Why Pilots Care
Signals generally fair weather with good visibility and light winds, often favorable for VFR flight.
Grounding Statement
Picture a wide dome of heavy air pressing down, then spreading outward along the ground.
Intuition Check
Do not read “anticyclone” as “no weather problem.” It means a high-pressure circulation opposite a cyclone, and it can still create visibility problems.
Example Sentence 1
A strong anticyclone parked over the region gave us several days of clear skies and smooth flying.
Example Sentence 2
Forecasters noted that the approaching anticyclone would replace the current low-pressure system and improve visibility.