Definition
A weather condition in which a low-pressure area extends through a deep vertical column of the atmosphere, with the lowest pressure at its center continuing upward through multiple altitude levels. The low is not just a surface feature — it is reflected on upper-air charts as well, producing strong, organized weather across a wide altitude range.
Plain English
A low-pressure system that goes deep — not just at ground level, but stacked up through the atmosphere. Because the low extends so far up, the weather it produces tends to be stronger and more widespread than a shallow surface low.
Context Anchor
Seen during aircraft maintenance or preflight inspection of panels made with a thin outer skin bonded to a lightweight inner core, such as some control surfaces, fairings, and composite parts.
Derivation
‘Core’ comes from the Latin ‘cor’ meaning ‘heart’ — the center of something. ‘Depression’ in meteorology comes from the Latin ‘deprimere,’ meaning ‘to press down,’ and refers to an area of lower pressure. Together: a low-pressure center that runs deep through the atmosphere.
Why Pilots Care
A core depression usually means more intense and widespread weather than a shallow low — stronger winds, larger areas of cloud and precipitation, and conditions that persist through climb and cruise altitudes rather than being escaped by climbing.
Grounding Statement
Picture a low-pressure area that isn't just a dent at the surface but a column of low pressure reaching far up into the sky.
Intuition Check
Core depression does not mean a problem with an engine core or a person’s mood. Here, “depression” means a physical low spot in the inner support material of an aircraft panel.
Example Sentence 1
The forecaster warned that a core depression over the region would bring widespread IFR conditions through all cruise altitudes.
Example Sentence 2
The pilot adjusted altitude to remain clear of the core depression and its associated turbulence.