Definition
On a Weather Depiction Chart, a hatched area is a region outlined and filled with diagonal shading lines to indicate Instrument Flight Rules (IFR) conditions, meaning ceilings below 1,000 feet and/or visibility less than 3 statute miles.
Plain English
An area on the chart marked with diagonal lines to show where the weather is bad enough that pilots must fly using instruments rather than by looking outside.
Context Anchor
Seen on the FAA Weather Depiction Chart when reviewing broad areas of visual, marginal, and instrument weather before a flight.
Derivation
Hatched' comes from the Old French 'hacher,' meaning to chop or cut, the same root as 'hatchet.' In drawing and mapmaking, hatching means filling an area with closely spaced parallel lines, like a series of small cuts. On weather charts, those lines visually 'fill in' the worst-weather zones so the eye finds them instantly.
Why Pilots Care
Pilots check hatched areas to anticipate reduced visibility, icing potential, and the need for route or altitude changes.
Intuition Check
Do not read “hatched area” as just a marked or shaded region with no special meaning. On this chart, the hatching specifically points to instrument weather conditions, not simply bad weather in a general sense.
Example Sentence 1
The pilot reviewed the Weather Depiction Chart and saw a large hatched area covering the destination airport, indicating IFR conditions on arrival.
Example Sentence 2
Reviewing the chart, I noted the hatched area along our planned path and added extra fuel for a possible delay.