Definition
The characteristic of a phosphor coating on a cathode-ray tube (CRT) that causes it to continue glowing for a short time after the electron beam has stopped striking it. Persistence determines how long an image, trace, or target remains visible on the screen before fading.
Plain English
How long the glow stays on a screen after the beam that drew it has moved on. A long-persistence screen holds the image; a short-persistence screen fades quickly.
Context Anchor
Seen in weather forecasting discussions, weather briefings, and short-term go/no-go decisions before a flight.
Derivation
From Latin persistere, 'to stand firm, continue.' In this context, it describes how the screen's glow continues — stands firm — for a moment after the beam has gone.
Why Pilots Care
Persistence helps pilots decide whether current ceilings, visibility, or winds are likely to remain suitable for the planned flight or whether a change is probable.
Grounding Statement
If the clouds, wind, and visibility have stayed steady for hours, a persistence forecast expects them to remain steady a little longer.
Intuition Check
Persistence does not mean determination or stubbornness here. In aviation weather, it means assuming present conditions will continue for a short period.
Example Sentence 1
The radar scope used a long-persistence phosphor so targets remained visible between sweeps of the antenna.
Example Sentence 2
High persistence of the high-pressure ridge meant clear skies would remain across the entire route.