Definition
In a METAR, qualifiers are short letter codes placed in front of a weather phenomenon to describe its intensity, proximity, or character. The three qualifier types are intensity (light, moderate, or heavy), proximity (in the vicinity of the airport but not at it), and descriptor (a code that further refines the weather, such as shower, thunderstorm, freezing, or blowing).
Plain English
Qualifiers are the small codes added before a weather abbreviation in a METAR to tell you how strong the weather is, whether it's at the airport or just nearby, and what kind of weather it is.
Context Anchor
Seen in the present-weather part of a METAR, the routine aviation weather report pilots use before and during a flight.
Derivation
From Latin qualis, meaning 'of what kind.' A qualifier answers 'what kind?' or 'how much?' about the weather that follows it.
Why Pilots Care
Qualifiers directly affect flight decisions by showing whether reported weather is light enough to ignore or strong enough to require rerouting or delay.
Intuition Check
Do not read qualifiers here as pilot qualifications or certificates. In a METAR, qualifiers are weather-report modifiers that add detail to a weather condition.
Example Sentence 1
The METAR showed -RA, with the minus sign acting as the intensity qualifier for light rain.
Example Sentence 2
Checking the qualifiers in the METAR revealed thunderstorms in the vicinity rather than overhead.