Definition
A METAR remark indicating that the station's atmospheric pressure is falling at a rate that meets the criteria for rapid change, typically a drop of at least 0.06 inches of mercury within the past hour, with the pressure still decreasing at the time of observation.
Plain English
The air pressure at the reporting station has been dropping fast, and it is still dropping when the report is made.
Context Anchor
Seen in the remarks section of an aviation routine weather report, especially when weather conditions may be changing quickly.
Derivation
A contraction of the words 'pressure' and 'falling rapidly,' shortened to fit the compact format used in METAR reports.
Why Pilots Care
Signals an approaching weather system that may bring wind shifts, turbulence, or reduced visibility.
Intuition Check
Do not read FR here as flight rules. In this METAR remark, PRESFR means pressure falling rapidly.
Example Sentence 1
The METAR included PRESFR in the remarks, so the pilot expected the weather to worsen within the next hour.
Example Sentence 2
PRESFR in the report prompted a delay in departure until the pressure trend stabilized.