When you look at airport METAR’s and on-line graphic media, remember that information is valid only from the Airport weather reporting station. Once away from that airport it is your responsibility to avoid the terrain if flying VFR, and to follow the flight plan and ATC instructions if flying IFR.
MVFR means high risk for VFR flight if the pilot isn’t absolutely sure of the terrain enroute and has a plan to minimize risk if the weather becomes worse while in flight. There are too many NTSB incident reports of crashes while pilots were flying in MVFR conditions in our area.
METAR weather reports are valid only for the immediate proximity of the airport.
- METAR reports are normally updated 5 minutes before the hour.
- METAR cloud reports: The vertical (directly overhead) distance visibility to clouds from the AWOS location. To compensate for rapidly changing sky cover, the data is averaged and weighted during a 30-minute period.
Flight Category Reported at the Airport:
The color of the circle at airports pictured on websites and tablets (e.g. NWS, SkyVector, Foreflight, Garmin, etc.,) represents the flight conditions reported at the airport.
- VFR (Green): Ceiling 3000’+ AGL AND Visibility 5 Statute Miles
- MVFR (Blue): Ceiling 1000’ to 3000’ AGL and/or Visibility 3 to 5 Statute Miles
- IFR (Red): Ceiling 500’ to 1000’ AGL and/or Visibility 1 to 3 Statute Miles
- LIFR (Magenta): Ceiling 500’ AGL or LOWER and/or Visibility 1 Statute Mile or LESS
Cloud Cover: The vertical reading at the airport where cloud (sky) cover represents the summation total of the sky condition element from the METAR report.
The official definitions of cloud cover are:
|1/8 to 1/4 sky covered|
|3/8 to 4/8 covered|
|5/8 to 7/8 covered|
Ceiling is reported when cloud cover is measured as Broken or Overcast.
This leaves the interesting questions for VFR pilots:
- If MVFR, how sure are you conditions will not get worse.
- If Scattered is 4/8 cloud cover, how long does it take to become Broken, and what is your plan for a safe flight?