A remote pilot reviews the following Terminal Aerodrome Forecast (TAF) excerpt before a planned evening survey flight: 'TAF KDEN 171720Z 1718/1818 27010KT P6SM BKN030 FM1800 29015G25KT P6SM OVC040 TEMPO 1800/2100 2SM TSRA OVC020CB'. What does the 'TEMPO 1800/2100 2SM TSRA OVC020CB' indicate for the forecast period?
- AA prevailing condition of 2 statute miles visibility, thunderstorms with rain, and an overcast ceiling at 20,000 feet cumulonimbus, expected throughout the forecast.
- BA change in wind speed to 2 knots with towering cumulus clouds from 1800Z to 2100Z.
- CA permanent change to the weather, with thunderstorms and rain starting at 1800Z and lasting until 2100Z.
- DA temporary condition of 2 statute miles visibility, thunderstorms with rain, and an overcast ceiling at 2,000 feet cumulonimbus, expected between 1800Z and 2100Z.
Show answer & explanationAnswer & explanation
Correct answer: D. A temporary condition of 2 statute miles visibility, thunderstorms with rain, and an overcast ceiling at 2,000 feet cumulonimbus, expected between 1800Z and 2100Z.
TEMPO indicates a temporary fluctuation in weather conditions that is expected to last for less than an hour at a time, and for less than half the forecast period. The '2SM TSRA OVC020CB' decodes to 2 statute miles visibility, thunderstorms with rain, and an overcast ceiling at 2,000 feet (020) composed of cumulonimbus (CB) clouds, specifically between 1800Z and 2100Z.
Why the other options are wrong
- A. TEMPO is temporary, not prevailing. '020' means 2,000 feet, not 20,000 feet.
- B. This option misinterprets '2SM' as wind speed and incorrectly identifies the cloud type and height.
- C. TEMPO signifies temporary, not permanent. The conditions are specific, not 'throughout'.
TAF 'TEMPO' Conditions
In a TAF, 'TEMPO' indicates a temporary fluctuation in weather conditions that is expected to occur for less than 1 hour at a time and cover less than half of the forecast period.
- Denotes temporary, short-lived changes.
- Conditions may or may not occur.
- Must be considered for flight planning due to potential severity.
Memory trick: TEMPO means 'Temporarily' bad weather, 'Too much' for a smooth flight.