UAS Weather Assessment 3 — Questions and Answers
Question 1: What does 'VV' followed by a number in a METAR sky condition field indicate?
- Variable visibility at that altitude
- Vertical visibility into an obscuration (Correct answer)
- Very low visibility warning
- Variable wind vector aloft
Correct answer: Vertical visibility into an obscuration
VV (Vertical Visibility) reports how far upward an observer can see into a surface-based obscuration such as fog or smoke.
Question 2: A sUAS remote pilot observes cumulus clouds growing rapidly in height during the afternoon. This indicates:
- Stable conditions favorable for flight
- Increasing convective activity and possible thunderstorm development (Correct answer)
- High pressure system moving in
- A cold front has passed the area
Correct answer: Increasing convective activity and possible thunderstorm development
Rapidly building cumulus clouds (towering cumulus) signal strong atmospheric instability and impending thunderstorm development.
Question 3: What is the primary cause of orographic lift?
- Surface heating from solar radiation
- Frontal boundaries pushing air upward
- Airflow forced upward by terrain like mountains (Correct answer)
- Low-pressure centers drawing air inward and upward
Correct answer: Airflow forced upward by terrain like mountains
Orographic lift occurs when horizontal wind encounters elevated terrain and is forced to rise over it.
Question 4: A remote pilot intends to fly at a site where the current dew point spread (temperature minus dew point) is 2°F. This suggests:
- Excellent visibility with no moisture concerns
- Fog or low cloud formation is likely imminent (Correct answer)
- Dry air with high fire danger
- Strong thermal activity beneficial for lift
Correct answer: Fog or low cloud formation is likely imminent
A small temperature-dew point spread (less than 4°F) means air is near saturation, making fog or low cloud formation very likely.
Question 5: Which type of fog is most common in valleys during clear, calm nights?
- Advection fog
- Upslope fog
- Radiation fog (Correct answer)
- Steam fog
Correct answer: Radiation fog
Radiation fog forms in valleys when clear skies allow rapid radiational cooling of the surface, cooling air to its dew point.
Question 6: What does a wind speed reported in a METAR as '15G25KT' mean?
- 15-knot maximum gust with 25-knot average
- 15-knot sustained winds gusting to 25 knots (Correct answer)
- 15 to 25 knot variable winds
- Wind from 150° at 25 knots
Correct answer: 15-knot sustained winds gusting to 25 knots
In METAR format, G indicates gusts; 15G25KT means sustained winds of 15 knots with gusts reaching 25 knots.
Question 7: During a preflight weather check, a pilot sees CB listed in the sky condition of a METAR. This means:
- Clear below a certain altitude
- Cumulonimbus clouds are present (Correct answer)
- Cloud base confirmed by balloon observation
- Cirrus broken layer aloft
Correct answer: Cumulonimbus clouds are present
CB denotes cumulonimbus clouds, which are thunderstorm clouds and indicate severe weather hazards including turbulence and lightning.
UAS Weather Assessment 3
What does 'VV' followed by a number in a METAR sky condition field indicate?