SPC Aviation Weather Information 3

Question 1

Which type of fog forms when warm, moist air moves over a cooler surface?

Accepted Answer

Advection fog

Answer

Advection fog forms when warm moist air moves horizontally over a cooler surface, cooling the air to its dew point — common along coastlines and in spring over cold land.

Question 2

What weather phenomenon is most likely when the temperature and dew point spread is 5°F or less and is decreasing?

Accepted Answer

Fog or low cloud formation

Answer

A small and decreasing temperature-dew point spread indicates the air is approaching saturation, making fog or low cloud formation likely.

Question 3

Mountain wave turbulence is most likely to occur when winds at mountaintop level are:

Accepted Answer

At least 25 knots and perpendicular to the ridge

Answer

Mountain wave turbulence is most severe when surface winds are at least 25 knots and blow nearly perpendicular (within 30°) to the ridge line.

Question 4

What is a lenticular cloud, and what does its presence indicate to a pilot?

Accepted Answer

A lens-shaped cloud forming in the crest of a mountain wave indicating turbulence

Answer

Lenticular (lens-shaped) clouds form at the crest of mountain waves and are a visual signal of potentially severe turbulence and strong up/downdrafts in the area.

Question 5

What ceiling and visibility values define Instrument Meteorological Conditions (IMC)?

Accepted Answer

Ceiling below 1,000 feet AGL and/or visibility less than 3 miles

Answer

IMC exists when the ceiling is below 1,000 feet AGL and/or visibility is less than 3 miles, requiring instrument flight rules for flight.

(SPC) Student Pilot Certificate Practice Test

(SPC) Student Pilot Certificate Practice Test

SPC Aviation Weather Information 3