Using the cloud base estimate with actual temperature 60 C and dew point 50 C, what is the estimated cloud base?

Using the cloud base estimate with actual temperature 60 C and dew point 50 C, what is the estimated cloud base?

• A. 4
• B. 3
• C. 5
• D. 6

Answer: (A)

Estimating cloud base height from temperature and dew point hinges on how far the air must rise before it cools to the dew point and forms condensation. That height scales with the difference between the actual air temperature and the dew point. In this case, the temperature is 60°C and the dew point is 50°C, giving a spread of 10°C. A handy rule of thumb is about 400 feet of cloud base per degree Celsius of spread (roughly 125 meters per degree). So 10°C × 400 ft/°C ≈ 4,000 ft. Using the more precise conversion (125 m per °C) gives 1,250 m, which is about 4,100 ft. The estimated cloud base is therefore around 4,000 feet above the surface.

Estimating cloud base height from temperature and dew point hinges on how far the air must rise before it cools to the dew point and forms condensation. That height scales with the difference between the actual air temperature and the dew point. In this case, the temperature is 60°C and the dew point is 50°C, giving a spread of 10°C. A handy rule of thumb is about 400 feet of cloud base per degree Celsius of spread (roughly 125 meters per degree). So 10°C × 400 ft/°C ≈ 4,000 ft. Using the more precise conversion (125 m per °C) gives 1,250 m, which is about 4,100 ft. The estimated cloud base is therefore around 4,000 feet above the surface.