Weather 3

Question 1

What is relative humidity?

Answer 1

amount of water vapor in the air compared to the amount the air can hold at the current temp.

Question 2

Describe the relationship between cold/warm air and the amount of water vapor each can hold

Answer 2

The colder the air, the LESS water vapor it can hold – the warmer the air, the MORE water vapor it can hold

Question 3

What is Dew Point

Answer 3

Point at which air is totally saturated and it can’t hold anymore water

Question 4

What happens when the temp drops and matches the dew point?

Answer 4

That is the saturation point

Question 5

What is the saturation point?

Answer 5

When the air drops and meets the dew point – when moisture starts to condense out of the air into fog, clouds, and precipitation

Question 6

What are the 4 ways that dew point and temperature can come together to lead to saturation?

Answer 6

1) warm air blows over a cool surface (the warm air is rapidly cooled to the dew point which can form fog) – 2) Warm air and cold air mix which causes temp and dew point to converge – 3) If air cools at night and comes into contact with cooler ground – 4) When air is lifted or forced up into the atmosphere by a front

Question 7

What is the convergence rate? - What is the average convergence rate?

Answer 7

We know that as altitude increases, air becomes cooler - this drives air temp and dew point closer together – the rate at which these two numbers come together is convergence rate – average convergence rate is 2.5 degrees per 1k feet

Question 8

What part of the cloud is where the dew point and temp meet (saturation point)?

Answer 8

the bottom of a cloud

Question 9

How is fog formed?

Answer 9

When the temp of the air near the ground is cooled to the airs dew point

Question 10

What are the different types of fog? (5)

Answer 10

Radiation, Advection, Upslope, Steam, and Ice

Question 11

What is radiation fog?

Answer 11

When the ground cools quickly because of terrestrial radiation – usually on clear nights with no wind present

Question 12

What is advection fog? What is required and at what average speed?

Answer 12

Usually in coastal regions – when wind blows across warmer ocean water and the warm air moves over the cooler terrain – must have wind present around 15 knots – any higher and the fog will rise and turn into clouds

Question 13

What is upslope fog?

Answer 13

Fog that is formed by strong winds that push the moist, stable air up a slope

Question 14

What is steam fog?

Answer 14

Fog that forms over water in colder months of the year – When the water is warmer than the air, which causes the the moisture to evaporate and rise over the water

Question 15

What is ice fog?

Answer 15

Only in freezing temps; causes water vapor to form into ice

Question 16

What is the convergence rate for Farenheit and Celsius?

Answer 16

4.4 for F and 2.5 for C

Question 17

How do you find the cloud base if the Surface temp is 86 degrees and the dew point is 81 degrees? – how high can you fly given this?

Answer 17

86-81 = 5; 5 is your dew point spread – 5 divided by 4.4 (for farenheit) equals 1.136 – multiply that by 1,000 and you get 1,136 feet AGL which is your cloud base – subtract 500 from this and you get 636 feet AGL, that is the max heigh you are allowed to fly given FAA rules