1. Which statement best explains why an increase in the water vapor content of a parcel of air generally increases the chance of precipitation?
(1) The dewpoint is farther from the condensation
point, causing rain.
(2) The air temperature is closer to the dewpoint,
making cloud formation more likely.
(3) The amount of moisture in the air is greater,
making the air heavier.
(4) The specific heat of the moist air is greater
than the drier air, releasing energy.

2. Actual temperature = dewpoint

4. Dewpoint Temperature

5. When is the atmosphere saturated?
(1) Around 6 pm
(2) Around 9 am
(3) Around 5 am
(4) Around 9 pm

6. When is the atmosphere the driest?
(1) Around 6 pm
(2) Around 9 am
(3) Around 5 am
(4) Around 9 pm

7. Dewpoint asks the question:
Dewpoint temperature indicates the amount of vapor in the atmosphere.
Dewpoint asks the question:
“How much vapor is in the atmosphere right now?”

8. This is RELATIVE HUMIDITY.
A similar question is:
“How FULL is the atmosphere now?” (or How close is the actual temperature to the Dewpoint?)
This is RELATIVE HUMIDITY.

9. RELATIVE HUMIDITY compares the amount of vapor to the capacity.
100% Relative Humidity means atmosphere is full (has all the vapor it can hold).
50% Relative Humidity means atmosphere is half full.
47% Relative Humidity means atmosphere has 47% of the vapor it can hold, etc…

10. …compared to what it could hold….
Both White Plains and Miami note humidity as 68% of capacity.
Which has more vapor?
CHECK DEWPOINTS!