Thunderstorms are most likely to form when the air is warm and humid.
Humid air is more dense.
Moisture (water droplets) is saturating the air when the weather is humid.
Warm air is less dense than cold air, which is the operating principle behind hot air balloons. I'm not sure of the effect of humidity on air density. That is a good question. Some humid air seems to float pretty well, as in high altitude clouds, while other humid air hugs the ground, such as fog.
Warm air
The lower the air temperature the lower the humidity, generally.
yes
Thunderstorms are most likely to form when the air is warm and humid.
Humid air is more dense.
Yes.
Humid air has more water vapor mixed in it than dry air has.
The difference between humid and dry air is the amount of water vapour held in the air "water vapor"Humid implies wet. Humid air is largely filled with water particles.
Moisture (water droplets) is saturating the air when the weather is humid.
The air was as sticky as glue in the humid forest.
When the air is humid and the glass is cold.
Warm air
Usually in cities it can be humid because of the industries and cars and low leverage and in the hills the air is more cool because, The lower air pressure allows the air to expand, causing it to cool.