http://media.tumblr.com/tumblr_lqjfq0FgMq1qm06i9.gif
The image above involves a thunderstorm which is only possible with unstable air mass and moisture to form clouds. Thunderstorms are divided into stages, for example the mature stage which results in a lot of updraft. The current stage that we see in the image is a Gus front which is caused from heavy rain and frequent lightning. As time passes the thunderstorm will eventually go through a dissipating stage which is developed through rain-cooled air flows.
http://i547.photobucket.com/albums/hh475/Malte279/The%20Land%20before%20Time/The%20Cold%20Time/02Strugglingthroughtheblizzard.jpg
The picture above depicts two characters having a hard time walking against a strong wind. The wind coming from in front of them and moving behind them shows that there must have been high atmospheric pressure in front of them and low atmospheric pressure behind them. This is in agreement with the third law of geography which states that air always flows from high pressure to low pressure. The wind being so strong in the picture indicated that there must have been steep pressure gradients, or many different air pressures over a short distance, because steep pressure gradients cause the strongest winds.
http://www.animationsensations.com/img/dinosaur2.jpg
The picture above shows three of the characters walking through a big area of fog. Due to the fact the it had just rained in the previous scene, this fog is probably radiation fog, which require a lot of moisture in the ground, such as right after it rains. It also requires that there is no wind so that it can collect. The ground starts cooling by conduction, meaning that the cold air near the ground comes in contact with other air molecules and cools them down as well. This conduction continues until the dew point is reached, which is when humidity is at 100% meaning that the air is saturated with the most moisture. The radiation for would eventually clear by either evaporation or when a wind comes in and disperses it.
