Learning to forecast the weather can help you to avoid getting caught in suddenly changing conditions that are potentially dangerous. The things you should be most concerned about are temperature, precipitation and wind, because these are the factors that do the most damage or create the most discomfort. The earth is surrounded by air masses that differ from one another in temperature. Areas where the cold and warm air bump up against each other are called frontal boundaries. Frontal boundaries are where most of the exciting weather develops, as warm and cold air mix, often creating violent storms with high winds and precipitation.
Warm air can hold more moisture than cold air.
When warm, moist air chills, the moisture that was previously invisible condenses and forms clouds. However, it is not only the formation of clouds that is important, but the sequence in which the clouds approach. When a cold front approaches, the colder air, which is much heavier than the warm air ahead of it, forces its way under the warm air mass. The result is an abrupt jump from clear skies to mountainous thunderheads and heavy rain squalls as the warm, moist air is rapidly forced to move into the cold upper atmosphere. The sequence that indicates an advancing cold front begins with thunderheads, lightning and thunder and violent squalls.