Weather on Earth is mostly affected by two atmospheric elements: air masses and fronts. Fronts are important for forecasting because they indicate a change in the weather. An air mass is the volume of air with uniform characteristics of temperature and humidity. The two different air masses do not mix into each other because they have different air density. Now, let’s look up the fronts in detail.
What are the fronts?
When two different air masses of the opposite direction come together, a sloping boundary develops between them, called Front. Basically, a front is a boundary that separates the two air masses of different temperature and humidity. The fonts are not vertical or horizontal at all, rather they are slightly inclined. At the front clouds and precipitation are often formed.
A process by which new fronts forms or old fronts regenerate is called frontogenesis. Whereas frontolysis refers to the weakening or dissipating of a front.
Types of weather fronts
The types of weather fronts are:
1. Cold fronts
2. Warm fronts
3. Stationary fronts
4. Occluded fronts
A cold front develops at a leading edge of the cold air mass when moving cold air mass enters a region of the warm air mass. The width of the cold front is typically 1-10 km. A cold front moves faster than warm fronts. Typically, a cold front moves at speed of 30 to 80 Km/h.
The air ahead of the cold front is warm and moist. Since warm air is less dense than cold air, the mass of cold air elevates the warm air. The risen warm air condenses into clouds. At the cold front and ahead of the cold front, a strong thunderstorm and heavy shower occur.
A cold front causes strong winds with a change in wind direction and a sudden drop in temperature. If you notice a sudden change in temperature over a short distance, it is a sign that a cold front is somewhere around.
When a warm air mass moves aggressively toward a region of a colder air mass, a warm front develops between warm and cold air masses. Warm air is lighter than cold air, so it rises over a cold air mass. A warm front moves more slowly than a cold front, typically at a speed of 20 kilometers per hour. As a warm front moves slowly, it has a mild slope usually (1: 200). A warm front may be several hundred kilometers in width.
When a warm front passes through a region, the air becomes noticeably warmer with an abrupt change in wind direction. The warm fronts are associated with stratus clouds with light to moderate rain. As the warm front moves ahead, Precipitation stops and clouds partially or completely dissipate. The air behind the warm front is usually hot and humid with a clear sky.
Stationary fronts occur between two unlike air masses ( typically cold and warm air masses) which are stationary and side by side. The stationary front remains stable for extended periods in the same region. The winds can flow parallel to both sides of the stationary front. In the stationary front area, the sky remains cloudy and experiences the light precipitation. Sometimes the weather remains cloudy for several days and experiences light precipitation.
An Occluded front occurs when fast-moving cold air mass overtakes the warm air mass and it completely displaces the warm air mass aloft. There are two types of occluded fronts: cold occluded and warm occluded fronts.