Fronts
Fronts exists at the edges of air masses, where another type of air (usually warmer or colder) is replacing the existing air.
Cold Fronts
Cold fronts replace warmer air with colder air. Cold fronts typically have a steep slope vertically, where the warmer air is forced upward by the cold air moving in below.
This often causes a narrow band of showers near or just ahead of the front. Thunderstorms are also possible if this warm air is unstable.
As a cold front passes, weather can include:
- Towering cumulus or cumulonimbus
- Heavy rain or hail
- Tornados possible
- Poor visibility
- Winds variable and gusting
Warm Fronts
Warm fronts replace colder air with warmer air. Warm fronts typically have a longer, more gentle slope, as the warm air overtakes the cold air below it. This supports the development of widespread, layered, stratiform clouds and precipitation.
As a warm front passes, weather can include:
- Drizzle
- Low ceilings
- Poor visibility
- Variable winds
Stationary Fronts
A stationary front is one that is largely unmoving.
Occluded Front
An occluded front occurs when a fast-moving cold front catches up to a slower-moving warm front. As the two fronts merge, cloud and precipitation is likely.
A cold front overtakes a warm front.