Overview
This lecture covers the four main types of weather fronts in aviation, their characteristics, effects on weather, and considerations for pilots.
Types of Fronts
- A front is the boundary between two different air masses.
- The four types of fronts are: warm fronts, cold fronts, stationary fronts, and occluded fronts.
Warm Fronts
- Warm fronts form when warm air advances over cold air, moving slowly (10–15 mph).
- Typical weather includes stratiform and cirrus clouds, fog, drizzle, and poor visibility.
- Precipitation is usually light to moderate; visibility improves after the front passes.
- After passage, barometric pressure rises slightly, then gradually falls.
Cold Fronts
- Cold fronts occur when cold air pushes under warm air, usually moving 25–30 mph, but can reach 60 mph.
- Common clouds: towering cumulus, cirrus, and cumulonimbus (thunderstorms, possible hail, and tornadoes).
- Squall lines (narrow bands of severe storms) may form ahead of fast cold fronts.
- Weather changes rapidly and clears quickly after passage; more intense than warm fronts.
Warm vs. Cold Fronts Comparison
- Warm fronts: move slowly, bring gradual weather changes, low ceilings, poor visibility, and rain.
- Cold fronts: approach quickly with little warning, cause rapid, intense weather changes, and clear rapidly.
Stationary Fronts
- Stationary fronts form when two air masses are balanced and not moving, causing prolonged mixed weather conditions.
Occluded Fronts
- Occluded fronts occur when a cold front overtakes a warm front.
- Two types: cold front occlusion (cold air replaces warm air) and warm front occlusion (coldest air is ahead of both fronts).
- Warm occlusion produces more severe weather, with thunderstorms, rain, and fog.
Key Terms & Definitions
- Front — boundary between two air masses.
- Warm front — warm air mass moves over and replaces cold air.
- Cold front — cold air mass moves under and replaces warm air.
- Stationary front — two air masses meet but neither moves.
- Occluded front — a faster cold front overtakes a slow warm front.
- Squall line — a narrow line of severe thunderstorms ahead of a cold front.
Action Items / Next Steps
- Watch the next video covering high and low pressure systems.