Weather Patterns and Fronts

High and Low Pressure Systems

• Low Pressure: Rising air, cooling, condensation → clouds, precipitation, storms.
• High Pressure: Sinking air, warming, drying → clear skies, calm weather.

Air Masses

• Large air bodies with consistent temperature and humidity.
• Form over oceans (moist) or land (dry), warm (tropical) or cold (polar) areas.
• Movement leads to fronts and weather changes.

Weather

• Short-term atmospheric conditions (temperature, humidity, wind).
• Influenced by air masses, pressure systems, and humidity.
• Fronts cause weather changes like storms or temperature drops.

Temperature

• Affects air density and pressure. Warm air rises (lower pressure), cold air sinks (higher pressure).
• Drives wind and pressure systems.

Humidity

• Amount of water vapor in the air.
• High humidity → cloud formation and precipitation, affects how hot or cold air feels.

Climate

• Long-term average of weather patterns.
• Influenced by pressure systems, temperature, humidity, and air mass behavior.

Types of Fronts

• Boundary between air masses with different temperatures and densities.

Cold Front

• Cold air mass pushes under warm air mass.
• Air Pressure: Rises after the front passes.
• Weather: Short, intense storms, then cooler, drier air.
• Clouds: Cumulonimbus.

Warm Front

• Warm air mass slides over cold air mass.
• Air Pressure: Drops slowly, then stabilizes.
• Weather: Steady rain or drizzle, then warmer, humid air.
• Clouds: Cirrus → altostratus → nimbostratus.

Stationary Front

• Cold and warm air masses meet but neither moves.
• Air Pressure: Little change.
• Weather: Days of clouds and precipitation, potential flooding.
• Clouds: Layered and rainy.

Occluded Front

• Cold front catches up with a warm front, lifting warm air.
• Air Pressure: Drops, then rises.
• Weather: Heavy rain, then clearing skies.
• Clouds: Mix of cumulonimbus and stratus.