Weather Phenomena

When warm and cold air meet, a front forms as their boundary, and clouds, rain, and wind change nearby. A warm front rises gently and brings drizzle over a wide area; a cold front undercuts sharply and brings showers in a narrow band. When a cold front catches a warm front an occluded front forms, and mid-latitude cyclone motion with front passage drives Korean weather. Here you can use the front-type slider to compare cross-sections of warm, cold, and occluded fronts.

What is a front?

🌦️ When two air masses meet

①When warm and cold air meet, a boundary forms

②The boundary surface is the frontal surface; where it meets the ground is the front

③Clouds, rain, and wind changes happen near fronts

Structure of fronts

Front type0

💡 Key observations

①Warm front (0): warm air rises gradually → stratiform clouds, wide drizzle

②Cold front (1): cold air pushes under sharply → cumuliform clouds, narrow showers

③Occluded (2): cold front catches up to warm front → cyclone dissipating

Front comparison

ChartWarm vs Cold front

Item	Warm front	Cold front
Slope	gentle (~1/200)	steep (~1/100)
Cloud type	stratiform (wide)	cumuliform (tall)
Precipitation	wide area, drizzle	narrow, showers
Speed	slow	fast
Temp after passage	rises	drops

Cyclones and weather changes

Mid-latitude cyclone motion

W → E motion (westerlies belt) / fronts attached

Korea is in the westerlies belt → cyclones move W → E

Weather change during cyclone passage

warm front approach → cloudy/rain → temp ↑ after passage → cold front approach → showers → temp ↓ after passage

south of cyclone center: warm front; west: cold front

📡 Reading a weather map

①Closely spaced isobars → strong wind

②Low pressure center: counterclockwise winds (N. Hemisphere)

③High pressure center: clockwise winds (N. Hemisphere)

Worked Examples and Exam Practice

Example 1

Right after a cold front passes, how do temperature and precipitation change there?

A cold front pushes cold air under warm air, making cumuliform clouds and showers over a narrow area.

After it passes, cold air moves in and the temperature drops.

▸ Showers over a narrow area; temperature drops after passage

Warm front: wide drizzle, temperature rises after; cold front: showers, temperature drops after.

Example 2

In which rotational direction do winds spiral into the center of a Northern Hemisphere cyclone (low)?

In the Northern Hemisphere, winds spiral counterclockwise into a low-pressure center.

Because of the Coriolis effect, winds spiral clockwise out of a high instead.

▸ Counterclockwise (low); clockwise for a high

Northern Hemisphere: lows converge counterclockwise, highs diverge clockwise. The Southern Hemisphere is reversed.

School-exam style

Which statement about fronts and mid-latitude cyclones is correct?

①A warm front brings showers over a narrow area

②After a cold front passes, the temperature drops

③Mid-latitude cyclones move from east to west

④Winds blow counterclockwise around a Northern Hemisphere high

⑤An occluded front forms when a warm front catches up to a cold front

▸ ② After a cold front passes, the temperature drops

Cold air settles behind a cold front, so the temperature drops after it passes.

A warm front brings wide drizzle (①), cyclones move W→E in the westerlies (③), Northern Hemisphere highs have clockwise winds (④), and an occluded front forms when the cold front catches the warm front (⑤).

Summary

Weather core

front = air mass boundary / warm (gentle, drizzle) / cold (steep, showers)

mid-latitude cyclone motion and front passage drive Korean weather

🎯 Exam Points

①Warm front: gentle slope, stratiform, wide drizzle, temperature rises after passage

②Cold front: steep slope, cumuliform, narrow showers, temperature drops after passage

③Occluded front: cold catches up to warm; cyclone dissipating

④Mid-latitude cyclone: W→E in westerlies belt, with fronts

⑤N. Hem. low: counterclockwise winds; high: clockwise winds

← Previous

Ocean Currents

Climate Change

Was this helpful? Support seegongsik