Not all fronts advance steadily. A stationary front makes little progress as neither air mass replaces the other across the boundary. An occluded front can develop when a cold front catches a warm front and lifts warmer air. These map patterns describe three-dimensional weather systems using a simplified surface view.
Weather and climate · Discover & try
What happens when air masses meet?
Reading level 5 of 5 · AdvancedChange
Word help
air mass
A large body of air with broadly similar temperature and moisture.
front
The boundary between different air masses.
stationary front
A front that makes little movement across the ground.
Watch · Try · Explain
See how it works
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Simplified cross-section and map symbols; fronts do not guarantee precipitation.
What to look for
- Which air mass replaces the other
- The direction of the map symbols
- Changes before and after the boundary passes
Explain what you noticed
What makes a moving boundary a cold front?
Keep this idea: Fronts mark air-mass boundaries, not guaranteed rain.
Follow the sources
- NOAA — How to read Surface Weather Maps
- NOAA — Weather systems and patterns
- NOAA National Weather Service — A Basic Discussion on Pressure Systems, Fronts, Jet Streams, and Precipitation
Source material checked 2026-10-28. Explanations and activities by Nepedia. Agency source links do not imply endorsement.
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