Reading Synoptic Weather Maps
Understanding weather station models, pressure systems, and fronts
This topic teaches you how to read the symbols and patterns on a synoptic weather map. In Grade 10 Geography, you must be able to use isobars, station models, pressure systems, and fronts to describe actual weather conditions over South Africa, especially in summer and winter.
The Weather Station Model
Each circle on a Synoptic Weather Map represents a specific town or city. The symbols surrounding it provide detailed information about current weather conditions.
Half shaded = 4 oktas
Measured in eighths. Clear circle = clear skies; fully shaded = overcast.
Air temperature
Displayed in °C at the top-left of the circle.
Dew point
Shown at bottom-left. Close to air temperature = high humidity.
Long feather = 10 knots, short = 5 knots
Tail shows wind direction (where it comes from). Feathers show speed.
1. What does a fully shaded circle on a weather station model indicate?
Lines and Pressure Systems
Isobars connect locations of equal air pressure. Their spacing indicates wind strength.
Clear, dry weather. In Southern Hemisphere: air circulates anticlockwise and outward.
Cloudy, rainy weather. Air moves clockwise and inward towards the center.
Isobar spacing: Close together = strong winds (steep pressure gradient). Far apart = calm winds.
2. In the Southern Hemisphere, what is the wind circulation pattern around a low pressure system?
Fronts
Fronts are boundaries between different air masses that significantly influence weather.
Blue line with triangles. Brings sudden temperature drop, heavy rain, thunderstorms.
Red line with semi-circles. Brings steady, lighter rain and temperature increase.
3. Which front is represented by a line with blue triangles on a weather map?
Determining the Season
In South African examinations, identify whether a weather map shows Summer or Winter conditions.
- Low pressure over interior regions
- High temperatures (often >30°C)
- Date range: October to March
- South Indian & South Atlantic Highs closer to land
- Cold fronts impact Western Cape
- Generally lower temperatures
4. What pressure pattern indicates a summer weather map in South Africa?
Weather Station Labeling Game
Match each part of the station model to its correct description.
Station Component 1
"Displayed at top-left of the circle in °C"
Station Component 2
"Shown at bottom-left of the circle; indicates humidity"
Station Component 3
"Represented by shading inside the circle (oktas)"
Station Component 4
"Tail shows where it comes from; feathers show speed"
Pressure Systems Challenge
Match each characteristic to the correct pressure system.
Characteristic 1
"Brings clear and dry weather"
Characteristic 2
"Air moves clockwise and inward in Southern Hemisphere"
Characteristic 3
"Associated with cloudy and rainy conditions"
Characteristic 4
"Air circulates anticlockwise and outward"
Isobar Spacing Challenge
What do closely spaced isobars indicate?
Closely spaced isobars
Weather Map Word Scramble
Unscramble these weather map terms.
Term 1
Term 2
Term 3
Term 4
Key Terms
CAPS Recap
To answer synoptic map questions well, you need to read the weather station model correctly, interpret isobar spacing, and tell the difference between high-pressure and low-pressure systems. You should also recognise cold fronts and connect them to the weather they bring.
A good self-check is this: if you see a cold front south-west of the country and closely spaced isobars, can you predict cooler, windier, and possibly rainy conditions for the affected area?
