Weather predictions and synoptic weather charts

SOCIAL SCIENCES: Geography

Grade 6

CLIMATE AND VEGETATION REGIONS OF THE WORLD

Module 7

Weather predictions and synoptic weather charts

The weather is important to all of us, because it affects our lives every day. We can be hot or cold or wet or dry. If we study the weather, we can say every day:

how hot, cold or moderate it is going to be;

how windy it is going to be;

from what direction the wind will blow;

the type of clouds that will occur;

the possibility of dew, frost or fog.

Different instruments are used to measure and notate different elements of the weather.

At weather stations readings are taken every few hours with these and other instruments. These readings are sent to the weather bureau in Bloemfontein. South Africa also has a permanent weather station on Marion Island and information also comes from Gough Island and ships at sea.

One of the biggest problems for South African weather forecasters in the past was that most weather systems come from the west, where there are few ships and weather stations. In the past storms hit the southwestern Cape without any warning. Today, satellite photos are also used to send out images. The photos show where cloud masses across the whole country and the oceans occur. Now the weather forecasters have constant information on the changing weather.

Figure 1: A satellite photo of Southern Africa

All this information is recorded on large charts at the weather bureau. Today computers do a lot of the work. The weather experts study these SYNOPTIC WEATHER CHARTS and make their forecasts accordingly.

A synoptic weather chart is not a map of a country because it contains elements that change continuously. A synoptic weather chart actually changes even before it is completed, because it indicates weather patterns that have already occurred. From these you must conclude that the weather conditions of 08:00 at a certain place have moved elsewhere by the evening. Weather forecasters take this fact into consideration and predict what is going to happen in the future. For example, if a weather forecaster knows what the temperature and humidity at a certain place is, as well as the direction in which the weather system is moving, he can predict the weather conditions later at a different place.

These predictions for the next 24 hours are published daily in newspapers and broadcast over the radio and television.

Activity 1:

To compare the weather forecasts and the actual weather conditions

[LO 1.2, 1.5]

The class divides into two groups.

Group 1 collects the synoptic weather charts and accompanying weather forecasts from the newspapers for a week.

Group 2 draws up a brief description of the actual weather for the specific days in your town. If possible (if you have the weather instruments), the temperatures, wind direction and rainfall can be measured.

At the end of the week you must compare the weather forecast in the newspaper with the actual weather conditions of your area (town).

1. Symbols on a synoptic weather chart

A system of international weather symbols is used to indicate information on weather on a synoptic chart. Each symbol represents a specific element of the weather. If you know these symbols, you can read the weather chart like an expert.