Weather forecasting is defined as a prediction of weather condition of a place at a given time approximately 24 to 48hrs. Weather forecasting is obtained through two methods namely, traditional and modern methods.
Modern method involves the use of modern equipment such as satellites, electronic computers, radar, and aircraft, balloons, ships, submarines, rockets and daily records from weather stations. This method of predicting weather is more reliable and accurate, this methods includes:-
1. Radiosonde: This is an instrument used to register pressure and temperature from the ground to roughly 12km above the ground. The instruments are fixed to balloons filled with helium gas and are released into the atmosphere every day at a particular time from different weather stations. The radiosonde transmits radio signals to computers on the ground station where they are analyzed. The signal transmitted give pressure, temperature and humidity readings at different altitude. These balloons are made in such a way that they burst when they reach a certain altitude.
2. Satellite The satellite used for predicting weather are human made space. They move around the earth so that they can provide various types of information. They are also used in radio, television and telephone communication. Satellite transmits photographs on weather conditions on a daily basis. The movement of clouds can be predicted from an analysis of the movement of winds force period of 24hours.
3. Persistence method: This is simpler way of making a weather forecast. It assumes that the atmosphere conditions of a place at the time of forecast will not change. For example, if it is 28°C in Dodoma today the persistence method predicts that it will still be 28°C in Dodoma tomorrow. If two inches of rain fell in Arusha yesterday, this method predicts that two inches of rain will fall in Arusha today.
4. Statistical forecasting In this method, meteorologists ask themselves how is the weather usually like at this time of the year?. They then collect records of average temperatures and rainfall over the last five years. This give forecasters an idea of what the weather is “supposed to be like” at the certain time of year.