Experts need samples of current atmospheric data such as density, pressure, temperature, humidity and wind to forecast the weather.
This information is collected through observations made on the land surface, in the upper air, on the sea surface and through satellites.
These observations are made by 193 member countries of the World Meteorological Organisation, an intergovernmental body governing this information exchange.
11,000+ land stations, 3000+ aircraft, 4000+ ships, 1200+ ocean buoys, 1300+ air balloons and around 20 satellites from these 193 countries exchange data globally through telecommunications every day.
Over and above, there are close to a million volunteers (known as weather spotters) who share weather-related information with weather agencies of their respective countries.
Once weather agencies receive all this data, they use supercomputers to process data to provide analyses and weather forecasts.
Because of the advancement in science and the increase in the quality and quantity of observations, weather forecasts have seen tremendous growth in accuracy.
A decade back, we could forecast only two-three days with accuracy; this number has reached 7 to 10 days and is believed to go up further.
