Weather forecasting is the prediction of the weather through applying the principles of physics which is supplemented by a variety of statistical and empirical techniques. Weather forecasting includes predictions of changes on Earth’s surface caused by atmospheric conditions; e.g., snow and ice cover, storm tides, and floods.

What is weather?

  • Weather may be defined as state or condition of atmosphere at a given place and at a given time.
  • It is state or variation of troposphere i.e., lower layer of atmosphere. Troposphere lies beyond the height of 8-18 km from the earth and is densest part of atmosphere where all weather phenomena e.g., rain, cloud, dew etc. occurs.
  • Weather is related to smaller area like village city or town and smaller duration of time i.e., day or part of a day and is always denoted by numerical value of meteorological parameters.


Essential features of weather forecasting

  • Proper recording of data.
  • Careful study of synoptic charts.
  • Search for similar situation from the historical data.
  • Preparation of the weather condition charts as may be possible in next 24-hours and,
  • Drawing quick, correct and definite conclusions regarding future weather phenomenon.

What is the forecasting information?

  • Sunshine: Its information is provided in the forecast so as to help the farmers in taking decisions on operations like harvesting of crops, drying the farm produce etc. The forecasted cloudiness is an average for the entire day. Sunny condition- when sky is almost clear with 90-100% sunshine. Partly cloudy or scattered cloudiness– when 50-90% sunshine, while considerable with 20-50% sunshine and mostly cloudy– 20% or less sunshine.
  • Precipitation: It is the most important aspect of weather forecasting. Rainfall is described in the forecast as isolated when <1/3rd of the specified area is expected to receive rains, scattered when 1/3rd to 2/3rd of the specified area is expected to record rain, and widespread when >2/3rd of the area is likely to receive rains.
  • Dew: is forecasted in six categories: very light, light, moderate, heavy, very heavy and wet.

Types of weather forecasting

Based on duration of forecasting period, it can be divided into:

  • Short range weather forecast: It is for a day or two. These daily forecasts are useful to irrigation engineers, mariners, aviation engineers and farmers.
  • Medium range forecasts are for a period of 3-4 days to two weeks.
  • Long range forecast is for period of more than four weeks, useful for choosing cropping patterns.

Method of forecasting

Data collection is important for weather forecasting which is collected through land-based station, ocean-based station, air-based station and space-based stations.

Forecasting method can be divided into three broad categories:

  • Conventional or synoptic method: This method involves detailed analysis of current weather reports from a large area. The current weather patterns are related with the past analogous situation and forecasts are prepared on the assumption that current situation will behave based on past analogous situations. This method is useful for short range forecasts.
  • Statistical methos: This method is useful for short and medium range forecasting. Regression equations or other sophisticated relationships are established between different weather elements and the resulting climate. Normally selection of predictors or weather parameters is based on a possible physical relationship with the predictant. Multiple regression equation is developed to predict annual rainfall based on 16-parameters by Indian meteorological department.
  • Numerical weather prediction method: The behaviour of atmosphere is represented by a set of equations based on physical laws governing air movement, air pressure and other information. This technique is suitable for medium range forecasts.

Importance of weather forecasting

  1. Agriculture- Almost all agricultural operations are related to weather or climatic factors. Weather forecasting helps the farmer to perform suitable agricultural operations.
  2. Fishing- Fisherman can be saved from weather abnormalities.
  3. Forestry
  4. Trade and transport- weather forecast also helps in trade and transport activities. The information of weather abnormalities helps trader to act accordingly which reduces the loss of goods and materials.
  5. Aviation-
  6. Tourism- Prediction of weather helps tourists from weather abnormalities.
  7. Health- Prediction of weather safeguard the health of humans and animals as well by adopting suitable measures.
  8. Education- Educational institutions are closed before weather abnormalities.

Frequently Asked Question (FAQ)

What is synoptic report and synoptic chart?

Observed weather conditions are marked in brief coded form as a synopsis of the conditions, this type of report is known as synoptic report.

The regular observatories record weather elements at the scheduled time and these readings are telegraphed to the concerned regional centre. They are charted on an outline map of India using the international code of signals and observations. These are called synoptic charts or weather charts.

What are weather abnormalities?

Abrupt or sudden changes in weather is called weather abnormality. These are floods, drought, untimely rain, thunder storm, hail storm, cold and heat waves, cyclones etc.

Headquarter of Indian meteorological Department (IMD) is situated at?

New Delhi. IMD was formed on January 15, 1875.

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