This story is part of “How Does It Work?” — The Better India’s series that takes the everyday things you see, use and rely on, and uncovers the clever technology, design and sustainable thinking that makes them work better. From the objects in your home to the systems around you, we break down the ideas behind them in simple, easy-to-understand language. Because innovation isn’t always about futuristic machines or complicated technology, sometimes, it’s hiding in the things we use every day.
You’re going about your day when your phone suddenly buzzes.
“Thunderstorm likely in your area.”
Or perhaps it warns you about heavy rain, lightning, or strong winds.
But how did your phone know a storm was on its way, sometimes even before the clouds appeared overhead?
The answer isn’t inside your phone. It begins hundreds of kilometres away, with weather radars, satellites and thousands of sensors collecting information about what is happening in the atmosphere. Powerful computers and AI systems then process that data before an alert finally reaches your screen.
It starts with thousands of eyes on the sky
Before an alert can be sent, India’s weather systems need to know what is happening in the atmosphere.
The India Meteorological Department and other agencies continuously collect data from 50 Doppler Weather Radars, more than 1,000 Automatic Weather Stations, rain gauges and satellites operated by ISRO, including INSAT systems.
These instruments measure everything from rainfall and wind to temperature, humidity, and the movement of weather systems.
Supercomputers process vast amounts of atmospheric data, running complex models to predict how weather conditions could evolve. Photograph: (Digital Watch Observatory)
A Doppler radar, for instance, can track rain-bearing clouds and even estimate how quickly they are moving. Satellites provide a much wider view, helping scientists monitor cloud formation and large weather systems over land and sea.
But collecting all this information is only the beginning.
Supercomputers turn data into a forecast
Imagine trying to predict the movement of every cloud, raindrop and gust of wind across a country.
That is where supercomputing comes in.
India’s Arka supercomputer, with a computing capacity of 11.77 petaflops and 33 petabytes of storage, is designed to process enormous amounts of weather data and run complex numerical weather prediction models.
These models divide the atmosphere into grids and use physics and mathematics to calculate how weather conditions could change over time.
Newer systems use high-resolution grids and indigenous models such as Mithuna, helping improve predictions for India’s tropical weather conditions.
The result? Calculations that once took hours can now be processed in minutes.
AI makes the forecast sharper
There’s another layer of technology helping make these predictions more useful: artificial intelligence.
Machine-learning models, including Convolutional Neural Networks, can help correct biases in weather models, predict lightning and convert broader rainfall forecasts into much more localised predictions.
Some systems can downscale rainfall information to grids as small as 300 metres to 1 kilometre.
That matters because weather rarely behaves uniformly across a city. One neighbourhood can receive heavy rain while another nearby gets only a drizzle.
AI helps turn broad weather forecasts into more localised predictions, identifying where heavy rain, lightning or storms could strike. Photograph: (NDTV)
India is also using GIS-based systems such as the Multi-Hazard Early Warning Decision Support System (MHEW-DSS) to combine live observations with forecasts and identify potential impacts.
So instead of simply saying “heavy rain expected”,technology can help answer a more useful question: Where could it happen, and who could be affected?
From a technical forecast to an alert on your phone
The final step is making sure this information reaches people quickly.
India’s SACHET platform acts as an integrated system for distributing disaster-related alerts through multiple channels.
Increasingly, this also involves cell broadcast technology, being developed with the Centre for Development of Telematics (C-DOT).
Unlike a regular SMS, a cell broadcast can send an alert to all compatible phones connected to specific mobile towers in a particular geographic area. It does not depend on each person’s internet connection, making it useful when networks are congested during emergencies.
AI is also being explored to make advisories easier to understand. Platforms such as MausamVani can use large language models to translate technical weather information into regional languages and more localised advisories.
Predicting weather, preparing people
Every weather alert is therefore the final product of a much bigger technology chain: sensors collect the data, satellites watch from above, supercomputers process it, AI sharpens the predictions, and communication networks deliver the warning.
For people in the path of a storm, a few minutes of early warning can mean time to get home, seek shelter or move to safety. Photograph: (Mint)
And this technology is only becoming more local and responsive.
As weather systems become more unpredictable and extreme events demand quicker action, the next step is not merely knowing that a storm is coming. It is being able to tell people where it may hit, when to expect it, and what they can do to stay safe, early enough to act.
That is what turns a weather forecast from information on a screen into a tool that can help protect lives.
