
Summary
- WeatherNext caught Hurricane Melissa's 2025 jump from Category 1 to Category 5 before official forecasts did
- A failed 2023 forecast for Hurricane Otis pushed Google DeepMind to build a cyclone-specific AI model
- WeatherNext trains on roughly 50 years of weather data, runs on a single TPU, and its code is open source
From Category 1 to Category 5, a Warning a Day Ahead
When Hurricane Melissa formed in the Caribbean in 2025, it didn't look like much of a threat at first. But the WeatherNext model picked up an early signal that the storm was about to rapidly intensify from Category 1 to Category 5. Acting on that forecast, the US National Hurricane Center (NHC) issued an unusual warning, and according to a post detailing Hurricane Melissa's landfall, Jamaican authorities used that extra day to shut down power infrastructure and put hospitals on emergency footing. Ferran Alet, a research scientist at Google DeepMind who worked on the model, said, "This was the first time we forecast Category 1 all the way to Category 5."
Born From Failure — The Lesson of Hurricane Otis
There's a specific reason the WeatherNext team zeroed in on cyclone intensity forecasting. In 2023, Google DeepMind released WeatherNext 1 for everyday weather forecasting. It did a reasonable job tracking storm paths, but it fell well short when it came to predicting how strong a storm would get. Then Hurricane Otis hit Mexico. Every physics-based model predicted a weak storm, but Otis suddenly made landfall as a Category 5 at 1 a.m., causing both infrastructure damage and loss of life.
That event set the direction for the WeatherNext team going forward. Having seen that physics equations alone could miss sudden intensity swings, the team decided to build a cyclone-specific AI model — and two years later, that model delivered its first real-world win with the Hurricane Melissa forecast.
Fifty Years of Data, Running on a Single TPU
Cyclone forecasting used to mean running fluid dynamics equations on a supercomputer the size of a three-story building. You'd feed in today's weather data — gathered from satellites, aircraft, and weather stations — and the computer would simulate physical laws directly to calculate tomorrow's weather. The trouble was that observational data was often sparse or noisy, and precise physics simulations demanded enormous computing power.
WeatherNext takes a different approach entirely. Instead of solving equations from scratch, it learns patterns by training on roughly 50 years of historical weather data. Alet explained that training the model on 40 to 50 years of daily weather data alongside a relatively small amount of cyclone data let it apply patterns learned from everyday weather to cyclones as well. As a result, the model can run on a single TPU instead of a building-sized supercomputer.
A Decade of Progress in One Generation
Meteorology has historically improved forecast accuracy at a pace of roughly one day of lead time per decade, achieved through better models, more satellites, and more computing power. Google DeepMind says WeatherNext achieved a decade's worth of progress in a single model generation. The gains covered not just where a storm will make landfall, but how strong it will be by the time it does. That's prompting weather agencies to consider extending public forecast windows from five days to seven.
| Category | Physics-based models (past) | WeatherNext (AI) |
|---|---|---|
| Compute required | Three-story-building-sized supercomputer | 1 TPU |
| Training method | Direct simulation of fluid dynamics equations | Pattern learning from ~50 years of weather data |
| Pace of accuracy gains | ~1 day of lead time per decade | A decade's worth of gains in one model generation |
| Public forecast window | 5 days | Push underway to extend to 7 days |
| Case | Timing | Forecast outcome |
|---|---|---|
| Hurricane Otis | 2023 | Physics models predicted a weak storm; it actually made landfall as a Category 5 overnight |
| Hurricane Melissa | 2025 | WeatherNext warned of the Category 1-to-5 rapid intensification in advance |

The Model Is Open Source — Here's Where to Look
Google DeepMind has open-sourced WeatherNext 2 along with its cyclone-specific model. The company says it hopes academic institutions and national weather agencies will experiment freely and uncover new findings. If you want to dig into the code itself, you can grab the code and weights from the github.com/google-deepmind/weathernext repository. If you'd rather just see the forecasts in action, the Weather Lab website lets you view the model's actual cyclone path and intensity predictions.
In Korea
Google DeepMind announced in April that it was setting up an AI campus in Korea and would pursue collaboration with local industry, academia, and research institutions. According to domestic media reports, a Google DeepMind vice president also held separate meetings with 17 Korean partner companies to discuss potential collaboration. There's no mention in this material of WeatherNext being directly linked with the Korea Meteorological Administration, but since the model is open source and the Weather Lab site is publicly accessible, Korean researchers and weather officials can use both regardless of national borders.
Editor's Take
What stands out in this interview isn't the achievement itself so much as the failure behind it. Google DeepMind's push into cyclone intensity forecasting wasn't driven by "look how good we are" — it came from "we got it completely wrong with Otis." It's rare for a piece promoting an AI model to spell out its own failure in such specific terms, which suggests just how stubborn a problem intensity prediction has been for meteorology.
The generational comparison makes the shift feel more concrete. Anyone who's worked with older weather models knows that physics-based simulations take time — from booking supercomputer time to getting results back — and storms often change direction in the meantime. Finishing the same job on a single TPU isn't just about cutting costs; it means forecasts can be rerun far more often. Being able to recalculate within hours every time conditions shift is a fundamentally different tool for disaster response teams.
In practical terms, what Korean local governments and disaster-safety agencies can do right now is compare WeatherNext's forecasts on Weather Lab against the Korea Meteorological Administration's existing forecasts side by side. There's no evidence yet that Korean weather authorities have formally adopted this model for official forecasting, so it makes sense to treat it as a reference tool for now. Still, since the code is open source, there's plenty of room for Korean university labs to run their own replication experiments with domestic data.
Over the coming months, it wouldn't be surprising to see other weather agencies start pulling WeatherNext into their own forecasting as a reference. The next thing worth watching is whether the discussion about extending forecast windows from five to seven days actually turns into real policy.





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