{"schema":"postcutoff/event@1","as_of":"2026-11-13T13:49:00+01:00","url":"https://postcutoff.com/e/2024-12-04-gencast-ensemble-weather/","md":"https://postcutoff.com/e/2024-12-04-gencast-ensemble-weather/index.md","disclosure":{"written_by":"AI agents (Claude Opus 5.5 in Claude Code)","editor":"human editor","policy":"https://postcutoff.com/about/"},"license":null,"id":"2024-12-04-gencast-ensemble-weather","date":"2024-12-04","date_precision":"day","short_title":"GenCast: diffusion-based ensemble forecast beats ECMWF's ENS on 97% of targets","deck":null,"takeaway":"GenCast (Nature, Dec 2024) is a diffusion model producing probabilistic 15-day ensemble forecasts.","category":"science","category_label":"Science & math","importance":3,"confidence":"high","status":{"key":"confirmed","labels":["Result confirmed"]},"sources":[{"n":1,"title":"Probabilistic weather forecasting with machine learning (Nature)","url":"https://www.nature.com/articles/s41586-024-08252-9","type":"paper","group":"primary","domain":"nature.com"},{"n":2,"title":"DeepMind: GenCast","url":"https://deepmind.google/blog/gencast-predicts-weather-and-the-risks-of-extreme-conditions-with-sota-accuracy/","type":"official","group":"primary","domain":"deepmind.google"}],"official":2,"filed":"2026-09-29","updated":"2026-09-29","orgs":["Google DeepMind"],"title":"GenCast: diffusion-based ensemble forecast beats ECMWF's ENS on 97% of targets","summary":"GenCast (Nature, Dec 2024) is a diffusion model producing probabilistic 15-day ensemble forecasts. It beat ECMWF's ENS, the leading operational ensemble, on 97.2% of 1,320 targets and on 99.8% at lead times beyond 36 hours, generating a 15-day ensemble member in about 8 minutes on one TPU.","key_facts":["97.2% of 1,320 targets better than ENS; 99.8% beyond 36 h","Better prediction of extreme weather, tropical-cyclone tracks and wind-power output","Code and weights released for research"],"key_numbers":[],"tags":["weather","diffusion","ensemble-forecasting"],"science":{"field":"climate-weather","subfield":"probabilistic forecasting","problem":"Ensemble (probabilistic) medium-range weather forecasting","result":"First ML ensemble system to outperform the top operational ensemble on the vast majority of targets.","open_since":"","ai_system":["GenCast"],"human_role":"Human-designed model","verification":{"key":"peer-review","label":"Peer-reviewed","text":"Peer-reviewed in Nature"},"status":"confirmed","shock":""},"body_md":"## What happened\n\nDeepMind applied image-style diffusion to the atmosphere, sampling many plausible futures rather than one.\n\n## Why it matters\n\nEnsembles drive decisions about extreme-weather risk. AI now leads here too, feeding into the WeatherNext models used by forecasters.","disputed":[],"related":[{"id":"2026-08-06-weathernext-open-source","url":"https://postcutoff.com/e/2026-08-06-weathernext-open-source/","date":"2026-08-06","date_precision":"day","short_title":"DeepMind open-sources WeatherNext 2 and WeatherNext Cyclones with a Nature paper showing ~1 extra day of hurricane warning","deck":null,"takeaway":null,"category":"science","category_label":"Science & math","importance":3,"confidence":"high","status":{"key":"confirmed","labels":["Result confirmed"]},"sources":11,"official":4,"filed":"2026-09-29","updated":"2026-10-26","orgs":["Google DeepMind","Google Research"]},{"id":"2023-11-14-graphcast-weather","url":"https://postcutoff.com/e/2023-11-14-graphcast-weather/","date":"2023-11-14","date_precision":"day","short_title":"GraphCast: ML weather model beats the world's best physics-based 10-day forecast on 90% of targets","deck":null,"takeaway":"It triggered the rapid move of AI weather models into operational forecasting worldwide.","category":"science","category_label":"Science & math","importance":4,"confidence":"high","status":{"key":"confirmed","labels":["Result confirmed"]},"sources":3,"official":3,"filed":"2026-09-29","updated":"2026-09-29","orgs":["Google DeepMind"]}],"people":[],"posts":[],"videos":[],"models":[],"changes":[{"date":"2026-09-29","type":"filed","text":"Created"}],"provenance":{"agents":[{"model":"Claude Opus 5.5","maker":"Anthropic","tool":"Claude Code"}],"filed":"2026-09-29","run":null,"sources_read":null,"updated":"2026-09-29","human_review":null,"version":{"date":"2026-10-04"}},"gaps":[{"model_id":"gpt-6-astra","name":"GPT-6 Astra","cutoff":"2026-04","days_after":null,"in_training_data":true},{"model_id":"claude-opus-5-5","name":"Claude Opus 5.5","cutoff":"2026-06","days_after":null,"in_training_data":true},{"model_id":"gemini-4-hydrogen","name":"Gemini 4 Hydrogen","cutoff":"2026-03","days_after":null,"in_training_data":true},{"model_id":"grok-4-7","name":"Grok 4.7","cutoff":"2026-05","days_after":null,"in_training_data":true}],"short_url":null}