# AIGFS by NOAA

Canonical page: https://technooptimist.io/ai/aigfs
Frontier: [AI](https://technooptimist.io/ai.md) · Field: Weather models · Company: [NOAA](https://technooptimist.io/companies/noaa.md)
Stage: Deploy (4 of 5: Research → Proto → Pilot → Deploy → Scaling)
Updated: last update 2026-07-27, facts checked 2026-10-11
Goal: Give US forecasters global forecasts as good as or better than the physics GFS at a sliver of the computing cost, so more and faster runs fit on the same machines.
Status: Operational since Dec 2025; v1.1 (July 2026) improved hurricane intensity and long-range blur.
Next milestone: Improve AI ensemble spread and hybrid intensity forecasts, target 2026

## Milestones

| Status | Milestone | Date | Slip |
| --- | --- | --- | --- |
| Done | AIGFS, AIGEFS and hybrid HGEFS go operational | 17 Dec 2025 |   |
| Done | AIGFS v1.1: better hurricane intensity, less long-range blur | 27 Jul 2026 |   |
| Current | Improve AI ensemble spread and hybrid intensity forecasts | 2026 |   |

## Upcoming events

- **2026**: Improve AI ensemble spread and hybrid intensity forecasts

## Most important updates

- **27 Jul 2026**: NOAA upgrades AIGFS to v1.1 to sharpen hurricane intensity and rainfall forecasts. The National Weather Service switched AIGFS to version 1.1 from the 12:00 UTC run on 27 July 2026. ([our story](https://technooptimist.io/stories/noaa-upgrades-aigfs-to-v1-1-to-sharpen-hurricane-intensity-and-rainfall-c559bd53.md) · [original source](https://www.weather.gov/media/notification/pdf_2026/scn26-68_AIGFS_v1.1.pdf))
- **17 Dec 2025**: NOAA puts AI global weather models into operation, led by a retrained GraphCast. NOAA launched three operational AI forecast systems: AIGFS (one best-guess forecast), AIGEFS (a 31-member AI ensemble) and HGEFS (a 62-member hybrid of AI and physics runs). ([our story](https://technooptimist.io/stories/noaa-puts-ai-global-weather-models-into-operation-led-by-a-retrained-cb104e08.md) · [original source](https://www.noaa.gov/news-release/noaa-deploys-new-generation-of-ai-driven-global-weather-models))

## Current obstacles

- **Peak winds in hurricanes**: Training to minimise average error rewards smooth forecasts, so storms come out too weak. v1.1 changed the loss to keep sharp detail.
- **Blurring at long lead times**: Forecasts get fuzzier days out. v1.1 trains the model on its own 72-hour forecasts to reduce the blur.

## Physics limits

- **Chaos caps how far ahead weather is knowable**: Tiny errors in today's state double every few days, so beyond about two weeks no model, AI or physics, can forecast daily weather.
- **AI learns only weather it has seen**: Trained on past decades, an AI model has few examples of record-breaking extremes and may underplay them in a warming climate.

## How it works

### Learn the weather: Trained on past atmospheres

The network learned how the global atmosphere changes from one step to the next by studying decades of past weather states.

### Start point: Today's analysis in, forecast out

Each run starts from NOAA's best estimate of the current atmosphere and steps forward repeatedly to 16 days, in about 40 minutes.

### Ensemble: Many runs, a range of outcomes

31 slightly different starting states give 31 forecasts; how much they disagree tells forecasters how sure to be.

### Hybrid: Pool AI with physics

HGEFS adds the 31 AI runs to the 31 physics runs; mixing two kinds of errors gives a better combined picture.

## Spec sheet

| Spec | AIGFS | Provenance |
| --- | --- | --- |
| Compute vs physics GFS (16 days) | 0.3% | reported |
| 16-day forecast run time | About 40 minutes | reported |
| AI ensemble members (AIGEFS) | 31 | reported |
| AIGEFS compute vs physics GEFS | About 9% | reported |
| Hybrid ensemble members (HGEFS) | 62 (31 AI + 31 physics) | reported |
| AIGEFS extra useful lead time | 18 to 24 hours (early results) | reported |
| Base model | GraphCast (Google DeepMind), fine-tuned | reported |

Provenance: reported = stated by the company; estimated = our estimate; sample = a sample figure.

## Papers and demos

- **Dec 2025** (code): [Project EAGLE change log: AIGFS v1.0 built on GraphCast](https://epic.noaa.gov/ai/eagle-change-log/). Documents the base model, training data and the loss changes made to improve hurricane intensity.

## About NOAA

The US National Oceanic and Atmospheric Administration runs the National Weather Service and its forecast models. Since December 2025 it also runs AI forecast models alongside its physics-based GFS.

- Runs AIGFS, an AI global model built by retraining DeepMind's GraphCast on NOAA's own weather analyses.
- A 16-day AIGFS forecast uses 0.3% of the computing of the physics GFS and finishes in about 40 minutes.
- HGEFS blends 31 AI and 31 physics forecasts; NOAA says no other forecaster runs such a hybrid ensemble.

- Headquarters: US
- Status: government
- Website: https://www.noaa.gov
- People: Neil Jacobs (NOAA Administrator)
- Partners, customers, investors: Google DeepMind (supplier); Earth Prediction Innovation Center (EPIC) (partner); WindBorne Systems (supplier)

Company page: https://technooptimist.io/companies/noaa.md

## Related programs

Everything in AI: https://technooptimist.io/ai.md

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