NHC blends DeepMind's ensemble into Hurricane Melissa forecasts

NHC blended Google DeepMind's AI ensemble into official Melissa forecasts from its first advisory on 21 October 2025; Cat 5 landfall in Jamaica 28 October 2025.

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AI system

System

Google DeepMind AI hurricane forecast model, ensemble mean designated GDMI in NHC guidance

Model

Not assessed

Release

Not assessed

Application developer

DeepMind

Role

Not assessed

Configuration

Not assessed

Inputs and outputs

Not assessed

Autonomy

Not assessed

Workflow

Forecasters received the experimental DeepMind ensemble in real time and combined it with conventional forecasts. They retained responsibility for the official track and intensity forecasts.

Human oversight

Not assessed

Relation to AI

NHC forecasters state in Discussions 8, 10, 12, 13 and 14 that official track and intensity forecasts were blended or aligned with Google DeepMind's ensemble. The official forecast remains a human synthesis of several aids. So the AI contribution to outcomes in Jamaica is not isolated.

AI contribution

NHC forecasters state in Discussions 8, 10, 12, 13 and 14 that official track and intensity forecasts were blended or aligned with Google DeepMind's ensemble. The official forecast remains a human synthesis of several aids. So the AI contribution to outcomes in Jamaica is not isolated.

Benefits

Outcome identifiers

Not assessed

Benefit

National Hurricane Center forecasters used Google DeepMind’s guidance in their official forecasts for Hurricane Melissa.

Category

Improved Task Accuracy

Status

Not assessed

Beneficiary groups

People. Organizations. Society.

Beneficiaries

National Hurricane Center forecasters. People in Melissa’s path were the intended beneficiaries of the forecasts.

Reach

No count of people who benefited from the AI guidance is established.

Distribution and access

Not assessed

Duration

Not assessed

Expected?

Yes

Costs and harms

Not assessed

Measurement

Studies

NHC’s forecast verification for Hurricane Melissa (AL132025). [8] [9] [10]

Study design

Retrospective verification of operational forecasts against the storm’s observed track and intensity. [8] [9] [10]

Measurement

NHC compared forecasts at matching lead times with its final estimates of the storm’s position and intensity. It compared official forecasts with model guidance on a common sample. [8] [9] [10]

Setting and sample

Hurricane Melissa in the Atlantic, 21–31 October 2025. The report compares forecasts at lead times through 120 hours. [8] [9] [10]

Measures

Track forecast error, intensity forecast error, and forecast lead time. [8] [9] [10]

Comparison

NHC’s official forecasts, conventional model guidance, and climatology-persistence forecasts for the same storm. [8] [9] [10]

Results

GDMI’s track forecasts were comparable to NHC’s official forecasts through 96 hours. NHC performed slightly better at 120 hours and had lower intensity errors than every guidance model through 96 hours. [8] [9] [10]

Additional value from AI

NHC credits GDMI and regional models jointly with increasing forecasters’ confidence at unusually long lead times. It does not isolate GDMI’s effect on the official forecast. [8] [9] [10]

Limitations

The sources establish that forecasters used the guidance. They do not establish that it changed protective actions, reduced losses, or prevented deaths. [8] [9] [10]

Denominators

Not assessed

Materials for replication

Not assessed

Money

Kind of value

Not assessed

Amount

Not assessed

Currency and prices

Not assessed

Period and unit

Not assessed

Realization

Not assessed

Recipients and payers

Not assessed

Gross or net

Not assessed

Included costs

Not assessed

Comparison

Not assessed

Method

Not assessed

Return and payback

Not assessed

People and places

Participants

Developer: DeepMind. Operator: NOAA National Hurricane Center.

Jurisdictions

Benefit: New Hope, Jamaica. Developer: United Kingdom. Operator: United States.

Ownership and control

Not assessed

Dependencies

Not assessed

Cross-border connections

Not assessed

Geopolitical implications

Not assessed

Follow-up

Conditions for replication

Forecasters need timely model output, checks before operational use, and conventional guidance for comparison. Later observations are needed to assess forecast accuracy.

Replication attempts

2 follow-up entries. Benefit recurred: 2.

Later findings

NHC published its Tropical Cyclone Report on 25 February 2026 and revised it on 19 May. The report evaluates the forecasts against the storm’s observed track and intensity.

Availability

Not assessed

Institutional decision

Not assessed

Grounds

Not assessed

Action and result

Not assessed

Success criterion

Not assessed

Evidence

Source numbers

AIBD-0088-source-0001–0010

Citations

Numbered references below.

Language

Not assessed

Source relationships

Operator

Original evidence

NHC’s operational advisories document its use of DeepMind guidance. Its later verification reports assess forecast accuracy. IFRC reports provide humanitarian context without isolating AI’s effects. [8] [9] [10]

Access and versions

The NHC interview, 2025 verification report, and revised Melissa report were accessible in full. Earlier access limits remain attached to the individual IFRC reports. [8] [9] [10]

Supported findings

Not assessed

Evidence strength

Not assessed

Missing evidence

Not assessed

Grades

Assessed benefits

People. Organizations. Society.

Depth

People: Not assessed. Organizations: 2. Society: 3.

Reasons

GDMI and regional models increased forecasters’ confidence in predicting rapid intensification. NHC’s later review found that GDMI track forecasts performed comparably to its official forecasts through 96 hours. No study isolates the AI’s effect on protective actions or losses.

Observed or intended

Not assessed

Rubric

Not assessed

Assessor and date

Not assessed

Alternative assessments

Not assessed

Fill

The deployer's account

Entry details

Kind

Not assessed

Field

Weather forecasting / tropical cyclones. Public-sector meteorological service.

Purpose

Experimental AI tropical cyclone forecast model providing ensemble track and intensity guidance to NHC forecasters.

Dates

Date basis unassessed: 2025 (precision unassessed). Updated: 25 October 2026.

Stage

Not assessed

Version

SHA-256: 7494545dd8ae…

References

Other identifiers

AI Incident Database: 1546.

Category mappings

Not assessed

Brief

Not assessed

Revisions

11 revisions. Latest: 25 October 2026.

Sources

  1. Report Deployer

    National Hurricane Center (2025). Tropical Storm Melissa Discussion Number 1, 1100 AM EDT Tue Oct 21 2025, forecasters Cangialosi/Bucci. NOAA/NWS.

    Original operational advisory establishing that DeepMind ensemble guidance contributed to the official forecast from the first advisory.

  2. Report Deployer

    National Hurricane Center (2025). Tropical Storm Melissa Discussion Number 2, 500 PM EDT Tue Oct 21 2025, forecaster Cangialosi. NOAA/NWS.

    Original operational advisory recording the blend of DeepMind and other guidance.

  3. Report Deployer

    National Hurricane Center (2025). Tropical Storm Melissa Discussion Number 8, 500 AM EDT Thu Oct 23 2025, forecaster Cangialosi. NOAA/NWS.

    Original operational advisory recording a later adjustment toward DeepMind and HCCA guidance.

  4. Report Deployer

    National Hurricane Center (2025). Tropical Storm Melissa Discussion Number 10, 500 PM EDT Thu Oct 23 2025, forecaster Papin. NOAA/NWS.

    Original operational advisory recording track and intensity guidance. It does not isolate downstream public benefits.

  5. Report Deployer

    National Hurricane Center (2025). Tropical Storm Melissa Discussion Number 13, 1100 AM EDT Fri Oct 24 2025, forecaster Papin. NOAA/NWS.

    Original operational advisory recording the ensemble’s Category 4-or-higher signal.

  6. Report Deployer

    National Hurricane Center (2025). Tropical Storm Melissa Discussion Number 14, 500 PM EDT Fri Oct 24 2025, forecaster Papin. NOAA/NWS.

    Original operational advisory recording the intensity forecast’s agreement with GDMI.

  7. Report Deployer

    National Hurricane Center (2025). Hurricane Melissa Tropical Cyclone Update, 100 PM EDT Tue Oct 28 2025. NOAA/NWS.

    Original landfall update establishing storm context, not the AI system’s effect on public outcomes.

  8. Press release Deployer

    National Weather Service (n.d.). AI in Hurricane Forecasting at the National Hurricane Center: A Q&A with NHC Science Operation Officer Wallace Hogsett. NOAA/NWS News Around NOAA.

    Original interview with NHC’s Science Operations Officer. NHC deployed the model and partnered in its development; this is not an independent evaluation.

  9. Report Deployer

    Cangialosi, J. P., Martinez, J., Reinhart, B., Papin, P. (2026). National Hurricane Center Forecast Verification Report: 2025 Hurricane Season. NOAA/NHC, 30 March 2026.

    Original seasonal verification by NHC and a cooperating researcher. It evaluates forecasting performance, but it is not an independent evaluation of AI-attributable humanitarian outcomes.

  10. Report Deployer

    Kelly, Larry A., José Álamo, and Aidan D. Mahoney. Hurricane Melissa (AL132025), 21–31 October 2025. National Hurricane Center Tropical Cyclone Report. Revised May 19, 2026, originally February 25, 2026. 16–17, Tables 5b and 6b.

    Printed pp. 16–17, Track Forecast and Intensity Forecast, Tables 5b and 6b.

    Original retrospective verification by the agency that used the guidance. The report compares track and intensity forecasts for Melissa and explains how GDMI and regional models contributed to forecasters’ confidence. It does not isolate the AI model’s effect on humanitarian outcomes.