{
  "schema": "cpx.poseidon.pre_registration.v1",
  "registered_on": "2026-11-13",
  "title": "POSEIDON / 2027–2030 Forward-Only Atlantic Seasonal Forecast Competition",
  "status": "RESEARCH_PRE_REGISTRATION_NO_FORECAST_VALUES_ISSUED",
  "independent_witness": "First public GitHub source commit and independent Cloudflare Pages release required; registration date in JSON is an author claim, not an independent timestamp.",
  "forecasts": [
    {
      "season": 2027,
      "freeze_by": "2027-03-15T23:59:59Z",
      "april_issue_deadline": "2027-04-01T23:59:59Z",
      "may_issue_deadline": "2027-05-15T23:59:59Z"
    },
    {
      "season": 2028,
      "freeze_by": "2028-03-15T23:59:59Z",
      "april_issue_deadline": "2028-04-01T23:59:59Z",
      "may_issue_deadline": "2028-05-15T23:59:59Z"
    },
    {
      "season": 2029,
      "freeze_by": "2029-03-15T23:59:59Z",
      "april_issue_deadline": "2029-04-01T23:59:59Z",
      "may_issue_deadline": "2029-05-15T23:59:59Z"
    },
    {
      "season": 2030,
      "freeze_by": "2030-03-15T23:59:59Z",
      "april_issue_deadline": "2030-04-01T23:59:59Z",
      "may_issue_deadline": "2030-05-15T23:59:59Z"
    }
  ],
  "metrics": [
    {
      "name": "named_storms",
      "units": "count",
      "primary_point_loss": "MAE",
      "secondary": "RMSE, bias"
    },
    {
      "name": "hurricanes",
      "units": "count",
      "primary_point_loss": "MAE",
      "secondary": "RMSE, bias"
    },
    {
      "name": "major_hurricanes",
      "units": "count",
      "primary_point_loss": "MAE",
      "secondary": "RMSE, bias"
    },
    {
      "name": "ACE",
      "units": "10^-4 kt^2",
      "primary_point_loss": "MAE",
      "secondary": "RMSE, bias"
    }
  ],
  "uncertainty": {
    "requirement": "Publish actual calibrated predictive distribution or honest uncalibrated band and label as such",
    "scoring": "CRPS/log scoring when a full density or proper categorical probabilities exist; interval coverage and width for honest predictive intervals",
    "no_posthoc_probability_creation": true
  },
  "matched_baselines": {
    "april": "Archived CSU pre-season April product, original issue date/source, same basin, target and information availability. If CSU releases after CPX April deadline, do not claim exact head-to-head equal-date comparison; report publication lead-time difference.",
    "may": "Official NOAA pre-season outlook, earliest available actual release and original ranges. Never treat NOAA range midpoint as a calibrated point forecast; compare intervals separately and annotate different issue dates.",
    "climatology": "Fixed trailing 30-year mean trained only on completed prior years, minimum 20 years. Count this as a separate baseline, not competitive evidence against official agency products."
  },
  "historical_era_policy": {
    "raw_hurdat2": "Use official NOAA revised best-track 1851-2025 with bytes hash, AOML crosschecks, revision date and retrospective label",
    "satellite": "No synthetic data or satellite observations predating sensor availability",
    "vintage": "Reanalyses published afterward cannot be used to claim pre-event historical skill",
    "season2026": "Do not use 2026 as final target truth until season closes and verified archive published"
  },
  "release_gate": [
    "Original forecast input snapshot and numeric forecast values exist before target outcome",
    "Immutable-by-policy forecast payload SHA256 with independently timestamped Git provider commit/deployment witness",
    "Forecast knowledge cutoff and original comparator issue cutoff archived",
    "No after-event model tweaks or selective target exclusions",
    "Every year and every pre-registered metric receives an outcome entry, even if missed",
    "Comparison only across contemporaneously comparable pre-season forecasts, with differences disclosed",
    "Independent technical reviewer reproduces results before public superiority claim",
    "No local flood-depth/emergency route or storm landfall years in advance attributed to annual season-count model"
  ],
  "claim_policy": {
    "single_year": "A single year can be described as a specific lower-error outcome only when verified, never general model superiority.",
    "multi_year": "Aggregate comparisons require all 2027–2030 eligible years, each metric, uncertainty and source provenance. Four years remain statistically limited.",
    "claim_superiority": false,
    "winner_status": "NONE — no forward model performance has yet been observed"
  },
  "versioning": {
    "immutable_rule": "Pre-registration is append-only by policy. Any change publishes amendment, original hash, reason, time and evidence; no retroactive replacement.",
    "allowed_amendments": "Data-source bug fixes with dated pre-event publication and visible changes; changed success criteria only prospective, never after seeing relevant outcome."
  }
}