{"abstract":"RH exactly 10% uses the very-dry regression.","category":"Weather index computation","checks":8,"contract":"Equilibrium moisture m: RH<10: 0.03229+0.281073RH-0.000578RH*T; 10<=RH<=50: 2.22749+0.160107RH-0.01478T; RH>50: 21.0606+0.005565RH^2-0.00035RH*T-0.483199RH. x=m/30; eta=1-2x+1.5x^2-0.5x^3; FFWI = eta*sqrt(1+U^2)/0.3002 clamped to [0,100] and rounded to 0.1.","evaluation_group":"w2-weather_index_computation-fosberg-ffwi","failed_approach":"Shrinking the dry branch to RH < 5 pushes 5-9% RH into the middle regression.","family":"w2-weather_index_computation-fosberg-ffwi-dry-branch-edge","id":"FA-71091","implementations":{"attempt":{"sha256":"9f87f33bb1a78e5749b6b975eb1cf4ec74f88f4a90c2c370542f1ca1ca2b9f3f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(t_f, rh, wind_mph):\n    if rh < 5:\n        m = 0.03229 + 0.281073 * rh - 0.000578 * rh * t_f\n    elif rh <= 50:\n        m = 2.22749 + 0.160107 * rh - 0.01478 * t_f\n    else:\n        m = 21.0606 + 0.005565 * rh * rh - 0.00035 * rh * t_f - 0.483199 * rh\n    x = m / 30.0\n    eta = 1 - 2 * x + 1.5 * x * x - 0.5 * x ** 3\n    f = eta * math.sqrt(1 + wind_mph ** 2) / 0.3002\n    return round(min(max(f, 0.0), 100.0), 1)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['40F 5% RH wind 0 mph', [40, 5, 0], 3.0], ['40F 5% RH wind 10 mph', [40, 5, 10], 30.6], ['40F 5% RH wind 30 mph', [40, 5, 30], 91.5], ['40F 9% RH wind 0 mph', [40, 9, 0], 2.8], ['40F 9% RH wind 10 mph', [40, 9, 10], 28.5], ['40F 9% RH wind 30 mph', [40, 9, 30], 85.2], ['40F 10% RH wind 0 mph', [40, 10, 0], 2.7], ['40F 10% RH wind 10 mph', [40, 10, 10], 26.8]], [['40F 10% RH wind 10 mph', [40, 10, 10], 26.8], ['40F 10% RH wind 30 mph', [40, 10, 30], 80.1], ['40F 11% RH wind 0 mph', [40, 11, 0], 2.6], ['40F 11% RH wind 10 mph', [40, 11, 10], 26.5], ['40F 11% RH wind 30 mph', [40, 11, 30], 79.2], ['40F 30% RH wind 0 mph', [40, 30, 0], 2.1], ['70F 5% RH wind 0 mph', [70, 5, 0], 3.1], ['70F 10% RH wind 10 mph', [70, 10, 10], 27.7]], [['40F 30% RH wind 30 mph', [40, 30, 30], 63.5], ['40F 49% RH wind 0 mph', [40, 49, 0], 1.7], ['40F 49% RH wind 10 mph', [40, 49, 10], 16.8], ['40F 49% RH wind 30 mph', [40, 49, 30], 50.2], ['40F 50% RH wind 0 mph', [40, 50, 0], 1.7], ['40F 50% RH wind 10 mph', [40, 50, 10], 16.6], ['70F 9% RH wind 30 mph', [70, 9, 30], 86.1], ['95F 10% RH wind 10 mph', [95, 10, 10], 28.4]], [['40F 10% RH wind 10 mph', [40, 10, 10], 26.8], ['40F 51% RH wind 0 mph', [40, 51, 0], 1.6], ['40F 51% RH wind 10 mph', [40, 51, 10], 15.9], ['40F 51% RH wind 30 mph', [40, 51, 30], 47.5], ['40F 80% RH wind 0 mph', [40, 80, 0], 0.9], ['40F 80% RH wind 10 mph', [40, 80, 10], 8.7], ['40F 80% RH wind 30 mph', [40, 80, 30], 26.0], ['95F 9% RH wind 30 mph', [95, 9, 30], 86.9]], [['40F 9% RH wind 10 mph', [40, 9, 10], 28.5], ['40F 100% RH wind 10 mph', [40, 100, 10], 1.7], ['40F 100% RH wind 30 mph', [40, 100, 30], 5.1], ['70F 5% RH wind 0 mph', [70, 5, 0], 3.1], ['70F 5% RH wind 10 mph', [70, 5, 10], 30.8], ['70F 5% RH wind 30 mph', [70, 5, 30], 92.0], ['70F 9% RH wind 0 mph', [70, 9, 0], 2.9], ['70F 10% RH wind 30 mph', [70, 10, 30], 82.6]]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"cb29006662b5da3ad7a6c302fafccc6c316db35e168948339af4b3f6f1d0ac8e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(t_f, rh, wind_mph):\n    if rh <= 10:\n        m = 0.03229 + 0.281073 * rh - 0.000578 * rh * t_f\n    elif rh <= 50:\n        m = 2.22749 + 0.160107 * rh - 0.01478 * t_f\n    else:\n        m = 21.0606 + 0.005565 * rh * rh - 0.00035 * rh * t_f - 0.483199 * rh\n    x = m / 30.0\n    eta = 1 - 2 * x + 1.5 * x * x - 0.5 * x ** 3\n    f = eta * math.sqrt(1 + wind_mph ** 2) / 0.3002\n    return round(min(max(f, 0.0), 100.0), 1)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['40F 5% RH wind 0 mph', [40, 5, 0], 3.0], ['40F 5% RH wind 10 mph', [40, 5, 10], 30.6], ['40F 5% RH wind 30 mph', [40, 5, 30], 91.5], ['40F 9% RH wind 0 mph', [40, 9, 0], 2.8], ['40F 9% RH wind 10 mph', [40, 9, 10], 28.5], ['40F 9% RH wind 30 mph', [40, 9, 30], 85.2], ['40F 10% RH wind 0 mph', [40, 10, 0], 2.7], ['40F 10% RH wind 10 mph', [40, 10, 10], 26.8]], [['40F 10% RH wind 10 mph', [40, 10, 10], 26.8], ['40F 10% RH wind 30 mph', [40, 10, 30], 80.1], ['40F 11% RH wind 0 mph', [40, 11, 0], 2.6], ['40F 11% RH wind 10 mph', [40, 11, 10], 26.5], ['40F 11% RH wind 30 mph', [40, 11, 30], 79.2], ['40F 30% RH wind 0 mph', [40, 30, 0], 2.1], ['70F 5% RH wind 0 mph', [70, 5, 0], 3.1], ['70F 10% RH wind 10 mph', [70, 10, 10], 27.7]], [['40F 30% RH wind 30 mph', [40, 30, 30], 63.5], ['40F 49% RH wind 0 mph', [40, 49, 0], 1.7], ['40F 49% RH wind 10 mph', [40, 49, 10], 16.8], ['40F 49% RH wind 30 mph', [40, 49, 30], 50.2], ['40F 50% RH wind 0 mph', [40, 50, 0], 1.7], ['40F 50% RH wind 10 mph', [40, 50, 10], 16.6], ['70F 9% RH wind 30 mph', [70, 9, 30], 86.1], ['95F 10% RH wind 10 mph', [95, 10, 10], 28.4]], [['40F 10% RH wind 10 mph', [40, 10, 10], 26.8], ['40F 51% RH wind 0 mph', [40, 51, 0], 1.6], ['40F 51% RH wind 10 mph', [40, 51, 10], 15.9], ['40F 51% RH wind 30 mph', [40, 51, 30], 47.5], ['40F 80% RH wind 0 mph', [40, 80, 0], 0.9], ['40F 80% RH wind 10 mph', [40, 80, 10], 8.7], ['40F 80% RH wind 30 mph', [40, 80, 30], 26.0], ['95F 9% RH wind 30 mph', [95, 9, 30], 86.9]], [['40F 9% RH wind 10 mph', [40, 9, 10], 28.5], ['40F 100% RH wind 10 mph', [40, 100, 10], 1.7], ['40F 100% RH wind 30 mph', [40, 100, 30], 5.1], ['70F 5% RH wind 0 mph', [70, 5, 0], 3.1], ['70F 5% RH wind 10 mph', [70, 5, 10], 30.8], ['70F 5% RH wind 30 mph', [70, 5, 30], 92.0], ['70F 9% RH wind 0 mph', [70, 9, 0], 2.9], ['70F 10% RH wind 30 mph', [70, 10, 30], 82.6]]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"e38de9aea17f4a84749f28d53c521046fe28a7d3c3ef3dcc9fcd29db3741a260","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(t_f, rh, wind_mph):\n    if rh < 10:\n        m = 0.03229 + 0.281073 * rh - 0.000578 * rh * t_f\n    elif rh <= 50:\n        m = 2.22749 + 0.160107 * rh - 0.01478 * t_f\n    else:\n        m = 21.0606 + 0.005565 * rh * rh - 0.00035 * rh * t_f - 0.483199 * rh\n    x = m / 30.0\n    eta = 1 - 2 * x + 1.5 * x * x - 0.5 * x ** 3\n    f = eta * math.sqrt(1 + wind_mph ** 2) / 0.3002\n    return round(min(max(f, 0.0), 100.0), 1)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['40F 5% RH wind 0 mph', [40, 5, 0], 3.0], ['40F 5% RH wind 10 mph', [40, 5, 10], 30.6], ['40F 5% RH wind 30 mph', [40, 5, 30], 91.5], ['40F 9% RH wind 0 mph', [40, 9, 0], 2.8], ['40F 9% RH wind 10 mph', [40, 9, 10], 28.5], ['40F 9% RH wind 30 mph', [40, 9, 30], 85.2], ['40F 10% RH wind 0 mph', [40, 10, 0], 2.7], ['40F 10% RH wind 10 mph', [40, 10, 10], 26.8]], [['40F 10% RH wind 10 mph', [40, 10, 10], 26.8], ['40F 10% RH wind 30 mph', [40, 10, 30], 80.1], ['40F 11% RH wind 0 mph', [40, 11, 0], 2.6], ['40F 11% RH wind 10 mph', [40, 11, 10], 26.5], ['40F 11% RH wind 30 mph', [40, 11, 30], 79.2], ['40F 30% RH wind 0 mph', [40, 30, 0], 2.1], ['70F 5% RH wind 0 mph', [70, 5, 0], 3.1], ['70F 10% RH wind 10 mph', [70, 10, 10], 27.7]], [['40F 30% RH wind 30 mph', [40, 30, 30], 63.5], ['40F 49% RH wind 0 mph', [40, 49, 0], 1.7], ['40F 49% RH wind 10 mph', [40, 49, 10], 16.8], ['40F 49% RH wind 30 mph', [40, 49, 30], 50.2], ['40F 50% RH wind 0 mph', [40, 50, 0], 1.7], ['40F 50% RH wind 10 mph', [40, 50, 10], 16.6], ['70F 9% RH wind 30 mph', [70, 9, 30], 86.1], ['95F 10% RH wind 10 mph', [95, 10, 10], 28.4]], [['40F 10% RH wind 10 mph', [40, 10, 10], 26.8], ['40F 51% RH wind 0 mph', [40, 51, 0], 1.6], ['40F 51% RH wind 10 mph', [40, 51, 10], 15.9], ['40F 51% RH wind 30 mph', [40, 51, 30], 47.5], ['40F 80% RH wind 0 mph', [40, 80, 0], 0.9], ['40F 80% RH wind 10 mph', [40, 80, 10], 8.7], ['40F 80% RH wind 30 mph', [40, 80, 30], 26.0], ['95F 9% RH wind 30 mph', [95, 9, 30], 86.9]], [['40F 9% RH wind 10 mph', [40, 9, 10], 28.5], ['40F 100% RH wind 10 mph', [40, 100, 10], 1.7], ['40F 100% RH wind 30 mph', [40, 100, 30], 5.1], ['70F 5% RH wind 0 mph', [70, 5, 0], 3.1], ['70F 5% RH wind 10 mph', [70, 5, 10], 30.8], ['70F 5% RH wind 30 mph', [70, 5, 30], 92.0], ['70F 9% RH wind 0 mph', [70, 9, 0], 2.9], ['70F 10% RH wind 30 mph', [70, 10, 30], 82.6]]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, solve(*args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Stipulated deterministic teaching model of an operational weather index; coefficients and thresholds are fixed by the contract and no claim of standards conformance is made. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-weather_index_computation-fosberg-ffwi-dry-branch-edge","generated_at":"2026-09-29T14:48:26.638643+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Red flag warnings and fire-weather dashboards chart FFWI.","repair":"Use the dry regression only for RH < 10.","root_cause":"The dry regression includes RH = 10.","sha256":"ee38159c43cd258e39fb7838b49d347356c8503d960fee32f45496d5fef17c24","title":"Fosberg fire weather index: dry branch edge · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":37.563,"exit_code":1,"observations":[{"actual":2.8,"check":"40F 5% RH wind 0 mph","expected":3.0,"passed":false},{"actual":28.4,"check":"40F 5% RH wind 10 mph","expected":30.6,"passed":false},{"actual":84.7,"check":"40F 5% RH wind 30 mph","expected":91.5,"passed":false},{"actual":2.7,"check":"40F 9% RH wind 0 mph","expected":2.8,"passed":false},{"actual":27.1,"check":"40F 9% RH wind 10 mph","expected":28.5,"passed":false},{"actual":81.0,"check":"40F 9% RH wind 30 mph","expected":85.2,"passed":false},{"actual":2.7,"check":"40F 10% RH wind 0 mph","expected":2.7,"passed":true},{"actual":26.8,"check":"40F 10% RH wind 10 mph","expected":26.8,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"40F 5% RH wind 0 mph\", \"actual\": 2.8, \"expected\": 3.0, \"passed\": false}, {\"check\": \"40F 5% RH wind 10 mph\", \"actual\": 28.4, \"expected\": 30.6, \"passed\": false}, {\"check\": \"40F 5% RH wind 30 mph\", \"actual\": 84.7, \"expected\": 91.5, \"passed\": false}, {\"check\": \"40F 9% RH wind 0 mph\", \"actual\": 2.7, \"expected\": 2.8, \"passed\": false}, {\"check\": \"40F 9% RH wind 10 mph\", \"actual\": 27.1, \"expected\": 28.5, \"passed\": false}, {\"check\": \"40F 9% RH wind 30 mph\", \"actual\": 81.0, \"expected\": 85.2, \"passed\": false}, {\"check\": \"40F 10% RH wind 0 mph\", \"actual\": 2.7, \"expected\": 2.7, \"passed\": true}, {\"check\": \"40F 10% RH wind 10 mph\", \"actual\": 26.8, \"expected\": 26.8, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.204,"exit_code":1,"observations":[{"actual":3.0,"check":"40F 5% RH wind 0 mph","expected":3.0,"passed":true},{"actual":30.6,"check":"40F 5% RH wind 10 mph","expected":30.6,"passed":true},{"actual":91.5,"check":"40F 5% RH wind 30 mph","expected":91.5,"passed":true},{"actual":2.8,"check":"40F 9% RH wind 0 mph","expected":2.8,"passed":true},{"actual":28.5,"check":"40F 9% RH wind 10 mph","expected":28.5,"passed":true},{"actual":85.2,"check":"40F 9% RH wind 30 mph","expected":85.2,"passed":true},{"actual":2.8,"check":"40F 10% RH wind 0 mph","expected":2.7,"passed":false},{"actual":28.0,"check":"40F 10% RH wind 10 mph","expected":26.8,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"40F 5% RH wind 0 mph\", \"actual\": 3.0, \"expected\": 3.0, \"passed\": true}, {\"check\": \"40F 5% RH wind 10 mph\", \"actual\": 30.6, \"expected\": 30.6, \"passed\": true}, {\"check\": \"40F 5% RH wind 30 mph\", \"actual\": 91.5, \"expected\": 91.5, \"passed\": true}, {\"check\": \"40F 9% RH wind 0 mph\", \"actual\": 2.8, \"expected\": 2.8, \"passed\": true}, {\"check\": \"40F 9% RH wind 10 mph\", \"actual\": 28.5, \"expected\": 28.5, \"passed\": true}, {\"check\": \"40F 9% RH wind 30 mph\", \"actual\": 85.2, \"expected\": 85.2, \"passed\": true}, {\"check\": \"40F 10% RH wind 0 mph\", \"actual\": 2.8, \"expected\": 2.7, \"passed\": false}, {\"check\": \"40F 10% RH wind 10 mph\", \"actual\": 28.0, \"expected\": 26.8, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.849,"exit_code":0,"observations":[{"actual":3.0,"check":"40F 5% RH wind 0 mph","expected":3.0,"passed":true},{"actual":30.6,"check":"40F 5% RH wind 10 mph","expected":30.6,"passed":true},{"actual":91.5,"check":"40F 5% RH wind 30 mph","expected":91.5,"passed":true},{"actual":2.8,"check":"40F 9% RH wind 0 mph","expected":2.8,"passed":true},{"actual":28.5,"check":"40F 9% RH wind 10 mph","expected":28.5,"passed":true},{"actual":85.2,"check":"40F 9% RH wind 30 mph","expected":85.2,"passed":true},{"actual":2.7,"check":"40F 10% RH wind 0 mph","expected":2.7,"passed":true},{"actual":26.8,"check":"40F 10% RH wind 10 mph","expected":26.8,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"40F 5% RH wind 0 mph\", \"actual\": 3.0, \"expected\": 3.0, \"passed\": true}, {\"check\": \"40F 5% RH wind 10 mph\", \"actual\": 30.6, \"expected\": 30.6, \"passed\": true}, {\"check\": \"40F 5% RH wind 30 mph\", \"actual\": 91.5, \"expected\": 91.5, \"passed\": true}, {\"check\": \"40F 9% RH wind 0 mph\", \"actual\": 2.8, \"expected\": 2.8, \"passed\": true}, {\"check\": \"40F 9% RH wind 10 mph\", \"actual\": 28.5, \"expected\": 28.5, \"passed\": true}, {\"check\": \"40F 9% RH wind 30 mph\", \"actual\": 85.2, \"expected\": 85.2, \"passed\": true}, {\"check\": \"40F 10% RH wind 0 mph\", \"actual\": 2.7, \"expected\": 2.7, \"passed\": true}, {\"check\": \"40F 10% RH wind 10 mph\", \"actual\": 26.8, \"expected\": 26.8, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}