Lifting Condensation Level (LCL) Height mechanism

Model scope

The honest-label wording correctly identifies this as a rule-of-thumb approximation. Release requires explicit temperature units, an explicit output unit or both-unit behavior, and validation that dew point is less than or equal to temperature.

• Espy's rule, LCL(m) ≈ 125·(T−Td), is a standard rule-of-thumb when T and Td are in °C (or temperature differences expressed in K) and the result is in meters.
• The specification does not define the required input temperature units or whether the output is meters, feet, or both.
• The specification does not state the domain constraint Td ≤ T; allowing Td > T produces a physically invalid negative cloud-base height.

Units and conventions

• The coefficient 125 applies to a temperature difference in °C; a difference in kelvins has the same numerical value.
• The primary result is assumed to be in meters.
• Feet are obtained with 1 m = 3.28084 ft.
• Fahrenheit inputs must be converted to °C before applying the formula; applying 125 directly to a Fahrenheit difference is invalid.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "temperature": 25,
    "dew_point": 17,
    "temperature_unit": "°C",
    "output_unit": "m_and_ft"
  },
  "expected_outputs": {
    "lcl_height_m": 1000,
    "lcl_height_ft": 3280.84
  },
  "working": "T − Td = 25 − 17 = 8 °C. LCL = 125 × 8 = 1000 m. Feet = 1000 × 3.28084 = 3280.84 ft."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The specification does not define temperature units or validation behavior for Td greater than T, and an extreme but finite JavaScript input overflows to Infinity. A robust implementation should require compatible temperature units, flag negative LCL results, and handle numeric overflow explicitly.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json