Description
Measure a forecast valid time's signed offset from its issue time.
Weather accumulation records need explicit reset, carry, observation-time and area-weight conventions. Trace or missing precipitation differs from measured zero, and radar dBZ must be converted to a linear basis before a linear reflectivity mean. Supplied density, timing and weighting terms do not create a forecast or verify actual weather conditions.
Measure a forecast valid time's signed offset from its issue time.
When to use this tool
Use Hourly Weather Forecast Validtime Offset when you already have issuedEpochHours, validEpochHours and need to measure a forecast valid time's signed offset from its issue time.
How to use the tool and how it works
- Enter issuedEpochHours, validEpochHours. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read signedGap. Use the output convention below.
Return validEpochHours-issuedEpochHours on the same epoch-hour basis.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| issuedEpochHours | Issued Epoch Hours | Required. Finite number. |
| validEpochHours | Valid Epoch Hours | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| signedGap | Signed Gap | Required. Finite number. |
{
"input": {
"issuedEpochHours": 12,
"validEpochHours": 17
},
"output": {
"signedGap": 5
}
}Limitations and assumptions
- The tool does not parse dates, convert timezones, produce a forecast or verify actual lead time.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Review the original gauge/radar series, clock and accumulation metadata, including resets and missing intervals. Use the complete spatial or process model for basin precipitation, snow or forecasting; local depth contributions and reference gaps do not infer unobserved weather.
References
Similar or alternative tools
- Weather Forcing Accumulation Offset
Calculate an accumulation increment using a supplied reset reference.
- Precipitation Reporting Window Carry Offset
Adjust a reported accumulation under an explicit carry-in/carry-out sign convention.