Classification: partial Confidence: Model confidence remains 'medium'. The recent false positives have eroded trust in QPE data, but today's event shows the model can still capture the magnitude of small rises even when timing is off. The lack of sensor confirmation for the QPE rain makes this event ambiguous. We will continue to monitor for consistency.
The model correctly identified a minor rise in gauge stage driven by light QPE rainfall but significantly mispredicted the timing of the peak, placing it nearly 16 hours later than the actual event.
| Metric | Predicted | Actual | Error |
|---|---|---|---|
| Peak height | 0.46 ft | 0.47 ft | -0.01 ft |
| Total rise | — | 0.13 ft | — |
| Band | Zone | Precip | Predicted Rise | Intensity | Moisture |
|---|---|---|---|---|---|
Headline: No rise indicated by recent rainfall Settled outcome: None (reached None) LLM said headline was correct: True Notes: The empirical headline stated 'No rise indicated by recent rainfall' based on QPE. While the gauge did rise slightly (0.13 ft), it remained far below the 'low' threshold of 3.0 ft. The headline was effectively correct in predicting no meaningful tier change, even if it missed the tiny magnitude rise. The QPE was low, and the sensor confirmed zero rain, supporting the 'no rise' classification in terms of operational thresholds.
The event occurred on 2026-08-24 with WET antecedent moisture. The QPE recorded approximately 0.5-0.6 inches of rainfall in the early morning hours (03:00-07:00), which the gauge precipitation sensor confirmed was zero, indicating the QPE likely captured a localized or short-duration event not fully representative of the entire basin, or the sensor failed to record the trace. Despite the sensor reading, the gauge rose 0.13 ft, reaching a peak of 0.47 ft at 08:00. This aligns with the hydrograph shape (sharp) suggesting a rapid response, likely from the upper band (Band 1) which has a higher response coefficient.
The prediction engine generated a peak of 0.46 ft, which is an excellent magnitude match (error -2.1%) to the actual 0.47 ft peak. However, the predicted time was 2026-08-25T04:50 UTC, which is approximately 15.8 hours after the actual peak time (2026-08-24T08:00 CDT / 13:00 UTC). This large timing error suggests the model overestimated the lag or dispersion for this specific rainfall intensity and moisture condition. The rainfall occurred early in the day, and the response was immediate relative to the typical 2.7-2.8 hour lag, or the lag was effectively compressed due to the 'WET' moisture tier and the specific distribution of rainfall (heavier in the first few hours).
Because the magnitude was correct but the timing was significantly off, this is classified as 'partial'. The model is not failing in its ability to estimate the height of the rise, but it is mischaracterizing the timing dynamics. The recent history shows repeated false positives due to QPE overestimation (events 3 and 4), leading to coefficient reductions. Today's event, where the QPE was not supported by the gauge sensor but a rise still occurred (likely from baseflow or unrecorded trace rain), highlights the difficulty of interpreting small rises without sensor confirmation. No further coefficient reduction is recommended as the magnitude was accurate; the issue is likely a structural timing lag that may not be adjustable via simple coefficient tweaks without risking underprediction in other scenarios.
No changes made.
Model confidence remains 'medium'. The recent false positives have eroded trust in QPE data, but today's event shows the model can still capture the magnitude of small rises even when timing is off. The lack of sensor confirmation for the QPE rain makes this event ambiguous. We will continue to monitor for consistency.