Classification: correct Confidence: The model is performing well across the spectrum of event magnitudes recently. It has moved from a false positive (overprediction) to accurate predictions on quiet days, suggesting the response coefficient is now well-calibrated for the Boxley basin's small size and steep response. The high confidence rating is justified.
The physics model accurately predicted a negligible peak flow response (1.5 CFS vs 1.64 CFS actual) following a small, light rainfall event in dry antecedent conditions.
| Metric | Predicted | Actual | Error |
|---|---|---|---|
| Peak CFS | 2 CFS | 2 CFS | -0 CFS |
| Total rise | — | 0.1 CFS | — |
| Band | Zone | Precip | Predicted Rise | Intensity |
|---|---|---|---|---|
The physics model demonstrated high accuracy in magnitude prediction for this quiet day. With only 0.449 inches of rainfall and a DRY antecedent moisture tier (0.5 multiplier), the predicted peak of 1.5 CFS was within 6.1% of the actual observed peak of 1.64 CFS. This falls well within the 'correct' classification threshold for a quiet day where the model correctly identified the lack of significant runoff generation. The primary discrepancy was in timing, with a 22.9-hour error, but given the minimal rise (0.1 CFS) and the nature of the event, the magnitude prediction is the critical factor for whitewater run usability and was successful.
No empirical forecast was issued for the Hailstone gauge today, so no assessment of the empirical headline can be made. The physics model's performance here reinforces the recent calibration adjustments made after the false positive on 2026-08-06, showing that the reduced response coefficient (206.5 CFS/inch) now appropriately scales down predictions for low-intensity, dry-basin events, avoiding the previous trend of overprediction on small events.
No changes made.