Classification: correct Confidence: Model confidence remains high as the magnitude prediction was very close to observed. The timing error is notable but does not warrant immediate coefficient changes given the small scale of the event. The model is stable.
The physics model accurately predicted the peak flow magnitude for a small evening rainfall event (18.8 CFS predicted vs 19.3 CFS actual), though the timing was off by nearly 6 hours.
| Metric | Predicted | Actual | Error |
|---|---|---|---|
| Peak CFS | 19 CFS | 19 CFS | -0 CFS |
| Total rise | — | 3.9 CFS | — |
| Band | Zone | Precip | Predicted Rise | Intensity |
|---|---|---|---|---|
The physics model performed exceptionally well regarding magnitude prediction. With a predicted peak of 18.8 CFS and an actual peak of 19.3 CFS, the error was a mere -2.6%, well within the 'correct' threshold of ±15-20%. The model correctly identified that despite 1.159" of rain falling in the late evening (21:05-23:05 UTC), the response would be minimal in terms of peak flow increase, rising only 3.9 CFS. This suggests the current response coefficient of 234.6 CFS/inch, combined with the NORMAL moisture multiplier (1.0), is appropriately tuned for low-intensity, delayed precipitation events.
However, the timing prediction was poor, with the model forecasting a peak 5.9 hours later than observed. Given the basin's steepness and fast response (~1.5 hr lag), a nearly 6-hour delay suggests the dispersion parameter or the handling of late-night/early-morning precipitation arrival might need refinement, but changing dispersion based on a single small event is risky. The magnitude accuracy is the primary calibration goal, which was met.
No empirical forecast headline was issued today. Since the rise was trivial (3.9 CFS) and did not reach any of the Hailstone gauge thresholds (low 500, medium 700, high 2000), the absence of a headline is arguably appropriate as no significant whitewater conditions were generated. However, strictly following the schema, since no headline was issued, the empirical assessment is null.
No changes made.