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Cossatot River — Daily Analysis: 2026-04-28

Classification: partial Confidence: Model continues to show reasonable magnitude predictions with persistent timing challenges - confidence remains stable

Event Summary

Model underpredicted a 0.2 ft rise by 0.14 ft (4.3%) during a light multi-band rainfall event with timing error of 23.7 hours.

Prediction vs Actual

Metric Predicted Actual Error
Peak height 3.14 ft 3.28 ft -0.14 ft
Total rise 0.2 ft

Band Contributions

Band Precip Predicted Rise Intensity Moisture
4 0.25" 0.10 ft LIGHT WET
5 0.29" 0.08 ft LIGHT WET

Analysis

The model predicted a peak of 3.14 ft but the actual peak was 3.28 ft, representing a 4.3% underprediction. The rainfall was distributed across multiple bands with Band 2 receiving the highest amount (0.32") followed by Band 5 (0.29") and Band 4 (0.25"). However, the gauge recorded 0.18" which suggests Band 1 also received rainfall that wasn't captured in the QPE snapshots. The sharp hydrograph shape indicates near-gauge dominance despite the multi-band distribution.

The timing error of 23.7 hours is significant, with the actual peak occurring at the start of the day while the model predicted it for the following morning. This suggests the rainfall impact was more immediate than the model anticipated. The light intensity classification appears correct given the gradual accumulation pattern. Given the modest underprediction and the apparent Band 1 contribution not fully captured in QPE, small upward adjustments to the primary contributing bands are warranted.

The WET moisture conditions were correctly identified, and the overall prediction magnitude was reasonable. The timing issue may be related to the immediate response suggesting stronger near-gauge influence than the QPE data indicated.

Coefficient Adjustments

Band Change Reason
1 +5% Gauge recorded 0.18" but QPE shows minimal Band 1 rainfall - likely undercounted contribution from near-gauge area
2 +3% Highest QPE rainfall (0.32") suggests significant contribution - modest increase for underprediction
4 +3% Moderate rainfall (0.25") with underprediction suggests small upward adjustment
5 +3% Second highest rainfall (0.29") with underprediction suggests small upward adjustment

Notes

Model continues to show reasonable magnitude predictions with persistent timing challenges - confidence remains stable

← 2026-04-27  |  2026-05-06 →