Flood Forecast

Last updated: 2026-09-01 12:00:00 SAST
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Weather Models

Statistics

Water Level
Min—
Mean—
Max—
Rainfall
Total—
Max Hourly—
Mean Hourly—
Wet Hours—

Forecast Accuracy

MAE (m) by forecast horizon
Model 1-6h 7-12h 13-24h 25-48h 49-72h 73h+
Ensemble Mean 0.0695 0.0698 0.0680 0.0659 0.0659 0.0665
Best Match 0.0681 0.0707 0.0681 0.0641 0.0663 0.0699
CMA GRAPES 0.0748 0.0748 0.0753 0.0710 0.0697 0.0724
ECMWF AIFS 0.0691 0.0684 0.0666 0.0658 0.0642 0.0687
ECMWF IFS 0.0679 0.0705 0.0679 0.0646 0.0656 0.0685
ECMWF IFS 0.25° 0.0707 0.0719 0.0686 0.0674 0.0675 0.0692
GFS Global 0.0737 0.0726 0.0731 0.0711 0.0695 0.0714
GFS Seamless 0.0737 0.0726 0.0731 0.0711 0.0695 0.0714
MET Norway 0.0679 0.0705 0.0679 0.0646 0.0656 0.0685
NCEP AI-GFS 0.0712 0.0703 0.0683 0.0681 0.0675 0.0719
NCEP HGEFS 0.0699 0.0690 0.0675 0.0678 0.0676 0.0675
UKMO Global 0.0760 0.0749 0.0732 0.0729 0.0763 0.0749
Based on 370,380 prediction-observation comparisons (all-time). Updates every hour as new observations verify past predictions.
How is this calculated?

Each hour, the system generates water level predictions for the next 7 days using each weather model's rainfall forecast. Once real observations come in, the predicted values are compared against what actually happened. MAE (Mean Absolute Error) is the average difference between predicted and observed levels — lower is better. Columns group predictions by how far ahead they were made: a "1-6h" prediction is easier to get right than a "73h+" one. Values are colour-coded: green < 0.02m, yellow < 0.05m, orange < 0.1m, red ≥ 0.1m.