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- Predictability: the IFS ensemble gave an early signal. The EFI for the 5-day precipitation over Crete was 0.6-0.8 in the forecast from 26 September 00UTC (4 days before the start of the event) and above 0.8 from 27 September, while there was little signal from 25 September. In the forecast evolution plot the ENS median for the box increased from below 20 mm (24 September and earlier) to about 90-100 mm (26-27 September) and about 200 mm in the last forecast, compared with 215 mm observed (station average) and 189 mm in the analysis. All 200 values in The observed total was well above the 99th percentile of the model climate are below 95 mm, so the event was far outside the model climate(about 83 mm); only 2 of the 1600 hindcast values reached it. Only from 29 September 00UTC did more than half of the ENS members exceed 150 mm.
- Systematic errors compared with observations: the short-range IFS forecast (HRES from 30 September 00UTC, 213 mm) matched the box observations well. However, all models put the maximum along the north coast and over the sea north of western and central Crete, and underestimated the rainfall over eastern Crete (Heraklion-Lasithi), where stations reported 200-400 mm while the forecasts gave mostly 50-150 mm. Stations on the south coast also had more rain (30-80 mm) than the forecast rain-shadow minimum (mostly 10-30 mm).
- IFS versus AIFS: AIFS-single and the AIFS ensemble were consistently drier than IFS. In the shortest-range forecast AIFS-single gave 109 mm in the box, against 213 mm for HRES. In the last two runs the AIFS-ENS median was 116-125 mm, against 160-196 mm for ENS, and only 28-38% of AIFS-ENS members exceeded 150 mm, against 66-90% of ENS members. The AIFS fields are smoother and lack the orographic detail of IFS, but the band of heavy rain was in a similar position.
- Run-to-run consistency: HRES jumped between consecutive runs (for example 102 mm from 28 September 00UTC, then 183 mm and 259 mm from the next two runs), while the ENS median increased steadily over the last 4-5 days before the event.
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