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Signs of a rainfall extreme was seen from 6 April - 10 days before the event in the ensemble (median passed the model climate maximum).
ecPoint
Below are show 95th percentile values of 12h rainfall from ecPoint, for global view, to put the Middle East forecasts into perspective (for that day), and a local view to highlight absolute values. Note first two things: 1. these are for a specific 12h period (12h being the ecPoint default at the moment) of 06-18UTC, whilst others have generally quoted 24h rainfall values (the event lasted more than 12h overall I think), 2. the 95th percentile is shown (so a 1 in 20 exceedance prob for a given site), but any integer percentile value could be referenced (from 1 to 99), or indeed I could have shown exceedance probabilities.
These plots re-emphasise the stunning long range predictability for the event, at least in the ECMWF IFS. At 8 days out not only was this region clearly seeing the strongest signal for heavy (point) rainfall anywhere in the world, but this is in a normally arid area. These patterns were evidently maintained as the event approach, with absolute values of the percentiles going up somewhat.
Day 8 ecPoint forecast (95th percentile)
Day 4 ecPoint forecast (95th percentile)
Day 2 ecPoint forecast (95th percentile)
As above row, but zoomed in versions
3.4 Monthly forecasts
3.5 Comparison with other centres
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