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The plots below show 72-hour precipitation (30 April 00UTC - 3 May 00UTC) in observations (first plot) concatenated short forecasts (second plot) and ENS control forecasts with different lead times. The box marks 0.25x0.25 degree centred on Caxias. The analysis plot based on 6-hour forecasts clearly underestimated the rainfall around Caxias, while the forecasts more or less missed the extreme on all lead times but instead had the maximum rainfall further to the west.
The plots below shows the same as above but forecasts from DestinE. The performance for Destine (4.4km) is similar to the 9-km version above.
The plots below shows the same as above but forecasts from AIFS. These forecasts also had the maximum rainfall shifted to the south, but the smoothness might have helped to bring up the totals around Caxias.
3.3 ENS
The plots below shows EFI for 3-day precipitation (30 April-2 May) from different initial dates. There was an early signal in the EFI, but in the short-range the rainfall shifted to the south and did not saturate towards 1.
The plot below shows the forecast evolution plot for 72-hour precipitation for Caxias.
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Model climate – cyan box-and-whisker
Ensemble mean as black diamonds. Triangle marks the maximum in the model climate based on 1800 forecasts.
While predicting extreme (around 99th percentile of the model climate) for Caxias, the forecast did not predict anything exceptional as seen in the observations. One can note that AIFS was somewhat higher than the ensemble mean for most forecasts.
The plot below shows the same as above but for Santa Maria. The plot from the concatenated analysis included to show the location of Santa Maria.
For Santa Maria the extreme was somewhat better captured, with the shortest forecast having an ensemble mean above the maximum in the model climatology but still only half of the measured 3-day precipitation. One can note that the control forecasts was always on the lower end of the ensemble in the short-range forecasts.
3.4 Monthly forecasts
The plots below show forecasts of weekly precipitation anomalies for 29 - 5 May. Already the longest forecast (5-week) predicted a wet anomaly in the region.
The plots below show forecasts of weekly z500 anomalies for 29 - 5 May.
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