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3. Predictability
3.1 Data assimilation
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The plot below shows the evolution of central pressure in Best Track (dots) and LWDA analysis (solid line). The analysis had difficulties to capture the intense phase on 5 September, but captured the second intensification.
3.2 HRES
3.3 ENS
The plots below show the tracks (ensemble -grey, best track - black), position and intensity on 14 September 00UTC (ensemble - squares, best track - hourglass) in forecasts from 13 September (first plot) to 4 September (last plot). Early forecasts had problems to capture the northward "kink" on 7 September. The forecast from 4 September also had a majority of members turning northward over the Atlantic. This changed on the 5 September, and the sensitivity analysis further down is targeting this change.
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The plots below shows EFI and SOT for 3-day accumulated precipitation valid 14-16 September. In the earliest forecast presented here (from 8 September), the SOT is already high while EFI is low. This is a sign of a few extreme members in the ensemble. As the forecast lead time decreases, the EFI increases as well.
The plot below shows the evolution of forecasts for 3-day accumulated precipitation (14-16 September) for Wilmington, North Carolina (34.3N,78W). The plot includes ENS (blue box-and-whisker), HRES (red dot) and model climate (red box and whisker). Although a few members highlighted the risk of extreme rainfall before, the majority of the ensemble picked up the signal gradually from 10 September 18UTC and onwards.
3.4 Monthly forecasts
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