Status: Finalised Material from: Ivan, Linus
1. Impact
Historic flooding occurred in Louisiana last week. Some areas received more than 20 inches (about 500 mm) in few days. Rainfall totals exceeded more than 3 times the normal rainfall for August. The worst rain came last Friday when some areas received more than 400 mm just in less than 24 hours. Three people have been reported dead in the floods and thousands more have been rescued. Several rivers in Louisiana and Mississippi are overflowing.
2. Description of the event
3. Predictability
3.1 Data assimilation
3.2 HRES
The series of plots below show 24-hour rainfall accumulations (00z -00z) from NEXRAD (top-left), 0-24h HRES forecast (top-right) and 96-120h HRES forecast (bottom-left). The bottom-right shows integrated values over the region covered by NEXRAD. The whole period was very wet over northern Gulf of Mexico and in coastal states. The worst rainfall in Louisiana fell on 12 and 13 August.
9 August
10 Aug
11 Aug
12 Aug
13 Aug
3.3 ENS
The plots below show the EFI and SOT for 3-day precipitation (11-14 August).
3.4 Monthly forecasts
The plots below show the weekly precipitation anomaly from monthly forecasts valid 8-14 August. An wet anomaly is present in the forecast from 4 August but not before.
3.5 Comparison with other centres
4. Experience from general performance/other cases