Status:Ongoing analysis Material from: Linus

Picture

1. Impact

The March 2017 northern Peru was hit by severe flooding. The rainfall is suggested to be linked to a warm SST anomaly along the coast (coastal El Nino).

http://www.accuweather.com/en/weather-news/more-rain-expected-as-death-toll-rises-to-75-from-peru-flooding/70001160

2. Description of the event

3. Predictability

3.1 Data assimilation

3.2 HRES

3.3 ENS

3.4 Monthly and seasonal forecasts

The plots below show the ensemble mean precipitation anomaly for March 2017 from seasonal (system 4) forecasts. The signal was well captured in the forecast from 1 February but on January. However, earlier forecasts had a signal of wetter than normal.

The plots below show the same as above but for SST anomalies. The precipitation anomalies are linked to warm SST along the coast, with also was well captured in February but missed in January. The forecasts from December, November and October had the coastal anomaly as well.

3.5 Comparison with other centres

4. Experience from general performance/other cases

5. Good and bad aspects of the forecasts for the event

• The seasonal forecast missed the warming in January forecast

6. Additional material