Status:Ongoing analysis Material from: Linus, Ahmed
Picture
1. Impact
A severe weather event that affected the Maldives on Sunday 31st December. A low pressure area formed west of the Maldives late 30th Dec and resulted in very heavy rainfall over the country, especially the central region and capital island Male'. Hulhule station (VRMM), Central Maldives, reported a total of 179.7mm within 24 hours for 31st December 2023. This broke the previous record of 175.9mm on 23 Dec 1977. The main city island Male' was completely flooded and was dewatered using pumps. National Disaster Management Authority reported 140 households were assisted during the flood response and 42 people from 8 households are currently in temporary shelters.
2. Description of the event
3. Predictability
3.1 Data assimilation
3.2 HRES
The plots below show 24-hour precipitation (31 December 00UTC - 1 January 00UTC) in concatenated short forecasts (first plot) and ENS control forecasts with different lead times. The box marks 0.5x0.5 degree centred on Male'. It was first the shortest forecast (from 31 December 00UTC) that captured the severe rainfall.
3.3 ENS
The plots below shows EFI and SOT for 1-day precipitation (31 December 00UTC - 1 January 00UTC) from different initial dates. An early signal was present for having a wetter than normal day but it was only the shortest ensemble that indicated the extreme around Male.
The plot below shows the forecast evolution plot for 24-hour precipitation (31 ecember 00UTC - 1 January 00UTC) a 0.5x0.5 box centred on Male. Concatenated 6-hour forecasts - green dot, ENS control –red, ENS blue box-and-whisker, Model climate – cyan box-and-whisker. Ensemble mean as black diamonds. Triangle marks the maximum in the model climate based on 1800 forecasts. While the wetter-than normal signal is visible also here, the extreme was only captured in the last forecast.
3.4 Monthly forecasts
3.5 Comparison with other centres
4. Experience from general performance/other cases
5. Good and bad aspects of the forecasts for the event
- Early signal for wet weather
- The extreme around Male appeared only in the last forecast before the event.