Status: Ongoing analysis Material from: Linus, Mohamed
1. Impact
In the last week of February a quasi stationnary low pressure trought brought very hight amounts of rainfal to South Quennsland and the North of New south Wales in Australia. The accumulated 3days rainfall exceeded 1400 in few locations (such as Mount Glorious). The persistent rainfal caused many rivers to overflow. The flood levels reached a record level of 14m for the river Lismore. Many casualties have been reported and a large number of people are still trapped by the flood. Although rain is still expected over the broad area the situation is improving.
2. Description of the event
The plots below show mslp from analysis and 6-hour precipitation forecasts from 24 February 00UTC to 28 February 00UTC.
The plots below show7 days accumulated rainfall (ending 28/02/2022) (left), table showing accumulated values for a subset of stations in Queensland (middle) and rain accumulations for Station Mount Glorious for different accumulation lengths (right) (Source?). From the right plot the most extreme day was approximated to 25 Feb 00UTC to 26 Feb 00UTC, and 3-day period was approximated to 25 Feb 00UTC - 28 Feb 00UTC.
3. Predictability
3.1 Data assimilation
3.2 HRES
25 February
The plots below show 24-hour precipitation on 25 February from concatenated 6-hour forecasts (first plot) and HRES forecasts with different initial times. The forecast from 24-hours before the start of the event (24 Feb 00UTC, third plot) missed the rain over the worst affected region (black box).
25-27 February
The plots below show 72-hour precipitation on 25-27 February from concatenated 6-hour forecasts (first plot) and HRES forecasts with different initial times.
3.3 ENS
25 February
The plots below show EFI and SOT for 1-day precipitation for 25 February, from different initial times.
The plot below shows the forecast evolution plot for 24-hour precipitation valid 25 February for the box outlined in the plots above. HRES –red, ENS blue box-and-whisker, Model climate – red box-and-whisker. Triangle marks the maximum in the model climate based on 1200 forecasts, The black square marks the ensemble/climate median and diamond ensemble/climate mean. (Climate and concatenated short forecasts to be added)
25-27 February
The plots below show EFI and SOT for 3-day precipitation for 25-27 February, from different initial times.
The plot below shows the forecast evolution plot for 72-hour precipitation valid 25-27 February for the box outlined in the plots above. Concatenated 6-hour forecasts (green), HRES –red, ENS blue box-and-whisker, Model climate – red box-and-whisker. Triangle marks the maximum in the model climate based on 1200 forecasts, The black square marks the ensemble/climate median and diamond ensemble/climate mean. (Climate to be added)
3.4 Monthly forecasts
The plots below show weekly precipitation anomalies for 21-27 March from extended-range forecasts. While the positive anomaly was present north and east of Australia in all 4 forecasts shown here, only the forecast from 21 February (first plot) had the rainfall extending towards Australia. At the same time an MJO was present over the Maritime continent.
3.5 Comparison with other centres
4. Experience from general performance/other cases
5. Good and bad aspects of the forecasts for the event
- Bad forecasts from 1 day before the event (24 February)