Material from: Linus

1. Overview

 On 7 March torrential rainfall fell over Bahia Blanca in Argentina, leading to at least 11 casualties. The city recorded 210 mm/6h. It is about 1/3 of the normal annual rainfall for that station. It followed an already very wet start of March for the region.

https://www.bbc.co.uk/news/articles/cvg1vd7xywpo

2. Analyses and Observations

2.1 Event Definition

The event is defined as the 24-hour rainfall for the period 6 March 18UTC to 7 March 18UTC for a 0.5x0.5 degree box centred on Bahia Blanca (38.7S, 62.3W).

2.2 Analyses

The plots below show analyses of MSLP and 6 hour rainfall from 5 March 00UTC to 8 March 00UTC, every 12th hour.

The plots below show analyses of z500 and T850 4 March 00UTC to 8 March 00UTC, every 24th hour.

2.3 Observations

2.4 Climatological perspective

3. Forecasts

3.1 Data assimilation and observation usage

3.2 Single Forecasts for the event (defined in Section 2.1)

Note that only precipitation over land is included in the plots.

Observations for the event

SYNOP observations (left) and concatinated analyses (right) for the event.

Control forecast (IFS 9-km resolution)

DestinE (IFS 4.4km resolution)

AIFS deterministic (AIFSv1.0 ~0.25 resolution)

AIFS ensemble (AIFS diffusion ensemble ~1 degree resolution)

3.3 Ensemble distribution

EFI (based on IFS 9-km ensemble)

Forecast Evolution plot

Legend:

Observation - green hourglass
Analysis - green dot
ENS CF - red dot
DestinE - dark-green dot

ENS distribution - blue
ENS m-climate - cyan
ENS m-climate maximum - black triangle

3.4 Sub-seasonal forecasts

3.5 Comparison with other centres

4. Hazard Forecasts

5. Dedicated Experiments

6. Event Summary

6.1 Good and bad aspects of the forecasts for the event

• Good signal in EFI 5-6 days in advance for extreme event
• Severely underestimation of the magnitude of the event on all forecasts (including DestinE)

6.2 Experience from general performance/other cases

7. Additional material