Status:Ongoing analysis Material from: Linus
1. Impact
On 27 January Auckland was hit but extreme rainfall. In 15 hours the city received more than 75% of the normal summer rainfall, and at least four people were killed.
https://www.bbc.co.uk/news/world-asia-64440319
2. Description of the event
Observations for 27 January 00UTC - 28 January 00UTC from ogimet.com . The Auckland Airport measured 234 mm/24.
The plots below show analyses of MSLP and 6 hour rainfall from 25 January 00UTC to 29 January 00UTC, every 12th hour.
The plots below show analyses of z500 and T850 from 24 January to 29 January 00UTC, every 24 hour.
3. Predictability
3.1 Data assimilation
3.2 HRES
The plots below show observations from concatenated 6-hour forecasts (first plot) and HRES forecasts of 24-hour precipitation valid 27 January 00UTC - 28 January 00UTC, from different initial dates. The black box show the area around Auckland.
3.3 ENS
The plots below show EFI for 1-day precipitation 27 January, from different initial times.
The plot below shows the forecast evolution plot for 24-hour precipitation valid 27 January 00UTC - 28 January 00UTC for the box around Auckland. Concatenated 6-hour forecasts - green dot, HRES –red, ENS blue box-and-whisker, Model climate – red box-and-whisker. Ensemble median as black box and ensemble mean as black diamonds. Triangle marks the maximum in the model climate based on 1200 forecasts. Note that the Auckland Airport measured 234 mm.
The plots below show the 99th percentile of 12h rainfall in the forecast from 27 January 00UTC for the 00-12 and 12-24. For Auckland the 99th percentile increase from 88 mm in ENS to 254 mm in EcCharts.
