Status:Ongoing analysis Material from: Linus, David
1. Impact
During end of of December and the first half of January California was hit by a series of Atmospheric River events. While bringing extreme rainfall, it was a the same time (hopefully) beneficial to restore the water storage in the state.
https://en.wikipedia.org/wiki/2022%E2%80%932023_California_floods
2. Description of the event
The plot below shows the NEXRAD 24-hour precipitation for 9 January.
The plots below show analyses of z500 and T850 from 6 January to 11 January.
The plots below show analyses of MSLP and 6 hour rainfall from 7 January 00UTC to 11 January 00UTC, every 12th hour.
3. Predictability
3.1 Data assimilation
3.2 HRES
The plots below show observations from SYNOP (first plot), concatenated 6-hour forecasts (2nd plot) and HRES forecasts of 24-hour precipitation valid 9 January 00UTC - 10 January 00UTC, from different initial dates.
3.3 ENS
The plots below show EFI for 1-day precipitation 9 January, from different initial times.
The plots below show EFI for 1-day IVT 9 January, from different initial times.
The plot below shows the forecast evolution plot for 24-hour precipitation valid 9 January 00UTC - 10 January 00UTC for the box along the Californian coast outlined above. 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.
3.4 Monthly forecasts
The plots below show verification of weekly precipitation anomalies for the weeks starting 2 January and 9 January.
3.5 Comparison with other centres
4. Experience from general performance/other cases
5. Good and bad aspects of the forecasts for the event
6. Additional material
https://cw3e.ucsd.edu/cw3e-ar-update-10-january-2023-outlook/