Status:Ongoing analysis Material from: Linus
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1. Impact
On 12 April a local convective cell caused extreme rainfall over Fort Lauderdale in Florida. Up to 660 mm of rain was reported, and the airport was flooded.
https://www.bbc.co.uk/news/world-us-canada-65245495
2. Description of the event
The plots below show analyses of MSLP and 6 hour rainfall from 10 April 00UTC to 13 April 00UTC, every 12th hour.
The plots below show analyses of z500 and T850 from 9 April to 13 April 00UTC, every 24 hour.
3. Predictability
3.1 Data assimilation
3.2 HRES
The plots below show 24-hour precipitation (12 April 00UTC - 13 April 00UTC) in NEXRAD (first plot) concatenated short forecasts (second plot) and o-suite HRES forecasts with different lead times.
Is looks like the forecast had problem to propagate the strong rainfall in over land.
Same as above but for e-suite forecasts.
3.3 ENS
The plots below shows EFI and SOT for precipitation on 12 April, from different initial dates.
There was an early signal in the model about a wet period.
The plot below shows the forecast evolution plot for 24-hour precipitation (12 April 00UTC - 13 April 00UTC) for 0.5 degree box around Fort Lauderdale. Mean of NEXRAD - green hourglass, 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. 48r1 e-suite is included in orange dot (HRES/ENS control) and purple (ENS distribution).
The forecast did captured a wet signal, but id not predict anything really extreme in terms of ensemble median (being around 99th percentile). But one can note one member in the e-suite ensemble from a day before the event being very extreme .
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 period
- The forecast had problem to propagate the strong rainfall in over land