Objective: The first batch of TC products for tropical cyclone HAIMA indicate a north-westward track towards Philippines Arquipelago. The impact of super typhoon HAIYAN is still deeply engraved in the memories of the population and the emergency authorities are under pressure to start evacuate the populations at risk (TC landfall) as soon as possible. Based on the Tropical Cyclone Strike Probability charts, EFI for Significant Wave height and Model Climate information and Significant Wave Height probability forecast, you are asked to provide guidance 3-4 days in advance before the landfall. Also is important to provide an estimate of the swell knowing that  swell+tide+storm surge combined can wreak havoc along the coastline.

An interesting video showing a powerful storm surge caused by HAIYAN can be seen here.

Skill forecast

Before starting looking at the tropical cyclone and wave products check the forecast performance.

Annual mean errors for intensity (forecast minus observed in hPa) and speed (m/s) by the HRES (blue) and Ctrl (green) models. Annual mean position errors (km) at D+3 and D+5 by the HRES. Reliability Diagram for the TC strike probability product.

Check also the forecast performance of the wave model here

Forecast products

Tropical cyclone products (left panel). EFI of significant wave height (SWH) and Model Climate 99% percentile of SWH for 96-120h forecast based on start date 17th October (mid panel). Probability of significant wave height above 6 m (right panel). All products are based on the forecast started on 15th October and valid for 20th.

EFI of total precipitation based on 15th Oct  and Model Climate 99% percentile of total precipitation (mm) for 96-120h forecast based on start date 17th October (right panel)

Do you now what is the current Model Climate configuration used to compute the Extreme Forecast Index? (if not read here)

Tropical cyclone products (left panel). EFI of significant wave height (SWH) and Model Climate 99% percentile of SWH for 72-96h forecast based on start date 17th October (mid panel). Probability of significant wave height above 6 m (right panel). All products are based on the forecast started on 16th October and valid for 20th.

EFI of total precipitation based on 16th Oct  and Model Climate 99% percentile of total precipitation (mm) for 96-120h forecast based on start date 17th October (right panel)

Tropical cyclone products (left panel). EFI of significant wave height (SWH) and Model Climate 99% percentile of SWH for 48-72h forecast based on start date 17th October (mid panel). Probability of significant wave height above 6 m (right panel). All products are based on the forecast started on 17th October and valid for 20th.

EFI of total precipitation based on 17th Oct  and Model Climate 99% percentile of total precipitation (mm) for 96-120h forecast based on start date 17th October (right panel)

Compare the model climate 99% percentile of total precipitation for 0-24h and 48-72h in the tropics (tip: click 'Forecasts' → 'Charts' → 'Extreme Forecast Index' → 'EFI precipitation'). Are the two charts very different? is it expectable? Check in the 'Forecast User Home' → 'Forecasting Issues' if there is any comment about the rainfall in the Tropics.

Verification (to show later)