Improving weather forecasting in the Philippines through WRF dynamical downscaling and data assimilation
An initial assessment of the performance of WISE shows an improvement to 70 – 80% accuracy for the dichotomous rainfall forecast with the highest accuracy observed in January, February and March period. It was also observed that assimilating expected rainfall from radar has the greatest impact in the model's skill with mostly positive Critical Success Index (CSI) anomalies. The performance is expected to be significantly improved with the availability of more than 800 new rain gauges installed around the country. Sensitivity testing was done for the case of Typhoon Haiyan, and it was found that the use of Grell-Divenyi cumulus physics scheme provided the best rainfall forecast while the WSM 6-class microphysics scheme provided the best forecast for pressure and wind speed and Kain-Fritsch cumulus physics scheme gave the closest to the observed typhoon track.
Future efforts will include assessment of impact of satellite data assimilation, particularly that of MODIS calibrated radiances, brightness temperature and cloud products. Greater utilization of satellite data is also expected in the validation and evaluation of forecast performance skills. Multi-model comparison and ensemble forecasting will be implemented in order to further improve the Philippines' numerical weather prediction capabilities.