Prediksi Debit Sungai Bengawan Solo Menggunakan Numerical Weather Model Global Forecast System Dan Integrated Flood Analysis System (Prediction of Discharge in Bengawan Solo River Using Numerical Weather Model Global Forecast System and Integrated Flood Analysis System)
Flood is one of the most common hydro-meteorological disasters. Bengawan Solo is one of thewatersheds in Indonesia that also hit by this disaster. This study discusses the flood disaster inthe Bengawan Solo area in early March 2019. The purpose of this study is to conduct adischarge simulation using numerical weather model Global Forecast System (GFS) datathrough Integrated Flood Analysis System (IFAS) so it is possible to predict discharge in thefuture. There are three types of numerical weather model GFS data that have been downscaleusing weather research and forecasting model which differentiated based on spin-up time. Thenumerical weather model product is then used as rainfall data input for IFAS simulation. Basedon the analysis, the flood discharge simulation using an 84-hour spin-up time has a satisfactoryperformance in describing the change in discharge with respect to time. This happens because numerical weather models will be better at quantifying processes that occur on a meso scalewith spatial scale of 10 to 1000 km. The result of this research shows that it is possible to predict river discharge up to 84 hours before the disaster so this is can support the mitigationprocess for hydrometeorological disasters.