Tracking Extreme Precipitation Events Using Satellite Infrared to Improve MCS Predictability

Precipitation over the Arabian Peninsula (AP) is often limited and highly variable. The majority of precipitation occurs as isolated, episodic convective events during November and April. Mesoscale convective systems (MCSs) cause the most extreme rainfall events in the AP and are important weather-related catastrophic hazards. The MCSs generate relatively large areas of precipitation (~100 km), with a leading line of intense rainfall and strong winds followed by a longer period of steadier and lighter rainfall. In recent years, reported MCSs in the AP have caused hundreds of deaths, and more than $1 billion USD of property damages. MCS-driven rainfall extremes are expected to intensify under climate projection scenarios in the region. Therefore, better predictability of extreme precipitation events is required by emergency managers to prepare an appropriate response to these events. In order to assess the predictability of extreme precipitation events, a tracking algorithm is used to indicate where the most intense organized convection is occurring based on satellite cloud top retrievals and radar reflectivity values. Due to limited observation data availability over the AP, a satellite-based tracking algorithm overlapping the successive satellite infrared (IR) brightness temperature (Tb) data will be used. Using the Advanced Research version of the Weather Research and Forecasting Model (WRF-ARW) at convective-permitting resolution (2 km), we dynamically downscale the tracking to simulate various forecasts at different lead times. Model simulated precipitation is evaluated against various precipitation products, including the Global Precipitation Mission (GPM), and locally available in-situ rain gauge measurements. Merged infrared brightness temperature from the National Centers for Environmental Prediction (NCEP) will be used as input to track individual cloud systems and to identify MCSs. The tracking algorithms have proven to be effective at tracking MCSs over the CONUS and China, and will be calibrated specifically for the AP.