Forecasting and Monitoring Intense Thunderstorms in the Hindu Kush Himalayan Region: Preliminary Results from Spring 2018 Demonstration (252)

Jonathan L. Case, ENSCO, Inc., Huntsville, AL

Patrick N. Gatlin, NASA Marshall Space Flight Center

Jayanthi Srikishen, Universities Space Research Association

Jeffrey Knickerbocker, Spatial Informatics Group

Jordan R. Bell, University of Alabama - Huntsville



Some of the most intense thunderstorms on Earth occur in the Hindu Kush Himalayan (HKH) region of South Asia &mdash where many organizations lack the capacity needed to predict, observe and/or effectively respond to the threats associated with high-impact convective weather. Among the convective hazards include tornadoes, damaging straight-line winds, lightning, large hail, and flash flooding, which typically peak in the pre-wet-monsoon season (~March through May), while flooding continues through the wet monsoon. Previous studies have documented a disproportionately large number of casualties associated with severe thunderstorms in this region. Therefore, the goal of this NASA Applied Sciences/SERVIR Team project is to enhance early warning services in the HKH region and increase situational awareness of these hazards and their impacts through improved short-term modeling and satellite assessment tools. Consistent with the National Weather Association meeting theme, this topic is a strong example of combining meteorological diversity with partnerships diversity.

At last year's annual meeting, we described the concept of a high-impact weather assessment toolkit that combines innovative numerical weather prediction (NWP) strategies, satellite-based precipitation products, and land-imagery techniques. The short-term NWP component is the focus of this presentation, which involves a regional convection-allowing ensemble system using the Weather Research and Forecasting (WRF) model, as implemented within the NOAA/NWS Unified Environmental Modeling System (UEMS). The WRF/UEMS is installed onto a cloud computing-like environment and configured for a real-time Spring Forecasting Demonstration during March to May 2018.

The NWP system consists of a 12-member ensemble with both initial condition and physical parameterization diversity to capture severe thunderstorm hazards in a suite of deterministic and probability products. The model domain has a 12-km/4-km mesh nested grid with the outer grid covering much of South Asia, and the inner grid covering Nepal, Bangladesh, Bhutan, and portions of northeastern India. The first ensemble member serves as a deterministic &ldquooperational run&rdquo, with initial and boundary conditions provided by the NCEP GFS model. The operational run generates products for assessing the environmental conditions favoring severe thunderstorm and flooding hazards. The remaining 11 ensemble members obtain initial/boundary condition diversity from individual NCEP GFS Ensemble Forecast System runs, while also varying the planetary boundary layer and microphysics parameterization schemes to achieve adequate spread in the system.

The ensemble output products consist of &ldquopaintball&rdquo and probability maps, probability matched means, and ensemble statistics for a variety of pertinent model fields such as simulated reflectivity, updraft helicity, total lightning flashes, interval maximum 10-m wind speeds, column-integrated graupel, and accumulated precipitation. Real-time NWP output is produced on a daily basis out to 48 hours for day-1 and day-2 severe weather guidance, focusing on the 4-km nested grid region. Model products are disseminated to collaborating organizations within NASA/SERVIR through a web mapping service, and also displayed on a web page hosted by the NASA Short-term Prediction Research and Transition (SPoRT) Center. This presentation will include case studies from the Spring 2018 Forecasting Demonstration focused on severe weather events in South Asia.