4D Visualization of Storm-Scale Forecasts Using VAPOR in the Hazardous Weather Testbed Spring Forecasting Experiment

During recent Spring Forecasting Experiments in the Hazardous Weather Testbed (HWT) in Norman, the Center for Analysis and Prediction of Storms (CAPS) at the University of Oklahoma (OU) has produced an ensemble of numerical weather forecasts with 3-km resolution covering the contiguous United States (CONUS), the Storm Scale Ensemble Forecasts (SSEF).   In order to gain greater understanding of the dynamics and morphology of forecasted storms and possible attendant severe weather, we endeavored to provide 4D Visualization of the results of selected set of members for use in the weather briefings and for further study.  The Visualization and Analysis Platform for Ocean, Atmosphere, and Solar Researchers (VAPOR) program from the National Center for Atmospheric Research is selected for this task.  The size of the 4D data sets and the fact that they are produced off-site presented some logistical challenges.  To address these challenges, we have devised programs to extract a sample sub-domain of 600x600 km from the CONUS forecast data and transmit these extracted data at 6-minute time resolution to OU.   Python code was added to the VAPOR program to produce diagnostic products such as updraft helicity.  Each morning the subdomain of interest was selected, data were converted into VAPOR Data Format (VDF) files and some diagnostic movies were created to better illuminate the processes at work in the storms and storm systems in the selected sub-domain.

Sample 4D visualization products that we used to diagnose thunderstorm rotation, downdraft intensity and trajectories will be presented from the 2015 and 2016 Hazardous Weather Testbed.

Figure Caption:

Example of VAPOR visualization of CAPS Control Run (WRF-ARW with 3DVAR-Cloud Analysis radar initialization) shown at the HWT weather briefing depicting near-surface wind (vectors), near-surface model reflectivity (2D shading), and updraft helicity (3D shading, red hues positive and blue hues negative), county boundaries (white) and state boundaries (yellow).    For a 25-hour forecast valid 0100 UTC 28-May-2015.   Domain shown is centered in the northeast Texas Panhandle, with view point looking northwest.  An EF2 tornado was observed in northern Hemphill Co., near the most dominant UH column depicted, in neighboring Roberts Co.