Assessing the Impact of Non-Conventional Radar and Surface Observations on High-Resolution Analyses and Forecasts of a Severe Hailstorm
Matthew T. Morris, Keith A. Brewster, and Frederick H. Carr
Abstract
A 2009 National Research Council study recommended that new mesoscale observing networks be integrated with existing networks to form a nationwide “network of networks”. The report also recommended that research testbeds be established, such as the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) DFW Testbed, to ascertain the potential benefit of proposed observing systems. In this work, we use various conventional and non-conventional observing systems from the DFW Testbed in a series of observing system experiments (OSEs). Of special interest are radar data from Terminal Doppler Weather Radars and CASA X-band radars, as well as novel surface observations. The Advanced Regional Prediction System (ARPS) model is used to perform OSEs that are designed to assess the impact of these observing systems. A three-dimensional variational analysis system and companion complex cloud analysis are used to produce analysis increments, which are assimilated in ARPS using Incremental Analysis Updating. Experiments are performed on a supercell thunderstorm case from 11 April 2016 that produced large, damaging hail. The analysis includes quantitative comparisons of model-derived hail with radar-observed hail, along with verification of surface fields. The CASA radial velocity data benefited the forecasted storm structure, as it positively affected subsequent storm morphology and model-derived hail forecasts. Of note in surface observation impacts, the dewpoint measurements from the non-conventional Earth Networks and CWOP networks slightly degrade the forecasted dewpoint field compared to independent standard observations, but did not prevent the successful prediction of hail.
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Citation:
Morris, M. T., K. A. Brewster, and F. H. Carr, 2021: Assessing the impact of non-conventional radar and surface observations on high-resolution analyses and forecasts of a severe hailstorm. Electronic J. Severe Storms Meteor., 16 (1), 1–39.
Keywords:
radar observations, supercells, surface observations, mesoscale models, data assimilation, hail