Microburst Detection With the WRF Model: Effective Resolution and Forecasting Indices

Abstract

Microbursts are meteorological phenomena in the lower troposphere which can producedamaging surface winds and pose a severe risk to aircraft flying close to the ground. As these eventsusually span less than 4 km and 15 min, the spatiotemporal resolution is a challenge for numericalsimulations. Although research of microburst using operative mesoscale models is scarce, the WeatherResearch and Forecasting (WRF) model has been used in the diagnosis of this phenomenon. In this paper,such model is used to simulate several microburst conducive days using two different boundary conditions.The energy spectra of the simulations are computed to evaluate the effective resolution of the model. Theresults are in line with previous studies and produce no notable differences among the boundary conditions.Nonetheless, the energy spectra show an overenergetic troposphere at microscale resolutions, rendering theeffective resolution inadequate for microburst forecasting using the simulated physics variables. Thus,mesoscale indices are analyzed as a prognostic tool. The wind index, the wet microburst severity index andthe microburst windspeed potential index do not show high forecasting performances, even thoughimproving the results of climatology. Also, notable differences among the boundary conditions can be seen.The most consistent results are achieved by the wet microburst severity index.