Sensitivity of a cold season, nocturnal squall line to planetary boundary layer and microphysical parameterizations

On January 9th, 2011, a severe squall line swept through the southern Gulf Coastal Plains of Texas. This cold season squall line was part of a larger mesoscale convective system that initiated in west Texas during the early morning hours. In close proximity of a warm front and deepening low pressure area, the squall line strengthened as it travelled eastward across the state's southern region before exiting the coast prior to sunrise. In addition to widespread, straight-line wind damages, a long-track, EF-1 tornado was also confirmed to have struck a portion of the greater metropolitan area of Corpus Christi. As squall lines can present significant threats to life and property, there is a need to more accurately forecast these systems of thunderstorms. Using the Weather Research and Forecast Environmental Modeling System (WRF-EMS), a sensitivity test involving the variation of planetary boundary layer (PBL) and microphysical parameterization schemes of the simulated January 9th, 2011 squall line was performed. The simulations were evaluated in comparison to quality-controlled, Weather Service Doppler radar (WSR-88D) data and data from Automated Surface Observing System/Automated Weather Observing System (ASOS/AWOS) sites on the basis of the following criteria: (i) respective areas of convective and stratiform regions, (ii) system speed, (iii) time of bowing initiation, and (iv) maximum 10-m wind gust speed.