The West Texas Mesonet is an automated surface network operated and maintained by the Atmospheric Science Group and the Wind Science and Engineering Research Center at Texas Tech University. The network located in the West Texas High Plains has 35 10-m instrumented towers and several boundary layer towers of height ranging from 70 to 200 m. The average spacing of the tower sites is about 40 km. Three of these sites have atmospheric profilers capable of sampling wind and stability measurements of the lowest kilometer of the atmosphere. The high temporal and spatial resolution low-level data provide a unique opportunity for research in many aspects of atmospheric boundary layer, and surface and mesoscale processes.

In this study, we focus on the impact of the Mesonet on the regional numerical weather prediction over West Texas using real data MM5 four-dimensional data assimilation (FDDA) experiments. The current Mesonet 10-m tower data consist of two arrays of observations at 5 and 15 min, respectively. The FDDA input files of hourly or 30-min wind, temperature, and humidity observations for the cases of interest are created using the 5-min array. Two cases are selected for the experiments. One is the dryline case of 14-16 April 2002 and the other is the 23-24 November 2002 case. Drylines are very significant weather phenomena in the spring and summer over West Texas because severe storms frequently form along them. The effects of input frequency ranging from 30 min to 3 h as well as the length of assimilation (e.g., 6 h vs. 12 h) will be examined. The November case represents relatively tranquil conditions. We are investigating whether the Mesonet data can improve the model performance in resolving the dryline near the surface and short-range (6-12 h) wind forecasting downwind of the Mesonet sites in an undisturbed environment.