High Quality Content by WIKIPEDIA articles! TWISTEX (an acronym for Tactical Weather Instrumented Sampling in/near Tornadoes EXperiment) is a tornado research experiment headed up by Tim Samaras from Denver, Colorado. The project normally runs from mid-April through the end of June with a domain that covers the Great Plains and portions of the Midwest. The project is normally at full strength for most of May and June with four vehicles, all equipped with roof-mounted mobile mesonet weather stations. One of the vehicles transports an array of in situ thermodynamic and video probes. Due to graduate and upper-division undergraduate student participant availability, a reduced vehicle compliment consisting of the in situ probe deployment truck and one support mesonet station vehicle is used in the first few weeks of the project.