Purpose and Organization of Manuscript

"The purpose of the present manuscript is to document what was a remarkable event. This is the first study that provides Doppler radar documentation of the rare combination of an anticyclonic tornado associated with an anticyclonic supercell. The fact that this unusual tornadic storm was photographed and also occurred in a region in which tornadoes and supercells are themselves relatively infrequent further establishes the uniqueness of this case."(Monteverdi, J.P., W. Blier, G. Stumpf, W. Pi, and K. Anderson, 2001: First WSR-88D Documentation of an Anticyclonic Supercell with Anticyclonic Tornadoes: The Sunnyvale–Los Altos, California, Tornadoes of 4 May 1998. Mon. Wea. Rev., 129, 2805–2814.)

"Despite the aforementioned considerable advantages of Lagrangian particle methods, to our knowledge no atmospheric model simulating mesoscale phenomena exists that is based on the “fully Lagrangian” formulation. In this paper we present a fully Lagrangian model for simulating atmospheric motion. First, the present work uses a fully Lagrangian scheme for the advective time evolution of the flow using a Lagrangian mesh of particles. Second, a simultaneous solution of all state variables (e.g., velocity and scalar field) is carried out in the Lagrangian framework, which is a clear step beyond conventional trajectory models (e.g., Lin et al. 2003) that do not solve the equations of motion.

In section 2 we present a detailed description of the proposed fully Lagrangian modeling system. Our approach is based on splitting the nonlinear advection process from all other properties of motion. The developed scientific contribution needs to be validated and verified, which is presented in section 3. In addition, we have compared the performance of the developed fully Lagrangian model with respect to two reference models—one is Eulerian and the other is semi-Lagrangian (section 4). Finally, we conclude this paper by summarizing our observations and findings in section 5, where we discuss some potential future research directions guided by the present study." (Alam, J.M., and J.C. Lin, 2008: Toward a Fully Lagrangian Atmospheric Modeling System. Mon. Wea. Rev., 136, 4653–4667.)

"This study is organized in the following manner. An overview of the typical synoptic-scale pattern associated with tornadic thunderstorms in the Central Valley is presented first. This is followed by a discussion of the buoyancy and shear characteristics associated with both the null and tornadic thunderstorm cases (or bins). The tornado cases are stratified into F0 and F1/F2 groupings or bins based upon shear values. Finally, preliminary forecast thresholds for distinguishing tornadic from nontornadic thunderstorms are suggested on the basis of 0–1- and 0–6-km positive shear values (see section 3 for definition of positive shear). Ongoing research objectives are summarized in the final section." (Monteverdi, J.P., C.A. Doswell, and G.S. Lipari, 2003: Shear Parameter Thresholds for Forecasting Tornadic Thunderstorms in Northern and Central California. Wea. Forecasting, 18, 357–370.)