Explanation of SPC Severe Weather Parameters

The SPC utilizes all available surface observations, in combination with short-term forecasts from the Rapid Refresh (RAP) model, to generate hourly mesoscale analyses of various parameters related to severe thunderstorms and tornadoes. Basic fields are displayed (surface MSL pressure, temperature, dewpoint, winds), along with short-term (0-2 hour) forecasts of upper air conditions. This document focuses on describing the sounding-derived parameters that the SPC uses to forecast severe thunderstorms.