In response to the increasing availability of satellite and aircraft temperature observations on the periphery of tropical cyclones, archived thickness and geopotential height data from National Meteorological Center analyses am compared as Atlantic cyclone predictors. For maximum use in motion prediction, thickness must be converted into deep-layer-mean or midtropospheric heights using an accurate reference-level height analysis. The 1000–700 mb thickness in the vicinity of cyclones in the poleward and eastward quadrant is a significant predictor of 24 h intensity change, even when combined with climatology and persistence.