An Analysis of Hurricane Opal’s Forecast Track Errors Using Quasigeostrophic Potential Vorticity Inversion

Abstract

Abstract Hurricane Opal’s landfall in October 1995 forms the basis of a serious hurricane forecast problem—the potential for hurricane conditions over land with insufficient warning time. Official National Hurricane Center (NHC, a division of the Tropical Prediction Center) forecasts predicted landfall and passage inland over the eastern United States at a later time than observed because of underestimation of the northward component of the steering flow by the National Centers for Environmental Prediction’s (NCEP) operational models and other hurricane track models. The goal of this paper is to isolate the cause of the poor forecast of meridional storm motion in NCEP’s early Eta Model by using quasigeostrophic potential vorticity (QGPV) inversion. QGPV inversion permits decomposition of the steering flow into contributions from different synoptic-scale features. The inversion procedure is applied to the Eta analysis and 48-h Eta forecast valid at 1200 UTC 5 October 1995. Analyses from the European Centre...