A study of a rapid cyclogenesis event during GALE

Abstract

An explosive cyclone that developed during intensive observation period (IOP)9 of the Genesis of Atlantic Lows Experiment (GALE) is studied. Detailed surface analysis is conducted based on operationally available data, late reporting ship observations and special observations acquired by GALE scientists to determine the surface storm track and deepening rate. GALE dropsonde and rawinsonde data are used to supplement the normal upper-level data base, and are analyzed by the Navy Operational Regional Analysis and Prediction System (NORAPS) using optimal interpolation objective analysis. These analysis are discussed with special emphasis given to possible factors contributing to the explosive cyclogenesis. Factors that influenced the cyclone's rapid development include upper-level positive vorticity advection, low-level warm temperature advection and low-level instability. Vertical soundings and cross-sections utilizing the dropsonde and rawinsonde data are used to study the environment in which the rapidly deepening cyclone initially developed.