The Presidents' Day cyclone of 18-19 Februarry 1979: influence of upstream trough amplification and associated tropopause folding on rapid cyclogenesis.

Abstract

A diagnostic analysis of an amplifying polar jet-trough system and associated topopause fold which preceded the 19 February 1979 Presidents' Day cyclone is presented. The analysis is based on conventional radiosonde data, infrared and visible satellite imagery, 6.7 micrometre water vapor measurements from the Temperature-Humidity Infrared Radiometer (THIR), and ozone measurements from the Total Ozone Mapping Spectrometer (TOMS). The case study indicates that dynamically forced meso-alpha scale vertical circulations played an important role in the extrusion of stratospheric air along the axis of a polar jet and the subsequent development of the storm system. -from Authors