The Life Cycle of Thunderstorm Gust Fronts as Viewed with Doppler Radar and Rawinsonde Data

• Published in: Monthly weather review 1982-01, Vol.110 (8), p.1060-1082
• Main Author: Wakimoto, Roger M.
• Format: Article
• Language: English
• ISSN: 0027-0644; 1520-0493
• DOI: 10.1175/1520-0493(1982)110<1060:TLCOTG>2.0.CO;2

The author presents the time-dependent analysis of the thunderstorm gust front with the use of Project NIMROD data. RHI cross sections of reflectivity and Doppler velocity are constructed to determine the entire vertical structure. The life cycle of the gust front is divided into four stages: 1) the formative stage; 2) the early mature stage; 3) the late mature stage; and 4) the dissipation stage. A new finding is a horizontal roll detected in the reflectivity pattern resulting from airflow that is deflected upward by the ground, while carrying some of the smaller precipitation ahead of the main echo core of the squall line. This feature is called a precipitation roll. As determined from rawinsonde data, the cold air behind the gust front is responsible for the observed surface pressure rise. Calculations confirm that the collision of two fluids produces a nonhydrostatic pressure at the leading edge of the outflow. The equation governing the propagation speed of a density current accurately predicts the movement of the gust front.