Earth and Atmospheric Sciences, Department of


Date of this Version



Duell, R. S., 2014: Eastern US Dryline Climatology and Synoptic-Scale Environment. Dept. of Earth and Atmo. Sciences, The University of Nebraska-Lincoln, 84 pp.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Earth and Atmospheric Sciences, Under the Supervision of Professor Matthew S. Van Den Broeke. Lincoln, Nebraska: August 2014.

Copyright (c) 2013 Rebecca S. Duell


The dryline is an important focal point for convection initiation, and the subject of many studies. While the most common location for drylines is the southern Great Plains, dryline passages and subsequent severe weather outbreaks have been documented in the Mississippi River Valley and into portions of the southeastern United States. Little is known about these “eastern” drylines or how often they occur, as no climatologies or detailed studies have been published on them. This thesis presents a fifteen-year climatology (1999-2013) of eastern drylines in an effort to identify how often and where they typically occur, and to identify synoptic patterns that result in drylines moving atypically far eastward. A computer algorithm was created that objectively identifies drylines from the North American Regional Reanalysis (NARR) dataset. Dryline events were divided into regional categories once the climatology of eastern drylines was compiled, and mean and anomaly synoptic composites were created of different variables for each regional category. Thirty-nine eastern drylines were identified through the study. These events occurred under synoptically-active conditions with amplified upper-air patterns, 500 mb shortwave troughs to the west or northwest of the drylines, and strong surface cyclones to the north.

Advisor: Matthew Van Den Broeke