| Summary: | Winter storms, including snowstorms and ice storms, are infrequent in the Southern Great Plains of the United States (SGP), but can produce significant hazard and socioeconomic disruption. During 2000-2010, several severe ice storms impacted the region. These events combined resulted in nearly $800 million in damages, over 30 fatalities, and power disruption to over 3 million homes and businesses. Hitherto, basic climatological information for winter storms in this region remain understudied. This dissertation examines the characteristics of freezing precipitation events for the SGP by developing a regional spatial and synoptic climatology (1993-2011). Thermal profiles conducive to winter precipitation of varying types and intensities are also examined and compared with past literature. A combination of sounding analysis, and Principal Component (PC)/composite techniques are used to derive this climatology. Results identified that the SGP experiences freezing precipitation of varying intensity, but that ice storms to the region are notable for their large above-freezing inversion layer (‘warm layer’) temperatures/depths and mixing ratio. Freezing precipitation occurs most often over the central and eastern domain during December-February, while snowfall maximizes northwest of this zone with broader seasonal occurrence. The synoptic analysis showed that patterns conductive to storms with a pronounced mixed-phase region typically involved topographically aided ageostropic down-gradient advection of cold stable air in the lee of the Rocky Mountains, with an arctic high pressure over the northern/central Great Plains. A mid-level trough and low-level warm air advection provided ascent, and anomalously warm air to the south provided sufficient support for a warm layer. Long-duration ice storms were observed with a slow-moving high-amplitude western trough, direct moisture transport from the Gulf of Mexico, and a ridge over the southeastern U.S. Based on the climatology and past literature, a hypothesis is proposed ...
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