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Severe weather impacts, climatology, and distribution patterns of mesoscale convective system structures across the eastern contiguous United States
- Publication Year :
- 2022
-
Abstract
- Mesoscale convective systems (MCSs) are one of the most common storm modes across much of the eastern contiguous United States, with quasi-linear convective systems (QLCSs) being the most common MCS mode. However, despite how commonly they occur, the predictability of these systems has historically been inconsistent, especially for predicting potential severe weather impacts. As these systems can produce substantial threats to life and property in the form of significant damaging wind gusts, large hail, and tornadoes, having a better understanding of these systems is essential in not only improving forecasting skill but also mitigating these impacts. This research examines characteristics of QLCSs with three different categories of precipitation structures in both space and time, and links these different QLCS structures to severe weather impacts produced.Archived radar data from the National Centers for Environmental Information (NCEI) were used to identify QLCSs from 2016-2018 in areas of the contiguous U.S. east of the Rocky Mountains. A QLCS was defined as an assemblage of thunderstorms that persisted for at least three hours, contained a continuous or semi-continuous convective area (reflectivity >40 dBZ) of at least 100 km along the system’s major axis, and occurred in a synoptic environment conducive for thunderstorms (e.g., in the warm sector of a mid-latitude cyclone or beneath a jet streak). The QLCSs were classified by structure based on where stratiform precipitation was located relative to the linear convective elements (trailing stratiform (TS), leading stratiform (LS), parallel stratiform (PS), embedded stratiform (ES), no stratiform (NS)). Severe weather reports were taken from the National Severe Weather Database provided by the Storm Prediction Center for the times and locations QLCSs were present.TS systems were by far the most common type of QLCS across all of the eastern contiguous United States, with relatively similar, although much fewer, numbers of LS and PS, as well as even numbers of ES and NS observed. The Southern Plains saw the highest number of QLCSs overall, and a general trend of increasing systems from north to south was seen due to the longer warmer season at lower latitudes. The TS archetype was the main driver of this geographical distribution, while LS and PS saw greater frequency over the central Plains states and ES and NS were most common in the Southeast. TS systems were significantly larger in both space and time measures, while the other archetypes were more homogenous in these dimensions. QLCSs followed a strong seasonal and diurnal variability, maximized around the typical times of maximal incoming radiation (warm seasons, near and just after the peak heating of the day). There was found to be a significant dependence on overall severe weather production by archetype, as well as for wind and hail production, with TS systems outproducing expectation and the other archetypes underproducing. However, tornado production was independent of archetype.
Details
- Language :
- English
- Database :
- OpenDissertations
- Publication Type :
- Dissertation/ Thesis
- Accession number :
- ddu.oai.etd.ohiolink.edu.ouhonors1650640596007033