Date of Award
2018
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Atmospheric Science
Committee Chair
Kevin Knupp
Committee Member
Timothy A. Coleman
Committee Member
Lawrence D. Carey
Subject(s)
Severe storms--Forecasting, Tornadoes, Boundary layer (Meteorology), Clouds
Abstract
Stratocumulus clouds, hypothesized to control boundary layer processes during cold season tornado events, are investigated. Associated observed boundary layer profiles of wind, low clouds (e.g., cloud base height, cloud fraction), water vapor, and boundary layer cloud depth near tornadogenesis events over northern Alabama and nearby areas of the Southeastern United States are presented. Observed stratocumulus cloud fraction for QLCS’s is 97%, and 83% for supercells. Furthermore, stratocumulus clouds first occurred an average of 200 and 90 minutes prior to tornadogenesis for QLCS’s and supercells respectively. Mean LCL heights for all QLCS cases were found to be 659 meters for QLCS, and 649 meters for supercell cases. Both the subcloud boundary layer and surface layer are often statically stable, unlike the dry adiabatic profile in classical cloud topped mixed layers. Thus, large bulk shear magnitudes of 14 and 18 m/s occur within the respective 0-500 m and 0-1 km layers.
Recommended Citation
Lisauckis, Christopher A., "Cold-season severe QLCS events over North AL : climatology, cloud, and boundary layer characteristics" (2018). Theses. 236.
https://louis.uah.edu/uah-theses/236