TY - JOUR
T1 - Squall line response to coastal mid-atlantic thermodynamic heterogeneities
AU - Lombardo, Kelly
N1 - Funding Information:
Acknowledgments. This research would not have been possible without the generous support from the National Science Foundation Grant AGS-1514115, Office of Naval Research Grant N00014-16-1-3199, and Office of Naval Research Grant N00014-17-1-2478. The author would like to acknowledge high-performance computing support from Cheyenne (doi: 10.5065/D6RX99HX) provided by NCAR’s Computational and Information Systems Laboratory, sponsored by the National Science Foundation. The author would like to greatly thank Dr. George Bryan for the development and continued improvements of the CM1, and for the related insightful conversations. The author would also like to thank Dr. Matthew R. Kumjian for MATLAB assistance; Dr. Ryan Hastings for assistance in developing the ‘‘mid-Atlantic’’ thermodynamic profile and preliminary discussions regarding the numerical simulations; and the Editor Dr. Lou Wicker and three anonymous reviewers for their insightful comments.
Publisher Copyright:
© 2020 American Meteorological Society.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2020/12/1
Y1 - 2020/12/1
N2 - Idealized 3D numerical simulations are used to quantify the impact of moving marine atmospheric boundary layers (MABLs) on squall lines in an environment representative of the U.S. mid-Atlantic coastal plain. Characteristics of the MABL, including depth and potential temperature, are varied. Squall lines are most intense while moving over the deepest MABLs, while the storm encountering no MABL is the weakest. Storm intensity is only sensitive to MABL temperature when the MABL is sufficiently deep. Collisions between the storm cold pools and MABLs transition storm lift from surface-based cold pools to wavelike features, with the resulting ascent mechanism dependent on MABL density, not depth. Bores form when the MABL is denser than the cold pool and hybrid cold pool-bores form when the densities are similar. While these features support storms over the MABL, the type of lifting mechanism does not control storm intensity alone. Storm intensity depends on the amplification and maintenance of these features, which is determined by the ambient conditions. Isolated convective cells form ahead of squall lines prior to the cold pool-MABL collision, resulting in a rain peak and the eventual discrete propagation of the storms. Cells form as storm-generated high-frequency gravity waves interact with gravity waves generated by the moving marine layers, in the presence of reduced stability by the squall line itself. No cells form in the presence of the storm or the MABL alone.
AB - Idealized 3D numerical simulations are used to quantify the impact of moving marine atmospheric boundary layers (MABLs) on squall lines in an environment representative of the U.S. mid-Atlantic coastal plain. Characteristics of the MABL, including depth and potential temperature, are varied. Squall lines are most intense while moving over the deepest MABLs, while the storm encountering no MABL is the weakest. Storm intensity is only sensitive to MABL temperature when the MABL is sufficiently deep. Collisions between the storm cold pools and MABLs transition storm lift from surface-based cold pools to wavelike features, with the resulting ascent mechanism dependent on MABL density, not depth. Bores form when the MABL is denser than the cold pool and hybrid cold pool-bores form when the densities are similar. While these features support storms over the MABL, the type of lifting mechanism does not control storm intensity alone. Storm intensity depends on the amplification and maintenance of these features, which is determined by the ambient conditions. Isolated convective cells form ahead of squall lines prior to the cold pool-MABL collision, resulting in a rain peak and the eventual discrete propagation of the storms. Cells form as storm-generated high-frequency gravity waves interact with gravity waves generated by the moving marine layers, in the presence of reduced stability by the squall line itself. No cells form in the presence of the storm or the MABL alone.
UR - http://www.scopus.com/inward/record.url?scp=85098843600&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85098843600&partnerID=8YFLogxK
U2 - 10.1175/JAS-D-20-0044.1
DO - 10.1175/JAS-D-20-0044.1
M3 - Article
AN - SCOPUS:85098843600
SN - 0022-4928
VL - 77
SP - 4143
EP - 4170
JO - Journal of the Atmospheric Sciences
JF - Journal of the Atmospheric Sciences
IS - 12
ER -