Advertisement

Observed interactions between boundary-layer mesoscale frontal features during summers in the Carolinas coastal region of eastern USA

  • Aaron P. Sims
  • Sethu Raman
Original Paper
  • 9 Downloads

Abstract

In the Carolinas of the United States, there are two significant land-surface features, the coastline and the Sandhills (inland), over which convection frequently forms during the summer months. The Sandhills, an area of sandy soil surrounded by other soil types, extends through the central Carolinas and is often the origin of convective storms. Nearby, sea-breeze circulations form along the coastline initiating convection during summers. The interaction between the outflow from the Sandhills convection, “the Sandhills front”, and the sea-breeze front initiates and enhances deep convection in the region. The objective of this paper is to characterize and classify these mesoscale interactions, taking into account the geography and the background flow. Using radar and in situ observations, it is found that these interactions typically occur on 24% of all days in June and 36% of the days in June when synoptic forcing is weak or absent. Onshore, offshore, and southwesterly background flows result in different strengths and locations of the convection associated with these interactions. Additionally, light winds (< 3 m s−1) and moderate winds (3–6 m s−1) influence these interactions differently. Interactions between the two fronts during moderate southwesterly flow produce widespread regional precipitation with the highest precipitation amounts due to the advection of warm, moist air from the Gulf of Mexico. Interactions during light offshore winds also produce strong interactions between the sea-breeze front and the Sandhills front possibly due to opposing flows that aid in the strengthening of a well-developed sea-breeze. Interactions occur less frequently during onshore flow and have the least precipitation amounts. The sea-breeze circulation is weak in such cases.

Notes

Acknowledgements

We thank Professor Sukanta Basu for his valuable comments on this research. We also thank the reviewers for their valuable comments. The NCAR Command language (NCL) was used in this study. The State Climate Office of North Carolina provided support for this research.

References

  1. Atkins NT, Wakimoto RM (1997) Influence of the synoptic scale flow on sea breezes observed during CaPE. Mon Weather Rev 125:2112–2130CrossRefGoogle Scholar
  2. Boyles R (2006) Investigation of mesoscale precipitation processes in the carolinas using a radar-based climatology. Doctoral Dissertation, Dept of Marine, Earth, and Atmos Sci, North Carolina State University. http://www.lib.ncsu.edu/resolver/1840.16/3895
  3. Charba J (1974) Application of gravity current model to analysis of squall-line gust front. Mon Weather Rev 102:140–156CrossRefGoogle Scholar
  4. Crouch AD, (2006) A climatology of the sea breeze front in the coastal Carolinas and Georgia. Master’s Thesis, Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University. http://www.lib.ncsu.edu/resolver/1840.16/217
  5. Dai AF, Trenberth KE (2004) The diurnal cycle and its depiction in the Community Climate System Model. J Clim 17:930–995CrossRefGoogle Scholar
  6. Daly CR, Neilson P, Phillips DL (1994) A statistical-topographic model for mapping climatological precipitation over mountainous terrain. J Appl Meteorol 33:140–158CrossRefGoogle Scholar
  7. Derbyshire SH, Beau I, Bechtold P, Grandpeix J-Y, Piriou J-M, Redelsperger J-L, Soares PMM (2004) Sensitivity of moist convection to environmental humidity. QJR Meteorol Soc 130:3055–3079.  https://doi.org/10.1256/qj.03.130 CrossRefGoogle Scholar
  8. Droegemeier KK, Wilhelmson RB (1987) Numerical simulation of thunderstorm outflow dynamics, Pt. 1, outflow sensitivity experiments and turbulence dynamics. J Atmos Sci 44:1180–1210CrossRefGoogle Scholar
  9. Fitzjarrald DR (1986) Slope winds in Veracruz. J Clim Appl Meteorol 25:133–144CrossRefGoogle Scholar
  10. Gilliam RC, Raman S, Niyogi DDS (2004) Observational and numerical study on the influence of large-scale flow direction and coastline shape on sea-breeze evolution. Bound Layer Meteorol 111:275–300CrossRefGoogle Scholar
  11. Goff RC (1976) Vertical structure of thunderstorm outflows. Mon Weather Rev 104:1429–1440CrossRefGoogle Scholar
  12. Helmis CG, Papadopoulos KH, Kalogiros JA, Soilemes AT, Asimakopoulos DN (1995) Influence of background flow on evolution of Saronic Gulf Sea Breeze. Atmos Environ 29:3689–3701CrossRefGoogle Scholar
  13. Hong X, Leach MJ, Raman S (1995) The role of vegetation in the generation of mesoscale circulation. Atmos Environ 29:2163–2176CrossRefGoogle Scholar
  14. Koch SE, Ray CA (1997) Mesoanalysis of summertime convergence zones in Central and Eastern North Carolina. Wea Forecast 12:56–77CrossRefGoogle Scholar
  15. Lakshmanan V, Smith T, Stumpf GJ, Hondl K (2007) The warning decision support system–integrated information. Wea Forecast 22:596–612CrossRefGoogle Scholar
  16. Lin Y, Mitchell KE (2005) 1.2 the NCEP Stage II/IV hourly precipitation analyses: 17 Development and applications. In: 19th conference on hydrology, San Diego, Amer Meteor SocGoogle Scholar
  17. Mahfouf J-F, Richard E, Mascart P (1987) The influence of soil and vegetation on the development of mesoscale circulations. J Clim Appl Meteorol 26:1483–1495CrossRefGoogle Scholar
  18. Raman S, Sims AP, Ellis R, Boyles R (2005) Numerical Simulation of mesoscale circulations in a region of contrasting soil types. Pure Appl Geophys 162:1981–2004CrossRefGoogle Scholar
  19. Rihani JF, Chow FK, Maxwell RM (2015) Isolating effects of terrain and soil moisture heterogeneity on the atmospheric boundary layer: idealized simulations to diagnose land-atmosphere feedbacks. J Adv Model Earth Syst 7:915–937CrossRefGoogle Scholar
  20. Simpson JE (1969) A comparison between laboratory and atmospheric density currents. QJR Meteorol Soc 95:758–765.  https://doi.org/10.1002/qj.49709540609 CrossRefGoogle Scholar
  21. Simpson JE, Mansfield DA, Milford JR (1977) Inland penetration of sea-breeze fronts. QJR Meteorol Soc 103:47–76.  https://doi.org/10.1002/qj.49710343504 CrossRefGoogle Scholar
  22. Sims AP, Raman S (2016) Interaction between two distinct mesoscale circulations during summer in the coastal region of Eastern USA. Bound Layer Meteorol 160:113–132.  https://doi.org/10.1007/s10546-015-0125-6 CrossRefGoogle Scholar
  23. Sims AP, Alapaty K, Raman S (2017) Sensitivities of summertime mesoscale circulations in the coastal carolinas to modifications of the kain–fritsch cumulus parameterization. Mon Wea Rev 145:4381–4399.  https://doi.org/10.1175/MWR-D-16-0047.1 CrossRefGoogle Scholar
  24. Taylor CM, de Jeu RAM, Guichard F, Harris PP, Dorigo WA (2012) Afternoon rain more likely over drier soils. Nature 489:423–426CrossRefGoogle Scholar
  25. Trapp RJ (2013) Mesoscale-convective processes in the atmosphere. Cambridge University Press, Cambridge, p 346CrossRefGoogle Scholar
  26. Wakimoto RM (1982) The life-cycle of thunderstorm gust fronts as viewed with Doppler radar and rawinsonde data. Mon Weather Rev 110:1060–1082CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2019

Authors and Affiliations

  1. 1.State Climate Office of NC, Department of Marine Earth and Atmospheric SciencesNorth Carolina State UniversityRaleighUSA
  2. 2.Department of Marine Earth and Atmospheric SciencesNorth Carolina State UniversityRaleighUSA

Personalised recommendations