Editorial Type:
Article
Article Type:
Research Article

A Dryline in Southeast Wyoming. Part I: Multiscale Analysis Using Observations and Modeling on 22 June 2010

Patrick C. Campbell Department of Atmospheric Science, University of Wyoming, Laramie, Wyoming

Search for other papers by Patrick C. Campbell in
Current site
Google Scholar
PubMed Close
,
Bart Geerts Department of Atmospheric Science, University of Wyoming, Laramie, Wyoming

Search for other papers by Bart Geerts in
Current site
Google Scholar
PubMed Close
, and
Philip T. Bergmaier Department of Atmospheric Science, University of Wyoming, Laramie, Wyoming

Search for other papers by Philip T. Bergmaier in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Jan 2014
DOI:
https://doi.org/10.1175/MWR-D-13-00049.1
Page(s):
268–289
Restricted access

Abstract

A first observational and modeling study of a dryline and associated initiation of deep convection over the high plains of southeastern Wyoming is presented. Radar and station measurements show that the dryline is a well-defined convergent humidity boundary with a modest density (i.e., buoyancy) gradient. Its development, intensity, and movement are regulated by the terrain, diurnal land surface and boundary layer processes, and synoptic-scale evolution. At least one of the thunderstorms that emerged from the dryline became severe. Weather Research and Forecasting Model (WRF) simulations accurately reproduce measured aspects of this dryline, as well as the timing and location of convection initiation. The WRF output is used further to characterize the dryline vertical and horizontal structures and to examine convection initiation processes. A dryline bulge over a local terrain ridge appears to be an essential ingredient in convection initiation on this day: just north of this bulge the surface convergence and buoyancy gradient are strongest, and deep convection is triggered. In this region especially, the WRF simulation produces horizontal convective rolls intersecting with the dryline, as well as small cyclonic vortices along the dryline. In fact, the primary storm cell initiates just downwind of one such vortex. Part II of this study describes the finescale vertical structure of this dryline using airborne Raman lidar data.

Corresponding author address: Patrick C. Campbell, Dept. of Atmospheric Science, University of Wyoming, 1000 East University Ave., Laramie, WY 82071. E-mail: pcampbe2@uwyo.edu

Abstract

A first observational and modeling study of a dryline and associated initiation of deep convection over the high plains of southeastern Wyoming is presented. Radar and station measurements show that the dryline is a well-defined convergent humidity boundary with a modest density (i.e., buoyancy) gradient. Its development, intensity, and movement are regulated by the terrain, diurnal land surface and boundary layer processes, and synoptic-scale evolution. At least one of the thunderstorms that emerged from the dryline became severe. Weather Research and Forecasting Model (WRF) simulations accurately reproduce measured aspects of this dryline, as well as the timing and location of convection initiation. The WRF output is used further to characterize the dryline vertical and horizontal structures and to examine convection initiation processes. A dryline bulge over a local terrain ridge appears to be an essential ingredient in convection initiation on this day: just north of this bulge the surface convergence and buoyancy gradient are strongest, and deep convection is triggered. In this region especially, the WRF simulation produces horizontal convective rolls intersecting with the dryline, as well as small cyclonic vortices along the dryline. In fact, the primary storm cell initiates just downwind of one such vortex. Part II of this study describes the finescale vertical structure of this dryline using airborne Raman lidar data.

Corresponding author address: Patrick C. Campbell, Dept. of Atmospheric Science, University of Wyoming, 1000 East University Ave., Laramie, WY 82071. E-mail: pcampbe2@uwyo.edu
Save
Cover Monthly Weather Review
Monthly Weather Review

  • Atkins, N. T., R. M. Wakimoto, and C. L. Ziegler, 1998: Observations of the finescale structure of a dryline during VORTEX 95. Mon. Wea. Rev., 126, 525–550.

    • Search Google Scholar
    • Export Citation

  • Banta, R. M., 1984: Daytime boundary-layer evolution over mountainous terrain. Part I: Observations of the dry circulations. Mon. Wea. Rev., 112, 340–356.

    • Search Google Scholar
    • Export Citation

  • Bergmaier, P. T., Z. Wang, B. Geerts, B. Liu, and P. C. Campbell, 2013: A dryline in southeast Wyoming. Part II: Airborne Raman lidar observations. Mon. Wea. Rev., submitted.

    • Search Google Scholar
    • Export Citation

  • Betts, A. K., 1982: Saturation point analysis of moist convective overturning. J. Atmos. Sci., 39, 1484–1505.

  • Bluestein, H. B., 1993: Observations and Theory of Weather Systems. Vol. II, Synoptic-Dynamic Meteorology in Midlatitudes, Oxford University Press, 608 pp.

    • Search Google Scholar
    • Export Citation

  • Buban, M. S., C. L. Ziegler, E. N. Rasmussen, and Y. P. Richardson, 2007: The dryline on 22 May 2002 during IHOP: Ground-radar and in situ data analyses of the dryline and boundary layer evolution. Mon. Wea. Rev., 135, 2473–2505.

    • Search Google Scholar
    • Export Citation

  • Buban, M. S., C. L. Ziegler, E. R. Mansell, and Y. P. Richardson, 2012: Simulation of dryline misovortex dynamics and cumulus formation. Mon. Wea. Rev., 140, 3525–3551.

    • Search Google Scholar
    • Export Citation

  • Coffer, B. E., L. C. Maudlin, P. G. Veals, and A. J. Clark, 2013: Dryline position errors in experimental convection-allowing NSSL-WRF model forecasts and the operational NAM. Wea. Forecasting, 28, 746–761.

    • Search Google Scholar
    • Export Citation

  • Coniglio, M. C., K. L. Elmore, J. S. Kain, S. J. Weiss, M. Xue, and M. L. Weisman, 2010: Evaluation of WRF model output for severe weather forecasting from the 2008 NOAA Hazardous Weather Testbed Spring Experiment. Wea. Forecasting, 25, 408–427.

    • Search Google Scholar
    • Export Citation

  • Crawford, T. M., and H. B. Bluestein, 1997: Characteristics of dryline passage during COPS-91. Mon. Wea. Rev., 125, 463–477.

  • Ek, M. B., K. E. Mitchell, Y. Lin, E. Rogers, P. Grummann, V. Koren, G. Gayno, and J. D. Tarpley, 2003: Implementation of Noah land surface model advances in the National Centers for Environmental Prediction operational Mesoscale Eta Model. J. Geophys. Res., 108, 8851–8865.

    • Search Google Scholar
    • Export Citation

  • Etling, D., and R. A. Brown, 1993: Roll vortices in the planetary boundary layer: A review. Bound.-Layer Meteor., 65, 215–248.

  • Fujita, T. T., 1981: Tornadoes and downbursts in the context of generalized planetary scales. J. Atmos. Sci., 38, 1511–1534.

  • Geerts, B., 2008: Dryline characteristics near Lubbock, Texas, based on radar and West Texas mesonet data for May 2005 and May 2006. Wea. Forecasting, 23, 392–406.

    • Search Google Scholar
    • Export Citation

  • Hane, C. E., 2004: Quiescent and synoptically-active drylines: A comparison based upon case studies. Meteor. Atmos. Phys., 86, 195–211.

    • Search Google Scholar
    • Export Citation

  • Hane, C. E., C. L. Ziegler, and H. B. Bluestein, 1993: Investigation of the dryline and convective storms initiated along the dryline: Field experiments during COPS-91. Bull. Amer. Meteor. Soc., 74, 2133–2145.

    • Search Google Scholar
    • Export Citation

  • Hane, C. E., H. B. Bluestein, T. M. Crawford, M. E. Baldwin, and R. M. Rabin, 1997: Severe thunderstorm development in relation to along-dryline variability: A case study. Mon. Wea. Rev., 125, 231–251.

    • Search Google Scholar
    • Export Citation

  • Hane, C. E., M. E. Baldwin, H. B. Bluestein, T. M. Crawford, and R. M. Rabin, 2001: A case study of severe storm development along a dryline within a synoptically active environment. Part I: Dryline motion and an Eta Model forecast. Mon. Wea. Rev., 129, 2183–2204.

    • Search Google Scholar
    • Export Citation

  • Hane, C. E., R. M. Rabin, T. M. Crawford, H. B. Bluestein, and M. E. Baldwin, 2002: A case study of severe storm development along a dryline within a synoptically active environment. Part II: Multiple boundaries and convective initiation. Mon. Wea. Rev., 130, 900–920.

    • Search Google Scholar
    • Export Citation

  • Hill, L. M., 2006: Drylines observed in Alberta during A-GAME. M.S. thesis, Dept. of Earth and Atmospheric Sciences, University of Alberta, 111 pp. [Available online at http://www.umanitoba.ca/faculties/environment/envirogeog/weather/unstable/images/20070724_images/LHill_MSc_Thesis.pdf.]

  • Hoch, J., and P. Markowski, 2005: Climatology of springtime dryline position in the U.S. Great Plains region. J. Climate, 18, 2132–2137.

    • Search Google Scholar
    • Export Citation

  • Horel, J., and Coauthors, 2002: Mesowest: Cooperative mesonets in the western United States. Bull. Amer. Meteor. Soc., 83, 211–225.

  • Koch, S. E., and J. McCarthy, 1982: The evolution of an Oklahoma dryline. Part II: Boundary-layer forcing of mesoconvective systems. J. Atmos. Sci., 39, 237–257.

    • Search Google Scholar
    • Export Citation

  • Lee, B. D., and R. B. Wilhelmson, 1997: The numerical simulation of non-supercell tornadogenesis. Part I: Initiation and evolution of pretornadic misocyclone circulations along a dry outflow boundary. J. Atmos. Sci., 54, 32–60.

    • Search Google Scholar
    • Export Citation

  • Mahrt, L., 1991: Boundary layer moisture regimes. Quart. J. Roy. Meteor. Soc., 117, 151–176.

  • Markowski, P., and Y. Richardson, 2010: Mesoscale Meteorology in Midlatitudes. J. Wiley and Sons, 407 pp.

  • Marquis, J. N., Y. P. Richardson, and J. M. Wurman, 2007: Kinematic observations of misocyclones along boundaries during IHOP. Mon. Wea. Rev., 135, 1749–1768.

    • Search Google Scholar
    • Export Citation

  • McCarthy, J., and S. E. Koch, 1982: The evolution of an Oklahoma dryline. Part I: A meso- and subsynoptic-scale analysis. J. Atmos. Sci., 39, 225–236.

    • Search Google Scholar
    • Export Citation

  • McCaul, E. W., Jr., and D. O. Blanchard, 1990: A low-precipitation cumulonimbus along the dryline in Colorado. Mon. Wea. Rev., 118, 2768–2773.

    • Search Google Scholar
    • Export Citation

  • Miao, Q., and B. Geerts, 2007: Fine-scale vertical structure and dynamics of some dryline boundaries observed in IHOP. Mon. Wea. Rev., 135, 4161–4184.

    • Search Google Scholar
    • Export Citation

  • Murphey, H. V., R. M. Wakimoto, C. Flamant, and D. E. Kingsmill, 2006: Dryline on 19 June 2002 during IHOP. Part I: Airborne Doppler and LEANDRE II analyses of the thin line structure and convective initiation. Mon. Wea. Rev., 134, 406–430.

    • Search Google Scholar
    • Export Citation

  • Ogura, Y., and Y. Chen, 1977: A life history of an intense mesoscale convective storm in Oklahoma. J. Atmos. Sci., 34, 1458–1476.

  • Peckham, S. E., R. B. Wilhelmson, L. J. Wicker, and C. L. Ziegler, 2004: Numerical simulation of the interaction between the dryline and horizontal convective rolls. Mon. Wea. Rev., 132, 1792–1812.

    • Search Google Scholar
    • Export Citation

  • Rinehart, R. E., 1997: Radar for Meteorologists. 3rd ed. Rinehart Publications, 428 pp.

  • Russell, R. W., and J. W. Wilson, 1997: Radar-observed “fine lines” in the optically clear boundary layer: Reflectivity contributions from aerial plankton and its predators. Bound.-Layer Meteor., 82, 235–262.

    • Search Google Scholar
    • Export Citation

  • Schaefer, J. T., 1974a: The simulative model of dryline motion. J. Atmos. Sci., 31, 956–964.

  • Schaefer, J. T., 1974b: The life cycle of the dryline. J. Appl. Meteor., 13, 444–449.

  • Schaefer, J. T., 1986: The dryline. Mesoscale Meteorology and Forecasting, P. S. Ray, Ed., Amer. Meteor. Soc., 549–572.

  • Schultz, D. M., C. C. Weiss, and P. M. Hofmann, 2007: The synoptic regulation of dryline intensity. Mon. Wea. Rev., 135, 1699–1709.

  • Shaw, B. L., R. A. Pielke, and C. L. Ziegler, 1997: A three-dimensional numerical simulation of a Great Plains dryline. Mon. Wea. Rev., 125, 1489–1506.

    • Search Google Scholar
    • Export Citation

  • Sipprell, B., and B. Geerts, 2007: Finescale vertical structure and evolution of a preconvective dryline on 19 June 2002. Mon. Wea. Rev., 135, 2111–2134.

    • Search Google Scholar
    • Export Citation

  • Skamarock, W. C., and Coauthors, 2008: A description of the Advanced Research WRF version 3. NCAR Tech. Note NCAR/TN–475+STR, 113 pp. [Available online at http://www.mmm.ucar.edu/wrf/users/docs/arw_v3.pdf.]

  • Sun, W.-Y., and Y. Ogura, 1979: Boundary layer forcing as a possible trigger to squall line formation. J. Atmos. Sci., 36, 235–254.

  • Sun, W.-Y., and C.-C. Wu, 1992: Formation and diurnal variation of the dryline. J. Atmos. Sci., 49, 1606–1619.

  • Taylor, N. M., and Coauthors, 2011: The Understanding Severe Thunderstorms and Alberta Boundary Layers Experiment (UNSTABLE) 2008. Bull. Amer. Meteor. Soc., 92, 739–763.

    • Search Google Scholar
    • Export Citation

  • Wakimoto, R. M., and H. V. Murphey, 2009: Analysis of a dryline during IHOP: Implications for convective initiation. Mon. Wea. Rev., 137, 912–936.

    • Search Google Scholar
    • Export Citation

  • Wang, Y., B. Geerts, and J. French, 2009: Dynamics of the cumulus cloud margin: An observational study. J. Atmos. Sci., 66, 3660–3677.

    • Search Google Scholar
    • Export Citation

  • Weckwerth, T. M., and Coauthors, 2004: An overview of the International H2O Project (IHOP_2002) and some preliminary highlights. Bull. Amer. Meteor. Soc., 85, 253–277.

    • Search Google Scholar
    • Export Citation

  • Weston, K. J., 1972: The dry-line of northern India and its role in cumulonimbus convection. Quart. J. Roy. Meteor. Soc., 98, 519–531.

    • Search Google Scholar
    • Export Citation

  • Xue, M., and W. J. Martin, 2006a: A high-resolution modeling study of the 24 May 2002 dryline case during IHOP. Part I: Numerical simulation and general evolution of the dryline and convection. Mon. Wea. Rev., 134, 149–171.

    • Search Google Scholar
    • Export Citation

  • Xue, M., and W. J. Martin, 2006b: A high-resolution modeling study of the 24 May 2002 dryline case during IHOP. Part II: Horizontal convective rolls and convective initiation. Mon. Wea. Rev., 134, 172–191.

    • Search Google Scholar
    • Export Citation

  • Zardi, D., and C. D. Whiteman, 2012: Diurnal mountain wind systems. Mountain Weather Research and Forecasting: Recent Progress and Current Challenges, F. K. Chow, S. F. J. De Wekker, and B. J. Snyder, Eds., Springer, 35–120.

  • Ziegler, C. L., and C. E. Hane, 1993: An observational study of the dryline. Mon. Wea. Rev., 121, 1134–1151.

  • Ziegler, C. L., and E. N. Rasmussen, 1998: The initiation of moist convection at the dryline: Forecasting issues from a case study perspective. Wea. Forecasting, 13, 1106–1131.

    • Search Google Scholar
    • Export Citation

  • Ziegler, C. L., T. J. Lee, and R. A. Pielke Sr., 1997: Convection initiation at the dryline: A modeling study. Mon. Wea. Rev., 125, 1001–1026.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 258 78 4
PDF Downloads 117 33 2