• Barnston, A. G., A. Leetmaa, V. E. Kousky, R. E. Livezey, E. O’Lenic, H. Van den Dool, A. J. Wagner, and D. A. Unger, 1999: NCEP forecasts of the El Niño of 1997–98 and its U.S. impacts. Bull. Amer. Meteor. Soc., 80 , 18291852.

    • Search Google Scholar
    • Export Citation
  • Battan, L. J., 1973: Radar Observations of the Atmosphere. University of Chicago Press, 324 pp.

  • Bergeron, T., 1965: On the low-level redistribution of atmospheric water caused by orography. Proc. Int. Conf. on Cloud Physics, Tokyo, Japan, IAMAP/WMO, 96–100.

  • Browning, K. A., 1974: Mesoscale structure of rain systems in the British Isles. J. Meteor. Soc. Japan, 52 , 314327.

  • Browning, K. A., 1980: Structure, mechanism, and prediction of orographically enhanced rain in Britain. Orographic Effects in Planetary Flows, R. Hide and P. W. White, Eds., GARP Publication Series, Vol. 23, 85–114.

    • Search Google Scholar
    • Export Citation
  • Browning, K. A., and G. A. Monk, 1982: A simple model for the synoptic analysis of cold fronts. Quart. J. Roy. Meteor. Soc., 108 , 435452.

    • Search Google Scholar
    • Export Citation
  • Browning, K. A., F. F. Hill, and C. W. Pardoe, 1974: Structure and mechanism of precipitation and the effect of orography in a wintertime warm sector. Quart. J. Roy. Meteor. Soc., 100 , 309330.

    • Search Google Scholar
    • Export Citation
  • Carbone, R. E., 1982: Severe frontal rainband. Part I: Stormwide dynamic structure. J. Atmos. Sci., 39 , 258279.

  • Carter, D. A., K. S. Gage, W. L. Ecklund, W. M. Angevine, P. E. Johnston, A. C. Riddle, J. S. Wilson, and C. R. Williams, 1995: Developments in UHF lower tropospheric wind profiling at NOAA’s Aeronomy Laboratory. Radio Sci., 30 , 9971001.

    • Search Google Scholar
    • Export Citation
  • Crum, T. D., and R. L. Alberty, 1993: The WSR-88D and the WSR-88D Operational Support Facility. Bull. Amer. Meteor. Soc., 74 , 16691687.

    • Search Google Scholar
    • Export Citation
  • Crum, T. D., R. L. Alberty, and D. W. Burgess, 1993: Recording, archiving, and using WSR-88D data. Bull. Amer. Meteor. Soc., 74 , 645653.

    • Search Google Scholar
    • Export Citation
  • Doyle, J. D., 1997: The influence of mesoscale orography on a coastal jet and rainband. Mon. Wea. Rev., 125 , 14651488.

  • Fabry, F., and I. Zawadzki, 1995: Long-term radar observations of the melting layer of precipitation and their interpretation. J. Atmos. Sci., 52 , 838851.

    • Search Google Scholar
    • Export Citation
  • Fulton, R. A., J. P. Breidenbach, D. J. Seo, D. A. Miller, and T. O’Bannon, 1998: The WSR-88D rainfall algorithm. Wea. Forecasting, 13 , 377395.

    • Search Google Scholar
    • Export Citation
  • Glickman, T. S., 2000: Glossary of Meteorology. 2d ed. Amer. Meteor. Soc., 855 pp.

  • Gordon, G. L., and J. D. Marwitz, 1986: Hydrometeor evolution in rainbands over the California valley. J. Atmos. Sci., 43 , 10871100.

  • Gourley, J. J., and C. M. Calvert, 2003: Automated detection of the bright band using WSR-88D data. Wea. Forecasting, 18 , 585599.

  • Harrold, T. W., 1973: Mechanisms influencing the distribution of precipitation within baroclinic disturbances. Quart. J. Roy. Meteor. Soc., 99 , 232251.

    • Search Google Scholar
    • Export Citation
  • Heggli, M. F., and D. W. Reynolds, 1985: Radiometric observations of supercooled liquid water within a split front over the Sierra Nevada. J. Climate Appl. Meteor., 24 , 12581261.

    • Search Google Scholar
    • Export Citation
  • Heggli, M. F., and R. M. Rauber, 1988: The characteristics and evolution of supercooled water in wintertime storms over the Sierra Nevada: A summary of microwave radiometric measurements taken during the Sierra Cooperative Pilot Project. J. Appl. Meteor., 27 , 9891015.

    • Search Google Scholar
    • Export Citation
  • Heggli, M. F., L. Vardiman, R. E. Stewart, and A. Huggins, 1983: Supercooled liquid water and ice crystal distributions within Sierra Nevada winter storms. J. Climate Appl. Meteor., 22 , 18751886.

    • Search Google Scholar
    • Export Citation
  • Hill, F. F., and K. A. Browning, 1979: Persistence and orographic modulation of mesoscale precipitation areas in a potentially unstable warm sector. Quart. J. Roy. Meteor. Soc., 105 , 5770.

    • Search Google Scholar
    • Export Citation
  • Hobbs, P. V., and P. O. G. Persson, 1982: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. Part V: The substructure of narrow cold-frontal rainbands. J. Atmos. Sci., 39 , 280295.

    • Search Google Scholar
    • Export Citation
  • Hobbs, P. V., T. J. Matejka, P. H. Herzegh, J. D. Locatelli, and R. A. Houze Jr., 1980: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. I: A case study of a cold front. J. Atmos. Sci., 37 , 568596.

    • Search Google Scholar
    • Export Citation
  • Hobbs, P. V., J. D. Locatelli, and J. E. Martin, 1990: Cold fronts aloft and the forecasting of precipitation and severe weather east of the Rocky Mountains. Wea. Forecasting, 5 , 613626.

    • Search Google Scholar
    • Export Citation
  • Houze Jr., R. A., 1993: Cloud Dynamics. Academic Press, 573 pp.

  • Houze Jr., R. A., and P. V. Hobbs, 1982: Organization and structure of precipitating cloud systems. Advances in Geophysics, 24 , Academic Press,. 225315.

    • Search Google Scholar
    • Export Citation
  • Houze Jr., R. A., S. A. Rutledge, T. J. Matejka, and P. V. Hobbs, 1981: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. III: Air motions and precipitation growth in a warm-frontal rainband. J. Atmos. Sci., 38 , 639649.

    • Search Google Scholar
    • Export Citation
  • Houze Jr., R. A., B. F. Smull, and P. Dodge, 1990: Mesoscale organization of springtime rainstorms in Oklahoma. Mon. Wea. Rev., 118 , 613654.

    • Search Google Scholar
    • Export Citation
  • James, P. K., and K. A. Browning, 1979: Mesoscale structure of line convection at surface cold fronts. Quart. J. Roy. Meteor. Soc., 105 , 371382.

    • Search Google Scholar
    • Export Citation
  • Jorgensen, D. P., Z. Pu, P. O. G. Persson, and W-K. Tao, 2003: Variations associated with cores and gaps of a Pacific narrow cold frontal rainband. Mon. Wea. Rev., 131 , 27052729.

    • Search Google Scholar
    • Export Citation
  • Klaasen, W., 1988: Radar observations and simulation of the melting layer of precipitation. J. Atmos. Sci., 45 , 37413753.

  • Knight, D. J., and P. V. Hobbs, 1988: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. Part XV: A numerical modeling study of frontogenesis and cold-frontal rainbands. J. Atmos. Sci., 45 , 915931.

    • Search Google Scholar
    • Export Citation
  • Lindzen, R. S., and K. K. Tung, 1976: Banded convective activity and ducted gravity waves. Mon. Wea. Rev., 104 , 16021617.

  • Marshall, J. S., and W. Mc K. Palmer, 1948: The distribution of raindrops with size. J. Meteor., 5 , 165166.

  • Marwitz, J. D., 1983: The kinematics of orographic airflow during Sierra storms. J. Atmos. Sci., 40 , 12181227.

  • Matejka, T. J., R. A. Houze Jr., and P. V. Hobbs, 1980: Microphysics and dynamics of the clouds associated with mesoscale rainbands in extratropical cyclones. Quart. J. Roy. Meteor. Soc., 106 , 2956.

    • Search Google Scholar
    • Export Citation
  • May, P. T., K. P. Moran, and R. G. Strauch, 1989: The accuracy of RASS temperature profiles. J. Appl. Meteor., 28 , 13291335.

  • Medina, S., and R. A. Houze Jr., 2003: Air motions and precipitation growth in Alpine storms. Quart. J. Roy. Meteor. Soc., 129 , 345371.

    • Search Google Scholar
    • Export Citation
  • Mendell, T., 1992: Integration of automated hydrological data. Preprints, Conf. on Interdisciplinary Approaches in Hydrology and Hydrogeology, Portland, OR, American Society of Civil Engineers.

  • Neiman, P. J., P. T. May, and M. A. Shapiro, 1992: Radio Acoustic Sounding System (RASS) and wind profiler observations of lower- and middle-tropospheric weather systems. Mon. Wea. Rev., 120 , 22982313.

    • Search Google Scholar
    • Export Citation
  • Neiman, P. J., F. M. Ralph, A. B. White, D. E. Kingsmill, and P. O. G. Persson, 2002: The statistical relationship between upslope flow and rainfall in California’s coastal mountains: Observations during CALJET. Mon. Wea. Rev., 130 , 14681492.

    • Search Google Scholar
    • Export Citation
  • Neiman, P. J., P. O. G. Persson, F. M. Ralph, D. P. Jorgensen, A. B. White, and D. E. Kingsmill, 2004: Modification of fronts and precipitation by coastal blocking during an intense landfalling winter storm in southern California: Observations during CALJET. Mon. Wea. Rev., 132 , 242273.

    • Search Google Scholar
    • Export Citation
  • Neiman, P. J., B. E. Martner, A. B. White, G. A. Wick, F. M. Ralph, and D. E. Kingsmill, 2005: Wintertime nonbrightband rain in California and Oregon during CALJET and PACJET: Geographic, interannual, and synoptic variability. Mon. Wea. Rev., 133 , 11991223.

    • Search Google Scholar
    • Export Citation
  • Newton, C. W., 1963: Dynamics of severe convective storms. Severe Local Storms, Meteor. Monogr., No. 27, Amer. Meteor. Soc., 33–58.

  • Overland, J. E., and N. A. Bond, 1995: Observations and scale analysis of coastal wind jets. Mon. Wea. Rev., 123 , 29342941.

  • Parish, T. R., 1982: Barrier winds along the Sierra Nevada mountains. J. Appl. Meteor., 21 , 925930.

  • Pruppacher, H. R., and J. D. Klett, 1997: Microphysics of Clouds and Precipitation. Kluwer Academic, 954 pp.

  • Ralph, F. M., P. J. Neiman, and G. A. Wick, 2004: Satellite and CALJET aircraft observations of atmospheric rivers over the eastern North Pacific Ocean during the winter of 1997/98. Mon. Wea. Rev., 132 , 17211745.

    • Search Google Scholar
    • Export Citation
  • Ralph, F. M., and Coauthors, 1999: The California Land-falling Jets Experiment (CALJET): Objectives and design of a coastal atmosphere–ocean observing system deployed during a strong El Niño. Preprints, Third Symp. on Integrated Observing Systems, Dallas, TX, Amer. Meteor. Soc., 78–81.

  • Ralph, F. M., P. J. Neiman, D. E. Kingsmill, P. O. G. Persson, A. B. White, E. T. Strem, E. D. Andrews, and R. C. Antweiler, 2003: The impact of a prominent rain shadow on flooding in California’s Santa Cruz Mountains: A CALJET case study and sensitivity to the ENSO cycle. J. Hydrometeor., 4 , 12431264.

    • Search Google Scholar
    • Export Citation
  • Rauber, R. M., 1992: Microphysical structure and evolution of a central Sierra Nevada orographic cloud system. J. Appl. Meteor., 31 , 324.

    • Search Google Scholar
    • Export Citation
  • Reed, R. J., and W. Blier, 1986: A case study of comma cloud development in the eastern Pacific. Mon. Wea. Rev., 114 , 16811695.

  • Rogers, R. R., and M. K. Yau, 1989: A Short Course in Cloud Physics. Pergamon, 293 pp.

  • Ross, B. B., and I. Orlanski, 1978: The circulation associated with a cold front. Part II: Moist case. J. Atmos. Sci., 35 , 445465.

  • Solak, M. E., T. J. Henderson, and R. B. Allan, 1984: Precipitation measurements–SCPP data collection and analysis for the period 1 January 1979 through 30 September 1984. Vol. II, Final Rep., U.S. Bureau of Reclamation, Denver, CO, 434 pp.

  • Stewart, R. E., J. D. Marwitz, J. C. Pace, and R. E. Carbone, 1984: Characteristics through the melting layer of stratiform clouds. J. Atmos. Sci., 41 , 32273237.

    • Search Google Scholar
    • Export Citation
  • Wallace, J. M., and P. V. Hobbs, 1977: Atmospheric Science: An Introductory Survey. Academic Press, 467 pp.

  • Weber, B. L., D. B. Wuertz, D. C. Welsh, and R. McPeek, 1993: Quality controls for profiler measurements of winds and RASS temperatures. J. Atmos. Oceanic Technol., 10 , 452464.

    • Search Google Scholar
    • Export Citation
  • White, A. B., J. R. Jordan, B. E. Martner, F. M. Ralph, and B. W. Bartram, 2000: Extending the dynamic range of an S-band radar for cloud and precipitation studies. J. Atmos. Oceanic Technol., 17 , 12261234.

    • Search Google Scholar
    • Export Citation
  • White, A. B., D. J. Gottas, E. T. Strem, F. M. Ralph, and P. J. Neiman, 2002: An automated brightband height detection algorithm for use with Doppler radar spectral moments. J. Atmos. Oceanic Technol., 19 , 687697.

    • Search Google Scholar
    • Export Citation
  • White, A. B., P. J. Neiman, F. M. Ralph, D. E. Kingsmill, and P. O. G. Persson, 2003: Coastal orographic rainfall processes observed by radar during the California Land-falling Jets Experiment. J. Hydrometeor., 4 , 264282.

    • Search Google Scholar
    • Export Citation
  • Yuter, S. E., and R. A. Houze Jr., 1995: Three-dimensional kinematic and microphysical evolution of Florida cumulonimbus. Part II: Frequency distributions of vertical velocity, reflectivity, and differential reflectivity. Mon. Wea. Rev., 123 , 19411963.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 157 85 2
PDF Downloads 91 46 1

Synoptic and Topographic Variability of Northern California Precipitation Characteristics in Landfalling Winter Storms Observed during CALJET

View More View Less
  • 1 University of Colorado–CIRES, and NOAA/Environmental Technology Laboratory, Boulder, Colorado
  • | 2 NOAA/Environmental Technology Laboratory, Boulder, Colorado
  • | 3 University of Colorado–CIRES, and NOAA/Environmental Technology Laboratory, Boulder, Colorado
Restricted access

Abstract

Observations from northern California during the California Landfalling Jets (CALJET) experiment are used to examine the mean characteristics of precipitation and their variances as functions of synoptic and topographic regimes. Ten cases involving the landfall of extratropical cyclones are analyzed with radar and rain gauge data collected at two sites: one in the coastal mountains north of San Francisco (CZD) and the other in the Central Valley just west of Sacramento (KDAX). Aside from the melting-layer bright band, the most striking feature in the 10-case composite vertical profile of radar reflectivity at CZD was a distinct change in slope about 2.5 km above the bright band. This “shoulder” is thought to represent a change in the growth rate of hydrometeors. Although the bright band was quite distinct, about one-third of the profiles in the composite did not exhibit this feature. These nonbrightband (NBB) profiles had a low-level slope where reflectivity increased with decreasing altitude, a structure suggesting that collision–coalescence was the primary growth process. The relationship between surface rainfall rate and low-level radar reflectivity implies that all profiles were composed of larger numbers of small drops than expected from a Marshall–Palmer drop size distribution, a trend that was especially apparent for NBB profiles.

Synoptic variability of precipitation characteristics at CZD were examined by identifying five distinct regimes (cold sector, warm front, warm sector, cold front, and cool sector) based on a simplified conceptual model. The shoulder remained approximately 2.5 km above the bright band in each regime. Rainfall intensity was highest during the cold-frontal regime and NBB rainfall was most common during the warm-frontal, warm-sector, and cool-sector regimes. Topographic variability of precipitation characteristics was investigated by comparing results at CZD and KDAX. A shoulder structure located about 2.5 km above the bright band was also evident in the KDAX profiles, suggesting that this feature is related to large-scale dynamic, thermodynamic, and microphysical processes rather than orographic effects. The relationship between surface rainfall rate and low-level radar reflectivity near KDAX closely followed a trend expected for a Marshall–Palmer drop size distribution, implying the presence of relatively larger raindrops than observed at CZD and indicating that NBB rainfall occurs less frequently near KDAX.

Corresponding author address: David E. Kingsmill, University of Colorado–CIRES, UCB 216, Boulder, CO 80309. Email: david.kingsmill@colorado.edu

Abstract

Observations from northern California during the California Landfalling Jets (CALJET) experiment are used to examine the mean characteristics of precipitation and their variances as functions of synoptic and topographic regimes. Ten cases involving the landfall of extratropical cyclones are analyzed with radar and rain gauge data collected at two sites: one in the coastal mountains north of San Francisco (CZD) and the other in the Central Valley just west of Sacramento (KDAX). Aside from the melting-layer bright band, the most striking feature in the 10-case composite vertical profile of radar reflectivity at CZD was a distinct change in slope about 2.5 km above the bright band. This “shoulder” is thought to represent a change in the growth rate of hydrometeors. Although the bright band was quite distinct, about one-third of the profiles in the composite did not exhibit this feature. These nonbrightband (NBB) profiles had a low-level slope where reflectivity increased with decreasing altitude, a structure suggesting that collision–coalescence was the primary growth process. The relationship between surface rainfall rate and low-level radar reflectivity implies that all profiles were composed of larger numbers of small drops than expected from a Marshall–Palmer drop size distribution, a trend that was especially apparent for NBB profiles.

Synoptic variability of precipitation characteristics at CZD were examined by identifying five distinct regimes (cold sector, warm front, warm sector, cold front, and cool sector) based on a simplified conceptual model. The shoulder remained approximately 2.5 km above the bright band in each regime. Rainfall intensity was highest during the cold-frontal regime and NBB rainfall was most common during the warm-frontal, warm-sector, and cool-sector regimes. Topographic variability of precipitation characteristics was investigated by comparing results at CZD and KDAX. A shoulder structure located about 2.5 km above the bright band was also evident in the KDAX profiles, suggesting that this feature is related to large-scale dynamic, thermodynamic, and microphysical processes rather than orographic effects. The relationship between surface rainfall rate and low-level radar reflectivity near KDAX closely followed a trend expected for a Marshall–Palmer drop size distribution, implying the presence of relatively larger raindrops than observed at CZD and indicating that NBB rainfall occurs less frequently near KDAX.

Corresponding author address: David E. Kingsmill, University of Colorado–CIRES, UCB 216, Boulder, CO 80309. Email: david.kingsmill@colorado.edu

Save