• Ashenden, R., and J. D. Marwitz, 1997: Turboprop aircraft performance response to various environmental conditions. J. Aircr.,34, 278–287.

  • Ashenden, R., and J. D. Marwitz, 1998: Characterizing the supercooled large droplet environment with corresponding turboprop aircraft response. J. Aircr.,35, 912–920.

  • Ashenden, R., W. Lindberg, and J. D. Marwitz, 1998: Two-dimensional airfoil performance degradation because of simulated freezing drizzle. J. Aircr.,35, 905–911.

  • Bennett, W. J., 1913: The sleet storm in northern New York, March 25–27. Mon. Wea. Rev.,41, 372–373.

  • Bernstein, B. C., and B. G. Brown, 1997: A climatology of supercooled large drop conditions based upon surface observations and pilot reports of icing. Preprints, Seventh Conf. on Aviation, Range and Aerospace Meteorology, Long Beach, CA, Amer. Meteor. Soc., 82–87.

  • Bernstein, B. C., T. A. Omeron, F. McDonough, and M. K. Politovich, 1997: The relationship between aircraft icing and synoptic-scale weather conditions. Wea. Forecasting,12, 742–762.

  • Bernstein, B. C., T. A. Omeron, M. K. Politovich, and F. McDonough, 1998: Surface weather features associated with freezing precipitation and severe in-flight aircraft icing. Atmos. Res.,46, 57–73.

  • Bernstein, B. C., T. P. Ratvasky, D. R. Miller, and F. McDonough, 1999: Freezing rain as in in-flight icing hazard. Preprints, Eighth Conf. on Aviation, Range, and Aerospace Meteorology, Dallas, TX, Amer. Meteor. Soc., 38–42.

  • Bocchieri, J., 1980: The objective use of upper air soundings to specify precipitation type. Mon. Wea. Rev.,108, 596–603.

  • Brooks, C. F., 1920: The nature of sleet and how it is formed. Mon. Wea. Rev.,48, 69–73.

  • Czys, R. R., R. W. Scott, K. C. Tang, R. W. Przybylinski, and M. E. Sabones, 1996: A physically based, nondimensional parameter for discriminating between locations of freezing rain and sleet. Wea. Forecasting,11, 591–598.

  • Forbes, G. S., R. A. Anthes, and D. W. Thomson, 1987: Synoptic and mesoscale aspects of an Appalachian ice storm associated with cold-air damming. Mon. Wea. Rev.,115, 564–591.

  • Hallett, J., and S. C. Mossop, 1974: Production of secondary particles during the riming process. Nature,249, 26–28.

  • Harris-Hobbs, R., and W. A. Cooper, 1987: Field evidence supporting quantitative predictions of secondary ice production rates. J. Atmos. Sci.,44, 1071–1082.

  • Henry, A. J., 1922: The great glaze storm of 21–23 February 1922 in the upper lake region: Discussion of general conditions. Mon. Wea. Rev.,50, 77–82.

  • Hobbs, P. V., and A. L. Rangno, 1985: Ice particle concentrations in clouds. J. Atmos. Sci.,42, 2523–2549.

  • Huffman, G. J., and G. A. Norman Jr., 1988: The supercooled warm rain process and the specification of freezing precipitation. Mon. Wea. Rev.,116, 2172–2182.

  • Jeck, R. K., 1996: Representative values of icing-related variables aloft in freezing rain and freezing drizzle. U.S. Department of Transportation Tech. Note DOT/FAA/AR-TN95/119, 44 pp.

  • Kocin, P. J., and L. W. Uccellini, 1990: Snowstorms along the Northeastern Coast of the United States: 1955 to 1985. Meteor. Monogr., No. 44, Amer. Meteor. Soc., 280 pp.

  • Martner, B. E., J. B. Snider, R. J. Zamora, G. P. Byrd, T. A. Niziol, and P. I. Joe, 1993: A remote sensing view of a freezing rainstorm. Mon. Wea. Rev.,121, 2562–2577.

  • Marwitz, J., M. Politovich, B. Bernstein, F. Ralph, P. Neiman, R. Ashenden, and J. Bresch, 1997: Meteorological conditions associated with the ATR72 aircraft accident near Roselawn, Indiana on 31 October 1994. Bull. Amer. Meteor. Soc.,78, 41–52.

  • Meisinger, C. L., 1920: The precipitation of sleet and the formation of glaze in the eastern United States, January 20 to 25, 1920, with remarks on forecasting. Mon. Wea. Rev.,48, 73–80.

  • Mossop, S. C., and J. Hallett, 1974: Ice crystal concentration in cumulus clouds: Influence of the drop spectrum. Science,186, 632–634.

  • NOAA, 1970–94: Storm Data. Vols. 12–36.

  • Pobanz, B., J. Marwitz, and M. Politovich, 1994: Conditions associated with large-drop regions. J. Appl. Meteor.,33, 1366–1372.

  • Pruppacher, H. R., and J. D. Klett, 1997: Microphysics and Clouds and Precipitation. 2d ed. Kluwer Academic, 954 pp.

  • Rasmussen, R., and Coauthors, 1992: Winter Icing and Storms Project (WISP). Bull. Amer. Meteor. Soc.,73, 951–974.

  • Rasmussen, R., B. Bernstein, M. Murakami, G. Stossmeister, J. Reisner, and B. Stankov, 1995: The 1990 Valentine’s Day outbreak. Part I: Mesoscale and microscale structure and evolution of a Colorado Front Range shallow upslope cloud. J. Appl. Meteor.,34, 1481–1511.

  • Rauber, R. M., M. K. Ramamurthy, and A. Tokay, 1994: Synoptic and mesoscale structure of a severe freezing rain event: The St. Valentine’s day ice storm. Wea. Forecasting,9, 183–208.

  • Robbins, C. C., and J. V. Cortinas Jr., 1996: A climatology of freezing rain in the contiguous United States: Preliminary results. Preprints, 15th Conf. on Weather Analysis and Forecasting, Norfolk, VA, Amer. Meteor. Soc., 124–126.

  • Sand, W. R., W. A. Cooper, M. K. Polotovich, and D. L. Veal, 1984:Icing conditions encountered by a research aircraft. J. Climate Appl. Meteor.,23, 1427–1440.

  • Young, W. R., 1978: Freezing precipitation in the southeastern United States. M.S. thesis, Dept. of Meteorology, Texas A&M University, College Station, TX, 123 pp.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 229 229 27
PDF Downloads 117 117 24

The Relative Importance of Warm Rain and Melting Processes in Freezing Precipitation Events

View More View Less
  • a Department of Atmospheric Sciences, University of Illinois, Urbana–Champaign, Urbana, Illinois
  • | b Midwestern Climate Center, Illinois State Water Survey, Champaign, Illinois
© Get Permissions Rent on DeepDyve
Restricted access

Abstract

The importance of warm rain and melting processes in freezing precipitation events is investigated by analyzing 972 rawinsonde soundings taken during freezing precipitation. The soundings cover regions of the United States east of the Rocky Mountain states for the period 1970–94. The warm rain process was found to be unambiguously responsible for freezing precipitation in 47% of the soundings. In these soundings, the clouds had temperatures entirely below freezing, or had top temperatures that were above freezing. Another 28% of the soundings had cloud top temperatures between 0° and −10°C. Clouds with top temperatures >−10°C also can support an active warm rain process. Considered together, the warm rain process was potentially important in about 75% of the freezing precipitation soundings. This estimate is significantly higher than the estimate of 30% in a previous study by Huffman and Norman. The temperature, moisture, and wind profiles of the soundings, their geographic distribution, and the common occurrence of freezing drizzle at the sounding sites suggest that most of these events were associated with shallow cloud decks forming over arctic cold air masses.

The “classic” freezing rain sounding, with a deep moist layer and a midlevel warm (>0°C) layer, was observed in only 25% of the sample. In these soundings, the depth of the cloud layer implies that melting processes were important to precipitation production. From the geographic distribution, the common occurrence of freezing rain, and the sounding profile, these cases appear to be associated primarily with cold air damming and overrunning along the U.S. East Coast, and with warm-frontal overrunning in the midwestern United States.

Corresponding author address: Robert M. Rauber, Department of Atmospheric Sciences, University of Illinois, 105 S. Gregory Ave., Urbana, IL 61801.

r-rauber@uiuc.edu

Abstract

The importance of warm rain and melting processes in freezing precipitation events is investigated by analyzing 972 rawinsonde soundings taken during freezing precipitation. The soundings cover regions of the United States east of the Rocky Mountain states for the period 1970–94. The warm rain process was found to be unambiguously responsible for freezing precipitation in 47% of the soundings. In these soundings, the clouds had temperatures entirely below freezing, or had top temperatures that were above freezing. Another 28% of the soundings had cloud top temperatures between 0° and −10°C. Clouds with top temperatures >−10°C also can support an active warm rain process. Considered together, the warm rain process was potentially important in about 75% of the freezing precipitation soundings. This estimate is significantly higher than the estimate of 30% in a previous study by Huffman and Norman. The temperature, moisture, and wind profiles of the soundings, their geographic distribution, and the common occurrence of freezing drizzle at the sounding sites suggest that most of these events were associated with shallow cloud decks forming over arctic cold air masses.

The “classic” freezing rain sounding, with a deep moist layer and a midlevel warm (>0°C) layer, was observed in only 25% of the sample. In these soundings, the depth of the cloud layer implies that melting processes were important to precipitation production. From the geographic distribution, the common occurrence of freezing rain, and the sounding profile, these cases appear to be associated primarily with cold air damming and overrunning along the U.S. East Coast, and with warm-frontal overrunning in the midwestern United States.

Corresponding author address: Robert M. Rauber, Department of Atmospheric Sciences, University of Illinois, 105 S. Gregory Ave., Urbana, IL 61801.

r-rauber@uiuc.edu

Save