Statistical Characteristics of a Real-Time Precipitation Forecasting Model

Brian Gaudet Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado

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William R. Cotton Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado

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Abstract

At Colorado State University the Regional Atmospheric Modeling System (RAMS) has been used to produce real-time forecasts of precipitation for the Colorado mountain region since 1991. Originally a so-called dump-bucket scheme was used to generate precipitation, but starting in the fall of 1995 real-time forecasts used the bulk microphysics scheme available with RAMS.

For the month of April 1995, a series of 24-h accumulated precipitation forecasts for the month were generated with both the dump-bucket and microphysics versions of the forecast model. Both sets of output were compared to a set of 167 community-based station reports and another set of 32 snow telemetry (SNOTEL) automatic pillow-sensor stations.

The addition of microphysics improved the forecasting of the areal extent and maximum amount of precipitation, especially when compared to the SNOTEL observational set, which is found at locations more representative of the model topography. Climatological station precipitation forecasts were improved on the average by correcting for the difference between a station’s actual elevation and the cell-averaged topography used by the model. The model had more problems with the precise timing and geographical location of the precipitation features, probably due in part to the influence of other model physics, the failure of the model to resolve adequately wintertime convection events, and inadequate initializations.

Corresponding author address: Brian Gaudet, Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523.

Abstract

At Colorado State University the Regional Atmospheric Modeling System (RAMS) has been used to produce real-time forecasts of precipitation for the Colorado mountain region since 1991. Originally a so-called dump-bucket scheme was used to generate precipitation, but starting in the fall of 1995 real-time forecasts used the bulk microphysics scheme available with RAMS.

For the month of April 1995, a series of 24-h accumulated precipitation forecasts for the month were generated with both the dump-bucket and microphysics versions of the forecast model. Both sets of output were compared to a set of 167 community-based station reports and another set of 32 snow telemetry (SNOTEL) automatic pillow-sensor stations.

The addition of microphysics improved the forecasting of the areal extent and maximum amount of precipitation, especially when compared to the SNOTEL observational set, which is found at locations more representative of the model topography. Climatological station precipitation forecasts were improved on the average by correcting for the difference between a station’s actual elevation and the cell-averaged topography used by the model. The model had more problems with the precise timing and geographical location of the precipitation features, probably due in part to the influence of other model physics, the failure of the model to resolve adequately wintertime convection events, and inadequate initializations.

Corresponding author address: Brian Gaudet, Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523.

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  • Anthes, R. A., 1983: Regional models of the atmosphere in middle latitudes. Mon. Wea. Rev.,111, 1306–1335.

    • Crossref
    • Export Citation
  • ——, Y.-H. Kuo, E.-Y. Hsie, S. Low-Nam, and T. W. Bettge, 1989: Estimation of skill and uncertainty in regional numerical models. Quart. J. Roy. Meteor. Soc.,115, 763–806.

    • Crossref
    • Export Citation
  • Arakawa, A., and V. R. Lamb, 1981: A potential enstrophy and energy conserving scheme for the shallow water equations. Mon. Wea. Rev.,109, 18–36.

    • Crossref
    • Export Citation
  • Barnes, S. L., 1973: Mesoscale objective map analysis using weighted time series observations. NOAA Tech. Memo. ERL NSSL-62, 60 pp. [NTIS COM-73-10781.].

  • Beitler, B. A., 1994: Mesoscale numerical prediction of Colorado snowfall and winds. M.S. thesis, Dept. of Atmospheric Science, Colorado State University, Fort Collins, CO, 84 pp. [Available from Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523.].

  • Bleck, R., and S. G. Benjamin, 1993: Regional weather prediction with a model combining terrain-following and isentropic coordinates. Part I: Model description. Mon. Wea. Rev.,121, 1770–1785.

  • Clark, T. L., and R. D. Farley, 1984: Severe downslope windstorm calculations in two and three spatial dimensions using anelastic interactive grid nesting: A possible mechanism for gustiness. J. Atmos. Sci.,41, 329–350.

    • Crossref
    • Export Citation
  • Colle, B. A., and C. F. Mass, 1996: An observational and modeling study of the interaction of low-level southwesterly flow with the Olympic Mountains during COAST IOP 4. Mon. Wea. Rev.,124, 2152–2175.

    • Crossref
    • Export Citation
  • Cotton, W. R., G. Thompson, and P. W. Mielke, 1994: Real-time mesoscale prediction on workstations. Bull. Amer. Meteor. Soc.,75, 349–362.

    • Crossref
    • Export Citation
  • ——, J. F. Weaver, and B. A. Beitler, 1995: An unusual summertime downslope wind event in Fort Collins, Colorado, on 3 July 1993. Wea. Forecasting,10, 786–797.

  • Cressman, G. P., 1959: An operational objective analysis system. Mon. Wea. Rev.,87, 367–374.

    • Crossref
    • Export Citation
  • Dickinson, R. E., A. Henderson-Sellers, P. J. Kennedy, and M. F. Wilson, 1986: Biosphere–Atmosphere Transfer Scheme for the NCAR Community Climate Model. Tech. Rep. NCAR/TN-275+STR, NCAR, Boulder, CO, 69 pp.

  • Doesken, N., and G. Schaefer, 1987: The contribution of SNOTEL precipitation measurements to climate analysis, monitoring, and research in Colorado. Proc. Western Snow Conf., 55th Annual Meeting, Vancouver, BC, Canada, Western Snow Conference, 20–30.

  • ——, and A. Judson, 1997: The Snow Booklet: A Guide to the Science, Climatology, and Measurement of Snow in the United States. 2d ed. Colorado Climate Center, Department of Atmopheric Science, Colorado State University, 86 pp.

  • Doswell, C. A., III, R. Davies-Jones, and D. K. Leller, 1990: On summary measures of skill in rare event forecasting based on contingency tables. Wea. Forecasting,5, 576–585.

    • Crossref
    • Export Citation
  • Flatau, P. J., G. J. Tripoli, J. Verlinde, and W. R. Cotton, 1989: The CSU-RAMS cloud microphysical module: General theory and code documentation. Atmospheric Science Paper 451, 88 pp. [Available from Dept. of Atmospheric Science, Colorado State University, Fort Collins, CO 80523.].

  • Gal-Chen, T., and R. C. J. Somerville, 1975: On the use of a coordinate transformation for the solution of the Navier–Stokes equations. J. Comput. Phys.,17, 209–228.

    • Crossref
    • Export Citation
  • Gartner, W. E., M. E. Baldwin, and N. W. Junker, 1996: Regional analysis of quantitative precipitation forecasts from NCEP’s early Eta and meso-Eta Models. Preprints, 15th Conf. on Weather Analysis and Forecasting, Norfolk, VA, Amer. Meteor. Soc., 169–171.

  • Giorgi, F., and G. T. Bates, 1989: The climatological skill of a regional model over complex terrain. Mon. Wea. Rev.,117, 2325–2347.

    • Crossref
    • Export Citation
  • Goodison, B. E., 1978: Accuracy of Canadian snow gauge measurements. J. Appl. Meteor.,27, 1542–1548.

    • Crossref
    • Export Citation
  • Hoke, J. E., N. A. Phillips, G. J. DiMego, J. T. Tuccillo, and J. G. Sela, 1989: The Regional Analysis and Forecast System of the National Meteorological Center. Wea. Forecasting,4, 323–334.

    • Crossref
    • Export Citation
  • Jarraud, M., A. J. Simmons, and M. Kanamitsu, 1987: The concept, implementation and impact of an envelope orography. Proc. Seminar/Workshop 1986 on Observation, Theory and Modeling of Orographic Effects, Vol. 2, Reading, United Kingdom, European Centre for Medium-Range Weather Forecasts, 81–127.

  • Junker, N. W., J. E. Hoke, and R. H. Grumm, 1989: Performance of NMC’s regional models. Wea. Forecasting,4, 368–390.

    • Crossref
    • Export Citation
  • ——, ——, B. E. Sullivan, K. F. Brill, and F. J. Hughes, 1992: Seasonal and geographic variations in quantitative precipitation prediction by NMC’s Nested-Grid Model and Medium-Range Forecast Model. Wea. Forecasting,7, 410–429.

    • Crossref
    • Export Citation
  • Klemp, J. B., and R. B. Wilhelmson, 1978: Simulations of right- and left-moving storms produced through storm-splitting. J. Atmos. Sci.,35, 1097–1110.

    • Crossref
    • Export Citation
  • Manikin, G. S., K. E. Mitchell, and E. Rogers, 1996: Severe weather forecasts using the Eta and meso Eta models. Preprints, 15th Conf. on Weather Analysis and Forecasting, Norfolk, VA, Amer. Meteor. Soc., 295–296.

  • Mason, I., 1989: Dependence of the critical success index on sample climate and threshold probability. Aust. Meteor. Mag.,37, 75–81.

  • McMillan, G. D., 1981: SNOTEL: A management tool for the future. Proc. Western Snow Conference, 49th Annual Meeting, St. George, UT, Western Snow Conference, 116–119.

  • Mesinger, F., Z. I. Janjić, S. Ničković, D. Gavrilov, and D. Deaven, 1988: The step mountain coordinate: Model description and performance for cases of Alpine lee cyclogenesis and for a case of an Appalachian redevelopment. Mon. Wea. Rev.,116, 1493–1518.

    • Crossref
    • Export Citation
  • Meyers, M. P., P. J. DeMott, and W. R. Cotton, 1992: New primary ice nucleation parameterizations in an explicit cloud model. J. Appl. Meteor.,31, 708–721.

    • Crossref
    • Export Citation
  • NCDC, 1995: Climatological Data. Vol. 100, No. 4. [Available from National Climatic Data Center, Asheville, NC 28801.].

  • Pielke, R. A., and Coauthors, 1992: A comprehensive meteorological modeling system—RAMS. Meteor. Atmos. Phys.,49, 69–91.

    • Crossref
    • Export Citation
  • Rangno, A. L., and P. V. Hobbs, 1994: Ice particle concentrations and precipitation development in small continental cumuliform clouds. Quart. J. Roy. Meteor. Soc.,120, 573–601.

    • Crossref
    • Export Citation
  • Reinking, R. F., and J. F. Boatman, 1986: Upslope precipitation events. Mesoscale Meteorology and Forecasting, P. S. Ray, Ed., Amer. Meteor. Soc., 437–471.

    • Crossref
    • Export Citation
  • Rhea, J. O., 1978: Orographic precipitation model for hydrometeorological use. Ph.D. dissertation, Colorado State University, Fort Collins, CO, 199 pp. [Available from Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523.].

  • Rogers, E., T. L. Black, D. G. Deaven, G. J. DiMego, Q. Zhao, M. Baldwin, N. W. Junker, and Y. Lin, 1996: Changes to the operational “early” eta analysis/forecast system at the National Centers for Environmental Prediction. Wea. Forecasting,11, 391–413.

    • Crossref
    • Export Citation
  • Schultz, P., 1995: An explicit cloud physics parameterization for operational numerical weather prediction. Mon. Wea. Rev.,123, 3331–3343.

    • Crossref
    • Export Citation
  • Snook, J. S., and R. A. Pielke, 1995: Diagnosing a Colorado heavy snow event with a nonhydrostatic mesoscale numerical model structured for operational use. Wea. Forecasting,10, 261–285.

  • Spreen, W. C., 1947: A determination of the effect of topography upon precipitation. Trans. Amer. Geophys. Union,28, 285–290.

    • Crossref
    • Export Citation
  • Thompson, G., 1993: Prototype real-time mesoscale prediction during 1991–92 winter season and statistical verification of model data. M.S. thesis, Department of Atmospheric Science, Colorado State University, Fort Collins, CO, 105 pp. [Available from Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523.].

  • Tremback, C. J., 1990: Numerical simulation of a mesoscale convective complex: Model development and numerical results. Ph.D. dissertation, Atmospheric Science Paper 465, Dept. of Atmospheric Science, Colorado State University, Fort Collins, CO, 247 pp. [Available from Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523.].

  • Tripoli, G. J., and W. R. Cotton, 1981: The use of ice-liquid water potential temperature as a thermodynamic variable in deep atmospheric models. Mon. Wea. Rev.,109, 1094–1102.

    • Crossref
    • Export Citation
  • ——, and ——, 1982: The Colorado State University three-dimensional cloud/mesoscale model—1982. Part I: General theoretical framework and sensitivity experiments. J. Rech. Atmos.,16, 185–220.

  • Walko, R. O., W. R. Cotton, J. L. Harrington, and M. P. Meyers, 1995: New RAMS cloud microphysics parameterization. Part I:The single moment scheme. Atmos. Res.,38, 29–62.

    • Crossref
    • Export Citation
  • Wilks, D. S., 1995: Statistical Methods in the Atmospheric Sciences. Academic Press, 467 pp.

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