Chris Davis

Senior Scientist
TIIMES - MMM
WCAS

Contact Information:
PO Box 3000, Boulder, CO 80307-3000
Office: FL3 - 2021
Telephone: 303-497-8990
Email: cdavis@ucar.edu
Home Page

Project Summary:

Click on picture to view the entire figure.

Diurnally averaged time-longitude diagram of rainfall (contours) and short-wave amplitude at 500 hPa. Data were averaged between 30 and 48°N and were conditional upon a rain streak having a associated short-wave trough. The analysis comprises 198 events from 1999-2006 during June, July and August.

Statistics and Mechanisms of Coherence of Continental Convection

There were several extensions of previous work on summertime convection over the continental U.S. First, it was found that free-tropospheric circulations (short-waves) were not phase-locked to the topography and the diurnal cycle upstream from convection over the U.S., but were substantially modified by convection and hence became phase-locked downstream. Hence, secondary convection during the subsequent diurnal cycle appears significantly modulated by remnants from the preceding diurnal cycle (Figure). The “generic” forcing for episodes was examined in the context of monthly mean, diurnally varying forcing over the western and central U.S. After approximately three diurnal cycles, convection settled down to a quasi-steady statistical state, with a corridor of convection emanating from the orographic afternoon maximum. This work was done with the WRF model at a grid spacing of 3 km. Finally, the statistics of propagating convection derived from both satellite and radar data were compared over the U.S. It was found that similar statistics result, though the propagation derived from satellite observations was slightly faster. This result bolsters the validity of satellite-derived climatologies that have been produced in Asia and Africa. The accumulation of radar observations for the past 11 warm seasons has led to a study of how propagating convection varies interannually.

In the coming year, work on the climatology of free-tropospheric disturbances and their relationship to North American convection will conclude, as will the 12-year climatology and satellite-radar comparison. Work on the idealized simulations of convection will continue.

TIIMES External Collaborators:

Kenneth Bowman, Texas A&M University
Ru-Shan Gao, National Oceanic & Atmospheric Administration (NOAA)

Publications:

Davis, C. A., W. Wang, S. Chen, Y. Chen, K. Corbosiero, M. DeMaria, J. Dudhia, G. Holland, J. Klemp, J. Michalakes, R. Rotunno, Q. Xiao, 2007: Prediction of landfalling hurricanes with the advanced hurricane WRF model. Mon. Wea. Rev.. (In Press)

Musgrave, K. D., C. A. Davis, M. T. Montgomery, 2007: Numerical simulations of the formation of Hurricane Gabrielle (2001). Mon. Wea. Rev.. (In Press)

Davis, C. A., C. S. Snyder, A. C. Didlake, 2007: A vortex-based perspective of eastern Pacific tropical cyclone formation. Mon. Wea. Rev.. (Submitted)

Pan, L. L., K. P. Bowman, M. Shapiro, W. J. Randel, R. S. Gao, T. Campos, C. Davis, S. Schauffler, B. A. Ridley, J. C. Wei, C. Barnet, 2007: Chemical behavior of the tropopause observed during the Stratosphere-Troposphere Analysis of Regional Transport experiment. J. Geophys. Res., American Geophysical Union, 112, D18110, doi: 10.1029/2007JD008645.

Trier, S. B., F. Chen, K. W. Manning, M. A. Lemone, C. A. Davis, 2007: Sensitivity of the PBL and precipitation in 12-day simulations of warm-season convection using different land surface models and soil wetness conditions. Mon. Wea. Rev.. (Submitted)

Davis, C., S. C. Jones, M. Riemer, 2007: Hurricane vortex dynamics during Atlantic extratropical transition. J. Atmos. Sci.. (In Press)

Weisman, M., C. Davis, W. Wang, K. W. Manning, J. B. Klemp, 2007: Experiences with 0-36h explicit forecasts with the WRF-ARW model. Mon. Wea. Rev.. (Submitted)

Trier, S. B., C. A. Davis, 2007: Mesoscale convective vortices observed during BAMEX. Part II: Influences on secondary deep convection. Mon. Wea. Rev., 135, 2051-2075, doi: 10.1175/MWR3399.1.

Davis, C. A., S. B. Trier, 2007: Mesoscale convective vortices observed during BAMEX. Part I: Kinematic and thermodynamic structure. Mon. Wea. Rev., 135, 2029-2049, doi: 10.1175/MWR3398.1.

Xiao, Q., X. Zhang, C. Davis, J. Tuttle, G. Holland, P. Fitzpatrick, 2007: Hurricane initialization using airborne doppler radar data for WRF. 8th WRF Users' Wkshp., Boulder, CO, US, UCAR.

Ahijevych, D. A., B. Brown, E. Ebert, E. Gilleland, C. Davis, L. Holland, 2007: Spatial verification of high-resolution weather forecasts: beyond traditional metrics. 22nd Conf. Wea. Anal. and Forecasting/18th Conf. Num. Wea. Pred., Park City, UT, US.

Conzemius, R. J., R. W. Moore, M. T. Montgomery, C. A. Davis, 2007: Mesoscale convective vortex formation in a weakly sheared moist neutral environment. J. Atmos. Sci., 64, 1443-1466, doi: 10.1175/JAS3898.1.

Young, L.-H., D. R. Benson, W. M. Montanaro, S.-H. Lee, L. L. Pan, D. C. Rogers, J. Jensen, J. L. Stith, C. A. Davis, T. L. Campos, K. P. Bowman, W. A. Cooper, L. R. Lait, 2007: Enhanced new particle formation observed in the northern midlatitude tropopause region. J. Geophys. Res., 112, D10218, doi: 10.1029/2006JD008109.

Weisman, M. L., C. A. Davis, W. Wang, K. Manning, 2007: Experiences with 0-36h explicit convective forecasts with the WRF-ARW model. Wea. Forecasting. (Submitted)

Riemer, M., S. C. Jones, C. A. Davis, 2007: The impact of extratropical transition on the downstream flow: an idealized modelling study with a straight jet. Quart. J. Roy. Meteor. Soc.. (Submitted)

Xiao, Q., C. Davis, X. Zhang, J. Tuttle, G. Holland, Y.-H. Kuo, 2007: Initialization of Hurricane Jeanne (2004) using airborne doppler radar data. 11th Symp. IOAS-AOLS, San Antonio, TX, US, American Meteorological Society.

Davis, C. A., B. G. Brown, R. Bullock, 2006: Object-based verification of precipitation forecasts from different models. 2nd THORPEX Intl. Science Symp., Landshut, DE.

McTaggert-Cowan, R., L. F. Bosart, C. A. Davis, E. H. Atallah, J. R. Gyakum, K. A. Emanuel, 2006: Analysis of Hurricane Catarina (2004). Mon. Wea. Rev., 134, 3029-3053.

Ahijevych, D., G. Bryan, M. Weisman, S. Trier, C. Davis, D. Dowell, 2006: Composite bow echo observed during BAMEX. 23rd Conf. on Severe Local Storms, St. Louis, MO, US.

Wakimoto, R. M., H. V. Murphey, C. A. Davis, N. T. Atkins, 2006: High winds generated by bow echoes. Part II: The relationship between the mesovortices and damaging straight-line winds. Mon. Wea. Rev., 134, 2813-2829.

Davis, C. A., L. F. Bosart, 2006: The formation of Hurricane Humberto (2001): The importance of extra-tropical precursors. Quart. J. Roy. Meteor. Soc., 132, 2055-2085.