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Dan Welsh, Bart Geerts, Xiaoqin Jing, Philip T. Bergmaier, Justin R. Minder, W. James Steenburgh, and Leah S. Campbell

vertical profiles of temperature and water vapor ( Ware et al. 2003 ). Through the measurement of passive microwave radiances at various frequencies, a profile of cloud LWC is also derived ( Ware et al. 2003 ). The MPR vertical resolution is inherently limited, and is best (~100 m) near the surface. A Particle Size Velocity (PARSIVEL) disdrometer is an optical sensor with laser diode; it measures particle concentration as a function of size and as a function of fall velocity. The instrument measures

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Scott M. Steiger, Tyler Kranz, and Theodore W. Letcher

observations were taken (the Henderson Harbor site and NR). Two additional important parameters that were analyzed include vertically integrated liquid water and water vapor amounts, which aid in assessing the presence of supercooled water in the lake-effect clouds. These data were collected at Sandy Creek and were made available at 1-min intervals during both IOP5 and IOP7 using the MIPS Microwave Profiling Radiometer [MPR; see Karan and Knupp (2006 ) for details]. In situ probes [Gerber Scientific, Inc

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Philip T. Bergmaier and Bart Geerts

saturation vapor pressure difference between a water surface and an ice surface), droplets should be consumed rapidly by nearby ice crystals, through the Bergeron process. Why these ice clouds reached SL, but not CL (cf. Fig. 3a ), is not clear. Fig . 8. As in Fig. 6 , but for WCL backscatter power. A 100-m-thick lidar blind zone surrounds the aircraft flight level. Given the orientation of the flight leg pattern with respect to the lakes (cf. Fig. 1b ), it is evident from these vertical profiles that

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Philip T. Bergmaier, Bart Geerts, Leah S. Campbell, and W. James Steenburgh

1. Introduction Cold-air outbreaks over the North American Great Lakes in late fall and early winter often lead to lake-effect (LE) snowfall, a phenomenon that occurs when relatively cool air moves across and is modified by a much warmer large body of water. Warming and moistening of the near-surface air produces a well-mixed boundary layer driven by moist convection and deepening with fetch from the upwind shore. Such convection tends to organize linearly into bands, parallel to the low

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David A. R. Kristovich, Richard D. Clark, Jeffrey Frame, Bart Geerts, Kevin R. Knupp, Karen A. Kosiba, Neil F. Laird, Nicholas D. Metz, Justin R. Minder, Todd D. Sikora, W. James Steenburgh, Scott M. Steiger, Joshua Wurman, and George S. Young

was ripped from the hands of SUNY-O and HWS students and blew horizontally into a tree a few hundred feet away. One of the students, a ski patroller at Alta ski area in northern Utah (average annual snowfall of 1250 cm) commented that she had never seen it snow as hard as it does on Tug Hill. Students encamped in a trailer in Canada experienced indoor rain as water vapor from their breathing created a frozen layer on the roof and sides and then melted as a portable heater warmed the interior

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Leah S. Campbell and W. James Steenburgh

1. Introduction Lake-effect snowstorms generated over the Great Lakes of North America and other bodies of water can produce intense, extremely localized snowfall (e.g., Andersson and Nilsson 1990 ; Steenburgh et al. 2000 ; Eito et al. 2005 ; Laird et al. 2009 ; Kindap 2010 ). Forecasters still struggle, however, to accurately predict the timing and location of the heaviest snowfall during lake-effect events, which disrupt local and regional transportation, education, utilities, and

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Daniel T. Eipper, Steven J. Greybush, George S. Young, Seth Saslo, Todd D. Sikora, and Richard D. Clark

the thermodynamic structure of each band and environmental baroclinity. The density potential temperature θ ρ accounts for the effects of both water vapor and hydrometeors on potential temperature; the formula for its computation is provided in Markowski and Richardson [2010 , their Eq. (2.22)]. We chose to position the cross sections over the approximate landfall location and inland portion of each band, where greater human impacts occur. Specifically, the cross sections were generated every 0

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Leah S. Campbell, W. James Steenburgh, Peter G. Veals, Theodore W. Letcher, and Justin R. Minder

elevated terrain (e.g., Kirshbaum and Grant 2012 ); 2) a vapor-diffusional seeder–feeder effect whereby increased cloud liquid water generated by gradual, forced ascent acts as a feeder to the existing hydrometeors with ice growing via diffusional growth at the expense of the additional supercooled liquid water (e.g., Choularton and Perry 1986 ); 3) a reduction in low-level sublimation due to the decreased distance between ground and cloud base and moistening by ascent (e.g., Murakami et al. 1994

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Peter G. Veals, W. James Steenburgh, and Leah S. Campbell

.1175/1520-0493(2000)128<3283:NSOTIB>2.0.CO;2 . 10.1175/1520-0493(2000)128<3283:NSOTIB>2.0.CO;2 DeCosmo , J. , K. B. Katsaros , S. D. Smith , R. J. Anderson , W. A. Oost , K. Bumke , and H. Chadwick , 1996 : Air–sea exchange of water vapor and sensible heat: The Humidity Exchange over the Sea (HEXOS) results . J. Geophys. Res. , 101 , 12 001 – 12 016 , . 10.1029/95JC03796 Durran , D. R. , 1990 : Mountain waves and downslope winds. Atmospheric Processes over Complex

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