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P. L. Houtekamer and Fuqing Zhang

, for now, a challenge to use this wealth of information in automated operational data assimilation systems. One approach, to deal with high spatiotemporal observations such as from Doppler radars or satellites, is to perform data thinning and quality control through superobservations (e.g., Lindskog et al. 2004 ; Zhang et al. 2009a ; Weng and Zhang 2012 ). This process combines multiple noisy observations into one high-accuracy “super” observation (SO). A data-thinning and quality control

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Zhiyong Meng and Fuqing Zhang

, significant data thinning of observations may be necessary. The process of combining multiple observations into one high-accuracy “super” observation (SO) is often referred to as “superobbing.” A data thinning and quality control procedure was developed in Zhang et al. (2009a) to generate SOs for ground-based Doppler radars (e.g., WSR-88Ds), with the observation error for radial velocity assumed to be 3 m s −1 . To avoid averaging of radial velocities (Vr) with significantly different directions, the

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Clark Evans, Kimberly M. Wood, Sim D. Aberson, Heather M. Archambault, Shawn M. Milrad, Lance F. Bosart, Kristen L. Corbosiero, Christopher A. Davis, João R. Dias Pinto, James Doyle, Chris Fogarty, Thomas J. Galarneau Jr., Christian M. Grams, Kyle S. Griffin, John Gyakum, Robert E. Hart, Naoko Kitabatake, Hilke S. Lentink, Ron McTaggart-Cowan, William Perrie, Julian F. D. Quinting, Carolyn A. Reynolds, Michael Riemer, Elizabeth A. Ritchie, Yujuan Sun, and Fuqing Zhang

improve both forecast quality and communication. By better quantifying the dynamic controls on ET and its outcomes, forecasts of these events should become more accurate. More accurate forecasts should, in turn, result in more timely warnings that save lives and property, so long as those forecasts convey the evolving hazards ( section 4 ) in an accessible fashion. This section discusses ET forecasting and analysis methods currently in use by operational centers, the current levels of ET-related track

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Tammy M. Weckwerth and David B. Parsons

Prediction Center (SPC) 1-day (i.e., the same afternoon/evening) boundary and CI forecast is shown in Fig. 6 . These forecast locations of boundaries and likelihood of CI were highly valued tools in defining which of the IHOP_2002 missions should be called for day 2 (i.e., the subsequent day), as well as for planning the current day-1 CI missions. Some of the IHOP_2002 CI cold-frontal missions had to be aborted because the ground-based mobile armada could not collect good quality data when the boundary

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Robert Wood

sufficient data to control for both aerosol concentration and w . For w < 1 m s −1 that is typical of most stratocumulus uprafts (e.g., Nicholls 1989 ), f act is not strongly dependent upon the aerosol concentration unless the concentration is very high (~300 cm −3 or higher), or if the mean aerosol radius is very small. Thus, in clean conditions the number of activated droplets in stratocumuli approaches the accumulation mode aerosol concentration N a , and observations generally support this

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Craig S. Schwartz and Ryan A. Sobash

compare verification metrics computed with the two neighborhood methods to demonstrate how they can yield differing conclusions about forecast quality, highlighting the need for precise descriptions of neighborhood methodologies and event definitions. 2. Review of neighborhood approaches applied to convection-allowing ensembles This section reviews two neighborhood techniques that have regularly been employed to postprocess and verify convection-allowing ensemble forecasts. Although the two methods

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Clifford Mass and Brigid Dotson

initialization of the Eta Model over the Pacific was poor and the quality control scheme rejected good buoy data. The 48-h forecast from the NCEP Aviation Model (AVN) was better but still possessed large errors, with the central pressure of the low center being 13 hPa too weak and displaced 200 km to the south of the observed position. Another recent failure was the 8 February 2002 “Valley Surprise” event, which brought winds gusting to 80 kt (41 m s −1 ) in the southern Willamette Valley without any warning

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Markus Gross, Hui Wan, Philip J. Rasch, Peter M. Caldwell, David L. Williamson, Daniel Klocke, Christiane Jablonowski, Diana R. Thatcher, Nigel Wood, Mike Cullen, Bob Beare, Martin Willett, Florian Lemarié, Eric Blayo, Sylvie Malardel, Piet Termonia, Almut Gassmann, Peter H. Lauritzen, Hans Johansen, Colin M. Zarzycki, Koichi Sakaguchi, and Ruby Leung

after being initialized from the operational Met Office global model analysis valid at 0000 UTC 18 August 2011. The lateral boundary conditions were provided every time step by a global model that was reinitialized from Met Office operational analyses every 6 h. The data presented here were taken from 0000 UTC 30 August 2011 after the convection-permitting simulation was fully spun up. The grid points are classified as cloudy or dry, depending on the presence or not of cloud condensate: the cloudy

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David M. Schultz and Philip N. Schumacher

was available previously, banded cloud and precipitation features are observed frequently and demand explanation. These bands possess many of the characteristics expected from CSI theory ( Emanuel 1983c , p. 233) and they tend to be present in regions where the criteria for CSI are satisfied. Hence, CSI typically is concluded to have played a role in their formation, at the expense of other, perhaps more plausible, mechanisms. 3) Due to the availability of gridded numerical-model data and the

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