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Joseph P. Zagrodnik, Lynn McMurdie, and Robert Conrick

. 2 . The WRF model output was saved every hour and output from the 1.33-km domain was composited to generate contoured frequency by altitude diagrams (CFADs) of simulated radar reflectivity and maps of various dynamic and microphysical parameters. Table 2. Cases, model initialization times, and model analysis times used in this study. Fig . 2. Map of the ocean and windward geographic regions used to generate the CFADs in Figs. 3 and 4 . Color shaded areas denote the ocean (light blue) and

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Robert Conrick and Clifford F. Mass

. Field , and A. P. Lock , 2012 : The surface downwelling solar radiation surplus over the Southern Ocean in the Met Office model: The role of midlatitude cyclone clouds . J. Climate , 25 , 7467 – 7486 , https://doi.org/10.1175/JCLI-D-11-00702.1 . 10.1175/JCLI-D-11-00702.1 Chaboureau , J.-P. , J.-P. Cammas , P. J. Mascart , J.-P. Pinty , and J.-P. Lafore , 2002 : Mesoscale model cloud scheme assessment using satellite observations . J. Geophys. Res. , 107 , 4301 , https

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Joseph P. Zagrodnik, Lynn A. McMurdie, Robert A. Houze Jr., and Simone Tanelli

bins (1.5–2.5 km) in the high-terrain region, where the ground clutter obstructs 77%, 57%, 46%, and 16% of the sample, respectively. The resultant CFADs have values ranging from 0% to 100% at each 0.25-km height interval. Difference CFADs were also generated by subtracting the ocean CFAD from the coast, windward, high-terrain, and leeside CFADs. Compared with the normalization-by-level methodology employed in McMurdie et al. (2018) where each height level is an independent sample, normalizing by

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Stephanie M. Wingo, Walter A. Petersen, Patrick N. Gatlin, Charanjit S. Pabla, David A. Marks, and David B. Wolff

comparisons ( Schwaller and Morris 2011 ). The Multi-Radar Multi-Sensor system (MRMS; Zhang et al. 2016 ) produces gridded quantitative precipitation estimation (QPE) products for the conterminous United States (CONUS) and southern Canada based on inputs from satellite, ground-based radars, rain gauge networks, and model analyses. As such, MRMS products have been used for validating satellite-based precipitation estimates (e.g., Kirstetter et al. 2012 ; Tan et al. 2016 ). Several recent studies have

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Joseph P. Zagrodnik, Lynn A. McMurdie, and Robert A. Houze Jr.

1. Introduction The west coast of North America is frequented by landfalling extratropical cyclones from the Pacific Ocean during the fall through early spring. When these storms pass over coastal mountain ranges, they produce copious precipitation on the windward slopes, frequently contributing to hazards such as flooding and landslides. These storms are also responsible for the accumulation of snow at higher elevations, which is crucial for summer water supply. Understanding the processes

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Yagmur Derin, Emmanouil Anagnostou, Marios Anagnostou, and John Kalogiros

methods to validate satellite constellation measurements with surface rainfall measured by dense rain gauge and disdrometer networks at various sites. One such campaign was OLYMPEX, which was conducted in the Pacific Northwest. The goal of OLYMPEX was to validate rain and snow measurements in midlatitude frontal systems as they moved from ocean to coast to mountains and determine how remotely sensed measurements of precipitation by GPM could be applied to a range of hydrological, weather forecasting

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Robert Conrick, Clifford F. Mass, and Qi Zhong

idealized or dry models. Large-eddy simulation (LES) experiments have investigated KH instability in a variety of real-world cases, including in a mesoscale convective system (MCS) over southern England ( Browning et al. 2012 ), within a hurricane boundary layer ( Nakanishi and Niino 2012 ; Na et al. 2014 ), during frontogenesis ( Samelson and Skyllingstad 2016 ), and for stratified flow over terrain ( Sauer et al. 2016 ). Recent studies have used full-physics NWP models to simulate KH waves. Mahalov

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David J. Purnell and Daniel J. Kirshbaum

1. Introduction The Olympics Mountains of Washington State, located in the U. S. Pacific Northwest, receive some of the heaviest precipitation of any midlatitude location. Their climate is dictated by their position within the wintertime midlatitude storm track, their proximity to a large water body (the Pacific Ocean), and their steep, compact terrain ( Fig. 1a ). In the cold season, midlatitude cyclones repeatedly make landfall in the region, producing a massive windward enhancement of

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Qian Cao, Thomas H. Painter, William Ryan Currier, Jessica D. Lundquist, and Dennis P. Lettenmaier

, which is ground validation of GPM products. In developing our product though, we have made use of ASO snow products for the first time in a mountain maritime environment with dense forest canopies and have integrated (low elevation) precipitation data from a number of sources, including different gauge networks and NWS precipitation radars. 2. Study region and data The Olympic Peninsula is situated in the northwest corner of Washington State, bounded by the Pacific Ocean to the west, the Straits of

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Zeinab Takbiri, Ardeshir Ebtehaj, Efi Foufoula-Georgiou, Pierre-Emmanuel Kirstetter, and F. Joseph Turk

of the snow. The annual maps of the probability of hit, false alarm, and HSS score are used to evaluate the detection skill of the KNN approach against the DPR as a reference ( Fig. 7 ). The probability of hit over the snow-covered regions is relatively high. The reason is that the presence of snow on the ground reduces the surface emission, which could lead to better detection of the precipitation emission signal ( Fig. 3 )—similar to radiometrically cold ocean surfaces. The low detection rates

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