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Joseph P. Zagrodnik, Lynn McMurdie, and Robert Conrick

enhancement to various upstream parameters associated with the passage of different frontal cyclone sectors. To test the role of the seeder–feeder process, they simulated an idealized warm sector with a uniform sounding and parameterized large-scale forcing over the realistic Olympic Mountains terrain. Similar to Richard et al. (1987) , they found that windward precipitation efficiency in both warm frontal and warm sector simulations was greatly improved by including a small amount (up to 0.5 mm h −1

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William Ryan Currier, Theodore Thorson, and Jessica D. Lundquist

significant uncertainty in spatially distributed precipitation estimates ( Gutmann et al. 2012 ; Livneh et al. 2014 ; Henn et al. 2016 ) due to a sparse network of gauges ( Lundquist et al. 2003 ) and observational uncertainty at the gauge itself ( Goodison et al. 1998 ; Rasmussen et al. 2012 ). WRF or PRISM are frequently used to force hydrologic models, which guide decisions regarding avalanche control, reservoir storage, and flood forecasting. Therefore, uncertainties in the estimation of

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

. 2017 ). COOP, ASOS, and SNOTEL stations have daily minima and maxima observations for temperature in addition to precipitation. SNOTEL temperature data were biased warm at cold temperatures, and the biases were corrected based on Currier et al. (2017) . In addition, we used hourly temperature data from 26 sites, which had HOBO U23 Pro v2 temperature/relative humidity sensors installed during the OLYMPEX period (see Fig. 2 ). Wind speed data, required as the VIC forcing, were obtained from the

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David J. Purnell and Daniel J. Kirshbaum

Olympics and avoid sharp terrain gradients at the land edges, the terrain surrounding the Olympics is flattened by creating an irregular pentagon encompassing the Olympics, outside of which the terrain height is set to either 2 m (land) or 0 m (ocean). To limit forcing at poorly resolved scales, and to damp terrain gradients at the polygon edges, a five-point horizontal boxcar smoother is applied to the resulting terrain field. The grid origin is located at the aforementioned Olympics center point. Fig

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Robert Conrick and Clifford F. Mass

mean vertical profiles of cloud water, rainwater, and snow mixing ratios averaged by storm sector. Postfrontal sectors generally had profiles with the smallest mixing ratios of all sectors. Considering that warm-sector environments are often associated with strong synoptic forcing and large IVT (e.g., Zhu and Newell 1994 , Zagrodnik et al. 2018 ), it was not unexpected that those environments had the greatest mixing ratios among sectors. Compared to GMI, cloud water profiles during pre- and

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Annareli Morales, Hugh Morrison, and Derek J. Posselt

condition. A positive definite advection scheme is used, and a Rayleigh damper with damping coefficient of 0.0003 s −2 is applied to the top 4 km to prevent reflection of vertically propagating gravity waves. Although interactions of radiation with the mountain surface can result in the forcing of mesoscale mountain circulations, for example, mountain-valley winds, our focus is on the interaction of microphysics and dynamics. Thus, radiative transfer and surface heat flux parameterizations are

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

precipitation rate in the small-drop regime at Prairie Creek is modestly but not significantly higher than Fishery and Bishop Field ( Fig. 4a ) and significantly higher than Graves Creek and Wynoochee ( Figs. 4b,c,d ) at a 99% confidence level. The absence of large drops and the weak low-level flow suggest that this orographic enhancement pattern has weak synoptic forcing and is predominantly the consequence of condensation and rapid fallout of small drops near the front of the Olympic Mountain barrier

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Aaron R. Naeger, Brian A. Colle, Na Zhou, and Andrew Molthan

/OLYMPEX/DOW/DATA201 . 10.5067/GPMGV/OLYMPEX/DOW/DATA201 Iacono , M. J. , J. S. Delamere , E. J. Mlawer , M. W. Shephard , S. A. Clough , and W. D. Collins , 2008 : Radiative forcing by long-lived greenhouse gases: Calculations with the AER radiative transfer models . J. Geophys. Res. , 113 , D13103 , https://doi.org/10.1029/2008JD009944 . 10.1029/2008JD009944 ICAO , 2010 : Meteorological service for international air navigation. Annex 3 to the Convention on International Civil Aviation, 17

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Robert Conrick, Clifford F. Mass, and Qi Zhong

enhancement . J. Atmos. Sci. , 62 , 3599 – 3623 , https://doi.org/10.1175/JAS3555.1 . 10.1175/JAS3555.1 Houze , R. A. Jr. , and Coauthors , 2017 : The Olympic Mountains Experiment (OLYMPEX) . Bull. Amer. Meteor. Soc. , 98 , 2167 – 2188 , https://doi.org/10.1175/BAMS-D-16-0182.1 . 10.1175/BAMS-D-16-0182.1 Iacono , M. J. , J. S. Delamere , E. J. Mlawer , M. W. Shephard , S. A. Clough , and W. D. Collins , 2008 : Radiative forcing by long-lived greenhouse gases: Calculations

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Robert Conrick and Clifford F. Mass

Mission . Bull. Amer. Meteor. Soc. , 95 , 701 – 722 , https://doi.org/10.1175/BAMS-D-13-00164.1 . 10.1175/BAMS-D-13-00164.1 Houze , R. A. , Jr. , and Coauthors , 2017 : The Olympic Mountains Experiment (OLYMPEX) . Bull. Amer. Meteor. Soc. , 98 , 2167 – 2188 , https://doi.org/10.1175/BAMS-D-16-0182.1 . 10.1175/BAMS-D-16-0182.1 Iacono , M. J. , J. S. Delamere , E. J. Mlawer , M. W. Shephard , S. A. Clough , and W. D. Collins , 2008 : Radiative forcing by long–lived greenhouse gases

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