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Doug McCollor and Roland Stull

region, lying between 48° and 51°N on the west coast of North America, is subject to landfalling Pacific cyclones and frontal systems, especially during the cool season months from October through March. Precipitation data for this study were collected from a mesonetwork of 27 gauges within 15 small watersheds in southwestern British Columbia (see Fig. 1 for a reference map). Twenty-four of the stations are part of the hydrometric data collection program in support of reservoir operations for BC

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Steven J. Greybush, Sue Ellen Haupt, and George S. Young

the surface stations, rendering a lapse rate temperature adjustment unnecessary. The application of bias correction to each ensemble member results in a typical improvement of 10%. The details of our bias correction scheme are discussed in the appendix . 3. Atmospheric weather regime characterization The North American Regional Reanalysis (NARR; Mesinger et al. 2006 ) provides a rich dataset from which to characterize atmospheric regimes. Data for 0000 UTC each day are obtained for the same 12

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Raul Fernando Mendez Turrubiates, Markus Gross, and Vanesa Magar

potential impacts of expected severe precipitation events commonly associated with El Niño in this region ( Pavia et al. 2016 ). Comparing the forecast with available ensemble prediction systems, such as the North American Ensemble Forecasting System ( Candille 2009 ), showed that these 70-mm amounts were likely a severe overestimate of a single deterministic forecast. For risk assessment and planning, knowledge of the probabilities associated with forecast events is essential ( Palmer 2002 ; Thielen

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M. L. Khandekar and R. Lalbeharry

statistics compare quite favor- ably with those for some of the global wave models that are in operational mode in Europe and North America. 1. Introduction In recent years, ocean surface wave analysis and prediction has become an important activity in na- tional weather ( and environmental) services of many countries. Since the pioneering development of wave forecasting relations by Sverdrup and Munk ( 1947) , significant advances have been made in our under- standing of the processes that govern

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Eric A. Aligo, William A. Gallus Jr., and Moti Segal

, and conceptually they are likely to be improved with an increased VGR. Physically, an adequate computation of the surface turbulent momentum and thermal fluxes requires that at least the first model level be in the surface layer. We pursued the study objective using a near-cloud-permitting configuration of the Advanced Research Weather Research and Forecasting model (ARW, hereafter termed WRF), and North American Regional Reanalysis (NARR) data focusing on illustrative simulations of Midwest

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Bo Cui, Zoltan Toth, Yuejian Zhu, and Dingchen Hou

calibrated NCEP and CMC global ensembles are then are merged to form a joint ensemble within the North American Ensemble Forecast System (NAEFS; Zhu et al. 2012b ). NAEFS is an operationally joined multimodel ensemble forecast system, which combines the NCEP and CMC ensemble forecasts after bias correction ( Zhu et al. 2012a ; Zhu and Cui 2012 ). We also test three different calibration experiments that are designed to assess and mitigate ensemble biases in the first (mean) moment of the ensemble on

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Jamie K. Wolff, Michelle Harrold, Tressa Fowler, John Halley Gotway, Louisa Nance, and Barbara G. Brown

horizontal grid spacing), whereas the application of these methods for models with a middle (>5–20 km) and coarse (>20 km) resolution is not well documented in the literature—though there is no fundamental reason suggesting they would be inappropriate. The Developmental Testbed Center (DTC) utilized output from the Global Forecast System (GFS; EMC 2003 ) and the operational North American Mesoscale Model (NAM; Janjić 2003 , 2004 ) to compare and contrast QPF performance when assessed using traditional

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Eric S. Blake and William M. Gray

). The TO systems are defined as those hurricanes that formed without any obvious midlatitude influences, typically from African easterly waves equatorward of 23.5°N. An alternative class was termed baroclinically initiated (BI) hurricanes wherein nontropical disturbances were involved. The latter class may include storms that develop along a stationary front, from a decaying midlatitude low, or from a mesoscale convective system (MCS) emerging from North America ( Elsner and Kara 1999

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Phillipa Cookson-Hills, Daniel J. Kirshbaum, Madalina Surcel, Jonathan G. Doyle, Luc Fillion, Dominik Jacques, and Seung-Jong Baek

. 2014 ), ECCC runs an operational global EnKF (GEnKF) with ~50-km grid spacing and 256 members ( Houtekamer et al. 2014 ), which drives an experimental 15-km, 256-member limited-area regional EnKF over North America ( Baek et al. 2012 ). The REnKF, in turn, drives the 2.5-km, 96-member HREnKF over the PNW ( Fig. 2 ). All three systems use continuous cycling. The HREnKF domain covers the PNW and extends westward over the open ocean, allowing it to drive regional ocean models used by Canada’s Marine

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John Lawson and John Horel

with roof-mounted GPS, wind, temperature, humidity, and pressure sensors. However, one of the roof-mounted racks was destroyed early the next day in the high winds. b. Model setup Numerical simulations were performed using the Advanced Research dynamical core of the Weather Research and Forecasting (WRF) Model, version 3.4. All runs comprised three nested domains of grid sizes 12, 4, and 1.3 km ( Fig. 3 ), whose initial and boundary conditions (updated every 6 h) were provided by North American

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