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Jen Henderson, Erik R. Nielsen, Gregory R. Herman, and Russ S. Schumacher

messages to the public ( Evans et al. 2017 ). Potential problems can likewise occur with messaging for other types of overlapping hazards at different scales, such as tornado watches and flash flood watches, leading to a potential need to expand the definition of TORFF (see section 5 ). Our research is in conversation with literatures that focus on challenges NWS forecasters face in an operational context before, during, and after warnings. These studies tend to emphasize the individual hazards and

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Jung-Hoon Kim, Robert D. Sharman, Stanley G. Benjamin, John M. Brown, Sang-Hun Park, and Joseph B. Klemp

clear-air turbulence (CAT) since it normally happens without visible convective activity (e.g., Sharman and Lane 2016 ). If CAT occurs over mountainous regions, it is often produced by mountain-wave breaking and/or critical-level interactions, and is usually referred to as mountain-wave turbulence (MWT). As the resolution of operational numerical weather prediction (NWP) models has increased, the capability to forecast MWT based on NWP model output has improved (e.g., Elvidge et al. 2017 ; Kim

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Gary P. Ellrod and David I. Knapp

150 WEATHER AND FORECASTING VOLUME7FORECASTING TECHNIQUESAn Objective Clear-Air Turbulence Forecasting Technique: Verification and Operational Use GARY P. ELLRODSatellite Applications Laboratory (NOAA/NESDIS), Washington, D.C. DAVID I. KNAPPAir Force Global Weather Central (AFGWC), Offutt Air Force Base, Nebraska6 June 1991 and 12 September 1991 An objective technique for forecasting clear

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John A. Knaff, Mark DeMaria, Debra A. Molenar, Charles R. Sampson, and Matthew G. Seybold

Islands. Nonetheless, the structure of the TC wind fields is routinely diagnosed at global operational forecast centers without aircraft reconnaissance. This diagnosis is often hampered by sparse in situ data and remotely sensed data from disparate sources. In a typical operational setting there are several sources of near-surface wind data located near TCs. Examples include wind speeds from the passive microwave sensors on the Special Sensor Microwave Imager (SSM/I) ( Goodberlet et al. 1989

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Thomas E. Adams III and Randel Dymond

is to determine the utility of using hydrologic ensemble mean or median forecasts of river stage from the NOAA/NWS Meteorological Model-Based Ensemble Forecast System (MMEFS), described in Adams and Ostrowski (2010) , as an alternative to current, operational, single-valued deterministic hydrologic stage forecasts at the OHRFC and, possibly, elsewhere. Section 2 of this paper describes the real-time hydrologic forecasting experiment used in this study. Model simulations are restricted to

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Antoni Jordi, Nickitas Georgas, Alan Blumberg, Larry Yin, Ziyu Chen, Yifan Wang, Justin Schulte, Venkatsundar Ramaswamy, Dave Runnels, and Firas Saleh

A coastal ocean operational system suitable for probabilistic flood forecast at street scale in the New York–New Jersey metropolitan region is introduced and retrospectively evaluated during Superstorm Sandy. Coastal flooding is one of the main natural hazards in terms of economic damages and losses of human life ( Jonkman 2005 ), as demonstrated by recent tropical cyclones such as Katrina, Ike, Irene, Sandy, Harvey, Irma, and Maria along the U.S. coasts. Floods have become the second

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Y. Qiang Sun, Fuqing Zhang, Linus Magnusson, Roberto Buizza, Jan-Huey Chen, and Kerry Emanuel

first questioned the perturbations used in Z19 , arguing EDA-only type perturbations and the rescaling of these perturbations “do not provide realistic simulations of either the current-day operational, or the future ideal evolution of the forecast errors.” Another major issue they raised is related to the impacts of model error on the growth of forecast uncertainty. They also suggested the use of a parametric model for estimates of the extension of the practical predictability. We would like to

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Gary A. Wick, Jason P. Dunion, Peter G. Black, John R. Walker, Ryan D. Torn, Andrew C. Kren, Altug Aksoy, Hui Christophersen, Lidia Cucurull, Brittany Dahl, Jason M. English, Kate Friedman, Tanya R. Peevey, Kathryn Sellwood, Jason A. Sippel, Vijay Tallapragada, James Taylor, Hongli Wang, Robbie E. Hood, and Philip Hall

. 2016 ) experiments, and the National Oceanic and Atmospheric Administration (NOAA)-led Winter Storms and Pacific Atmospheric Rivers (WISPAR) investigation, those projects did not explicitly evaluate the potential impacts of GH observations on operational weather forecasting. Since satellite data play such a key role in the delivery of accurate weather forecasts, any gap in the environmental satellite system creates a potential risk to the overall quality of the forecasts. The range and endurance of

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Peter D. Düben, Martin Leutbecher, and Peter Bauer

variable such that the overall number of bits that are stored for ensemble forecast data can be reduced. We test the approach for storage of model output of an operational ensemble forecast with the Integrated Forecast System (IFS) at ECMWF and investigate savings and errors for data that are stored in GRIB format. It is not the focus of this paper to show that the new methods for data storage can compete with existing methods for lossy data compression in terms of the potential reduction of data

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Milija Zupanski

2396 MONTHLY WEATHER REVIEW VOLUME 121Regional Four-Dimensional Variational Data Assimilationin a Quasi-Operational Forecasting Environment MILIJA ZUPANSKIUC,4R Visiting Research Program, National Meteorological Center, Washington, D.C.Manuscript received 31 August 1992, in final form 20 January 1993) Four-dimensional variational data assimilation is applied to a o

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