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Bruce Ingleby, David Moore, Chris Sloan, and Robert Dunn

-level humidity from some types of radiosonde, especially around the 1990s. In the Met Office NWP system, surface humidity is assimilated in both regional and global models ( Ingleby et al. 2013 ) and also used to update soil moisture ( Dharssi et al. 2011 ). In NWP high relative humidity (RH) conditions are particularly important, as they are linked to poor visibility [in the regional U.K. forecasting system, visibility reports can have a significant effect on the humidity analysis; see Clark et al. (2008

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A. Alvarez and B. Mourre

provided by the ROMS model forecast simulation that was run operationally during the Recognized Environmental Picture 2010 (REP10) experiment, and that which slightly differs from the above-described ROMS configuration (hindcast version) in terms of model internal and boundary parameters. The control run is the mean of an ensemble of simulations with the same perturbations as those represented in the EnKF (i.e., of the initial conditions, winds, and lateral boundary values). The reduction of the error

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Steven D. Smith and Robert M. Rabin

measurements, knownas Modified Velocity-Volume Processing (MVVP) is examined from both theoretical and operational perspectives.For this technique, radar data within limited spatial volumes are fit to a model which usually assumes tinearityof the Cartesian wind components. The accuracies and limitations of this technique are illustrated with examplesfrom a case study of a severe storm outbreak in central Oklahoma on 17 May 1981. Implications for use of theMVVP in convective storm forecasting are considered

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Jia Wang

1. Introduction For many scientific and practical purposes, a Nowcast/Forecast System for Coastal Ocean Circulation (NFS-COC) is essential to advance ocean science from the descriptive stage to a numerical prediction stage. In meteorology, numerical weather forecasts ( Black 1994 ; Rogers et al. 1995 ) have been conducted operationally (and in the research model) for three decades now. In oceanography, numerical prediction has lagged behind due to the lack of process understanding, well

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Christopher A. Roseman and Brian M. Argrow

operational weather hazard risk assessment tool; some enabling research thrusts are now discussed. Many sUAS operations have a geographic footprint on the order of one square kilometer or less. The resolution of the HRRR, and other commonly available weather products, might be insufficient for risk assessment for these missions, especially where weather is highly variable in space and time, such as urban environments, requiring forecasts on smaller scales. Because of the general susceptibility of sUAS to

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Robert C. Mcarthur, James R. Davis, and David Reynolds

operational forecasters; 2) its top-down logic constrains when, where, and how objective algorithms should be applied. We first describe our understanding of nowcasting expertise and the use of pattern recognition ("manual")by human forecasters. We then briefly review the current use of automatic pattern recognition in nowcasting,present the elements within a scenario and discuss a KBS architecture for using scenarios. Finally, we close bydiscussing the practical benefits of merging a qualitative KBS

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Daniel E. Wolfe and Seth I. Gutman

1. Introduction Water vapor is one of the most important constituents of the atmosphere since it contributes to the transport of moisture and latent heat. The measurement of atmospheric water vapor is vital for weather and climate research as well as operational weather forecasting. An important goal in modern weather prediction is to improve the accuracy of short-term cloud and precipitation forecasts, but our ability to do so is limited by the lack of timely water vapor data. At approximately

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Evan Ruzanski, V. Chandrasekar, and Yanting Wang

operational nowcasting systems, extrapolation of radar echoes, satellite imagery of clouds, and/or lightning location data are the primary mechanisms that are used to generate forecasts in the 0–3-h time frame, with such forecasts gradually being combined with numerical weather prediction (NWP) model forecasts made during the 3–6-h forecast lead time period ( Wolfson et al. 2008 ; Dupree et al. 2009 ; Bowler et al. 2004 ; Li and Lai 2004 ). The underlying assumption that the relatively predictable

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Colin Y. Shen, Thomas E. Evans, and Steven Finette

ensemble of forecasts is produced and the uncertainty determined from the ensemble. The adequacy of such selection of initial conditions for determining forecast uncertainty has been investigated by Anderson (1997) by using the models of Lorenz (1963 , 1984) . He showed that the subspace spanned by the dominant error vectors in the ensemble may not be enough to capture the forecast spread and other higher moments of error statistics. Whether this conclusion carries over to realistic operational

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Timothy J. Schmit, Jun Li, Steven A. Ackerman, and James J. Gurka

1. Introduction The next-generation geostationary environmental satellite series will enable many improved and new capabilities for imager-based products. Although the Advanced Baseline Imager (ABI) ( Schmit et al. 2005 ) on the next-generation series of Geostationary Operational Environmental Satellite (GOES-R) will provide a good horizontal representation of the atmosphere, the critical vertical dimension needed for weather forecasting will remain grossly undersampled ( Schmit et al. 2008

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