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Edward I. Tollerud, Fernando Caracena, Steven E. Koch, Brian D. Jamison, R. Michael Hardesty, Brandi J. McCarty, Christoph Kiemle, Randall S. Collander, Diana L. Bartels, Steven Albers, Brent Shaw, Daniel L. Birkenheuer, and W. Alan Brewer

dropsonde measurements of wind, pressure, temperature, and moisture) were included in some parallel runs via a modified telescoping Barnes scheme. The vertical resolution of the LAPS analyses was 25 hPa. During the field experiment, the NOAA Forecast Systems Laboratory (now the Global Systems Division of the ESRL) provided real-time mesoscale numerical model guidance to the IHOP_2002 operations center from multiple advanced modeling systems with the goal of assessing their performance in a quasi-operational

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John R. Mecikalski, Kristopher M. Bedka, Simon J. Paech, and Leslie A. Litten

“AutoNowcaster”; Wilson et al. 1998 ; Mueller et al. 2003 ), the Met Office’s Generating Advanced Nowcasts for Deployment in Operational Land Surface Flood Forecast (GANDOLF; Pierce and Hardaker 2000 ), the Central American Flash Flood Guidance System (CAFFG; see online at www.hrc-lab.org/right_nav_widgets/realtime_caffg/index.php ), and the Corridor Integrated Weather System (CIWS; Wolfson et al. 2005 ) as developed at the Massachusetts Institute of Technology, requires knowledge of both the accuracy

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Robin L. Tanamachi, Wayne F. Feltz, and Ming Xue

mesoscale networks, on the 9-km grid. The analysis was performed for 0600 UTC using the 6-h forecast from the 0000 UTC cycle of the operational NCEP Eta Model as the background. The special data used include surface observations from the Oklahoma, southwest Kansas, and west Texas Mesonets, the Atmospheric Radiation Measurement (ARM) Program Surface Meteorological Observation System (SMOS) data, Big Bend (Kansas) groundwater Management District Number 5 soil and surface observations, and aircraft

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Roger M. Wakimoto and Hanne V. Murphey

1. Introduction There has been an increased emphasis placed on understanding the initiation of deep convection during the summer months when large-scale forcing is weak or absent (e.g., Wilson et al. 1998 ). Indeed, Olsen et al. (1995) have shown a dramatic drop in the ability to forecast convection during the summer when major precipitation events occur. The main reason for this difference in skill is that winter season precipitation events are predominately associated with

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Roger M. Wakimoto and Hanne V. Murphey

1. Introduction There have been important advances in short-term forecasts (nowcasts) of thunderstorm initiation during the warm season. These advances are critical as illustrated by Olsen et al. (1995) . They highlighted the pronounced drop in our predictive skill during the summer months when the precipitation totals are the greatest. The improvements in our understanding of thunderstorm formation are largely attributed to the recognition that storms frequently develop near boundary layer

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John H. Marsham, Stanley B. Trier, Tammy M. Weckwerth, and James W. Wilson

-relative winds throughout the paper. Radiosonde sites are shown by plus signs in Fig. 1 . Data from the Oklahoma mesonet ( Brock et al. 1995 ; McPherson et al. 2007 ) were used to provide 5-min means of air temperature (at heights of 1.75 and 9 m), humidity (at 1.5 m), wind speed (at 2 and 10 m), wind direction (at 10 m), rainfall, and air pressure. One-degree gridded operational analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF) were also used, together with 11- μ m infrared

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F. Couvreux, F. Guichard, P. H. Austin, and F. Chen

atmospheric model) on a 4-km grid for an 18-month spinup period starting 1 Jan 2001, so that the soil profiles used in this June 2002 case are physically reasonable. The land surface initialization uses a variety of observed and analyzed conditions including 1) NCEP stage IV rainfall data (discussed in section 2a ) on a 4-km national grid; 2) 0.5° hourly downward solar radiation derived from the Geostationary Operational Environmental Satellites ( GOES-8 and GOES-9 ); 3) near-surface atmospheric

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S. B. Trier, F. Chen, K. W. Manning, M. A. LeMone, and C. A. Davis

al. 1996 ; Pan et al. 1996 ; Giorgi et al. 1996 ; Bosilovich and Sun 1999 ; Xue et al. 2001 ; Anderson et al. 2003 ) models. Contrasting results on the role of soil wetness were found in studies of this period. Beljaars et al. (1996) concluded that less accurate precipitation forecasts were related to capping inversions above the PBL, which arose from strong sensible heating over anomalously dry soil located ∼1 day upstream. Viterbo and Betts (1999) found that more realistic soil moisture

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Margaret A. LeMone, Mukul Tewari, Fei Chen, Joseph G. Alfieri, and Dev Niyogi

; Chen and Dudhia 2001b ; Ek et al. 2003 ) for both warm and cold seasons. Chen et al. (2001a) demonstrated that replacing a “bucket model” with the Noah LSM improved 24–48-h precipitation forecasts in the National Centers for Environmental Prediction (NCEP) Eta Model as much as doubling the model horizontal resolution. Today, Noah is used in operational NWP models at NCEP and the U.S. Air Force Weather Agency. In the first two papers of this series, we used data for the moist grasslands and

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Steven E. Koch, Wayne Feltz, Frédéric Fabry, Mariusz Pagowski, Bart Geerts, Kristopher M. Bedka, David O. Miller, and James W. Wilson

, which we believe is a far greater challenge for a model to be able to predict correctly. We performed simulations with a very high resolution version of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) initialized with real data. The MM5 model was set up in a quadruple nested-grid configuration, beginning with an 18-km resolution domain run initialized at 0000 UTC 4 June 2002 with operational 20-km RUC analysis fields. Three

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