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Charles R. Sampson, Paul A. Wittmann, Efren A. Serra, Hendrik L. Tolman, Jessica Schauer, and Timothy Marchok

(JTWC/WW3 and OFCL/WW3) has been running in real time for maritime forecasting use for approximately 4 yr. Although the product is inherently desirable because it produces output that is geographically consistent with the official forecast, evaluating the error and bias characteristics is critical to the technique’s application in operations and its utility in other operationally oriented applications. We evaluated OFCL/WW3 and NOGAPS/WW3 in the Atlantic during 2010–11 and found the following

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Dan L. Bergman, Linus Magnusson, Johan Nilsson, and Frederic Vitart

1. Introduction Tropical cyclones (TCs) are among the most destructive geophysical phenomena on Earth ( Emanuel 2005 ; Pielke et al. 2008 ; Blake et al. 2011 ). They cause extensive damage and result in catastrophic loss of life. Efforts to forecast tropical cyclone activity on a seasonal time scale were pioneered by Nicholls (1979) and Gray (1984) . In 1984, Gray demonstrated a link between hurricane activity and slow irregular climate modes, most notably El Niño–Southern Oscillation

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John A. Knaff, Charles R. Sampson, and Brian R. Strahl

1. Introduction The Joint Typhoon Warning Center (JTWC) provides tactical tropical cyclone (TC) forecasts for U.S. Department of Defense installations operating in the western North Pacific, Indian, and South Pacific Oceans. These forecasts include position, intensity, 1 and the radii of 34-, 50-, and 64-kt (kt; 1 kt = 0.514 m s −1 ) winds through 5 days. The last decade or so has seen improvement in JTWC’s intensity forecasts due to the availability of skillful intensity guidance coming from

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Sharanya J. Majumdar and Peter M. Finocchio

Carr (2000) . Further efforts to produce quantitative predictions of track forecast uncertainty include those of Weber (2003 , 2005) , who extended his statistical track prediction system by adding a Gaussian distribution of strike probabilities to a statistically weighted track. These results were installed on the Automated Tropical Cyclone Forecast (ATCF) at the Joint Typhoon Warning Center (JTWC; see Sampson and Schrader 2000 ). Goerss (2007) developed a regression-based technique to

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Stevie Roquelaure, Robert Tardif, Samuel Remy, and Thierry Bergot

upon the 12-h forecast period. c. LEPS calibration The calibration technique for LEPS follows the BMA method described by Raftery et al. (2005) . The BMA approach is applied on a training dataset (winter seasons from 2002/03 to 2006/07) to determine which members are the most efficient for the prediction of any quantity X , which is the LVP in our case. Therefore, the BMA calibration is applied on the LVP variable without any consideration of the LVP type. Thanks to the learning over the training

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Richard L. Thompson, Bryan T. Smith, Jeremy S. Grams, Andrew R. Dean, and Chris Broyles

using a new hodograph technique . Wea. Forecasting , 15 , 61 – 79 . Cohen, A. E. , 2010 : Indices of violent tornado environments . Electron. J. Oper. Meteor. , 11 , 2010-EJ6 . [Available online at .] Craven, J. P. , and Brooks H. E. , 2004 : Baseline climatology of sounding derived parameters associated with deep moist convection . Natl. Wea. Dig. , 28 , 13 – 24 . Davies, J. M. , 2004 : Estimations of CIN and LFC associated with tornadic

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Fumin Ren, Wenyu Qiu, Chenchen Ding, Xianling Jiang, Liguang Wu, Yinglong Xu, and Yihong Duan

; Lee et al. 2006 ; Lonfat et al. 2007 ). Second, assuming constant rainfall rates during the landfalling process, the LTC precipitation prediction can be estimated by integrating the rainfall rates obtained at the initial time along the NWP forecast LTC track for the forecast period ( Kidder et al. 2005 ; Liu 2009 ; Ebert et al. 2011 ). A third type of the LTC precipitation forecasts involves applying analog forecast techniques. Based on analog analyses of a target TC within a forecast period

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Denilson Ribeiro Viana and Clóvis Angeli Sansigolo

and difficult to be predicted. The set of atmospheric, oceanic, and surface patterns and teleconnection mechanisms associated was used jointly and objectively for seasonal rainfall climate forecasting. It is possible that teleconnections and the physical processes associated between the predictors key regions and the predictands (rainfall homogeneous regions) could be studied using dynamic modeling techniques as influence functions. Acknowledgements This paper is part of the DRV’s Ph

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Bryan T. Smith, Richard L. Thompson, Jeremy S. Grams, Chris Broyles, and Harold E. Brooks

discrete or cluster RM events. From a forecasting perspective, this implies that May potentially can be a more predictable time of year for supercell tornadoes as a result of decreasing relative frequencies of QLCS tornadoes during winter and prior to increasing relative frequencies of disorganized convective modes during summer. However, this is dependent on utilizing techniques for discrimination between tornadic and nontornadic supercells. Future work will include continued expansion of the database

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Qinglan Li, Zenglu Li, Yulong Peng, Xiaoxue Wang, Lei Li, Hongping Lan, Shengzhong Feng, Liqun Sun, Guangxin Li, and Xiaolin Wei

Elsberry (2014 , 2015 ) developed a weighted analog technique for 5-day intensity and intensity spread predictions for TCs in the western North Pacific and Atlantic, based on the rankings of the 10 best historical track analogs to match the official track forecast and current intensity. Previous studies mainly considered TC intensity change over open water. However, TCs that make landfall or move close to the coast are usually responsible for most loss of life and damage. Therefore, forecasting the

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