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Gabriel A. Vecchi, Rym Msadek, Whit Anderson, You-Soon Chang, Thomas Delworth, Keith Dixon, Rich Gudgel, Anthony Rosati, Bill Stern, Gabriele Villarini, Andrew Wittenberg, Xiasong Yang, Fanrong Zeng, Rong Zhang, and Shaoqing Zhang

suggesting that initialization can increase the skill in multiyear hurricane forecasts ( S10 ). In this paper, we explore the ability of a hybrid statistical–dynamical hurricane forecasting system to retrospectively predict multiyear hurricane activity in the Atlantic using two different coupled climate models, including the one used by S10 . We explore the skill of North Atlantic hurricane frequency resulting from changing radiative forcing and from natural variability. We assess the improvement in

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Brian A. Colle, Zhenhai Zhang, Kelly A. Lombardo, Edmund Chang, Ping Liu, and Minghua Zhang

explain the cyclone differences, such as low-level temperature gradients and the upper-level jet? Is there any indication of future cyclone change in terms of frequency, intensity, or spatial distribution? 2. Data and methods The Climate Forecast System Reanalysis (CFSR; Saha et al. 2010 ) at ~38-km grid spacing (64 vertical levels) was used to verify and compare the cyclone properties with the CMIP5 models for a few domains [East Coast land (ECL), East Coast water (ECW), and East Coast western and

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Leila M. V. Carvalho and Charles Jones

unchanged or has little change and that the flow is unchanged, the poleward vapor transport and the pattern of evaporation minus precipitation ( E − P ) increases proportionally to the lower-tropospheric vapor. As a consequence, they postulated that wet regions will get wetter and dry regions will get drier in a warming planet. In a recent study, Jones and Carvalho (2013) analyzed the Climate Forecast System Reanalysis (CFSR) and phase 5 of the Coupled Model Intercomparison Project (CMIP5) ( Taylor

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Gabriel A. Vecchi, Rym Msadek, Whit Anderson, You-Soon Chang, Thomas Delworth, Keith Dixon, Rich Gudgel, Anthony Rosati, Bill Stern, Gabriele Villarini, Andrew Wittenberg, Xiasong Yang, Fanrong Zeng, Rong Zhang, and Shaoqing Zhang

In our original paper ( Vecchi et al. 2013 , hereafter V13 ), we stated “the skill in the initialized forecasts comes in large part from the persistence of the mid-1990s shift by the initialized forecasts, rather than from predicting its evolution.” Smith et al. (2013 , hereafter S13 ) challenge that assertion, contending that the Met Office Decadal Prediction System (DePreSys) was able to make a successful retrospective forecast of that shift. We stand by our original assertion and present

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Doug M. Smith, Nick J. Dunstone, Rosie Eade, David Fereday, Leon Hermanson, James M. Murphy, Holger Pohlmann, Niall Robinson, and Adam A. Scaife

Vecchi et al. (2013 , hereafter V13 ) show that retrospective decadal predictions (reforecasts) of multiyear North Atlantic hurricane frequency have high correlations with observations, in agreement with an earlier study ( Smith et al. 2010 , hereafter S10 ). However, V13 state that “the skill in the initialized forecasts comes in large part from the persistence of a mid-1990s shift by the initialized forecasts, rather than from predicting its evolution.” Here, we provide a different

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Paul A. Dirmeyer, Yan Jin, Bohar Singh, and Xiaoqin Yan

of the land surface onto the atmosphere during summer (e.g., Koster et al. 2004 ; Findell et al. 2011 ). Guo et al. (2011) showed that potential predictability from soil moisture is high over North America. North America also demonstrates the strongest improvement in prediction skill from the realistic initialization of the land surface for seasonal forecasts ( Koster et al. 2011 ). The location of maximum land–atmosphere coupling can vary in space ( Koster et al. 2011 ), and its strength can

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Suzana J. Camargo

, these models are able to capture interannual variability associated with El Niño–Southern Oscillation (ENSO) and have been used successfully to develop dynamical ( Vitart and Stockdale 2001 ; Camargo and Barnston 2009 ) and statistical–dynamical ( Wang et al. 2009 ) seasonal forecasts of TC activity. More recently, multiyear hurricane forecasts have been developed using these models ( Smith et al. 2010 ; Vecchi et al. 2013 ). In the last few years, many centers have started to use high

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Kerrie L. Geil, Yolande L. Serra, and Xubin Zeng

and found that the model's enhanced representation of the surface boundary produced an acceptable diurnal cycle of summer precipitation in the monsoon region that was not captured by the driving reanalysis. A recent study by the same group using the Weather Research and Forecasting Model (WRF; Castro et al. 2012 ) showed the potential for limited-area models to improve seasonal NAMS forecasts. The use of higher resolution limited-area models that are able to capture the diurnal cycle of

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Meng-Pai Hung, Jia-Lin Lin, Wanqiu Wang, Daehyun Kim, Toshiaki Shinoda, and Scott J. Weaver

1. Introduction Tropical convection is often organized into synoptic- to planetary-scale disturbances whose time scale is less than a season (~90 days) ( Wheeler and Kiladis 1999 , hereafter WK ; Wheeler and Weickmann 2001 ). This “subseasonal” variability plays an important role in the global climate system by modulating the location and timing of tropical deep convection and has been suggested as a key source of untapped predictability for the extended-range forecasts in both the tropics

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Justin Sheffield, Andrew P. Barrett, Brian Colle, D. Nelun Fernando, Rong Fu, Kerrie L. Geil, Qi Hu, Jim Kinter, Sanjiv Kumar, Baird Langenbrunner, Kelly Lombardo, Lindsey N. Long, Eric Maloney, Annarita Mariotti, Joyce E. Meyerson, Kingtse C. Mo, J. David Neelin, Sumant Nigam, Zaitao Pan, Tong Ren, Alfredo Ruiz-Barradas, Yolande L. Serra, Anji Seth, Jeanne M. Thibeault, Julienne C. Stroeve, Ze Yang, and Lei Yin

western Atlantic storm track. The Hodges (1994 , 1995 ) cyclone tracking scheme was implemented to track cyclones in 15 models (of which 12 were in the core set) for the cool seasons (November–March) for 1979–2004. The Climate Forecast System Reanalysis (CFSR) was used to estimate observed cyclone tracks. Six-hourly mean sea level pressure (MSLP) data were used to track the cyclones, since it was found that including 850-hPa vorticity tracking yielded too many cyclones. Since MSLP is strongly

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