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Richard Seager, Neil Pederson, Yochanan Kushnir, Jennifer Nakamura, and Stephanie Jurburg

Surface Temperature analysis (HadISST) ( Rayner et al. 2003 ). To examine if the 1960s drought and subsequent wetting can be reproduced as an atmospheric response to global SST variations we have examined a number of ensemble simulations with atmospheric general circulation models (GCMs) forced by historical SSTs. These include three models developed by NCAR, the Community Climate Model 3 [CCM3, which has been used extensively by us for North American drought research (e.g., Seager et al. 2005b

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Andrea J. Ray, Gregg M. Garfin, Margaret Wilder, Marcela Vásquez-León, Melanie Lenart, and Andrew C. Comrie

1. Introduction The goal of the multinational, multiyear North American Monsoon Experiment (NAME) program is to improve our understanding of monsoon dynamics to improve prediction skill ( NAME Project Science Team 2004 ). A larger goal for monsoon research is to enhance society’s ability to cope with climate variability and therefore reduce its vulnerability by providing monsoon information and predictions. Lemos and Morehouse (2005) recently described models to facilitate the “co

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Carl J. Schreck III, Jason M. Cordeira, and David Margolin

1. Introduction The Madden–Julian oscillation's (MJO; Madden and Julian 1994 ; Zhang 2005 ) convection can initiate and amplify Rossby wave trains ( Matthews et al. 2004 ; Roundy et al. 2010 ; Weare 2010 ) that manifest themselves in teleconnections such as the North Atlantic Oscillation (NAO; Cassou 2008 ; Lin et al. 2009 ) and the Pacific–North American (PNA) patterns ( Kiladis and Weickmann 1992 ; Higgins and Mo 1997 ; Moore et al. 2010 ). The interactions between the MJO and the

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Macy E. Howarth and Neil F. Laird

the rate of heat loss from a cylinder of water under varying freezing temperature and wind conditions) was founded with application to assessing impacts on researchers in Antarctica. Since then several formulations of the WCI and WCT have been used for studies at locations in the Arctic, Europe, Asia, South America, and North America. Although many are familiar with WCT from its use in operational meteorology to describe outdoor conditions in winter environments, only a small handful of studies

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Andrew C. Winters, Daniel Keyser, and Lance F. Bosart

2016 ). To characterize this variability, Winters et al. (2020) conducted a climatological analysis of North American jet superposition events by classifying events in the National Centers for Environmental Prediction Climate Forecast System Reanalysis (CFSR; Saha et al. 2010 ) based on the extent to which the polar and subtropical jets deviated from their respective climatological locations to form a superposition. “Polar dominant” events were classified as those events in which the polar jet

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Kingtse C. Mo, Lindsey N. Long, Youlong Xia, S. K. Yang, Jae E. Schemm, and Michael Ek

the monthly-mean runoff, similar to the SPI, is used to measure the deficiency of runoff. It is used to classify hydrological droughts ( Mo 2008 ; Shukla and Wood 2008 ). Soil moisture monthly-mean anomaly percentiles measure the soil moisture (SM) anomaly deficit and are used to classify agricultural droughts ( Maurer et al. 2002 ; Andreadis et al. 2005 ). SPI can be derived from the P analysis. The SRI and soil moisture anomaly percentiles are based on the North American Land Data

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Christopher J. Watts, Russell L. Scott, Jaime Garatuza-Payan, Julio C. Rodriguez, John H. Prueger, William P. Kustas, and Michael Douglas

1. Introduction The North American monsoon (NAM) is an important regional phenomenon that provides the majority of annual rainfall over large parts of western Mexico and the southwestern United States. The premonsoon conditions in this region are of extreme dryness, with very high air temperatures and little or no rainfall occurring in the months before the arrival of the monsoon rains. The onset of the monsoon typically occurs in early June in the coastal areas of the Mexican states of Jalisco

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Ron McTaggart-Cowan, Lance F. Bosart, John R. Gyakum, and Eyad H. Atallah

; Atallah et al. 2007 ), and modeling studies ( McTaggart-Cowan et al. 2003 ; Colle 2003 )]. Recent work by Anwender et al. (2006) and Harr et al. (2006) has shown that ET events—in particular those that lead to redevelopment—present a significant challenge to both deterministic and ensemble forecasting systems. Harr et al. (2006) demonstrate that uncertainty associated with transitioning systems in the western North Pacific Ocean can readily impact medium-range forecasts over North America

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Samantha Stevenson, Axel Timmermann, Yoshimitsu Chikamoto, Sally Langford, and Pedro DiNezio

twenty-first century ( Seager et al. 2007 ; Sheffield and Wood 2008 ). Ensuring that the causes and frequency of observed North American droughts are well understood is a crucial step toward improving projections of future drought variability. As the twentieth century is fairly short compared with the time scales of natural low-frequency climate variability, paleoclimate records [mainly from tree rings; e.g., Cook et al. (2004) ; Herweijer et al. (2007) ] are often used to assess the intensity and

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Richard Seager, Martin Hoerling, Siegfried Schubert, Hailan Wang, Bradfield Lyon, Arun Kumar, Jennifer Nakamura, and Naomi Henderson

are marked. The ongoing California drought lies within a larger-scale context whereby, at any one time, drought has been afflicting much of southwestern North America since the end of the 1990s ( Seager 2007 ; Weiss et al. 2009 ; Hoerling et al. 2010 ; Cayan et al. 2010 ; Seager and Vecchi 2010 ; Seager and Hoerling 2014 ) and shortly after a devastating 1-yr drought struck the U.S. Great Plains and Midwest ( Hoerling et al. 2014 ). Concern for the future of southwestern water is only

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