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Jeremiah O. Piersante, Russ. S. Schumacher, and Kristen L. Rasmussen

western Paraguay during the South American Low-Level Jet Experiment (SALLJEX; Vera et al. 2006 ). Given these impacts and complex initiation modes of MCSs, there is a serious demand for numerical weather prediction (NWP) to accurately represent and forecast such events. Unsurprisingly, convection-permitting models yield the most accurate forecasts, particularly when it comes to warm-season precipitation at long and short forecast lead times, such as the National Center for Atmospheric Research (NCAR

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T. Connor Nelson, James Marquis, Adam Varble, and Katja Friedrich

1. Introduction Incorrect forecasts of the specific timing and location of the initiation of deep moist convection in operational models are a major factor limiting the predictability of severe weather, hydrology, and accuracy of quantitative precipitation forecasting (e.g., Davis et al. 2003 ; Weisman et al. 2008 ; Duda and Gallus 2013 ). Operational predictability of deep moist convection initiation (CI) is limited by a number of factors, including our ability to routinely sample

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Robert J. Trapp, Karen A. Kosiba, James N. Marquis, Matthew R. Kumjian, Stephen W. Nesbitt, Joshua Wurman, Paola Salio, Maxwell A. Grover, Paul Robinson, and Deanna A. Hence

a similar convective morphology and evolution. Finally, in section 5 , we will summarize our findings and discuss future research directions with this novel dataset. 2. Observational-strategy planning and execution during intensive observational period 4 a. Overview of relevant meteorology and forecast process The axis of a vigorous upper-level trough over the Pacific Ocean was positioned just upstream of the Andes Mountains at 1200 UTC 10 November 2018, and slowly progressed eastward during

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Jake P. Mulholland, Stephen W. Nesbitt, Robert J. Trapp, and John M. Peters

induced by terrain. Mulholland et al. (2019) provided a detailed case study of an orographic supercell-to-MCS transition event in Argentina, South America. In addition to an observational overview of the event, the authors conducted a series of Weather Research and Forecasting (WRF) Model simulations in which the terrain of the Sierras de Córdoba was systematically raised or lowered between −40% and +40%, relative to the control terrain height peak of ~2500 m. Their results showed that higher

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Russ S. Schumacher, Deanna A. Hence, Stephen W. Nesbitt, Robert J. Trapp, Karen A. Kosiba, Joshua Wurman, Paola Salio, Martin Rugna, Adam C. Varble, and Nathan R. Kelly

storms analysis forecasting in the United States and elsewhere because they synthesize numerous individual variables in a standardized manner ( Thompson et al. 2012 ). One such parameter that has been shown to discriminate between environments supporting supercell and nonsupercell storms is the supercell composite parameter (SCP, Thompson et al. 2004 ). SCP incorporates MUCAPE, and the vector wind difference and storm relative helicity over the effective inflow layer ( Thompson et al. 2007

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Jeremiah O. Piersante, Kristen L. Rasmussen, Russ S. Schumacher, Angela K. Rowe, and Lynn A. McMurdie

, and K. L. Rasmussen , 2021 : Comparison of biases in warm-season WRF forecasts in North and South America . Wea. Forecasting , 36 , 979 – 1001 , https://doi.org/10.1175/WAF-D-20-0062.1 . Rasmussen , K. L. , and R. A. Houze , 2011 : Orogenic convection in subtropical South America as seen by the TRMM satellite . Mon. Wea. Rev. , 139 , 2399 – 2420 , https://doi.org/10.1175/MWR-D-10-05006.1 . 10.1175/MWR-D-10-05006.1 Rasmussen , K. L. , and R. A. Houze , 2016 : Convective

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Sujan Pal, Francina Dominguez, María Eugenia Dillon, Javier Alvarez, Carlos Marcelo Garcia, Stephen W. Nesbitt, and David Gochis

of these events due to a lack of long-term observations. This is the first study to analyze the flash flood response in the complex terrain of Córdoba, Argentina, resulting from some of the most intense storms on Earth. While severe convection in the region has been highlighted in past literature ( Saulo et al. 2004 ; Saulo et al. 2007 ; Rasmussen and Houze 2016 ), flash floods resulting from these storms have not been previously analyzed, and the community is lacking a forecasting framework to

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Zachary S. Bruick, Kristen L. Rasmussen, and Daniel J. Cecil

November–18 December 2018; https://www.eol.ucar.edu/field_projects/relampago ) and the Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign (1 October 2018–30 April 2019; https://www.arm.gov/research/campaigns/amf2018cacti ). This study will contribute to a better global understanding of hailstorms to help to improve forecasting and diagnosis of hailstorms in subtropical South America. 2. Method Because of the lack of a hail-report database in subtropical South America, satellite

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Hernán Bechis, Paola Salio, and Juan José Ruiz

eastern slope of the Andes Mountains over central Argentina, local forecasters acknowledge that drylines are a regular feature of the warm season climatology. Between the elevated arid northern Patagonia plateau (NPP; Fig. 1 ) dominated by a steppe landscape, and the lower, moister central Argentina plains (CAP) characterized by a grassland landscape, strong moisture gradients usually develop in the absence of a well-defined low-level front. These boundaries, which are frequently oriented northwest

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Stephen W. Nesbitt, Paola V. Salio, Eldo Ávila, Phillip Bitzer, Lawrence Carey, V. Chandrasekar, Wiebke Deierling, Francina Dominguez, Maria Eugenia Dillon, C. Marcelo Garcia, David Gochis, Steven Goodman, Deanna A. Hence, Karen A. Kosiba, Matthew R. Kumjian, Timothy Lang, Lorena Medina Luna, James Marquis, Robert Marshall, Lynn A. McMurdie, Ernani Lima Nascimento, Kristen L. Rasmussen, Rita Roberts, Angela K. Rowe, Juan José Ruiz, Eliah F.M.T. São Sabbas, A. Celeste Saulo, Russ S. Schumacher, Yanina Garcia Skabar, Luiz Augusto Toledo Machado, Robert J. Trapp, Adam Varble, James Wilson, Joshua Wurman, Edward J. Zipser, Ivan Arias, Hernán Bechis, and Maxwell A. Grover

Abstract

This article provides an overview of the experimental design, execution, education and public outreach, data collection, and initial scientific results from the Remote sensing of Electrification, Lightning, And Mesoscale/microscale Processes with Adaptive Ground Observations (RELAMPAGO) field campaign. RELAMPAGO was a major field campaign conducted in Córdoba and Mendoza provinces in Argentina, and western Rio Grande do Sul State in Brazil in 2018-2019 that involved more than 200 scientists and students from the US, Argentina, and Brazil. This campaign was motivated by the physical processes and societal impacts of deep convection that frequently initiates in this region, often along the complex terrain of the Sierras de Córdoba and Andes, and often grows rapidly upscale into dangerous storms that impact society. Observed storms during the experiment produced copious hail, intense flash flooding, extreme lightning flash rates and other unusual lightning phenomena, but few tornadoes. The 5 distinct scientific foci of RELAMPAGO: convection initiation, severe weather, upscale growth, hydrometeorology, and lightning and electrification are described, as are the deployment strategies to observe physical processes relevant to these foci. The campaign’s international cooperation, forecasting efforts, and mission planning strategies enabled a successful data collection effort. In addition, the legacy of RELAMPAGO in South America, including extensive multi-national education, public outreach, and social media data-gathering associated with the campaign, is summarized.

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