An increasing appreciation of intra-seasonal interactions between the tropics and extra-tropics has raised the possibility of increased predictability of significant circulation and weather anomalies in many regions. This school will introduce this new perspective to the students, giving them hands-on experience in the computer lab. During the first week of the School, the lecturers will review the state of knowledge of Tropical- Extratropical interactions, with an emphasis on basic dynamics, and on hypotheses that can be tested with the forecasts and re-forecasts from a number of operational centers and possibly experiments with the ICTP climate model. Lectures will be held in the mornings. In the afternoons, the students (participants) will form teams to design lab projects to explore the relationships discussed in the morning, using the S2S forecast database http://journals.ametsoc.org/ doi/abs/10.1175/BAMS-D-16-0017.1 and possibly design experiments with the ICTP climate model (SPEEDY) https://www.ictp.it/research/esp/models/speedy. aspx. During the second week, the lecturers will cover more advanced research, and the participants will continue their projects, in consultation with the lecturers. The topics center on the role of intra-seasonal interactions between the tropics and extra-tropics in increased potential predictability of significant circulation and weather anomalies in many regions. Speakers: John Albers (University of Colorado, USA) Mariano S. Alvarez (CIMA/CONICET-UBA, Argentina) Laura Ferranti (ECMWF, UK) Nicholas Hall (LEGOS/University of Toulouse, France) Ivana Herceg Bulic (University of Zagreb, Croatia) Manish Joshi (RCCS, Busan, Rep. of Korea) Fred Kucharski (ICTP, Italy) Hai Lin (McGill University, RPN, Quebec, Canada) Franco Molteni (ECMWF, UK) Josefina Moraes Arraut (University of Campina Grande, Brazil) Ángel Muñoz (Princeton University, USA ) Ana Carolina Nóbile Tomaziello (University of Sao Paulo, Brazil)  Andrew Robertson (IRI, Columbia University, USA) Ascanio Scambiati (Metweb, Italy) Noureddine Semane (EHTP, Morocco) Kamil Shahzad (King Abdulaziz University, Saudi Arabia) Cristina Stan (George Mason University, USA) David Straus (George Mason University, USA) Adrian Tompkins (ICTP, Italy) Fei Zheng (IAP, CAS, China)