• Gerrit Hiemstra, MSc

    Co-founder and Chief Executive Officer

    Gerrit is a meteorologist with in-depth experience in the meteorological field. He graduated in 1986 at Wageningen University as Agricultural Engineer, with a specialisation in Agricultural Meteorology, followed by a 9-year period as operational weather forecaster in a commercial weather company.

    After a brief period as head of the operational weather service at Schiphol Airport he founded the successful commercial weather company WeerOnline, which was sold in 2009.

    Gerrit is also the well-known weather presenter of NOS, the national news organisation of the Netherlands, since 1998.

    At Weather Impact Gerrit is responsible for project acquisition and contract management.

  • Arnold Lobbrecht, PhD

    Co-founder and Chief Technology Officer

    Arnold graduated in 1986 from Delft University of Technology as Civil Engineer. He gained experience in hydrology, water management and informatics during a 12-years period at a multinational consultancy firm.

    After 4 years of research he obtained in 1997 his PhD in operational water management. After that he became part-time professor of hydroinformatics at UNESCO-IHE in Delft, guiding a group of PhD researchers. In 2000 he established HydroLogic, a hydroinformatics company, working on water & ICT projects.

    His experience is in decision support systems with focus on flood forecasting, water availability and droughts.

  • Stefan Ligtenberg, PhD

    Project leader and consultant

    Dr. Stefan Ligtenberg works at Weather Impact as project leader and consultant.

    Stefan graduated in 2009 at Wageningen University in Meteorology and Air Quality. He finished his PhD in 2014 on the field of polar meteorology at Utrecht University. Subsequently he started two postdoctoral positions at Utrecht University, for the last he received an NWO VENI scholarship.

    At Weather Impact, Stefan works as consultant and project leader. He has experience with weather forecasting in Southeast Asia and East Africa. He is an expert in translating meteorological weather parameters in messages that fit the local context of a farmer.

  • Bob Ammerlaan, MSc


    Bob Ammerlaan MSc. works at Weather Impact as consultant.

    Bob has a background in Physics and Meteorology and graduated in 2018 at Utrecht University in Meteorology, Physical Oceanography and Climate.

    At Weather Impact, Bob works as consultant meteorology and climate change. He is responsible for the operational services at Weather Impact. He has experience with weather forecasting in Southeast Asia and East Africa and is an expert in using agricultural and meteorological information to give the best advice to local farmers.

  • Pleun Bonekamp, PhD

    Project leader and consultant

    Dr. Pleun Bonekamp works at Weather Impact as consultant meteorology and climate change and project leader.

    Pleun has a background in Physics and Meteorology and graduated in 2016 at Utrecht University in Meteorology, Physical Oceanography and Climate. She finished her PhD in mountain meteorology and climate change at Utrecht University in 2020. Over the years, she gained experience with different (atmospheric) models and big data analysis. She has great analytic capabilities and very good communication and presentation skills.

    At Weather Impact, Pleun develops various weather services for farmers and conducts in depth analysis related to the impacts of climate change and weather extremes.

  • Tamara Lancel

    Management Assistant

    Tamara Lancel works at Weather Impact as Management Assistant.

    She graduated in Hotel & Hospitalitymanagement in 2007 and has a background in the hospitality industry, organizing congresses and events. In her last job she worked as a training coordinator and arranged technical IT trainings for the Benelux and Africa region. Tamara is very strong in planning, coordinating and organizing, and has experience in broad administrative and logistic work. At Weather Impact she supports the team in marketing, HR, administration, acquisition and other organizational tasks, to share our expertise about smart weather solutions.


  • Valeria di Fant


    Valeria is a student originally from Italy who has been living in the Netherlands for a while now. This year she is completing her MSc Climate Studies at Wageningen University & Research, where she is specialized in human-environment interactions. She is particularly interested in user engagement in the context of climate services and in climate adaptation in general. During her internship at Weather Impact she is working on the pilot ‘Extreme precipitation forecasting system’, for which she will carry out a final evaluation on the basis of users’ feedback and impressions of the project.

  • Jane Roque


    Jane Roque has a background in Agricultural Engineering. She is currently studying the Master Climate Studies at Wageningen University and Research with a specialization in the Physical Climate System. As an intern at Weather Impact, she is working on developing crop climate suitability maps for different countries in the world under current and future climatic conditions.