An increased incidence of extreme weather events (e.g., storms and droughts) is expected to profoundly impact the functioning of the lake ecosystem in the future. Despite this, the impact of these events, and their interaction with existing stressors (e.g., eutrophication, catchment land use, hydrological regulation), are not well understood. Here we present a novel approach that incorporates data from sediment core environmental reconstructions (including a spectrum of paleoecological [i.e., diatom, Cladocera, and pigment analysis] and eDNA proxies), historical land use imagery, and high-frequency monitoring buoys, to develop high-resolution reconstructions of whole lake ecosystem change. This novel combination of data is then to be used to configure and calibrate coupled one-dimensional catchment-lake ecosystem models to forecast the lake ecosystem response to extreme weather events and their interaction with existing stressors. As an initial case study, we investigated the impacts of extreme events on ecosystem functioning in Lake Tūtira, a warm-monomictic lake situated in the Hawke’s Bay region of New Zealand’s North Island. Lake Tūtira was selected for investigation due to its unique combination of long-term environmental data and its sensitivity to infrequent, high-magnitude storm events—including Cyclone Gabrielle in February 2023, which has been estimated as at least a 1-in-70 year event. High-frequency monitoring of temperature, dissolved oxygen, turbidity, and chlorophyll-a demonstrated an almost complete disruption of the lake’s preexisting stratification. Moreover, turbidity remained elevated above pre-Gabrielle baseline conditions well into the subsequent summer-stratified period. We integrate these findings—alongside sediment core reconstructions and historical land-use imagery—as a proposed approach for the configuration and calibration a coupled one-dimensional catchment–lake ecosystem model to forecast the impacts of future extreme weather events and their interactions with existing stressors.