Skilful precipitation nowcasting using deep generative models of radar

TLDR

Precipitation nowcasting, which forecasts rainfall up to two hours ahead, is vital for many weather‑dependent sectors, yet current operational methods that advect radar fields with wind estimates fail to capture nonlinear events, and recent deep‑learning approaches that predict rain rates directly lack physical constraints. The study introduces a Deep Generative Model to probabilistically nowcast precipitation from radar data. The model employs a deep generative architecture that produces realistic, spatio‑temporally consistent precipitation predictions over 1536 km × 1280 km regions for 5–90 min lead times. In a systematic evaluation by more than fifty Met Office forecasters, the generative model ranked first in accuracy and usefulness in 88 % of cases against two competitive methods, and quantitative verification shows skillful, non‑blurry nowcasts that improve forecast value where alternative methods struggle.

Abstract

Precipitation nowcasting, the high-resolution forecasting of precipitation up to two hours ahead, supports the real-world socio-economic needs of many sectors reliant on weather-dependent decision-making. State-of-the-art operational nowcasting methods typically advect precipitation fields with radar-based wind estimates, and struggle to capture important non-linear events such as convective initiations. Recently introduced deep learning methods use radar to directly predict future rain rates, free of physical constraints. While they accurately predict low-intensity rainfall, their operational utility is limited because their lack of constraints produces blurry nowcasts at longer lead times, yielding poor performance on more rare medium-to-heavy rain events. To address these challenges, we present a Deep Generative Model for the probabilistic nowcasting of precipitation from radar. Our model produces realistic and spatio-temporally consistent predictions over regions up to 1536 km x 1280 km and with lead times from 5-90 min ahead. In a systematic evaluation by more than fifty expert forecasters from the Met Office, our generative model ranked first for its accuracy and usefulness in 88% of cases against two competitive methods, demonstrating its decision-making value and ability to provide physical insight to real-world experts. When verified quantitatively, these nowcasts are skillful without resorting to blurring. We show that generative nowcasting can provide probabilistic predictions that improve forecast value and support operational utility, and at resolutions and lead times where alternative methods struggle.