Abstract Flash droughts pose severe risks to societies and ecosystems due to their sudden onset and rapid intensification. Predicting their vegetation impacts at subseasonal timescales remains difficult. Advances in hybrid physics‐AI models and weather forecasting create new opportunities to enhance the predictability of evaporative stress, a key indicator of flash drought onset. Here, we present a novel subseasonal global framework that integrates bias‐corrected, high‐resolution weather forecasts with a hybrid evaporation model to predict flash drought onset, persistence, and termination up to 10 days in advance. The framework shows high skill in persistence and termination, especially in semiarid regions, with median Critical Success Index of 0.68 and 0.56, respectively. Over 70% of flash‐drought‐affected areas in the United States and Europe achieve a Probability of Detection above 0.5 against operational monitors. Our framework supports the development of operational early warning systems to reduce flash drought risks to food and water security.