How Atlantic Hurricane Prediction May Change with Climate Warming

Subseasonal to seasonal hurricane prediction at forecast leads of two weeks to two months is currently a new frontier for the climate and weather forecasting communities. After discussing the outlook and what we have seen so far for the current hurricane season, how predictions might change in a future warmer climate will be discussed. In the current climate, tropical phenomena called the Madden-Julian oscillation (MJO) and the El NiƱo-Southern oscillation provide enhanced prediction skill for Atlantic and east Pacific hurricanes and tropical storms several weeks in advance. The MJO is associated with eastward-moving regions of heavy tropical precipitation in the Indian and west Pacific Oceans that send pulses of wind over the Atlantic to affect hurricane activity. Its cycle repeats every 40-50 days. This talk will review recent evidence not only for how Atlantic and east Pacific tropical cyclone activity may change with climate warming on average, but also how predictions of tropical cyclones several weeks in advance may change with warming. Evidence will be presented that winds associated with the MJO may weaken with climate warming. This may make tropical storms and hurricanes less predictable in the Atlantic and east Pacific in a warmer climate. Given the expected general increase in hurricane intensity in a warmer climate, the consequences of potential decreases in prediction skill will be discussed.