3-km HFV3 Forecasts of High-Impact 2018 Atlantic and Pacific Hurricanes

High resolution nested FV3 (HFV3) forecasts of high-impact 2018 Atlantic and Pacific hurricanes are evaluated, specifically Atlantic Hurricanes Florence and Michael and Pacific Hurricane Lane. Specifically, the model’s ability to predict periods of rapid intensification in several different environments is examined. Hurricane Lane experienced periods of rapid intensification both early in the lifecycle and also as a strong hurricane, providing the opportunity to study the different mechanisms in each phase. For Hurricane Florence, while the second period of intensification was well-forecast, the first rapid intensification (in a moderate to high shear environment) was not well-forecast by several numerical models, and thus provides an opportunity to study RI in marginal environments. Similarly, Hurricane Michael underwent RI in the Gulf of Mexico despite 20 knots of shear and nearby dry mid-level air, and then took advantage of lowering shear to continue to intensify through landfall in the Gulf of Mexico. The mechanisms leading to and TC structures allowing for RI in these marginal environments will be examined with the 3-km HFV3.