Evaluating Hurricane Harvey's Rapid Intensification and Precipitation in the ERA5 Reanalysis

In August 2017, Hurricane Harvey made landfall on the southeast Texas coast as a Category 4 hurricane after periods of rapid intensification. Shortly after landfall, Hurricane Harvey stalled and produced over 60 inches of rain in some areas, breaking records for hurricane total accumulated precipitation. As the Earth’s climate continues to change, hurricanes are expected to rapidly intensify at a faster rate, stall more frequently, and precipitate more, allowing for hurricanes to become more impactful to coastal communities. In order to establish predictors to rapid intensification events, past hurricanes must be analyzed for similar conditions prior to rapid intensification events. However, up until the recent release of the ECMWF’s ERA5 reanalysis dataset, reanalyses were not spatially or temporally fine enough to study hurricanes. This research investigates the ability of the ERA5 reanalysis dataset to capture the precipitation amounts and rapid intensification phase of Hurricane Harvey. Precipitation estimates from the ERA5 reanalysis dataset and the Tropical Rainfall Measuring Mission (TRMM) are compared with in situ observations. In addition, wind speed, pressure and track data are estimated from ERA5 and compared with the National Hurricane Center’s Best Track Data (HURDAT2). Each variable is plotted on either an hourly (ERA5), three-hourly (TRMM), or six-hourly (HURDAT2) interval to analyze its time evolution. Finally, atmospheric conditions prior to rapid intensification are analyzed for ERA5, with a focus on the moist physics, to better understand the conditions leading to rapid intensification and extreme amounts of precipitation.