Upper-Air Observations in Landfalling Hurricanes

Upper-air observations within hurricanes are critical to understanding storm morphology and structure but are typically limited in coverage. These observations are obtained primarily through the use of aircraft, such as the NOAA P-3, and dropsondes; however, these observations are usually obtained over the open ocean as the tropical system develops. Once over land, most upper-air observations cease, thus leaving the transition from open ocean to land largely under-sampled. Understanding this transition, and the hazards associated with landfalling systems (e.g., tornadoes, microbursts, etc.), is paramount to improving forecasts that directly affect lives and property.

To increase observations in this data-sparse region, a mobile sounding vehicle from NOAA’s National Severe Storms Laboratory was used to launch surface-based soundings in hurricanes Harvey and Irma in the fall of 2017. Though not the first soundings of their kind, the profiles captured rapid temporal and highly-localized changes in the hurricane environments and documented likely the highest-recorded values of precipitable water observed in a CONUS sounding. Several profiles from both hurricanes will be presented and discussed, documenting not only the environments but also potential pitfalls when examining derived sounding parameters in hurricanes. Additionally, the soundings will be used to validate forecast model fields of the landfalling systems and measure the ability of current models to accurately depict the potent environments present.