Hurricane eyewalls are often observed to be nearly circular structures, but they are occasionally observed to take on distinctly polygonal shapes. The shapes range from triangles to hexagons and, while they are often incomplete, straight line segments can be identified. Other observations implicate the existence of intense mesovortices within or near the eye region. Is there a relation between polygonal eyewalls and hurricane mesovortices? Are these phenomena just curiosities of the hurricane's inner-core circulation, or are they snapshots of an intrinsic mixing process within or near the eye that serves to determine the circulation and thermal structure of the eye? As a first step toward understanding the asymmetric vorticity dynamics of the hurricane's eye and eyewall region, these issues are examined within the framework of an unforced barotropic nondivergent model. Polygonal eyewalls are shown to form as a result of barotropic instability near the radius of maximum winds. After reviewing linear theory, simulations with a high-resolution pseudospectral numerical model are presented to follow the instabilities into their nonlinear regime. When the instabilities grow to finite amplitude, the vorticity of the eyewall region pools into discrete areas, creating the appearance of polygonal eyewalls. The circulations associated with these pools of vorticity suggest a connection to hurricane mesovortices. At later times the vorticity is ultimately rearranged into a nearly monopolar circular vortex. While the evolution of the finescale vorticity field is sensitive to the initial condition, the macroscopic end-states are found to be similar. In fact, the gross characteristics of the numerically simulated end-states are predicted analytically using a generalization of the minimum enstrophy hypothesis. In an effort to remove some of the weaknesses of the minimum enstrophy approach, a maximum entropy argument developed previously for rectilinear shear flows is extended to the vortex problem, and end-state solutions in the limiting case of tertiary mixing are obtained. Implications of these ideas for real hurricanes are discussed.

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The required meteorology coursework for 22 accredited professional flight baccalaureate degree programs was examined and compared.Significant differences were noted in both the number of required meteorology courses as well as the number of required meteorology credit hours. While all programs required at least one three-credit meteorology course, not all programs required an aviationspecific meteorology course. In addition to the required number of meteorology courses and credit hours, topics within the aviation-specific meteorology courses were also examined. The study showed the topics of "flight hazards" and "aviation weather reports and charts" were identified most frequently in course descriptions, followed third by "weather applications to flight." However, based on the course descriptions alone, it was unclear if the meteorological theory of flight hazards was addressed in the courses or if the courses only addressed the interpretation of weather hazards charts. To improve and standardize aviation-meteorology education in professional flight-degree programs, a recommendation was made to either provide aviation-meteorology curriculum guidelines through the University Aviation Association (UAA) Curriculum Committee or to form a separate UAA Aviation-Meteorology Education Committee.

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BACKGROUND: General Aviation (GA) pilots who encounter hazardous weather inflight have a high probability of incurring fatal accidents. To mitigate this problem, previous research investigated pilot decision making and the effects of new technology. Limited investigations have examined usability and interpretability of observation and forecast weather products available to pilots. Therefore, this study examined the interpretability of weather observation and forecast reports that GA pilots use for preflight weather planning and the impact of pilot certification level on the interpretability of these displays.METHOD: There were 204 GA pilots (Mean age = 22.50 yr; Median flight hours = 131.0) who completed a 90-item multiple choice Aviation Weather Product Test. The questions portrayed static weather displays available on the NOAA/National Weather Service Aviation Weather Center website. The questions were designed to have high cognitive fidelity in comparison with preflight weather planning tasks.RESULTS: The results revealed overall low mean interpretability scores (Mean percent correct= 59.29%, SD = 16.01%). The scores for observation products and product attributes were lower for student pilots than experienced pilots. Forecast product scores for student and private pilots did not differ, however, student pilot scores were significantly lower than instrument rated private and commercial pilots.DISCUSSION: The low interpretability scores indicate that GA pilots misinterpret weather information provided by most weather observation and forecast products. Possible contributing factors to the low product interpretation scores include poor usability and a lack of training. Future research should measure the usability of weather displays designed for pilots.Blickensderfer BL, Guinn TA, Lanicci JM, Ortiz Y, King JM, Thomas RL, DeFilippis N. Interpretability of aviation weather information displays for general aviation. Aerosp Med Hum Perform. 2020; 91(4):318–325.

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