Are Inland Tropical Cyclone Impacts Dependent on the Diurnal Timing of Landfall?

Does the time of day that a tropical cyclone (TC) makes landfall impact the magnitude of inland winds? This question is critical for understanding and predicting the societal impacts of landfalling TCs. We hypothesize that storms making landfall in the afternoon will present a more substantial inland wind threat due to increased non-local momentum transport within a convective boundary layer. Due to inland decay and momentum evolution being dependent on many variables such as TC size, landfalling intensity, geographical location, etc., the question is difficult to answer observationally. Here, we use idealized simulations of a suite of landfalling tropical cyclones to test our hypothesis using the Weather Research and Forecasting (WRF) model version 4.5.2. To spin up TCs, a weak Rankine-based bogus vortex is added to a completely quiescent domain. Our experimental domain includes a fixed sea-surface temperature and a homogenous land mass; the idealized tropical cyclones track to the northwest due to Beta drift before making landfall at an angle nearly perpendicular to the idealized coast. These simulations use the Mellor-Yamada-Nakanishi-Niino (MYNN) PBL parameterization with non-local components of the EDMF scheme enabled due to its realistic handling of a TC boundary layer. We then use these simulations to analyze the inland wind evolution of tropical cyclones as a function of the time of day to assess the sensitivity of inland wind evolution and to either support or disprove our hypothesis.