| dc.description.abstract | Tropical cyclone tornadoes (TCTORs) are a hazard to life and property during landfalling tropical cyclones (TCs). The threat is often spread over a wide area within the TC envelope, and must be continually evaluated as the TC moves inland and dissipates. To diagnose the risk of TCTORs, forecasters use high-resolution, rapidly-updating models such as the Rapid Refresh (RAP) and High-resolution Rapid Refresh
(HRRR), and an ingredients-based approach similar to that used for forecasting continental mid-latitude tornadoes. Though RAP and HRRR model errors have been identified in typical midlatitude convective environments, this study seeks to evaluate the performance of the RAP and the HRRR within the TC envelope up to 800 km from the TC center, with particular attention paid to variables identified in previous studies as useful for TCTOR forecasting.
A sample of 1,730 observed upper-air soundings is sourced from 13 TCs that made landfall along the US coastline between 2017-2019. The observed soundings are paired with their corresponding model grid point soundings from the RAP analysis, RAP 12-hour forecast, and HRRR 12-hour forecast. Model errors are calculated for both the raw sounding variables of temperature, dew point, and wind speed, as well as for the quantities of selected sounding-derived parameters. Results show a moist bias that worsens with height across all model runs. There are also significant underpredictions in stability-related parameters such as convective available potential energy (CAPE) and kinematic parameters such as vertical wind shear. | |
