Track forecast: Operational capability and new techniques - Summary from the Tenth International Workshop on Tropical Cyclones (IWTC-10)

Development of Interpretable Probability Ellipse in Tropical Cyclone Track Forecasts Using Multiple Operational Ensemble Prediction Systems

“…TCs contributed to approximately 48% of the natural disaster damage in the Republic of Korea (hereinafter Korea) in the period 2012–2021 (Ministry of the Interior and Safety, 2022). Efforts have been expended to mitigate their effects by providing more accurate predictions of TC movement (Cheung et al., 2021; Conroy et al., 2023; Gall et al., 2013; Hamill et al., 2012). However, recent assessments of TC track predictions show that short‐term track predictability is approaching its theoretical limit in some forecast basins (Landsea & Cangialosi, 2018).…”

ECMWF Ensemble Forecasts of Six Tropical Cyclones That Formed during a Long-Lasting Rossby Wave Breaking Event in the Western North Pacific

“…There are several review articles from the 10th International Workshop on Tropical Cyclones that provide the context for this submission to the Special Issue on Typhoon/Hurricane Dynamics and Prediction. Operational warning agencies have achieved major improvements in tropical cyclone (TC) track forecasts by utilizing a consensus of numerical model track forecasts, but the rate of improvement has been slowing in recent years (Conroy et al, 2023) [1]. Most TC warning centers utilize an unweighted consensus (i.e., assume all model tracks are equally likely) that usually is a combination of deterministic models, although a growing number of centers also include unweighted ensemble mean track forecasts (again, assuming all ensemble member track forecasts are equally likely).…”

“…Most TC warning centers utilize an unweighted consensus (i.e., assume all model tracks are equally likely) that usually is a combination of deterministic models, although a growing number of centers also include unweighted ensemble mean track forecasts (again, assuming all ensemble member track forecasts are equally likely). Conroy et al [1] describe an example of the Joint Typhoon Warning Center (JTWC) unweighted consensus tracker (CONW; Sampson and Schrader, 2000 [2]) that consists of nine members (six deterministic models and three ensemble models). The consensus tracker shifts each model track forecast in space and time to match the recent working best-track position analyzed by the JTWC.…”

“…The forecaster does have the option to select/omit among the CONW member track forecasts based on known model biases and the previous forecast. Conroy et al ( [1], their Figure 1) present as an example of a difficult CONW forecast the track of Tropical Storm 16 W initialized at 1200 UTC 14 September 2022, which started at ~23 • N, 140 • E after an anticyclonic loop, and later translated northwestward to make landfall on southern Japan. Coincidentally, TS 16 W was one of a sequence of six TCs during August-September 2022 that had difficult track forecasts, which we attribute to these six TCs forming at higher latitudes (20)(21)(22)(23)(24)(25) • N) in association with a long-lasting Rossby wave breaking (RWB) event.…”

“…Conroy et al [1] note an increased use of ensemble mean tracks to improve track forecast guidance, and to issue situation-dependent depictions of track uncertainty. In this study, we utilize the European Centre for Medium-Range Weather Forecasts' ensemble prediction system (ECEPS) to demonstrate its capability to predict those six TCs.…”