Emerging Airborne Technologies for improved TC Track and Intensity Forecasting: A vision for the next Decade based on Preliminary Observations from SHOUT and EPOCH Programs

Two recent Tropical Cyclone (TC) Forecast Demonstration Projects (TCFDP) have utilized new and innovative technologies and targeted observing strategies for improving TC track and intensity forecasting: 1) Sensing Hazards with Operational Unmanned Technologies (SHOUT) and 2) East Pacific Origins and Characteristics of Hurricanes (EPOCH). Both of these projects share the common objective of demonstrating observational capability of the lower stratosphere and entire tropospheric column using new and improved aircraft dropsonde technology deployed from Global Hawk UAV vehicles to extend legacy mid-troposphere observations from mid- to high-level surveillance aircraft flown over the past 20 years using IFEX NOAA/AOC Gulfstream G-IVSP aircraft (Aberson, 2010; Wang, et al., 2015). Preliminary evaluations show significant improvement in TC track forecasts using Global Hawk high-altitude ‘minisondes’ that may be a result of resolving key features in the Upper Troposphere and Lower Stratosphere over the TC Inner Core, such as Outflow Jets (OJs), as well as Subtropical Jets (SJs) in the surrounding environment. Recent results presented at the Cyclone Workshop, 1-6 Oct., St Adele, Quebec, Canada by Sippel and Emerging Technologies Workshop, 22-23 Aug., NCEP, College Park, MD by Tallapragada have shown a 10-20% improvement in GFS global model track forecasts for some SHOUT cases, not only in the dropsonde-observed TC’s, but in downstream TC’s in other basins.

Global Hawk UAV ‘minisondes’ deployed in the environment and inner core of East Coastal-following Hurricane Matthew (2016) during SHOUT and Hurricane Harvey (2017) prior to landfall on the Texas Coast during EPOCH are examined in detail in concert with coincident IFEX WP-3D observations and 53^rd WRS WC-130J operational reconnaissance observations. Additionally, initial GFS and HWRF forecast results using the new ‘minisonde’ technology will be discussed as well as speculation regarding the importance to forecast improvement of future high-level observations from surveillance and reconnaissance aircraft. Comparison with similar GH minisonde observational impact in ECMWF model runs for these cases will also be discussed.

These new high-altitude observations may signal a paradigm shift jn TC observational impacts on TC forecast improvement when coupled with new model Data Assimilation (DA) schemes that utilize the entire sonde data profile in BUFR format correctly located in a storm-centric coordinate system, rather than only at the sonde launch location, which is current practice with limited mandatory and significant level data contained in TEMPDROP messages