Exploring CopterSonde Use for National Weather Service Operations

Abstract

The CopterSonde is a state of the art sampling platform that can be used to advance the field of meteorology in operational forecasting and data collection. One capability of the CopterSonde is that it can collect high-resolution observations in the lowest levels of the atmosphere, including in the atmospheric boundary layer, which traditionally is not well sampled. CopterSonde data were collected during a mixed-phase precipitation event in central Oklahoma in February 2019 and during a quasi-linear convective system event in the Mississippi Delta in March 2022. The primary goal of this study was to determine the operational benefits of CopterSonde data when used by National Weather Service forecasters. Specifically, a virtual post-event forecast experiment investigated the impacts on forecasters’ operational processes, decisions, and communication of hazards.

Volunteers from four National Weather Service Weather Forecast Offices in the Southern Region initially participated in a background survey during the winter of 2021. This survey investigated the current suite of boundary layer observations available and introduced the CopterSonde platform to them. The survey results suggested that the most anticipated benefits from incorporating CopterSonde data in NWS operational forecasting were: improved understanding of numerous weather phenomena (severe and winter weather were highlighted), increased forecaster confidence and situational awareness, and enhanced communication of hazard expectations to core partners and the public. These findings guided the goals and creation of a forecast experiment that followed.

In the fall of 2022, 16 total forecasters from the 4 Weather Forecast Offices completed 2 case studies over the course of 4 days. The goals were to investigate the impact of the CopterSonde data focusing on their situational awareness, hazard identification, and communications. For each case, CopterSonde data were only provided to half of the forecasters, and focus groups were held at the end of each day. These meetings allowed forecasters to discuss the impacts of the CopterSonde data for both cases.

A situational awareness framework was used to guide the thematic coding of data collected during the case studies. Forecasters with the CopterSonde data reported greater levels of situational awareness and higher confidence in their environmental analysis and decisions. One key finding between the two cases was that the CopterSonde data had a demonstrably more significant impact on the winter weather case versus the severe weather case. This difference in impact is due to the greater uncertainty regarding expected outcomes for the winter weather case. When using the CopterSonde data to identify precipitation types, the probability of detection for forecasters, during the winter weather case, was 0.50. This exceeded that of the group without the CopterSonde data by 0.12. During the severe weather case, an outflow boundary and its impacts were identified in the CopterSonde data. This feature went unnoticed by participants that did not have CopterSonde data available. Overall, forecasters were very enthusiastic about the potential to include CopterSonde data in their day-to-day operations when making decisions and communicating expected weather impacts to their audiences.