An Introduction to OCTANE Optical Flow Sandwich Products and Demonstrations at the 2024 Hazardous Weather Testbed

Rapid scan Geostationary Operational Environmental Satellite (GOES)-R imagery enables methods to extract dense (every image pixel) motions observed from drifts in cloud and water-vapor features, or the Optical Flow. These motions can be blended (or “Sandwiched”) with the 0.64 and 10.3 μm channel brightness from the imagery to view developing and mature deep convection and highlight a) initiation in strong vertical wind shear, and b) cloud-top divergence signals which trend with storm intensity. In addition, motions can be used to objectively quantify trends of moving clouds at an unprecedented near-pixel level, such as cloud-top cooling (relevant for identifying early signals of convection initiation). The numerous applications of dense optical flow motivate applied research to find uses for such products in convection warning operations. The so-called Optical flow Code for Tracking, Atmospheric Motion Vector, and Nowcasting Experiments (OCTANE) Speed, Direction, Divergence, and Cooling sandwich products were evaluated in near-real-time by National Weather Service forecasters at the 2024 Hazardous Weather Testbed (HWT) Satellite Proving Ground experiment in Norman, Oklahoma. This presentation will cover how the products are created, how signals in the products are related to storm development and severity, and an overview of the results of these HWT demonstrations from a developer’s perspective. This overview will include interesting phenomena which occurred during the experiment and highlight key results from daily and weekly surveys that will guide future product development. Specifically, we will highlight how forecasters used and improved the nighttime-only products (a focus for the 2024 experiment), and how forecasters tested with different display techniques with divergence and cooling (such as overlaying cooling with the commonly used day-cloud phase distinction RGB). Further, we will cover areas forecasters found the OCTANE products to struggle, and where more artifact mitigation may be needed with future research.