Developing and Testing Watch-Scale Forecast Products in the FACETs Paradigm

One of the challenges facing the FACETs continuum is bridging the gap between long lead time convective outlook probabilities and short lead time warning-scale probabilities. Previous work has shown that a majority of convective outlook day events occur in just 4-hours of the 24-hour day. This lead to the development and testing of a forecast product aimed at identifying when that 4-hour period would occur. This product, called isochrones, was verified and evaluated during the 2016 and 2017 Spring Forecasting Experiments in Norman, OK. Forecasters generally identified the start time of an event accurately, but often progressed events too slowly, forecasting areas downstream of initiation to be later than what observations showed. However, forecasters showed improvement in the second year of the experiment, likely due to better training and identifying the temporal bias from the year before.

The major concern expressed by forecasters in the 2016 and 2017 experiments was the utility of this product, especially with outside partners. Confusion over what the graphics were conveying and how long it would take for users to interpret them raised questions about how useful this product would be even if forecasters produced a perfectly accurate product. Due to these challenges, researchers have re-invented a timing product related to isochrones, but resembling the current watch box system. Forecasters in the 2018 HWT will test a watch box forecast product with convective outlook lead-time, hopefully alleviating some of the challenges of the isochrones while still providing a forecast product consistent with the FACETs paradigm.