Thursday

The paradigm shift that space weather is real, relevant, and knowable to a general audience is not as impossible as once imagined. Although it remains an extremely difficult topic to convey, new modes of communicating space weather to a very eager public are becoming available. In return, the appetite for more timely and accurate space weather information by the public is driving more robust observation and prediction methodologies in forecasting space weather events. One such example is in the raised awareness of "stealth" CMEs, which are CMEs that are often observed in coronagraph data but not in coronal images. These events often cause problem geomagnetic storms because they go unnoticed until they hit Earth. Largely identified during the deep minimum of cycle 23/24, stealth CMEs appear to be on the rise. Since solar cycle 25 brings with it the possibility of yet another low activity cycle, it is very likely that the number of stealth CMEs will remain a significant fraction of ejecta, which presents additional challenges for the forecasting community. We investigate the properties of stealth CMEs, paying special attention to their proximity to coronal holes, and discuss how these near-invisible events have defined a new form of “extreme” when it comes to space weather forecasting. We outline changes in observation techniques required to more routinely detect these events, and we illustrate the kinds of public beneficiaries of these improvements in forecasting, demonstrating the intersection of heliospheric science, meteorology, and public use of space weather information.