Understanding Problem Forecasts of ISEST Campaign Flare-CME Events

Abstract

The goal of the International Study of Earth-affecting Solar Transients (ISEST) project as part of the Variability of the Sun and Its Terrestrial Impact (VarSITI) program is to understand the origin, evolution, and propagation of solar transients through the space between the Sun and Earth, and to improve our prediction capability for space weather. A goal of ISEST Working Group 4 (Campaign Events) is to study a set of well-observed Sun-to-Earth events to develop an understanding of why some events are successfully forecast (textbook cases), whereas others become problem or failed forecasts. In this article we study six cases during the rise of Solar Cycle 24 that highlight forecasting problems. Likely source coronal mass ejections (CMEs) were identified in all six cases, but the related solar surface activity ranged from uncertain or weak to X-class flares. The geoeffects ranged from none to severe as in the two Sun–Earth events in 2015 that caused severe storms. These events were chosen to illustrate some key problems in understanding the chain from cause to geoeffect.