G2 (Moderate) geomagnetic storm conditions were reached earlier on 11 September, 2018 due to anticipated effects from a coronal hole high speed stream (CH HSS). The images show output from the OVATION Prime Model during a peak in activity (11/0935 UTC or 11/0535 ET) and a plot of the Estimated Planetary K-index for each 3-hour synoptic period. G2 conditions were first reached at 11/0817 UTC (11/0417 ET) and continued at those levels for about four hours. Geomagnetic storm conditions at the G1 (Minor) levels first began on 10 September, 2018, with the arrival of a co-rotating interaction region (CIR) ahead of the CH HSS. The CIR has since passed, but Earth remains under the influence of elevated solar wind speeds from the CH HSS. Due to the continuing influence of the CH HSS, Minor storm conditions remain likely, therefore a G1 Watch is still in effect for 12 September. Continue to visit https://swpc.noaa.gov for the latest information and updates.