Product: Forecast Discussion Issued: 2018 Sep 21 0030 UTC Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
.24 hr Summary… Solar activity was very low. The visible disk was spotless and no Earth-directed CMEs were observed in available satellite imagery.
.Forecast… Solar activity is expected to be at very low levels on 21-23 Sep.
.24 hr Summary… The greater than 2 MeV electron flux reached high levels this period with a peak flux of 8,310 pfu at 20/1930 UTC. The greater than 10 MeV proton flux was steady at background levels throughout the period.
.Forecast… The greater than 2 MeV electron flux is expected to reach high levels on 21-23 Sep and the greater than 10 MeV proton flux is expected to persist at background levels throughout the period.
.24 hr Summary… The solar wind environment reflected ambient background conditions.
.Forecast… Solar wind parameters are expected to be at nominal levels on day one (21 Sep) and most of day two (22 Sep). Late on day two and continuing into day three (23 Sep) the solar wind environment is expected to become enhanced due to the arrival of a recurrent, positive polarity CH HSS.
.24 hr Summary… The geomagnetic field was at quiet levels.
.Forecast… The geomagnetic field is expected to be at mostly quiet levels on day one (21 Sep) and the majority of day two (22 Sep). Late on day two, quiet to unsettled conditions are expected due to influence from a recurrent, positive polarity CH HSS. Unsettled to G1 (Minor) storm levels are likely on day three (23 Sep) as persistent CH HSS effects linger.
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