Product: Forecast Discussion Issued: 2021 Jul 31 1230 UTC Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
.24 hr Summary… Solar activity was very low as the visible solar disk remained spotless. No Earth-directed CMEs were detected in available coronagraph imagery.
.Forecast… Very low solar activity is expected to continue on 31 Jul-02 Aug.
.24 hr Summary… The greater than 2 MeV electron flux was at normal to moderate levels with a peak flux of 779 pfu observed at 30/1600 UTC. The greater than 10 MeV proton flux maintained background levels.
.Forecast… The greater than 2 MeV electron flux is expected to be at normal to moderate levels, with a chance for high levels, on 31 Jul-02 Aug due to CH HSS influences. The greater than 10 MeV proton flux is expected to remain at background levels.
.24 hr Summary… Solar wind parameters remained indicative of weak CH HSS influences. Total IMF strength ranged between 1-5 nT while the Bz component varied between +5/-4 nT. Solar wind speeds meandered between about 440-525 km/s. The phi angle was predominantly oriented in the positive solar sector.
.Forecast… A slightly enhanced solar wind environment is expected to continue through 02 Aug due to CH HSS influences. Additionally, several CMEs (from 25, 27, and 28 Jul) are anticipated to pass close to Earth on 31 Jul and 01 Aug. While model analysis suggested these transients were mostly near misses, weak disturbances in the solar wind field could be experienced all three days of the forecast period.
.24 hr Summary… The geomagnetic field was at quiet levels.
.Forecast… The geomagnetic field is expected to be at quiet to unsettled levels on 31 Jul through 02 Aug, with isolated active intervals on 01 Aug. These varying responses are anticipated reactions to CH HSS effects and possible additional influences from the close proximity of passing transients.
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