The solar wind environment is expected to become enhanced and disturbed later on September 27, 2019 (UTC). G1 - Minor Geomagnetic Storm Watch is in effect for September 27, G2 - Moderate for September 28.
Quiet to unsettled geomagnetic field conditions are expected early on September 27 due to Co-Rotating Interaction Region (CIR) arrival ahead of a positive polarity Coronal Hole High Speed Stream (CH HSS).
Increasing solar wind speed is anticipated to approach speeds of 650 km/s as the day progresses, and may likely reach near 700 km/s by September 28. Elevated solar wind speed is expected to continue into September 29 as CH HSS influence continues.
CIR arrival followed by CH HSS onset is likely to result in elevated responses of active to G1 - Minor storm levels later on September 27. CH HSS effects are anticipated to intensify, likely resulting in periods of G1 and G2 - Moderate storm levels on September 28, and an early isolated period of G1 storm conditions on September 29, SWPC forecasters noted 00:30 UTC today.
With no sunspots present on the visible disk, solar activity continues at very low levels.
Century-class Solar Minimum
The Sun has been spotless 72% of the time this year (January - September).
"This is comparable to annual averages during the century-class Solar Minimum of 2008 (73%) and 2009 (71%). The current Solar Minimum appears to be century-class as well, meaning you have to go back to the beginning of the 20th century to find lulls in solar activity this deep," Dr. Tony Phillips of the SpaceWeather noted September 24.
Featured image credit: Solen