M1.3 and C9.9 solar flares occurred while Earth expects impact of September 28 CME

Sunspot 1583 on the western limb produced an M1.3 flare on Sept. 30 at 04:33 UTC. Region 1583 had grown rapidly in the past 24 hours, however it is only hours away from rotating off the solar disk and out of view. SIDC and NOAA/SWPC expect mostly eruptive conditions (C class flares likely) for the next 48 hours. C9.9 solar flare occurred at 23:39 UTC on September 30, possibly from Sunspot 1577. NOAA forecasters estimated 10% chances for M-class solar flares. They gave 10% chances today as well and M-class solar flare occurred. Geomagnetic conditions are expected to be active with isolated periods of minor storm conditions from now on and during the next 24 hours.

A coronal mass ejection (CME) from September 28. swept past Earth on morning on September 30. The Bz component of the IMF is now tilting south (17.4 nT ) and this could lead to disturbance at high latitudes.  A sudden impulse of 15 nT was measured by the Boulder magnetometer, as the CME reached Earth at 11:38. Solar wind increase (to 400+ km/s) was detected by ACE spacecraft  at 22:10 UTC. With the lower than expected solar wind speeds, very little geomagnetic effects have been observed. NOAA/SWPC warns about possible Geomagnetic Sudden Impulse after registering shock passage at 22:13 UTC.

Bright auroras are expected around polar circles. The full moon may make viewing the aurora more difficult, but high latitude aurora watchers should stay on the lookout.

Sunspot 1577 poses a slight threat for M-class solar flares. New Region 1584 was numbered early today.  The active region cluster, located in the northwest quadrant, should rotate around the western limb on October 3. For now, there are no large coronal holes on the Earth side of the sun.

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