Monday, August 20, 2012

Rapid-Fire M-Class Flares from AR 1548!

The above X-ray image of the sun was taken August 20th at 03:24 UTC by the Solar X-ray Imager (SXI) aboard the GOES-15 satellite. Image Credit: NOAA

On August 18th, Active Region 1548 (AR 1548) produced two M1 solar flares in rapid succession. The first was at 22:54 UTC and at 23:22 UTC. But AR 1548 has grown quiet since then. In addition, a new region was designated on the 19th, AR 1549. Forecast: The solar activity low through the 22nd, with a  20-percent chance of M-class flares.

Here at home, the geomagnetic field's activity ranged from quiet to unsettled over the 19th. A high-speed stream, caused by that coronal hole now turned toward Earth, began having an affect in the last 24 hours or so. You'll remember that on the 18th, around 08:00 UTC, the Advanced Composition Explorer (ACE) satellite recorded the solar wind speed increase from 400 km/s to 580 km/s. And soon thereafter, the Bz component of the interplanetary magnetic field (IMF) became negative, eventually reaching -12nT.  Bz returned to positive values around 14:00 UTC.  Earth currently remains in the positive region of the IMF. Forecast: The geomagnetic field is expected to be mostly unsettled with a chance for active conditions on the 20th (because of that high-speed stream) decreasing to a slight chance on the 21st and 22nd. Stay tuned...

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center (

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO) (, the Solar and Heliospheric Observatory (SOHO) ( and the Advanced Composition Explorer (ACE) (


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