Prepared jointly by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center and the U.S. Air Force. UPDATED 2013 Sept 12 1230 UTC .24 hr Summary... Solar activity was very low. A single low-level B-class flare occurred. There were four numbered regions on the disk, all of which were simply-structured and unremarkable. There were no Earth-directed coronal mass ejections during the period. .Forecast... Solar activity is expected to be very low through the period (Sep 12 - 14) with a slight chance for a C-class flare. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux at geosynchronous orbit was at normal to moderate levels. The greater than 10 MeV proton flux at geosynchronous orbit was at background levels. .Forecast... The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at normal to moderate levels during Sep 12 - 13, then increase to normal to high levels on Sep 14 due to coronal hole high-speed stream (CH HSS) effects. The greater than 10 MeV proton flux at geosynchronous orbit is expected to be at background levels during the period (Sep 12 - 14). Solar Wind .24 hr Summary... ACE data indicated the continued presence of a weak negative-polarity CH HSS. Wind speed ranged from 337 to 440 km/s. IMF Phi data indicated a Toward (negative-polarity) solar sector orientation during most of the period. IMF Bt hovered around 4 nT during most of the period. IMF Bz was variable in the +/- 5 nT range. .Forecast... Wind speed is expected to gradually increase during Sep 12 - 14 as the CH HSS persists. Geospace .24 hr Summary... The geomagnetic field was quiet. .Forecast... Geomagnetic field activity is expected to increase to quiet to active levels on Sep 12, with a chance for minor storm levels (G1 - Minor), due to CH HSS effects. Quiet to active levels, with a slight chance for minor storm levels, are expected on Sep 13 as CH HSS effects persist. Activity is expected to decrease to quiet to unsettled levels, with a slight chance for active levels, on Sep 14 as CH HSS effects subside.
Posted on: Thu, 12 Sep 2013 13:56:01 +0000