AFFECTS Space Weather Reports

July 17, 2012 - Comparison of Forecast and Observations

The real arrival time of the CME at L1 as measured by ACE was 17:30 UT on July 14. So it was 9 hours (4 taking the estimated error of 5 hours into account) late compared to the arrival time forecasted by the AFFECTS CME propagation model. The reason for the delay is presumably the very slow wind ahead of the CME en route to Earth. The magnetic polarity of the CME agrees according to our interpretation with the predicted one generally, though it is likely that the CME center which had propagated south of the ecliptic has not been encountered. The N to S variation following the CME's shock sheath region turned into a long lasting radial -Bz component, being likely the CME's stretched magnetotail. The overall Kp-amplitude of the disturbance is under analysis, but it is likely a Kp 8 event.

July 13, 2012 - Solar storm is heading towards Earth

A CME associated with a X1.4 Flare occurred around 4.30 pm on July 12 near S15W01. The disk centered CME had a speed of 1200-1500 km/s and is expected to arrive at Earth on Saturday July 14 around 10:30 LT (08:30 UT). The magnetic configuration is inferred to be of right-handed NES type according to the Bothmer & Schwenn magnetic flux rope model. Peak phase of the storm is expected to occur during passage of the center to rear part of the CME, after about 6 pm on Saturday July 14. Polar lights are likely to be visible in Northern Europe near midnight. The geomagnetic storm strength is estimated to reach Kp 8-9 values. The full analysis of the event (in German language) can be found at http://www.astro.physik.uni-goettingen.de/~bothmer/SpaceWeatherReports. ENLIL simulations are available at NOAA-SWPC (http://www.swpc.noaa.gov/wsa-enlil/). The arrival time calculated from ENVI simulations is 2 hours later.

June 17, 2012 - Perfect match: CME has arrived as predicted

The June 14 frontside halo CME has reached Earth on June 16 at 9 pm CEST (7 pm UT) and has caused a medium geomagnetic storm. The flux rope structure of the CME was NES in agreement with the modeling results. The main storm started when the magnetic fields turned south at the center of the CME and was strongest in its trailing edge. What a perfect forecast - congratulations to the team for this success!

June 15, 2012 - CME en route to Earth

Disk centered active region 1504, located south of the solar equator, has emitted several CMEs into space. A frontside halo CME occurred around 2 p.m. on June 14. Analysis of its near Sun evolution, 3D structure, source region location and magnetic polarity yields the following results: - The northern edge of the CME is estimated to strike Earth on June 16 around 9 pm CEST, i.e. at times of the last European championship matches of group A. The CME arrival time has been deduced from its propagation speed of about 1.000 km/s in the field of view of the STEREO and SOHO coronagraphs and analysis of CME travel times to Earth orbit. Such CMEs are expected to decelerate en route to Earth to about 700 km/s. Arrival time of the associated shock wave will be several hours earlier. - Peak time of the geomagnetic storm and auroral activity is estimated to occur after midnight on June 17 based on the CME's magnetic flux rope structure (type NES according to the Bothmer & Schwenn flux rope scheme) when the center of the CME and trailing edge pass Earth. Inclination of the flux rope will be about 45 degrees with respect to the ecliptic plane. Forecast provided by the University of Göttingen AFFECTS team (Volker Bothmer (VB), Jonas Hesemann (JH), Malte Venzmer (MV), Eckhard Bosman (EB)).

June 01, 2012 - Active region and coronal hole

A complex active region has emerged at the Sun's North-East limb. This region is a potential candidate of solar storms, i.e. of faster CMEs and flares, during the next week. The situation appears particularly threatening because of the presence of a coronal hole ahead of the active region, which will give rise to increased solar wind speeds and enhanced geomagnetic activity starting 4-5 June. During the time of Venus transit across the solar disk on June 5-6, both planets will be engulfed in the solar wind high speed stream.

May 23, 2012 - Decaying active regions

Most active regions seen on the solar disk reveal decaying magnetic flux. No major solar storms are currently expected to happen but the Earth is engulfed in a high speed solar wind stream originating from a coronal hole near disc center. Intensified aurora is expected to occur at northern latitudes.

May 09, 2012 - Large sunspot region not likely to cause major storms at Earth

The large sunspot region North-East of the solar equator currently shows no magnetic signatures indicative of triggering strong geomagnetic storms. Coronal mass ejections magnetic fields are estimated to be directed antiparallel to the Earth magnetic field. No major CMEs have occurred so far. The ones observed en route to Earth are of low propagation speed (ca. 500 km/s) as derived from analysis of STEREO/SECCHI/COR2 beacon images. However, the situation might be subject to change depending on the evolution of the magnetic field in the active region and in its neighborhood.

May 07, 2012 - Coronal hole on visible solar disk and new active region

Fast solar wind originating from a coronal hole near the Sun's visible disk is expected to reach Earth on May 08 to 10, causing increased geomagnetic activity and small ionospheric perturbations. New emerging magnetic flux is associated with appearance of a new sunspot area North-East of the solar equator. It will appear disk centered around May 11 and may give rise to geo-effective coronal mass ejections.

May 03, 2012 - No major solar storms are expected the next days

Most active regions on the visible disk are currently showing decaying magnetic flux.

April 21, 2012 - Several Active Regions North and South of the Equator

Several active regions can be seen North and the South of the solar equator. The magnetic flux in these regions indicates the potential of the onset of only medium fast (up to 1000 km/s) CMEs. No solar superstorms and major flares are expected to occur the next days. For SDO images see the "The Sun Today" link.

April 10, 2012 - Equatorial Coronal Holes

The Sun's disk facing Earth shows no major active regions and associated signatures of strong magnetic flux increases. An equatorial coronal hole is currently passing central meridian. Solar wind speed will be increased the next two days. Upcoming conditions: Active regions seen by STEREO-B near the East-limb south of the solar equator are likely candidates for solar storms during the next ten days.