Marcel de Bont Posted April 11, 2013 Share Posted April 11, 2013 SpaceWeatherLive Report Middle Latitude Auroral Activity Watch - 13th April 2013 Solar Activity and Geophysical Activity Summary On April 11th 2013, Active Region 1719 errupted with a M6,51 class flare. This Active Region was located almost central on the visible solar disk during the flare. The flare launched an asymmetric full halo Coronal Mass Ejection (CME). The blast left the sun with a speed of about 1100km/sec and slowed down shortly after to about 800km/sec.Synopsis Auroral Activity chances A severe geomagnetic storm could develop on the 13th of April when the CME arrives. The time window for the impact is from Saturday morning 6:00 until Saturday afternoon 14:00. It is very difficult to decide a preciser time because the CME already slowed down a bit according to the images. An early impact would be most favorable to create a heavy geomagnetic storm. A later impact means a slower impact and that would not be favorable for heavy geomagnetic storming. Nonetheless, we expect a relatively strong impact with an initial north-turning IMF according to the Wang-Sheerley-Arge model. According to SIDC, the IMF could turn south later with the possibility of developing a G3 geomagnetic storm with a KP of 7. The SWPC issued a G2 level geomagnetic watch for April 13th what means a KP of 6. Attention: only after the impact it will be really possible to decide what the chances will be! All times in this article are in UTC. Low Latitudes: 5% chanceMiddle Latitudes: 50% chanceHigh Latitudes: 90% chance PS.: Because of the expected amount of visitors it could be that the site is going to be difficult to reach at times, we hope that this won't happen.Donate and support this project so we can invest in heavier servers to give you a better experience on our site and can stay online during major events. Link to comment Share on other sites More sharing options...
Marcel de Bont Posted April 12, 2013 Author Share Posted April 12, 2013 SpaceWeatherLive ReportMiddle Latitude Auroral Activity Watch update for April 13th 2013When do we expect the impact?Now we have and analysed all available footage and know the exact path of the CME we can better estimate when the CME will arrive. As always, there is an uncertainty of about 12 hours around the provided time. As we mentioned yesterday, the CME showed signs that it was slowing down directly after it left the sun. This makes it likely that the impact will be a bit later then originally expected. We now expect an impact during the evening of April 13th around Saturday evening 20h UTC with a plus/minus of 6 hours.The EPAM monitor wil tell us when the CME is about to arrive. At the moment the values are still below the so-called event-level. More information about how to use the EPAM monitor can be found here.Synopsis Auroral Activity chancesBecause the CME is slower then expected and thus arrives later, it means that the impact will be weaker. The IMF will still turn north on impact and it is expected to stay so the first few hours after the impact. In the first hours after the impact we predict that because of the northward IMF only a G1 geomagnetic storm will develop. This means a KP of 5. Only a few hours after the impact when the IMF might turn south we could expect to see a G2 geomagnetic storm with a KP of 6. We like to make a note that only AFTER the impact we can really estimate what the chances will be. If the IMF turns south right after the impact we might see a complete different situation with a heavier storm then expected.Low Latitudes: 5% chanceMiddle Latitudes: 50% chanceHigh Latitudes: 90% chance We will continue to monitor the activity and post updates on the forum, Facebook, Twitter and Google+. Keep following us for the latest information. Got questions or comments? Feel free to post in this topic and we will do our best to help you out! We also have an email alert system which informs you of solar flares, CME impacts and much more. Link to comment Share on other sites More sharing options...
Marcel de Bont Posted April 13, 2013 Author Share Posted April 13, 2013 SpaceWeatherLive Report Middle Latitude Auroral Activity Watch update We are now one hour after the predicted impact time and have yet to see the arrival of the CME. The EPAM monitor however shows that the CME is not far away and we will see an impact in the coming hours. Values are now above the so called ''event-level'' and will make one more steep climb, then we know that an impact is not far away. There is a small chance that a S1 proton storm will develop because of the approaching CME. Got questions or comments? Feel free to post in this topic and we will do our best to help you out! Also keep following us on Facebook and Twitter for the latest information. We also have an email alert system which informs you of solar flares, CME impacts and much more. Click here to sign up. Update: EPAM is rising faster now and we could see an impact very soon. Link to comment Share on other sites More sharing options...
Marcel de Bont Posted April 13, 2013 Author Share Posted April 13, 2013 SpaceWeatherLive Report Middle Latitude Auroral Activity Watch update Weak CME impact Currently we see the effects of the arrival of a Coronal Mass Ejection (CME) at the ACE satellite. The solar wind speed rose with 112.1 km/sec to 484.5 km/sec. Solar wind speed: 484.5 km/sec and density 0.5 p/cm3 IMF Bt (strength): 10.5 nT - Bz 3.8 nT The impact is very weak and not what was expected. The density did not even increase and the strength of the IMF and the speed of the solar wind are not impressive. It can be compared to a weak coronal hole. It seems that the CME on the way to earth slowed down significantly. A weak impact like this means that the chances for aurora on middle latitudes are very low. http://www.spaceweatherlive.com/community/uploads/monthly_04_2013/post-94-0-02967700-1365893990.pnghttp://www.spaceweatherlive.com/community/uploads/monthly_04_2013/post-94-0-67584400-1365893993.pnghttp://www.spaceweatherlive.com/community/uploads/monthly_04_2013/post-94-0-11256200-1365893998.pnghttp://www.spaceweatherlive.com/community/uploads/monthly_04_2013/post-94-0-53062800-1365894004.pngUpdate 23:30 UTC: Judging by data from SOHO the density of the CME cloud was about 12 protons/cm3. The ACE satellite proton detection is not working correctly. Link to comment Share on other sites More sharing options...
Marcel de Bont Posted April 13, 2013 Author Share Posted April 13, 2013 SpaceWeatherLive Report Middle Latitude Auroral Activity Watch update A new thought on the weak impact from the SpaceWeatherLive team: is this the real impact of the M6 flare? Time to take another look at the LASCO images from the M6 CME. We see a clear halo CME with most of the material going west. If we look a bit closer we see a second halo which is brighter and also earth directed. The first halo is not bright and will arrive first. We just seen the arrival of this first halo. The second bright halo could still be on way to earth and the IMF could react more strongly on the second impact. We made an image to clarify the situation. The ENLIL model also supports this theory. A second jump in the solar wind speed can be seen there. There was also no significant drop showing on the EPAM monitor to really say that the full shock wave arrived. UPDATE 00h08: A secondary impact alert was triggered moments ago. The solar wind speed rose with 62.1km/sec to 534.8km/sec. The plasma cloud will reach the Earth in 47 minutes. Solar wind speed 534.8km/sec & density 1.0p/cm3 IMF Bt (strength): 11.9nT - Bz: 3.0nT The sharp rise went together with a rise in temperature. This secondary shock did not have much effect. Our alert system will keep you all updated if conditions get better. Link to comment Share on other sites More sharing options...
Vancanneyt Sander Posted April 14, 2013 Share Posted April 14, 2013 We are now 12 hours after the impact so it's time for a final recap... This storm was very disappointing, with a very weak impact and a very weak strength of the interplanetary magnetic field this storm failed to give even high latitudes a strong auroral display. The direction of the IMF stayed north al along so this couldn't trigger any nice aurorae above high latitude regions, a K-indice of 3 was the maximum. It's likely that the CME slowed further down on route and the density of the plasma cloud was way to low to cause a better impact. We will have to wait until a new active region appears on the visible solar disk and wait for a new Earth directed flare. We would like to thank all of the visitors here on the website, Facebook and Twitter for following our alerts and updates. Keep following us if you don't want to miss further chances. Link to comment Share on other sites More sharing options...
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