Coronal mass ejection arrival

Sunday, 16 July 2017 - 09:47 UTC

Coronal mass ejection arrival

The anticipated coronal mass ejection from the M2.4 solar flare has arrived at Earth. It arrived at DSCOVR at 05:15 UTC which is about 9 hours earlier than we expected, and more than 15 hours earlier than the NOAA SWPC expected.

The solar wind speed increased to about 450km/s which is fairly slow considering the relatively fast transit time of this CME. This is a bit puzzling as solar wind speeds of about 600km/s are to be expected with CMEs that have a transit time of 2 days but we have to assume this is the M2.4 CME as there were no other CMEs expected to arrive.

The strength of the IMF has now increased to well over 20nT and the north-south direction of the IMF (Bz) has now dipped strongly southwards peaking as low as -22nT. Excellent values for increased geomagnetic activity.

A moderate G2 geomagnetic storm watch remains in effect for the remainer of this day. With the current values, we shouldn't even exclude a strong G3 geomagentic storm.

Thank you for reading this article! Did you had trouble with some of the technical terms used in this article? Our help section is the place to be where you can find in-depth articles, a FAQ and a list with common abbreviations. Still puzzled? Just post on our forum where we will help you the best we can! Never want to miss out on a space weather event or one of our news articles again? Subscribe to our mailing list, follow us on Twitter and Facebook and download the SpaceWeatherLive app for Android and iOS!

Latest news

Support SpaceWeatherLive.com!

A lot of people come to SpaceWeatherLive to follow the Sun's activity or if there is aurora to be seen, but with more traffic comes higher server costs. Consider a donation if you enjoy SpaceWeatherLive so we can keep the website online!

91%

Latest alerts

Get instant alerts!

Space weather facts

Last X-flare:2017/09/10X8.2
Last M-flare:2017/10/20M1.0
Last geomagnetic storm:2019/05/14Kp7 (G3)
Number of spotless days in 2019:77
Current stretch spotless days:5

This day in history*

Solar flares
12000C9.5
22000C5.6
32000C5.4
42000C4.3
52013C3.9
ApG
1200278G4
2200734G1
3200029G3
4199520G2
5201417G1
*since 1994

Social networks