Geomagnetic storm in progress (April 30, 2012)

A solar wind stream hit Earth’s magnetic field during the early hours of April 30th, sparking a high-latitude geomagnetic storm (slowly subsiding). In the United States, auroras descended as far south as Marquette, Michigan, where Shawn Malone took this picture before sunrise:

High-latitude sky watchers should remain alert for auroras. The solar wind speed is high and gusty, and NOAA forecasters estimate a 40% chance of more geomagnetic activity during the next 24 hours. (SpaceWeather)

Planetary K-index
Now: Kp= 4 unsettled
24-hr max: Kp= 5 storm

Interplanetary Mag. Field
B_total: 5.2 nT
B_z: 0.3 nT north

Solar wind
speed: 643.8 km/sec
density: 0.1 protons/cm³

Multiple C-Class flares have taken place on Saturday morning around Sunspot 1195 and 1199. There will continue to be a chance for C-Class activity around both regions which are currently rotating towards the western limb. An M-Class event is not out of the question.

The geomagnetic field ranged from unsettled to minor storm conditions as the result of coronal hole (CH) high-speed stream (HSS) effects. The solar wind speeds at the ACE spacecraft ranged between 640 km/s and 700 km/s during the period. The geomagnetic field is expected to range from unsettled to active conditions with isolated minor storms possible for days 1 and 2 (1-2 May). Mostly quiet to unsettled conditions are expected on day 3 (3 May), when CH HSS effects begin to subside. (SolarHam/NOAA/SWPC)

Eye

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