Brief G1 geomagnetic storm over

Solar wind  reached near 700 km/s and this helped stir up a brief G1 Level Geomagnetic Storm (Kp=5) at high latitudes during the early hours of Wednesday morning. Migratory animals are affected at this and higher levels and aurora is commonly visible at high latitudes.

The high-speed stream was the result of a Solar Sector Boundary Crossing. A sector boundary crossing occurs when the polarity of the Interplanetary magnetic field (IMF) reverses. A well-defined sector boundary crossing has a uniform field direction for about 4 days before and after the crossing. As the solar wind flows away from the Sun, the IMF is carried with it and has a spiral shape. Along the ecliptic plane, the IMF generally has 2 or 4 sectors per solar rotation (27 days) where it is pointed toward or away from the Sun.

Solar activity is currently at very low levels. Regions 1482 and 1483 are now rotating towards the western limb and will soon be out of direct Earth view. All other regions, including new sunspot 1488, remain stable and quiet.

3-day Solar-Geophysical Forecast issued May 23 22:00 UTC

Solar Activity Forecast: Solar activity is expected to be very low to low with a slight chance for an M-class flare for the forecast period (24 – 26 May).

Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled with a chance for further active periods on day 1 (24 May). Mostly quiet conditions are expected on day 2 (25 May). On day 3 (26 May), quiet to unsettled conditions are expected with a chance for isolated active periods around mid-day as a glancing blow from the 22 May CME is possible.

Featured image: Aurora display seen from Big Bay, ON, Canada (Credit: Steve Irvine)