Northern Lights Now – The Space Weather Prediction Center in Boulder Colorado has issued a G1 storm watch for October 11-12 indicating the potential for KP values at or above 5 and active aurora. This is due to the expected high speed solar wind coming from a large northern hemisphere coronal hole.
Models, such as the WSA-Enlil below, are predicting that the first phase of the storm should start midday on Tuesday as plasma densities rise to around 15 p/cm3. 6-12 hours later, solar wind should pick up and may reach 550 km/s. The coronal hole covers a large area longitudinally, so once the wind speed readings increase, they may remain elevated for over three days. It would not be surprising to see the G1 watch extended into a third day.
As of this writing, the periods of KP=5 and above are predicted to start midday on Oct 11 and continue on and off throughout Oct 12.
Northern Lights Now – The fall aurora season kicks off around the end of August when the nights in the Nordic countries (Sweden, Finland, Norway, Iceland and Denmark) start to get long enough and dark enough to see the northern lights. This year, the season should start off with a bang as a G1 storm is predicted that should bring a nice show.
Northern Lights Now Twitter follower Mia Stålnacke captured these pictures in Sweden earlier this week as aurora season gets under way.
Earth will come under the influence of a coronal hole, a corotating interaction region (CIR) and a solar storm over the next several days. There is a chance conditions may reach G2 on September 1st as the edge of a solar storm delivers a glancing blow.
On August 31st the high speed winds generated by the coronal hole shown below will start to push on Earth’s magnetosphere. The CH, which is the dark area on the image below, covers much of the northern hemisphere and crosses into the southern hemisphere. That means it is highly likely the winds will pick up at Earth about 3 days after the region was pointed towards Earth on the center of the disk. At about the same time, the CIR will also arrive. Current models indicate the solar wind speeds could reach between 550 and 600 km/s.
Later, on Sept 1 a small solar storm that was released during an eruption near active region 2672. Watch that eruption in this video. The eruption happened on the very western edge of the Earth stike zone and is not large. Most of the plasma emitted will miss earth to the west, but in the WSA-Enlil model below, see that the flank of the cloud may brush by Earth. Earth’s magnetosphere is likely to be activated as a result of 36 hours of high speed wind. That activation should accentuate any impact from the solar storm.
With this space weather setup, there is a good chance that at least one of the features will produce G1 storming (KP=5 or higher) in the next three days. If the solar storm is oriented just right, and is moving slightly faster than modeled and arrives in closer proximity to the high speed solar wind, KP values may reach G2 storm levels. Below is the official forecast from SWPC as displayed by the NLN auroraCast clock. Orange shows periods when G1 storming is expected:
Aurora hunters should be watching the data over the next three days and have their cameras ready.
Northern Lights Now – SWPC has issued two geomagnetic storm watches for G2 storming (KP=6+) on August 2nd and G1 storming (KP=5+) on August 3rd. These watches are the result of a pair of solar features that will impact Earth starting midday UTC on August 2nd. The NLN AuroraCast shows the current predicted timing for the timing. As always, these can be within +/- 6 hours:
Please visit NLN’s live blog of this storm and follow out Twitter feed for the most up-to-date information.
The first solar event that will impact Earth is the arrival of a very slow moving CME (Coronal Mass Ejection) that was launched during the July 28th filament eruption. The eruption happened almost dead center (near N01E06) on the solar disk. The associated CME was estimated to be travelling at 125-150 km/s. At that speed, it could take as many as 7 days for the CME to arrive at Earth, but it should be pushed by the ambient solar wind to 350 km/s or so. Then, an even higher wind from a coronal hole high speed wind stream should push it even faster to 600-650 km/s. There are several factors making the timing on this forecast complex – current models show the CME arriving midday to late August 2nd, 5 days after it’s launch.
In the animated GIF below watch the filament eruption in a composite of AIA 211, 193 and 171 wavelengths. These frames are about 14 hours of images taken by the Solar Dynamic Observatory (SDO) cameras. Note that just to the east (left) of the eruption, the coronal hole rotating into center disk is visible as a darker area:
The second feature is a large coronal hole that rotated into geoeffective position on July 31. The high speed stream from this CH measured at STEREO Ahead indicated that winds could reach 650-750 km/s at L1. This very strong wind will likely start impacting Earth either with or just after the CME arrives. If it “pushes” the particles in the CME, they will arrive at the leading edge of the shock. Due to the elongated shape of the CH, the period of elevated winds could be extended in duration. Here is an image of the coronal hole from SDO in AIA 211 from July 31 as it rotated toward Earth:
Together these storms have the potential to arrive with a strong shock and an extended period of high solar wind and active geomagnetic conditions. If they do, it should be a very good couple of nights for aurora hunters worldwide. As an added bonus, the Moon will be waxing just past new, so skies should be dark.