Look to the skies this weekend for a chance to see the bright northern lights.
In the early hours of July 21, a solar flare erupted from an active sunspot on the Sun’s surface. The eruption was relatively weak, it caused a “solar tsunami” that spread far away from the sunspot.
The Sun ejected a fast but diffuse CME from the central disk ~0100Z on the 21st, producing a faint halo in the COR images. This means there is a transiting solar storm headed straight for Earth and it should arrive on the 23rd. What do the data and forecast show? Let’s talk about it!
The Sun ejected a fast but diffuse CME from the central disk ~0100Z on the 21st, producing a faint halo in the COR images. This means there is a transiting solar storm headed straight for Earth and it should arrive on the 23rd. What do the data and forecast show?
Let’s talk about it! ⤵️ 🧵 💫 Sara Housseal 💫 on Twitter: “The Sun produced a fast but diffuse CME from the central disk ~0100Z on the 21st, creating a faint halo in COR images. This means there is a solar storm in transit headed straight for Earth & due to arrive on the 23rd. What do the data and forecast show? Let’s talk about it! ⤵️ 🧵 pic.twitter.com/sP6zNRUNT2 / Twitter”
— 💫 Sara Housseal 💫 (@SNHWx) 💫 Sara Housseal 💫 on Twitter: “The Sun produced a fast but diffuse CME from the central disc ~0100Z on the 21st, producing a faint halo in COR images. That means there’s a solar storm in transit headed straight for Earth and due to arrive on the 23rd. What do the data and forecast show? Let’s talk about it! ⤵️ 🧵 pic.twitter.com/sP6zNRUNT2 / Twitter”
At the same time, it also caused a “coronal mass ejection” to erupt into space. This cloud of charged solar particles, sometimes called a “solar storm,” was more or less aimed directly at Earth.
A large coronal mass ejection (CME) as recorded by SOHO/LASCO. Expected speed: 1355 km/s. Simulations suggest it will impact Earth on 2022-07-22T16:38Z (plus or minus 7 hours). The maximum Kp index can reach 8-9 (severe to extreme). pic.twitter.com/XrL7pOEl9B
A large coronal mass ejection (CME) as recorded by SOHO/LASCO. Expected speed: 1355 km/s. Simulations suggest it will impact Earth on 2022-07-22T16:38Z (plus or minus 7 hours). The maximum Kp index can reach 8-9 (severe to extreme). SOHO_Mission on Twitter: “Large Coronal Mass Ejection (CME) as recorded by SOHO/LASCO. Expected speed: 1355 km/s. Simulations suggest it will hit Earth on 2022-07-22T16:38Z (plus or minus 7 hours). Maximum Kp index can reach 8-9 (severe to extreme). pic.twitter.com/XrL7pOEl9B / Twitter”
— SOHO_Mission (@MissionSoho) SOHO_Mission on Twitter: “Large Coronal Mass Ejection (CME) as recorded by SOHO/LASCO. Expected speed: 1355 km/s. Simulations suggest it will hit Earth on 2022-07-22T16:38Z (plus or minus 7 hours). The maximum Kp index can reach 8-9 (severe to extreme). pic.twitter.com/XrL7pOEl9B / Twitter”
The CME is expected to sweep over us late Friday night. When it does, it can cause a geomagnetic storm around the planet. This means we can see auroras.
How bright the auroras are and how far south they are visible will depend on how strong the geomagnetic storm is.
Although the solar flare was weak and the coronal mass ejection quite diffuse, according to NOAA’s Space Weather Prediction Center, when the effects of the CME are combined with the effects of the solar wind, it could produce a G1 (minor) or possibly even a G2 (moderate ) , stormy conditions Friday night into Saturday.
The Geomagnetic Storm Watch combines the effects of two coronal holes with the coming CME to warn of potential space weather impacts Friday night. Credit: NOAA SWPC
The NOAA SWPC classifies geomagnetic storms as one of five classes: G1 (minor), G2 (moderate), G3 (strong), G4 (severe), and G5 (extreme). The severity is based on the predicted density, energy and speed of the CME. The potential impacts, for the aurora borealis and for effects on our technology and power grids, increase with each successive rank.
If a small geomagnetic storm results from this encounter, the auroras are likely to be visible for the northern regions of eastern Canada and the prairie provinces.
In the map below, a G1 (minor) storm typically has auroras extending south to the green line.
On this map, the colored arcs show how far south the Northern Lights can usually be seen based on the geomagnetic conditions around Earth.
During a G2 (moderate) geomagnetic storm, the auroras can be seen as far south as between the yellow and green lines. Thus, it may be possible for sky watchers in southern Ontario to spot them, although they are usually not bright enough to see through urban light pollution.
Depending on what happens, there could even be some residual effects on Saturday night, which could lead to a second night of auroras.
Thumbnail image courtesy of glow chasers Alberta Tree and Dar Tanner.
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