NOAA SWPC is predicting a higher than anticipated G3-level geo-mag storm this evening due to the arrival of a coronal hole high speed stream (CH HSS).
This is unrelated to the recent X-class flares off the western edge of the Sun.
Coronal holes are cooler, less dense regions than the surrounding plasma. Their open, magnetic field line structure allows the solar wind to escape more readily into space, resulting in streams of relatively fast solar wind.
https://www.swpc.noaa.gov/
4/n
The Sun's region 4299 produced an M8.1 (R2/Moderate) at 2039 UTC today. An hour earlier, it produced an M1.1 (R1/Minor) flare at 1921 UTC.
This is the same region that rotated into view & produced an X1.9 flare on Dec 1 (an X1.9 flare is ~2.3x more energetic than an M8.1). It is now located just above the center of the Sun as seen from Earth. Any associated CME will be directed towards Earth. Geo-mag storms and auroras are likely on Dec 8-9.
https://www.star.nesdis.noaa.gov/goes/SUVI.php?sat=G19
https://www.swpc.noaa.gov/
5/n
The M8.1 solar flare that erupted from solar region 4299 at 2039 UTC on Saturday 06 December resulted in an earth-directed full-halo coronal mass ejection (CME).
The CME is expected to impact Earth early to midday UTC on Tuesday 09 December, potentially causing periods of G3 (Strong) geomagnetic storming. There is a good possibility of auroras before sunrise in N. America.
https://www.swpc.noaa.gov/
6/n
The Sun's surface has been quite active overnight.
Region 4298 emitted an X1.1 flare at 05:01 UTC, 1.3x stronger than the M8.1 flare from region 4299 on 06 Dec. Since region 4298 is towards the eastern edge of the Sun, any associated CME is unlikely to impact earth.
Region 4299 has stayed active and there were two medium-strength flares at 00:10 and 6:54 UTC resp., not reported by SWPC yet.
For GOES-19 SUVI time-lapse videos, see https://www.swpc.noaa.gov/products/goes-solar-ultraviolet-imager-suvi
7/n
Here is a link to a GOES-19 SUVI time-lapse video covering the past 11 hours. One can see eruptions of plasma that loop along the magnetic lines of force; some material falls back to the surface, other escapes into space.
https://helioviewer.org/?movieId=210Y5
8/n
Chances are excellent for some good aurora viewing tonight in the upper- and mid-latitudes, esp. in the latter half of the night in Canada and northern U.S. states, due to the anticipated passage of the CME from 06 December.
Keep those cameras ready!
https://www.swpc.noaa.gov/
9/n
AkaSci 🛰
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