PJM issued a geomagnetic disturbance warning, then an action. No emergency actions, and it's already over.

    Msg ID:     104606
    Message Type:  Geomagnetic Disturbance Action 
    Priority:     Action
    Effective Start Time:  06.01.2025 09:31
    Effective End Time:  06.01.2025 12:25
    Regions  COMED

    A Geomagnetic Disturbance Action has been issued as of 09:31 on 06.01.2025 to protect
    the power system from damage or disruptions due to increased geomagnetic activity.

Background:

These messages are from the US east coast power grid control room in Valley Forge, PA sending to people at generating stations and other key control centers. This is a slow-moving event. If the grid was stressed, there would be "Pre-Emergency Load Reduction" and "Conservative Operation" actions ordered. If there was real trouble, there would be many more actions. But things never got beyond preparing for trouble.

A geomagnetic disturbance event in 1989 caused transformer damage leading to outages. The solar flux going between power lines and conductive ground induces DC currents into the ground and lines, so that ground potential is different at different points. This causes partial saturation of transformers, and heating. That wasn't noticed until it was too late. So now, DC current in some key AC lines is monitored continuously, so power levels can be reduced if necessary.

Training materials for understanding this:[1] Start at slide 21.

Background info on how a power grid works.[2] Start with "PJM 101"

[1] https://pjm.adobeconnect.com/p63ultsdb2v/

[2] https://www.pjm.com/training/training-resources

M8.2 is in the upper medium range (M = M1.0 to M9.9). Next comes X1 which is 10 times stronger than M10. M2 is 10 times stronger than M1.

We might see several of these per year during a solar maximum. So maybe we get some nice auroras.

Edit, TIL: Though the G4 is a different issue, which classifies the impact of a solar flare on our earth. These range from G1 (minor) to G5 (extreme). This means that it can disrupt radio communications and GPS, put stress on power grids and, interestingly, increase satellite drag. G4 storms are rare events and occur only a few times per 11-year solar cycle.

I know absolutely nothing about solar weather beyond aurora visuals being a possible outcome depending on where you live. I missed the last chance to see at my latitude (rare) and don't want to miss again.

What could I subscribe to so as to be notified when such events happen?

You can kinda follow news about it on

https://community.spaceweatherlive.com/topic/3947-ar14100-m8...

Although it often sounds like people throwing fancy words around just to sound smart. And their predictions mostly dont work out

NOAA Experimental Aurora Viewline prediction for tonight/tomorrow night -- https://www.swpc.noaa.gov/products/aurora-viewline-tonight-a...

On October 10th 2024 there was an x1.8 event and it was basically right at us. First time I’d seen the aurora - happened to be on cape cod at the time where the light pollution isn’t so bad. Was pretty amazing with the naked eye but absolutely incredible in long exposure photos.

> CME Passage Continues; G3-G4 Still Possible Tonight, June 1st

https://www.swpc.noaa.gov/news/cme-passage-continues-g3-g4-s...

if I read all the websites correctly... it has already ended??

---

NOAA map (https://www.swpc.noaa.gov/products/aurora-30-minute-forecast) shows huge auroras were at ~7-9 UTC and now are gone

https://solarham.com/ says "arrived faster than expected" and "threshold was reached at 08:00 UTC"

and the website linked, the https://www.spaceweatherlive.com/en/.html says "14:00 UTC - Geomagnetic activity Severe G4 geomagnetic storm (Kp8)" followed by "17:30 UTC - Geomagnetic activity Minor G1 geomagnetic storm"

My brain tried twice to turn this title into the name of a new nvram device.

Hams: How’s the RF propagation with this one?

Hey, m8, it’s a big solar flare!

Good luck to any directional drillers out there trying to drill your well blind.