Solar Cycle 25 Update for the End of '23

It's just over six months since the last time Dr. Scott McIntosh of the National Center for Atmospheric Research, NCAR, gave a solar cycle 25 update on a radio group that I follow, so this week he joined the group again for another update which was posted to YouTube on Friday.   

Since I've posted NOAA's smoothed sunspot number  (SSN) regularly when I do these updates, here's the latest.

The 10.7 cm solar flux (2800 MHz) plot, also at the link just above the previous plot, is on a different scale so it's not an exact duplicate of this, but it "rhymes" in the sense of having the same general shape.  I'm going to zoom in on the latest data to point out something that's visible in both plots.  After this data is smoothed we see what appears to be an 8 month subcycle.  "Cycles within cycles."  We appear to be on the rising edge of another cycle with its coming peak.

Scott points out that X-flares are only observed on the rising edge of those subcycles.  Depending on where you get your news, you might have heard that last Thursday, Dec. 14, we had an X2.8 flare at 17 hours UTC (1PM EST).  Further evidence we're on the rising edge of another one of those 8 month subcycles. The accompanying CME played out over the weekend with apparently just a G1 class (Minor) geomagnetic storm.  That's the highest I saw. 

I saw references to "one of the largest solar flares ever recorded" which is sensationalism at its worst.  It's the strongest one of this cycle, which means probably the strongest since the declining part of the previous cycles, maybe 2014 to 2015, and conceivably back to the end days of cycle 23, around 2003.  That just doesn't mean much. As I've pointed out before, cycle 24 was the weakest cycle in a hundred years; being stronger than that just doesn't mean much.   

The big questions are always, "when will this cycle peak?" and "how big will the peak be?"  Scott McIntosh is sticking by an earlier prediction that this will peak toward the end of 2024, or early '25.  He says he'd like to see it peak with the SSN at 200, as he predicted before, but isn't sure it will get there.  The sun regularly shows asymmetric behavior between its northern and southern hemispheres and that's a major factor in solar cycles that have double versus single hump.   That's something that he doesn't seem willing to predict, possibly from never having seen a cycle with a single peak.  

Let me update another plot I've presented regularly: an overlay I like to call my ham radio biography (from here - bottom plot on the page).  Every plot since I was first licensed in 1976 is on this, and each cycle has been progressively lower than the one before it until now.  While cycle 25 doesn't appear to be challenging even cycle 23, it has made cycle 24 look as bad as it was.  The plot for cycle 25 is in the lower left quadrant, just above the pink curve of cycle 24 over most of its life.

Every life on this planet depends on the sun.  The amount of study that goes into predicting what it will do is far from trivial and Dr. McIntosh is the director of the NCAR.  There are still vast areas of study that humanity doesn't understand. 

EDIT at 0820 EST Dec. 19 to Add:  Added link to a bogus story about the X2.8 flare being "one of the largest flares ever recorded."