Solar Cycle 25/26 Update at the End of '24

I notice that I haven't done one of these in over six months - although I have done updates for solar storms and other headline news.  So let's get on with it.  

First, I want to reference the videos I have used regularly for these posts, a talk to a ham radio group by Scott McIntosh that Scott gave about a month ago, and this is going to be based on what he talked about. I’m going to lead with NOAA Solar Cycle Progression chart from their web site as I often do.  

As always, the red curve is the predicted number, the gray area is the bounds of numerical uncertainty of the prediction and the erratic looking bunch of dots almost entirely above the uncertainty region is the measured monthly value.  The last dot on the right of the series is this month's, at 115.3 as of today. The top of the uncertainty range is 125.2. 

In case it's not immediately obvious we're around the peak of red prediction curve and it's possible that the peak of the cycle has already happened within the last few months but possibly back in the late summer.  Perhaps the biggest improvement to forecasting Dr. McIntosh has introduced is a way of identifying the exact time when the new sunspot cycle starts.  That's noted when new sunspots happen at very far northern or southern latitudes and have a magnetic polarity opposite the current cycle.  In the big picture sense, there are practically always spots of both polarities, which means two different sunspot cycles, measurable on the sun.   These are depicted as red and blue areas on this graphic.

The colors represent opposite polarities.  It doesn't matter which color you call magnetic north or south - as long as the people you're talking with understand it.  The center square is from a bigger plot, and was a bit too dark when I was working on the draft of this post, so I contrast enhanced it in my main photo editor, to better show the colors in the big element in the middle.  The two important parts of this plot are (1) the two red areas at the top and (2) red and blue always alternate - from left to right (W to E) and top to bottom (N to S). The topmost portion extends to the lower left (earlier in time, lower in latitude) in the uppermost marked off area. The red diagonal band at the top is first appearing around the vertical line marked 2024 on the bottom. It is clearly red as you look at 2025.  

The red and the blue areas at 2025 are indicating that cycle 26 has begun. So what does that mean?

The big thing is we probably have at least another year of better propagation, but solar flares and other sources are likely to be more common, especially from the solar latitudes closer to the poles.  In the last couple of months, we had some very high 10.7cm solar flux numbers (2803.738 MHz solar emissions - which you'd call noise if you heard it on a radio).  For the first time in my ham radio years on the 6 meter band (50-54 MHz) I could hear people within a couple of hundred miles having contacts with Alaska.  Solar flux (SFI) was over 300.  I never heard any of the half dozen Alaskan stations I saw reports of being heard near Florida.  Of the hams on that band, the most common situation I hear is folks saying they have every state worked and confirmed except Hawaii and/or Alaska.  At least I have Hawaii.

Finally, a plot I’ve shown regularly which shows the Smoothed Sunspot Number (SSN) for the last five cycles back to 1976. I like this plot because it’s my ham radio biography in one plot. I was first licensed in February 1976 (the blue curve), so every cycle I’ve been through is on this plot (and I was a shortwave listener for the cycle before that). The plot is posted to Space Weather News (bottom of the page) but is created by a separate site, Solen.info.

The sunspot number for Cycle 25 is approaching the dip between the dual peaks of cycle 23 at the latest measurement, month 52 after the cycle start.  It's the closest that the monthly SSN has come to exceeding a cycle 23 value, although a daily measurement has done that a few times. The last couple of weeks have had lower SSNs than the period that brought the dream of working Alaska hundreds of miles closer to me.  As I've said practically every time I've done an update on cycle 25, it's clearly a stronger cycle than 24 in the light pink, which ran from November of 2008 until December of 2019.  The negative, though, is Cycle 24 was the weakest cycle in a hundred years so being better than that isn't saying much.