Solar Cycle 25. I Was Wrong!!

Happy Meteorological Fall,

I hope everyone had a great Summer. It wasn't as hot this year here in North Central Texas. We had to endure about 20 days between 100 and 105.  Last year we had about 30 days from 105 to 110.  I don't handle heat in my older age, so I looked for opportunities to stay cool in the A/C by having fun on the radios.

This Summer we were blessed (or cursed depending on how you see it) with the most Solar Activity in 20-22 years. By August, we saw the highest Solar Activity in 33 years. We saw an almost daily M-Class Solar Flare, some days multiple ones. X-Class flares did occur, but were never overly powerful as had occurred 22-24 years prior. Rather than some VHF Aurora, there were way too many radio blackouts and a healthy decline in Sporadic Es. There was still Es, just not consistent. On the other hand, there were many times that 20 Meters was open all night and 15 Meters was open as late as Midnight.

During the Summer, F2 MUF declines. When there is high solar activity, 20 Meters is the highest frequency in which can be open all night. Long distant propagation on 15, 10 and even 6 Meters will only be dependent on solar events like flares and Coronal Mass Ejections (CME).  Sporadic Es still occur, but are highly erratic in their appearance. On VHF there is a phenomena that appears called FAI (Field Aligned Irregularities), but had been non-existent for over 20 years. Solar Cycle 24 was lousy.

What Has Happened

The last time I posted, it appeared that the Solar Cycle had peaked. Despite the trends indicating it had, in addition to the actions of past Solar Cycles (4 years incline, 7 years decline) there was a good possibility the Cycle was done. So I thought ......

I am an optimus. The past three Solar Cycles had dual peaks. I was hopeful that the same would occur for this one. What it appears is that the second peak is MUCH better.

Almost as soon as I posted last January, the Solar activity began to increase again. Once we got into the Summer, it has really taken off.

Solar Cycle Trends

The graph displays the monthly observed 10.7 cm Solar Flux since the accepted month that the Solar Cycle began.
Blue line is the current Cycle (25).
Red line is the past Cycle (24).
Green line is Cycle 23.
A polynomial trendline (line of best fit) to an odd power (3) is used to show an increase correlation for those events. The graphs shows 57 months in the Cycles.

The trendlines of both Solar Cycles 23 and 24 have shown that their decline had begun on or about 48  months. For the current Cycle although monthly values had begun a decline at 45 months, by the 53rd month it rapidly increased.  It has not slowed down since.

The August 2024 monthly value was the highest since February 1991 (Solar Cycle 22). It has exceeded all monthly values experienced in Cycles 23 and 24.

6-Month Moving Average

A six-month moving average also shows what is happening in the immediate versus what has happened overall.

The moving average for this Cycle shows that it has approached a level close to what was experienced during the Cycle 23 peak. Obviously, this Cycle has far exceeded the past Solar Cycle (24) and what was predicted for this one.

What to Expect

Summer has ended. Fall begins. The F2 MUF will gradually rise each week and peak around the Winter Solstice. If Solar activity remains close to current values we should see exciting conditions from 15 Meters all the way up to 6 Meters.

The graph displays the potential F2 MUF for an optimum single hop reflection for a Solar Flux level of 190. The Earth has experienced levels far in excess for many weeks this Summer.

It's time to take advantage. This Solar Cycle has been unpredictable and for us in the Northern Hemisphere not very timely.  Don't waste it this Winter.

73 Art K7DWI/5 

Solar Cycle 25 Was Off to a Great Start - It May Have Peaked

Happy Holidays

My journey back to my home state of Texas has been a challenge, but on the Hamming side it has been much better than expected. 

When I retired in 2014 and moved to Arizona, by the time I put up the tower the peak of Solar Cycle 24 had occurred. My entire tenure in Arizona was productive. I managed to work a lot of DX, was 3 entities short of a Worked-All-States Triple Play, over 40 States on the standard HF Bands plus 6-Meters. As my time in Arizona passed, the Solar Cycle quickly ended. 

Solar Cycle 24 was a large disappointment, but was predicted and warned early by Astrophysicist Jim Kennedy, K6MIO. The magnetic poles of the Sun were out of sync and would lead to much lower Solar activity. Sadly, he was very correct. For my sake, I am glad I was inactive for most of the peak and did get to work some DX on the higher HF bands. I did not hear or decode any F2 on 6-Meters, nor experienced any Auroral activity in Arizona as well.

In 2019, the XYL and I decided we would have another change of scenery and moved to the Rouge Valley of Southern Oregon. The timing was good. By then Cycle 24 was ending and Cycle 25 was beginning.  Predictions seemed to be dire that Cycle 25 would be like Cycle 24. I thought I would compare the data between the last 3 Solar Cycles to see if a pattern would draw a different conclusion.

I charted the decline of the past 3 Solar Cycles to determine any identifying factors.

The purpose of the Exponential Trend-Line was to determine when Solar Flux data showed that a 65 level was achieved. Exponential is used for single directional measurements (Up or Down). The rate of decline is expressed by the Root value of "x" (x to the power of).

The first item I noted was the very slow decline of Solar Cycle 23.  The decline of Cycle 23 lasted between 14-17 months longer than the declines of Cycles 24 and 22. Due to the fact that conditions prior to the peak of Cycle 24 showed the inevitable (23), would a similar rate of increase show another inactive Solar Cycle. The decline of Cycle 24 was indeed faster than Cycle 23 despite declining from a lower peak value.

Past Solar Cycle Patterns:

The accepted period of a normal Solar Cycle is 11 years. Generally the Cycle increases (Sunspot #s, Solar Flux) for 4 years. It then declines for 7 more years. Generally any cycle will not follow the pattern of the prior one. Predictions are difficult and rarely correct. So my challenge was to come up with my own assessment for Cycle 25. I knew the Magnetic poles were still not in sync, but how bad for the new Cycle. Early indication was it wasn't as extreme as what was observed 11 years before.

Once the Smoothed Solar Flux indices identified the bottom of Cycle 24 (13 months) thus the beginning of Cycle 25, I started to measure the monthly trend of the new and past 2 Solar Cycles.

Within 18 months of the new Cycle, there was evidence that the new Cycle (25) was going to be better than the prior one (24). Within 2 years it was a definite trend that Cycle 25 would be better. It still appeared that it would not be as good as Cycle 23, but definitely much better than what was predicted. 

By 3 years, this new Cycle (25) was close to matching the rise of Cycle 23. I was confident that I would see some Trans-Equatorial (TE) as well as F2 on 6 Meters (both missing in Cycle 24).

Now The Bad News:

For a number of months after the 3rd year, the rate of growth and Solar Flux level ran very close to the one for Cycle 23. During January and February of 2023, Solar activity had well exceeded Cycle 24 levels and was running even with Cycle 23 .............. then it crashed. It has recovered some and the trendline has flattened out into the 49th month.

No telling where we go from here, but a second peak is more probable than possible. The last 2 Solar Cycles had dual peaks. I do think it will not get significantly higher, but much much better than Cycle 24 ever was (20 or so Solar Flux units).  We should expect good conditions and activity for at least 3 to 4 years.

Enjoy it while you can.

I will update this Blog in a few months.

73 Art K7DWI/5