W3LPL's forecast for upcoming Solar Cycle 25 - Apr 2021

Frank Donovan, W3LPL is one of the top contesters in the USA and is a key forecaster of upcoming conditions on the HF amateur radio bands.

In a recent forecast (April 2021), he made a forecast about how good upcoming Solar Cycle 25 would be based on the Solar Flux numbers at the end of December 2021. I have put together a graphic which shows this above. The starting point for April 2021 is a solar flux index of 77 which is roughly the average for the month.

W3LPL wrote... “If the SFI persists below 90 through December 2021, then propagation should improve gradually until a solar maximum weaker than Cycle 24’s arrives in 2024.

If the SFI persists above 110 through December 2021, then propagation should improve rapidly until a solar maximum similar to Cycle 24’s arrives in 2024.

“If the SFI persists above 125 through December 2021, then propagation is likely to improve more rapidly until a solar maximum stronger than Cycle 24’s arrives in 2024.”

(SFI = Solar Flux Index)

As with everything on the sun, there is always an amount of uncertainty in solar forecasts but it will be interesting to revisit this at the end of the year and see where we're at.

Link...
1) K7RA Solar Update - 23rd April 2021

Scientist predicts the peak of the next Solar Cycle will be one year earlier than expected

In a recent interview, Lisa Upton of Space Systems Research Corporation and co-chair of the NOAA/NASA Solar Cycle 25 Prediction Panel said...  “The sun is performing as we expected–maybe even a little better. In 2019, the panel predicted that Solar Cycle 25 would peak in July 2025 (± 8 months) with a maximum sunspot count of 115 ± 10. The current behavior of the sun is consistent with an early onset near the beginning of our predicted range.”

The diagram above shows the new solar cycle running ahead of schedule. If it continues like this then Solar Cycle 25 may peak in 2024, a year earlier than expected.

As with all solar predictions, only time will tell how accurate they are.

Sun starts to sizzle as solar flux hits 100

After a long solar minimum slumber, the sun has really begun to wake up in the last few weeks. On the 24th of November 2020, the solar flux hit 100 for the first time in about three years. The last time the solar flux was over 100 was back on the 10th of September 2017.

The photo above shows some of the sunspots on the solar disk including region 2786 which has a dark core which is slight larger than planet Earth.

The chart below shows the dramatic change in the solar flux in the last 12-months...

The biggest change in the conditions on the HF bands is that the higher bands like 10-metres are now opening. At the end of 2019 at the sunspot minimum, there were some hints of propagation but mostly on north-south paths. Fast forward to the 26th of November 2020, you can see that there was a nice opening to the USA on the 28 MHz band.

It's been a long time since I heard signals from Texas on 28 MHz via F2 propagation.

28 MHz wakes up as the sunspots return - Nov 2020

 After reading reports of recent activity on 28 MHz, I started listening again on FT8 on the 10-metre band to see what conditions were like.

As the PSK Reporter map above shows, there was plenty of activity on the band on Friday the 6th of November 2020.

While there was some evidence of Sporadic-E activity around Western Europe, there was plenty of evidence of F2 propagation from Russia and SE Europe. Outside of some North-South propagation to Africa and South America, it was interesting to see openings to Indonesia and Australia.

There's always something special for me about hearing Australia on 28 MHz. It's no big deal on the other HF bands but for the path to be open at 28 MHz then something must be happening.

The Sunspots Return... The improvement in conditions on 28 MHz is due to the sunspots returning and the solar flux getting up into the low 90's. The chart below from NOAA (National Oceanic and Atmospheric Administration) in the USA shows the number of sunspots from 2009 to 2020 and projected out to the next peak of the solar cycle projected to be in 2025-2026.

It shows a peak back in 2014 and the minimum of the sunspot cycle in December of 2019. It also shows an increase in the sunspot number.

The chart below shows the minimum period in more detail.

The Purple line shows the smoothed sunspot number with the minimum clearly shown at the end of 2019. The Black line shows the smoother sunspot number for each month.

What is significant here is the average sunspot number for October 2020. The last time it was that high was back in October 2017, three years ago.

As we come out of the sunspot minimum, there will be peaks and dips but the overall projection is still upwards. As the solar flux increases, the higher HF bands will spring into life especially on North-South paths.

It will be interesting to see when will we get regular openings to the USA on 28 MHz from NW Europe? It will probably start with openings to Florida but it's the F2 openings to Newfoundland, Nova Scotia and Maine that I'd be really interested to see.

Link...

1) Solar Cycle Progressions - NOAA

Solar Cycle 25 has officially begun

At a press conference on Tuesday the 15th of September 2020, scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA) announced that Solar Cycle 25 has officially begun and the actual sunspot minimum between cycles 24 and 25 had occurred in December of 2019. In a previous press release  in December of 2019, the panel of scientists had predicted that the minimum would occur during a period stretching from October 2019 to October 2020 i.e. April 2020 +/- 6 months.

As with all sunspot cycles, it's only several months after the minimum that scientists can look back and be sure of when it occurred. There was however some signs that we had passed the peak as there was an increase in the number of sunspots which had spotted recently with the correct polarity for cycle 25.

Ultra-violet image of the sun at the sunspot minimum

The next sunspot maximum is predicted to occur in the middle of 2025 and the peak is expected to be the same in intensity as Cycle 24.

What does all this mean??? ... In the short term, not a lot will change. For stations in northern latitudes, the upper HF bands of 15m, 12m and 10m will struggle to open and when they do, it will tend to be over North-South paths.

In the second half of 2021, things should start improving and by 2022, we should start seeing more openings on East-West paths.

By 2025, we should see worldwide openings on 28 MHz but the 50 MHz band is unlikely to be as spectacular as say Cycles 22 and 23 back in 1989 and 2001. At the sunspot peak, there will probably be plenty of North-South openings on the 6 metre band but the multi-hop openings East-West may be more of an issue.

Digital Modes ... It's very likely that Sunspot Cycle 25 will be the first one where digital modes like FT8 will dominate. This may well  allow some propagation paths to appear that may not have been so obvious on SSB or CW. Interesting times ahead.

Links...
1) NASA Press Release

2) NOAA Press Release

Latest forecast for the next Solar Cycle - Dec 2019

An international panel of scientists co-chaired by NOAA and NASA release reports every few months on the state of the sunspot cycle. This is probably the most accurate source in terms of what is likely to happen.

Back in April of 2019, the previous report predicted that the  solar minimum would likely happen between July 2019 and September 2020. In the most recent report dated December 2019, they are predicting that the minimum has been pushed back. They predict that it will now occur sometime between November 2019 and October 2020.

As for the upcoming Solar Cycle 25, they are still predicting that it will be similar in intensity to the last solar cycle with a smoothed sunspot number (SSN) of 115. The peak is predicted to occur between November 2024 and March 2026.

Original press release...
SOLAR CYCLE 25 FORECAST UPDATE published: Monday, December 09, 2019 22:30 UTC The NOAA/NASA co-chaired, international panel to forecast Solar Cycle 25 released their latest forecast for Solar Cycle 25. The forecast consensus: a peak in July, 2025 (+/- 8 months), with a smoothed sunspot number (SSN) of 115. The panel agreed that Cycle 25 will be average in intensity and similar to Cycle 24. Additionally, the panel concurred that solar minimum between Cycles 24 and 25 will occur in April, 2020 (+/- 6 months). If the solar minimum prediction is correct, this would make Solar Cycle 24 the 7th longest on record (11.4 years).