The K7RA Solar Update


Tad Cook, K7RA, Seattle, reports: Four new sunspots appeared this week and were visible every day. issued a warning on April 22: “CME is heading for Earth. and can cause a geomagnetic storm when it arrives on April 25th. NOAA forecasters say moderate G2 storms are possible, meaning aurora borealis could sink in the United States from north to Maine to Washington. “

The average daily number of sunspots increased from 7 to 35.1, while the average daily sunlight increased from 75 to 78.

Due to the seemingly constant solar wind, the average planetary index A has risen from 5.1 to 16.4, and the average daily index of average latitude A has risen from 4.1 to 13.

The forecasted solar flux is 84 on April 23-24; 82 on April 25 – 27; 80 on April 28; 78 on April 29-30; 68 on May 1-2; 78 on May 3; 72 on May 4 – 9; 75 on May 10 – 15; 78 on May 16; 75 on May 17-18; 72 on May 19; 70 on 20 – 23 May and 68 on 24 – 29 May.

Predicted planetary index A is 10, 8, 25 and 12 on April 23-26; 5 on April 27 – May 3; May 15; 5 on 5 – 7 May; May 8 to 8; 5 on 9 – 10 May; 8, 12, 20, 30, 15, 12 and 8 on 11 – 17 May; 5 on 18 – 19 May and 8, 12 and 5 on 20 – 22 May.

Here is the forecast for geomagnetic activity for April 23 – May 18 from FK Janda, OK1HH.

The geomagnetic field will be:

  • quietly on 1 – 3, 5, 18 May
  • quietly to unsettled on 28 – 30 April, 6 – 11 May, 17
  • quietly to actively on April 26, May 12
  • unsettled until active April 27, May 16 18
  • active until broken April 23, (24 – 25,) May (4,) 13 – 14, (15)
  • The solar wind will intensify on April 23 – 25, (then irregularly between April 26 – May 1), May 3 – 5, (6 – 7, 10 – 11, 16,) 17 – 18, (18)


– Brackets mean less likely to improve performance.

– Contradictory readings significantly reduce the accuracy of the forecast.

Frank Donovan, W3LPL, says long-awaited significant increase in solar cycle activity 25 may have started on April 19.

“As a result, 30- and 20-meter spread at night and 17- and 15-meter during the day reproduction will probably be improved at least until April 26. The solar flux index (SFI) is likely to remain at 85 or higher until at least April 26 due to two active areas on the sun’s surface, 2816 and 2817, containing a total of 16 sunspots. Two additional active sunny regions on the far side of the sun are is expected to be in the spotlight later this week, possibly increasing SFI and extension of extended breeding by the end of April “.

See Donovan’s article “What to Expect in the Growing Years of the Solar Cycle 25” in the May 2021 issue. QST.

Donovan says the new sunspots are fading faster than he hoped, but the steady trend of increasing sunspots should soon keep the sun’s flux above 80.

Long-range forecast for Thursday-Friday, April 22-23 by Frank Donovan, W3LPL:

“My distribution forecast obtained from today’s NOAA / SWPC websites is published five days a week (M – F) in Daily DX.

“Breeding in low and medium latitudes is likely to be normal until Friday. Breeding passing through the oval and polar regions is likely to be mostly normal, with intervals below normal until Friday.

“The latest today planetary Kp index, is updated every 3 hours

„N0NBH current conditions of HF tape, updated regularly

“The solar flux index (SFI) will probably be around 78 by Friday.

“Three active areas, containing a total of 17 mostly small sunspots, have minimal effect on the spread of HF.

“We are coming out of the most troubled weeks of the geomagnetic storm season from March to April, when the Earth passes through the part of the interplanetary magnetic field (IMF) with the most frequent, longest duration oriented south. Approximately twice as many brief minor and moderate geomagnetic storms occur in March and April compared to the quieter IMF in June and July. Short minor to moderate geomagnetic storms can be triggered with a small warning when the IMF turns south and lasts for several hours, coinciding with the effects of high-velocity coronal hole flows toward the ground and coronal mass ejection (CME) improvements. in solar energy wind.

“The short path of 160 and 80 meters from North America to VK / ZL will probably be normal until Friday. The distribution of the eighty-forty-meter short trail to South Asia is likely to be mostly normal around 0030 UTC on Friday. The distribution of the eighty-forty-meter short trail from North America to East Asia after about 0900 UTC is likely to be mostly normal at intervals below normal until Friday.

“The spread of thirty meters through the polar ovals and through the polar regions will probably be mostly normal with intervals below normal until Friday. The 30-meter spread always deteriorates significantly within a few hours of local lunch due to the E-region coverage of the long-range spread of F2. The 30-meter spread during the night is likely to improve slightly by Friday, due to the solar flux index of 78.

“Twenty-meter day and evening reproduction through the polar ovals and across the polar regions is likely to be predominantly normal, with intervals below normal by Friday. Twenty-meter northern transpolar distribution within hours of sunrise and sunset will improve steadily with gradually increasing electron density in the polar region. region F2 to June.Twenty meters of long-distance night propagation in the northern hemisphere is likely to improve slightly by Friday due to the solar flux index of 78.

“Long-distance propagation over seventeen-fifteen meters in the northern hemisphere is likely to improve slightly by Friday due to solar flux of 78. Twelve-meter long-distance propagation during the day is likely to be largely unreliable and limited to distribution from North America to South Africa. , South Atlantic, South America and the South Pacific.

“Geomagnetic disturbances caused by high-velocity coronal hole fluxes are likely to remain predominantly short, insignificant, and less common at least until the end of 2021. The IMF’s north-south (Bz) component plays a crucial role in triggering short insignificant to moderate geomagnetic storms when maintained in a south (–Bz) orientation with increased field strength for several hours, coinciding with the effects of a high-velocity corona hole directed to the ground or CME improvements in the solar wind.

“The strength of the IMF field, the speed of the solar wind near the ground and the geomagnetic activity are likely to be close to the background levels by Friday with a possible improvement at the end of Friday due to the effects of high-velocity coronal flow. A M-class solar flare is unlikely to cause a brief sudden disruption of the ionosphere and the disappearance of short waves on the solar side of the Earth late Thursday.

“Geomagnetic storms and ground-based CMEs are strong enough to affect high-frequency propagation unlikely until Friday.

“The mid-latitude northern hemisphere sunset is now 32 minutes later, and the light period is 81 minutes longer than on March 20.

“The period of daylight increases by 2 minutes per day, which continuously prolongs the duration of total daylight between distant places in the northern hemisphere. Solar altitude in the Arctic increases by about 3 degrees per week, with the 20-meter north transpolar distribution continuously improving in June.

“Today’s Penticton 10.7 cm solar flux index is updated at 1700, 2000 and 2300 UTC every day. “

Today’s 2-day Forecast for GFZ Planetary K Index is updated every 3 hours.

Today’s SIDC Daily Newsletter on Solar and Geomagnetic Activity is updated 1230 UTC every day.

Today’s SWPC Discussion of solar activity forecast is updated at 0030 and 1230 UTC every day.

Today’s Australian Space Forecast Center Summary and forecastis updated 2330 UTC every day.

These are probably the most useful HF distribution pages for DXers.

April 2021 NASA Solar Flux Index Forecast for Solar Cycle 25 has been published, mostly extending the date for the solar maximum until 2024. SFI, represented by a 50% percentile (green line) is similar to Solar Cycle 24. Double peak solar cycle – similar to recent Solar Cycles 23 and 24 – can delay the solar maximum by a year or more.

Here’s a slightly updated wording for May on the W3LPL QST an article unrestricted by the limitations of the QST page and reflecting NASA’s projected solar maximum in 2024:

“If the SFI continues below 90 until December 2021, then the spread should improve gradually until the solar maximum, weaker than cycle 24, arrives in 2024.

“If the SFI continues above 110 until December 2021, then the spread must improve rapidly until the solar maximum, similar to cycle 24, reaches 2024.

“If the SFI continues above 125 until December 2021, then the spread is likely to improve faster until the solar maximum, stronger than cycle 24, arrives in 2024.”

Vote for your favorite may QST article.

N4SO recommends an article in the March-April issue QEX, “The beginning of the solar cycle 25 and the MGII index”, by VE6TL.

John Jones, N0JK, announced the TEP on April 20, opening 6 meters to South America, and sent a long list of stations copied from 2022-2023 UTC, and this report:

“CE6CGX is copying me. 10 W, whip with a quarter wave. Jon N0JK EM28 hp

“RX on Tuesday, April 20, 2021. 20:25:01 GMT.”

“From N0JK to CE6CGX Loc FF31qp

“Frequency: 50.314.248 MHz (6m), FT8, 6dB

“Distance: 8846 km, bearing 162 °”

On April 19, John, N0JK, reported that the Falkland Islands VP8EME could be heard 6 meters from KE8FD and K1TOL around 1800 UTC. “It seems that the sporadic summer season E has begun,” he noted.

KA3JAW of Easton, Pennsylvania, reported a long 6-foot hole on April 19, 1435. 1706 UTC. “The best DX range was with the N5DG [EM20AB] Hampstead, Texas, 1,374 miles, ”he said.

And from Cuba:

“Hello, CO7WT, Pavel Milanes here from Camaguey Cuba, FL11bj. I would like to announce a huge opening of 6 meters on Saturday, April 17, 2020. I calibrated my 6-meter converter for homemade beer to gain access to the magic tape (noise generator, SDR, NanoVNA) and suddenly, a digital signal appeared for a few seconds on my SDR screen. Hmm … weird. No antenna is connected, only forced by tests, after which there is a reasonable calculation, noticed 18.313 MHz, also known as 50.313 (32.000 MHz XTAL). This is FT8! Local ham, I think at first. I connected my antenna (Cushcraft 3 element Yagi) and boom! Strong signals from North America and some from the LU and CE side / rear of the Yagi. Unfortunately, the transmitter side of the converter is not ready yet. Here are the links (1) (2) to some photos on Twitter.

“I noticed at least three beacons, one from W4 and the other was too unstable to decode properly when they came and went. See photos. Some of those calling FT8 had signals dancing up and down in a pattern of a few minutes. I think sporadically Well, because this is the season. “

The sunspot numbers for April 15-21 were 22, 44, 28, 15, 36, 54 and 47, with an average of 35.1. The 10.7 cm flux was 72, 76.5, 75.3, 78.1, 85.9, 80 and 78, with an average of 78. The expected planetary indices A were 13, 19, 29, 16, 18, 13 and 7, with an average value of 16.4. The average width index A is 11, 15, 20, 13, 15, 10 and 7, with an average value of 13.

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Title Yours reports and observations.