K7RA's Solar Report Hit refresh if this report appears out of date. It is updated every friday morning. Last update: Friday, 03-May-2024 02:05:43 GMT

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SB PROP @ ARL $ARLP018
ARLP018 Propagation DE K7RA
QST DE W1AW
ARRL Propagation Bulletin 18 ARLP018 From Tad Cook, K7RA
Seattle, Washington May 3 2024
To all radio amateurs

"ASWFC GEOMAGNETIC DISTURBANCE WARNING ISSUED 1817 UTC/02 MAY 2024 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE.

"A period of planetary G3 geomagnetic conditions has been observed on 02-May, associated with two recent CME arrivals and a sustained period of southward IMF conditions. Further periods of G3 are possible over 02-03 May.

"INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL MASS EJECTION FROM 02-03 MAY 2024.

"GEOMAGNETIC ACTIVITY FORECAST02 May: G2-G3 03 May: G2, chance G3, declining to G1'D

After the record sunspot numbers in last week's bulletin ARLP017, the April 25 through May 1 reporting week has more modest numbers. In fact, the average daily sunspot number (124.6) is less than half the value (265.9) in the previous bulletin.

Seven new sunspot groups appeared this week.

One new sunspot group emerged on April 25, another on April 27, two more on April 29 and one each on April 30 and May 1.

Average daily solar flux shifted from 216 to 144.9.

Average daily planetary A index dropped from 13.9 to 9.6.

The solar flux estimate for the next month has values peaking at 205 on May 15-16 and again on June 11-12.

The values are 135 on May 3, 132 on May 4-5, then 134 and 136 on May 6-7, 138 on May 8-9, then 140, 155, 160, 175 and 180 on May 10-14, 205 on May 15-16, then 200, 195, 190, 185, 180, and 165 on May 17-22, 145 on May 23-24, then 140, 135, 130, and 125 on May 25-28, then 120, 115 and 120 May 29-31, 125 on June 1-2, 130, 145, and 150 June 3-5, 155 on June 6-7, then 160, 175 and 180 on June 8-10, and 205 on June 11-12.

Predicted planetary A index is 18, 20, 18 and 10 on May 3-6, 5 on May 7-22, 15 on May 23, 12 on May 24-25, then 10, 8, 15, 18 and 10 on May 26-30, then 8 on May 31 through June 3, and 5 on June 4 through the middle of the month.

"Weekly Commentary on the Sun, the Magnetosphere, and the Earth'sIonosphere ' May 2, 2024 from OK1HH.

"The number of sunspot groups at the present stage of the 11-year cycle varies between five and twelve. Of these, one to three can be described as active regions, whereby their size and magnetic configuration suggest the possibility of energetic flares of intermediate magnitude. A number of these are accompanied by CMEs, which, given their position on the Sun, are expected to strike the Earth. Therefore, predictions of increased geomagnetic activity are quite often made, but most of them do not come true. Conversely, if the Earth is affected, a geomagnetic disturbance so strong that it affects the conditions for shortwave propagation will develop.

"CME collisions with the Earth have mainly caused magnetic storms and subsequent deterioration of shortwave propagation on 21-22 April and 27-28 April. Especially in the latter case, the recovery from the disturbance was very slow, even multi-day, due in part to the decrease in solar radiation. Added to this was another geomagnetic disturbance in the late evening hours UTC on 30 April, which caused a decrease in MUF and a worsening on 1 May.'D

Cycle 25 progress.

https://bit.ly/3WshU2e

In an email Thursday morning, Tamitha Skov wrote:

"Region 3654 sure has been a point of contention this week. Despite a lot of big flares, the eruptions that have occurred have been rather unspectacular-- or so we all thought. Twice now, we have had stealthy solar storms hit Earth. The first one that hit yesterday, was not particularly impactful. In fact, for those who have been following the news in our community chat here on Patreon, you have seen me discuss the event there, instead of posting an official "Snapshot." I did this because that storm was weak and slow, without much southward-pointing field. In other words, it was so yawn-worthy, I haven't bothered to update my twitter feed with the news.

"That all changed when yet another stealthy solar storm hit, just a few hours ago. This one is much stronger. The top solar disk image shows the source region for this event. It was an unimpressive event in coronagraphs, with no clear Earthward directed signature. However, it has a strong magnetic field, that is pointing southward, and is fast. This one has given us G3-levels momentarily, but could keep us at sustained G2-level conditions.

"Both of these events have eluded detection by several (if not all of the big space weather forecasting agencies) so it is clear, stealthy solar storms continue to be a problem through solar maximum. I had been working on a formal forecast, but I am thinking I will do an impromptu live forecast today since things are unfolding faster than I can update my current work. Stay tuned. I will likely go live this afternoon (PDT time), a few hours from now! Till then, know that we could very easily hit G2-levels within the next hour at SWPC, if conditions remain as they are."

Blackout.

https://bit.ly/4bkCHsL

There was another blackout on Thursday, when two CMEs caused a G3 geomagnetic storm. According to Spaceweather.com, another CME is expected on May 4.

An earlier disturbance.

https://bit.ly/3UpNF9J

Fluffy corona, thanks to reader David Moore.

https://bit.ly/3w9B3eP

Solar fury.

https://bit.ly/3UFE6Vg

Cosmic rarity, But did they really need to reference astrology?

https://bit.ly/3wiEaAX

Blackouts

https://bit.ly/3UIWyfW

Solar max.

https://bit.ly/3wjtr9o

Send your tips, reports, observations, questions and comments to k7ra@arrl.net. When reporting observations, don't forget to tell us which mode you were operating.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals . For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere .

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation . More good information and tutorials on propagation are at http://k9la.us/

Also, check this.

https://bit.ly/3Rc8Njt

Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins .

Sunspot numbers for April 25 through May 1 2024 were 196, 154, 126, 119, 88, 85, and 104 with a mean of 124.6. 10.7 cm flux was 166.7, 152.6, 152.6, 140.1, 137.6, 130.2, and 134.8, with a mean of 144.9. Estimated planetary A indices were 3, 19, 12, 7, 6, 12, and 8, with a mean of 9.6. Middle latitude A index was 3, 11, 12, 7, 7, 10, and 10, with a mean of 8.6. NNNN