Propagation de K7RA
For several weeks we expected today, May 2 to have active geomagnetic conditions

Propagation de K7RA
We saw a string of zero-sunspot days over the past couple of weeks, but this week saw a brief but significant sunspot lasting only a couple of days

Propagation de K7RA
No sunspots for seven days, as of Thursday, April 10. We may see sunspots return around April 21-28. This is based on recent activity rotating out of view around the Sun and (we hope) reappearing later this month

Propagation de K7RA
The past few days have had very stable geomagnetic conditions

Propagation de K7RA
It is exciting to see heightened solar activity one week into Spring

Propagation de K7RA
This is an off-schedule propagation bulletin based on last Friday's release, Propagation Forecast Bulletin ARLP011.  There will be another off-schedule bulletin on Thursday, March 20, because ARRL headquarters will close for the Good Friday holiday

Propagation de K7RA
With just a few scattered sunspots in the past two weeks (February 28 to March 12), it isn't meaningful to ponder the change in weekly averages. There were just four days with sunspots during that time, February 28, March 5-6 and March 10

Propagation de K7RA
Following five days of no sunspots, we saw one (number 984) on March 5 and 6, but it is fading off the west limb of the earth-facing portion of the Sun. Solar activity is still very low

Propagation de K7RA
A sunspot emerged a few days ago, a welcome sight at cycle minimum

Propagation de K7RA
No sunspots appeared this week. Solar flux was about the same as last week

Propagation de K7RA
Sixteen consecutive days with no visible sunspots, and still counting. This is the way it is at solar cycle minimum

Propagation de K7RA
Sunspots have returned. After nearly three weeks with nothing visible (January 9-28), sunspot group 982 emerged on January 29

Propagation de K7RA
Sixteen consecutive days with no visible sunspots, and still counting. This is the way it is at solar cycle minimum

Propagation de K7RA
We've seen another seven days with no sunspots. After observing the first sunspot of Cycle 24, we hope to see more and more of these, signaling the beginning of the next sunspot cycle and the end of Cycle 23

Propagation de K7RA
We just saw eight days of sunspots, but now the solar disk is spot-free. The big story this week is the sighting of the first spot of sunspot Cycle 24

Propagation de K7RA
It's a new year, and now time to review 2007 sunspot cycle progression. In 2006 there was a consensus that solar minimum would occur in early 2007, but we actually may not be there still

Propagation de K7RA
Last week this bulletin reported sunspot 978 rotating from view. Now through a process called helioseismic holography, an image of the Sun's far side shows the spot fading away

Propagation de K7RA
Sunspot 978 faded this week, with Tuesday, December 18 its last day visible. The average daily sunspot number dropped nearly 13 points from last week to 24.1, and average daily solar flux was down over three points to 83.9

Propagation de K7RA
Sunspot 978 made a strong showing this week, and daily sunspot numbers are up as a result. The average daily sunspot number for this week rose over 25 points to 36.7, and average daily solar flux rose over 14 points to 87.2

Propagation de K7RA
More sunspots emerged this week, with every December day so far showing spots. In addition to the sunspot numbers listed through Wednesday at the end of this bulletin, Thursday, December 6 had a sunspot number of 29

Propagation de K7RA
Sunspots appeared over several days in the past week. November 24-27 had daily sunspot numbers of 15, 12 and 11. Otherwise, the Sun has been blank. In the previous reporting period, November 15-21, there were only two days with sunspots, and the daily sunspot numbers on both days were 13

Propagation de K7RA
This is an off-schedule post-Thanksgiving bulletin. Because ARRL headquarters was closed on Friday, the day this bulletin is normally released, and the last Propagation Forecast Bulletin ARLP048 was written before the end of our reporting week, the sunspot, solar flux and geophysical numbers normally at the end of the bulletin are in this bulletin, but were not a part of ARLP048

Propagation de K7RA
This is an off-schedule bulletin before Thanksgiving.
Because ARRL headquarters is closed on Friday, the day this bulletin is normally released, and this bulletin was written before the end of our reporting week (which is Thursday through Wednesday), the sunspot, solar flux and geophysical numbers normally at the end of this bulletin will appear in a new propagation bulletin on Monday

Propagation de K7RA
Another quiet week, but strangely, like the previous week there was just a single sunspot appearing for one day, and it was also on a Tuesday. Just like the previous week, the daily sunspot number was 11, and then it went back to 0 when the spot disappeared. No spots expected in the near future

Propagation de K7RA
A single sunspot (number 973) appeared briefly toward the end of Wednesday, November 6, then quickly faded. This broke a 29-day stretch of no sunspots

Propagation de K7RA
Average daily solar flux and sunspot numbers were unchanged from last week. The average sunspot number was easy to figure, since there were none.

Propagation de K7RA
Zero, zero, zero sunspots for 18 straight days now. A single
sunspot appeared briefly October 6-7, no sunspots for four days prior, one sunspot for the final few days of September, and none for the three whole weeks prior to that

Propagation de K7RA
Our Sun is still blank. The past week has shown no sunspots, and we will probably see more of nothing

Propagation de K7RA
The average sunspot number for the past week is about half what it was the week before, but this doesn't mean much, since only two days of the last seven had any sunspots. In fact, on only 7 out of the last 29 days did the sun show any spots

Propagation de K7RA
Sunspots reappeared, but only briefly. In fact, it was one sunspot, number 971, emerging September 28 for just a few days. This after 21 days of no sunspots. Now we are back into a zero-sunspot period of indeterminate length, just four days so far

Propagation de K7RA
Last week's report stated the possibility that zero-sunspot days were about to end, but no such luck. Instead we've seen no sunspots for three weeks straight, since September 7

Propagation de K7RA
Fifteen days in a row with no sunspots, but this may change soon

Propagation de K7RA
The Sun has been blank, with no visible sunspots, for the past seven days, September 7-13. We may not see another sunspot until September 22, just before the Autumnal Equinox

Propagation de K7RA
In little more than two weeks the northern hemisphere will see the Autumnal Equinox, marking the start of Fall north of the equator and the beginning of Spring south of the equator.

Propagation de K7RA
Sunspot numbers pulled up from 0 this week, but barely. Average daily sunspot numbers rose over nine points to 12.9. Geomagnetic conditions were quiet. Conditions have been quiet for so long that we may not appreciate this, as many of us wish for more solar activity and sunspots

Propagation de K7RA

Propagation de K7RA
We are seeing new sunspots over the past few days after eleven days with none at all. Lack of solar activity made Field Day this year (June 23-24) a real cycle minimum experience

Propagation de K7RA
June 23-24 is ARRL Field Day, and it follows a week with no sunspots

Propagation de K7RA
In last week's Propagation Forecast Bulletin ARLP024, we had erroneous solar flux values for June 5-6. Instead of 88.8 on June 5, the solar flux was actually 81.2

Propagation de K7RA
After five days of no sunspots from May 24-28, spots returned on May 29, and have increased since in number and size. There are currently several sunspots visible, and the sunspot number for the past five days (Sunday through Thursday) was 58, 58, 63, 47 and 59.Coupled with quiet and stable geomagnetic indicators, this is good for HF propagation

Propagation de K7RA
The average daily sunspot number this week dropped nearly 23 points to 3.3, while average daily solar flux declined exactly five points to 68.8

Propagation de K7RA
This week saw a return to active geomagnetic conditions after a period of relative quiet.

Propagation de K7RA
This week saw a rise in sunspot numbers, with the average daily value up over 11 points to 29.3

Propagation de K7RA
Over the past week, sunspot activity has again declined, with average daily sunspot number down by more than 7 points to 18

Propagation de K7RA
In the past few days sunspots have reappeared after six days of nothing. In April so far we've seen 18 days with 0 spots. But currently a large sunspot, number 953 is rolling into view. A solar wind stream is also expected to hit earth, causing geomagnetic upset on Saturday, April 28

Propagation de K7RA
This week we are on the road in Boise, Idaho. This was another week with little or no sunspots. Most days had 0 spots, but from time to time a new sunspot will appear, but only briefly

Propagation de K7RA
So far this month we've observed 9 days in a row with 0 sunspots, and all of our reporting week for this bulletin (April 5 through 11) falls within this string of inactive solar days.

Propagation de K7RA
Here we are at the bottom of the sunspot cycle, although we won't know when it occurs for sure until a year after it passes. This is because daily and monthly variations are so great that we need to look at averages derived from many months of daily readings to determine a cycle peak or minimum

Propagation de K7RA
The daily sunspot number ended the stretch of zeroes on March 23, after 10 days of totally blank sun

Propagation de K7RA
For the past ten days we've observed no sunspots at all. Periods like this, or longer, are expected at the bottom of the sunspot cycle

Propagation de K7RA
We just saw more 0-sunspot days, followed by the brief emergence of small spots, then more days with no sunspots. The average daily sunspot number for the past week was down nearly 70% from the previous week, to 5.9

Propagation de K7RA
This bulletin is out a day early. Look for the next bulletin on
Friday, February 23

Propagation de K7RA
Average daily sunspot numbers and solar flux were up this week, while average daily geomagnetic indices were down, which is a nice combination

Propagation de K7RA
This week (January 18-24) saw lower sunspot numbers (seven points lower, on average) than the previous week.

Propagation de K7RA
Average daily sunspot numbers for the week were down 16 points to 27.4 from the previous week. Geomagnetic conditions were unsettled on Monday through Wednesday, January 15-17

Propagation de K7RA
Average daily sunspot numbers for the week more than doubled from the previous seven days, rising 24 points to 43.4. This is a nice number for what should be the bottom of the sunspot cycle

Propagation de K7RA
This is the first bulletin of 2007, the year we'll likely see the end of sunspot cycle 23, the beginning of cycle 24, and the minima between cycles

Propagation de K7RA
More zero sunspot days are finishing out the month, which seems appropriate as we descend near the bottom of Solar Cycle 23

Propagation de K7RA
More of the stormy space weather appeared this week, while at the same time sunspot activity was lower

Propagation de K7RA
The past couple of days have seen robust solar activity, with flares and strong solar wind. On Wednesday and Thursday, December 6 and 7, the planetary A index rose to 28, then 25. On December 5 a large X9 class solar flare emerged from the sun's eastern side, but it wasn't earth directed

Propagation de K7RA
The IMF, or Interplanetary Magnetic Field, dipped south early Thursday UTC (Wednesday night, November 29 in North America) letting in a blast of solar wind

Propagation de K7RA
This issue of the propagation bulletin is released on an irregular schedule because of the Thanksgiving holiday.
This bulletin has the updated numbers from November 16-22. This Friday, December 1, Propagation Forecast Bulletin ARLP050 will come out on the regular schedule with solar data from November 23-29

Propagation de K7RA
This is an early bulletin because of the Thanksgiving holiday, but the timing is wrong for publishing another week of solar and geomagnetic data, so the numbers at the bottom of this bulletin are the same as in last week's Propagation Forecast Bulletin

Propagation de K7RA
This week saw the odd combination of the average daily sunspot number declining while the solar flux rose. It isn't so odd for this to happen when there are very few sunspots, and one rises slightly while the other declines slightly. But this time, the solar flux rose quite a bit

Propagation de K7RA
Average daily sunspot numbers more than doubled this week over last, up nearly 27 points to 46.3. While there were more sunspots, the geomagnetic K index was 0, and on some days the A index was 0 as well

Propagation de K7RA
Early on Friday morning before the CQ World Wide SSB DX Contest, conditions are stable and quiet, and after the sunspot number rose to 50 this week following eight days of no sunspots, the average daily sunspot number increased from nothing to 23.3

Propagation de K7RA
Sunspot numbers this week were 0 on every day.
In fact, 0 was the sunspot number for eight days in a row, from October 11 through 18.

Propagation de K7RA
September 30 ended the third quarter of 2006, so now is a good time to review quarterly averages of daily sunspot numbers and solar flux, to examine the current solar cycle's downward trend

Propagation de K7RA
Bill Huntimer, KI0CW in Dell Rapids, South Dakota wrote to ask, "Would you explain what sunspots do to radio interference?"

Propagation de K7RA
Average daily sunspot numbers this week were down nearly 31 points to 13.4, and average daily solar flux declined over 8 points to 77

Propagation de K7RA
The Autumnal Equinox for the Northern Hemisphere will occur on September 23 this year (at 0402z). We've been moving from summertime propagation conditions to fall, which is generally a better time for HF propagation, except for the lack of sporadic-E skip

Propagation de K7RA
Average daily sunspot number was 12 points lower this week than last, but the geomagnetic indices were higher. Active geomagnetic conditions on August 19-22 were the result of an August 19 change in the IMF (Interplanetary Magnetic Field) opening toward the south, which allowed a solar wind to affect the earth