The geomagnetic field was at quiet levels on October 2. Solar wind speed at SOHO ranged between 345 and 417 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels. The above 10 MeV proton flux was at background levels at the end of the day.
Solar flux density measured at 20h UT on 2.8 GHz was 274.4 - increasing 33.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 177.06. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 177.06 on April 3, 2024). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6). Three hour interval K indices: 22222111 (planetary), 22122321 (Boulder), 33122022 (Andenes).
The background x-ray flux is at the class C4 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 15 active regions using 2K resolution (SN: 441) and in 13 active regions using 1K resolution (SN: 277) SDO/HMI images.
AR 13836 [S11W47] decayed further and was quiet.
AR 13839 [S14W07] was mostly quiet and stable.
AR 13841 [N13W07] developed further before noon. Later on slow decay
set in with some loss of area. The region is still complex with a
significant magnetic delta configuration and could produce further M flares.
AR 13842 [S15E06] gained area and lost some small spots. There is
still a magnetic delta in a trailing penumbra, however, the delta area is
smaller and there is more separation between opposite polarity umbrae. A
major flare is possible.
AR 13843 [S09W29] was mostly quiet and has M class flare potential.
AR 13844 [S16W16] lost the magnetic delta, however, an M flare is
still possible.
AR 13845 [N17W57] decayed significantly and could soon become
spotless.
AR 13846 [S09W79] decayed in the trailing spot section and was quiet.
AR 13847 [S28E47] was quiet and stable.
New AR 13848 [N13E68] rotated into view with a huge penumbra. A major
flare is possible. The spot group has a magnetic delta configuration in the
southern part of the huge penumbra, however, opposite polarity umbrae are at
such a distance from each other that this barely classifies as a magnetic
delta.
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S10169 [S19W28] was quiet and stable.
S10171 [S05W01] was quiet and stable.
S10186 [N16E26] was quiet and stable.
New region S10189 [N10E04] emerged with tiny spots.
New region S10190 [S20E28] was observed with tiny spots in an
old plage area.
Minor update added at 14:10 UT: AR 13842 unleashed the largest flare of solar cycle 25 peaking at 12:18 UT at a magnitude of X9.05. A fast full halo CME was observed soon afterwards. The CME could reach Earth sometime between late on October 4 and noon on October 5. Expected active to very severe geomagnetic disturbance levels after the impact.
C2+ flares
Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
C9.2 | 00:23 | 13843 | GOES16 | ||
C8.5 | 01:01 | 13844 | GOES16 | simultaneous flare in AR 13841 | |
C7.5 | 01:12 | 13842 | GOES16 | ||
C7.0 | 01:20 | 13844 | GOES16 | ||
C7.0 | 01:26 | 13841 | GOES16 | ||
C7.5 | 01:33 | 13841 | GOES16 | ||
C8.2 | 01:40 | 13843 | GOES16 | ||
M1.1 | 01:52 | 13842 | GOES16 | ||
M1.2 | 02:39 | N12E08 | 13841 | GOES16 | simultaneous flare in AR 13842 |
C6.0 | 03:26 | 13842 | GOES16 | ||
C6.7 | 03:56 | N12E08 | 13841 | GOES16 | |
M1.0 | 05:16 | 13843 | GOES18 | ||
C6.9 | 05:21 | 13848 | GOES18 | ||
M3.6 | 05:38 | 13842 | GOES16 | small CME, moderate type II radio sweep | |
M1.1 | 06:24 | N11E78 | 13848 | GOES16 | simultaneous flare in AR 13842 |
C6.2 | 06:33 | 13843 | GOES16 | simultaneous flare in AR 13842 | |
C5.7 | 06:59 | 13835 | GOES16 | simultaneous flare in AR 13842 | |
C6.0 | 07:05 | 13848 | GOES16 | simultaneous flare in AR 13841 | |
C4.0 | 07:32 | 13843 | GOES16 | simultaneous flare in AR 13841 | |
C4.6 | 08:06 | 13844 | GOES16 | ||
C5.1 | 08:12 | 13841 | GOES16 | ||
C5.7 | 09:22 | S22W59 | 13835 | GOES16 | |
C4.6 | 09:36 | 13842 | GOES16 | ||
C4.7 | 09:40 | 13835 | GOES16 | ||
C4.3 | 09:49 | 13841 | GOES16 | ||
C3.5 | 10:01 | 13841 | GOES16 | ||
C7.4 | 10:14 | 13844 | GOES16 | initially attributed to AR 13842 by SWPC | |
C4.1 | 11:18 | 13848 | GOES16 | ||
C4.0 | 12:09 | 13842 | GOES16 | ||
C4.5 | 12:23 | 13842 | GOES16 | ||
C4.5 | 13:01 | 13841 | GOES16 | ||
C7.4 | 13:11 | S15W11 | 13844 | GOES16 | |
M3.2/1N | 13:38 | S19E07 | 13842 | GOES16 | |
M1.0 | 14:56 | 13841 | GOES16 | ||
C5.8 | 15:39 | 13841 | GOES16 | ||
C5.7 | 16:35 | 13842 | GOES16 | ||
C7.6 | 17:02 | 13841 | GOES16 | ||
C5.0 | 17:30 | 13843 | GOES16 | ||
C7.6 | 17:41 | N20W56 | 13845 | GOES16 | |
C5.7 | 17:59 | 13841 | GOES16 | ||
C7.1 | 18:30 | 13841 | GOES16 | initially attributed to AR 13843 by SWPC | |
C6.8 | 18:38 | 13842 | GOES16 | ||
C9.2 | 18:42 | 13842 | GOES16 | ||
C7.9 | 19:00 | 13841 | GOES16 | ||
C9.2 | 19:08 | 13843 | GOES16 | ||
C4.9 | 19:48 | 13841 | GOES16 | ||
M1.4 | 20:15 | 13842 | GOES16 | ||
M3.3 | 20:51 | 13842 | GOES16 | ||
C8.0 | 21:44 | 13835 | GOES16 | ||
C6.1 | 22:14 | 13848 | GOES16 | ||
C6.9 | 22:41 | 13841 | GOES16 | ||
C6.0 | 23:16 | 13841 | GOES16 |
September 30 + October 2: No obviously Earth directed CMEs observed.
October 1: A faint, full halo CME was observed after the X7.1 flare
in AR 13842. The CME is likely to arrive sometime between late on October 3
and noon on October 4 and cause unsettled to severe geogmagnetic storm
levels.
[Coronal
hole history (since October 2002)]
[Compare today's report to the situation one solar rotation ago:
28 days ago
27 days ago
26 days ago]
A small positive polarity trans equatorial coronal hole (CH1245) will likely rotate into an Earth facing position on October 4-5.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be at quiet levels most of October 3. Late in the day or during the first half of October 4 the October 1 CME is likely to arrive and cause unsettled to severe storm levels.
Coronal holes (1) | Coronal mass ejections (2) | M and X class flares (3) |
1) Effects from a coronal hole could
reach Earth within the next 5 days. When the high speed stream has arrived
the color changes to green.
2) Effects from a CME are likely to be observed at Earth within 96
hours.
3) There is a possibility of either M or X class flares within the
next 48 hours.
Green: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% probability.
(Click on image for 2K resolution).
4K resolution.
Compare to the previous
day's image. 0.5K image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue is positive.
Data for all officially numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC, all other regions are numbered sequentially as they emerge using the STAR spot number. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers. SWPC data considered to be not sufficiently precise (location, area, classification) are colored red.
Active region | SWPC date numbered STAR detected |
Spot count | Location at midnight | Area | Classification | SDO / HMI 4K continuum image with magnetic polarity overlays |
Comment | ||||
---|---|---|---|---|---|---|---|---|---|---|---|
SWPC/ USAF |
Magnetic (SDO) |
SWPC | STAR | Current | Previous | ||||||
2K | 1K | ||||||||||
13835 | 2024.09.22 2024.09.22 |
S22W70 | location: S22W67 | ||||||||
13836 | 2024.09.22 2024.09.23 |
3 | 15 | 6 | S12W48 | 0030 | HAX | CRO |
location: S11W47 |
||
13845 | 2024.09.23 2024.10.01 |
6 | 2 | 1 | N19W60 | 0010 | BXO | HRX | location: N17W57 | ||
13838 | 2024.09.24 2024.09.26 |
N15W40 | location: N16W38 | ||||||||
S10160 | 2024.09.25 | S03W52 | |||||||||
13840 | 2024.09.25 2024.09.27 |
N14W56 | location: N12W54 | ||||||||
13841 | 2024.09.25 2024.09.28 |
17 | 54 | 31 | N13W08 | 0220 | DAI | DAC |
beta-gamma-delta location: N13W07 area: 0420 |
||
13839 | 2024.09.26 2024.09.26 |
2 | 13 | 6 | S15W08 | 0060 | CSO | CSO |
area: 0120 location: S14W07 |
||
S10165 | 2024.09.26 | S38W50 | |||||||||
13842 | 2024.09.27 2024.09.28 |
27 | 69 | 32 | S15E06 | 0380 | EKC | EKC |
beta-gamma-delta area: 1010 |
||
S10169 | 2024.09.27 | 10 | 2 | S19W28 | 0020 | AXX | |||||
S10170 | 2024.09.27 | N25W30 | |||||||||
S10171 | 2024.09.27 | 6 | 1 | S05W01 | 0012 | BXO | |||||
S10172 | 2024.09.27 | S03W31 | |||||||||
13843 | 2024.09.28 2024.09.29 |
17 | 38 | 22 | S09W25 | 0180 | DAI | DAI |
location: S09W29 area: 0410 |
||
S10176 | 2024.09.28 | N17E27 | |||||||||
S10177 | 2024.09.28 | N16W23 | |||||||||
S10178 | 2024.09.28 | S14E09 | |||||||||
13844 | 2024.09.29 2024.09.30 |
11 | 51 | 27 | S15W16 | 0160 | DAI | DAC |
location: S16W16 area: 0330 |
||
S10180 | 2024.09.29 | N01E06 | |||||||||
13846 | 2024.09.30 2024.10.01 |
5 | 4 | 3 | S09W65 | 0020 | CRO | CAO |
location: S09W79 area: 0060 SWPC location is way off |
||
S10182 | 2024.09.30 | S07E28 | |||||||||
13847 | 2024.09.30 2024.10.01 |
1 | 2 | 2 | S28E45 | 0020 | HRX | HAX |
area: 0040 location: S28E47 |
||
S10184 | 2024.09.30 | N28W08 | |||||||||
13848 | 2024.10.01 2024.10.02 |
5 | 18 | 13 | N14E70 | 0280 | DHC | DKC |
beta-delta location: N13E68 area: 1200 |
||
S10186 | 2024.10.01 | 1 | N16E26 | 0003 | AXX | ||||||
S10187 | 2024.10.01 | N34W17 | |||||||||
S10188 | 2024.10.01 | S34E05 | |||||||||
S10189 | 2024.10.02 | 2 | 1 | N10E04 | 0005 | BXO | |||||
S10190 | 2024.10.02 | 6 | S20E28 | 0010 | BXO | ||||||
Total spot count: | 94 | 291 | 147 | ||||||||
Sunspot number: | 194 | 441 | 277 | (total spot count + 10 * number of spotted regions) | |||||||
Weighted SN: | 145 | 347 | 203 | (Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10) | |||||||
Relative sunspot number (Wolf number): | 213 | 243 | 222 |
Month | Average solar flux | International sunspot number (WDC-SILSO) |
Smoothed sunspot number (4) | Average
ap (3) |
|
---|---|---|---|---|---|
Measured | 1 AU | ||||
2014.02 | 170.3 (cycle peak) |
166.3 | 146.1 (SC24 peak) | 110.5 | 10.70 |
2014.04 | 143.9 | 144.8 | 112.5 | 116.4 (SC24 solar max) | 7.88 |
2017.09 | 91.3 | 92.3 | 43.6 | 18.2 (-1.3) | 18.22 (SC24 peak) |
2019.11 | 70.2 | 68.7 | 0.5 | 2.0 (-0.6) (Solar minimum using 365d smoothing: November 17, 2019) |
4.19 |
2019.12 | 70.8 | 68.6 | 1.6 | 1.8 (-0.2) (ISN 13 months smoothed solar minimum) |
3.22 |
2023.01 | 182.4 | 176.6 | 144.4 | 113.3 (+6.6) | 8.73 |
2023.02 | 167.2 | 163.2 | 111.3 | 117.8 (+3.5) | 14.48 |
2023.03 | 157.2 | 155.6 | 123.3 | 121.1 (+3.3) | 14.42 |
2023.04 | 145.4 | 146.4 | 97.6 | 122.9 (+1.8) | 13.40 |
2023.05 | 155.6 | 159.2 | 137.4 | 124.2 (+1.3) | 10.67 |
2023.06 | 161.7 | 166.8 | 160.5 | 125.3 (+1.1) | 8.95 |
2023.07 | 176.4 | 182.2 | 160.0 | 124.6 (-0.7) | 8.15 |
2023.08 | 153.7 | 157.6 | 114.8 | 124.3 (-0.3) | 7.19 |
2023.09 | 154.4 | 156.0 | 134.2 | 124.0 (-0.3) | 14.26 |
2023.10 | 142.8 | 141.9 | 99.4 | 124.8 (+0.8) | 8.16 |
2023.11 | 153.5 | 150.2 | 105.4 | 127.8 (+3.0) | 12.20 |
2023.12 | 151.1 | 146.4 | 114.2 | 129.4 (+1.6) | 9.60 |
2024.01 | 164.6 | 159.3 | 126.0 | 131.1 (+1.7) | 5.46 |
2024.02 | 172.5 | 168.3 | 123.0 | 136.8 (+5.7) | 5.31 |
2024.03 | 154.4 | 152.9 | 103.7 | 141.3 (+4.5) | 11.03 |
2024.04 | 161.3 | 162.6 | 136.5 | (145.3 projected, +4.0) | 9.69 |
2024.05 | 187.7 | 191.9 | 171.7 | (151.6 projected, +6.3) | 23.56 (SC25 peak) |
2024.06 | 184.3 | 190.2 | 164.2 | (155.5 projected, +3.9) | 10.24 |
2024.07 | 196.6 |
203.0 | 196.5 | (158.4 projected, +2.9) | 7.13 |
2024.08 | 246.1 (cycle peak) |
252.2 | 215.5 (SC25 peak) | (160.4 projected, +2.0) | 15.96 |
2024.09 | 195.7 | 197.8 | 141.4 | (163.1 projected, +2.7) | 15.3 |
2024.10 | 259.5 (1) | 12.6 (2A) / 195 (2B) / 194.4 (2C) | (165.4 projected, +2.3) | (5.5) | |
2024.11 | (163.7 projected, -1.7) | ||||
2024.12 | (160.7 projected, -3.0) | ||||
2025.01 | (156.3 projected, -4.4) | ||||
2025.02 | (149.6 projected, -6.7) | ||||
2025.03 | (144.8 projected, -4.8) | ||||
2025.04 | (141.6 projected, -3.2) |
1) Running average based on the daily 20:00 UTC observed solar flux value
at 2800 MHz and any corrections applied to that measurement.
2A) Current impact on the monthly sunspot number based on the Boulder
(NOAA/SWPC) sunspot number (accumulated daily sunspots / month days).
2B) Boulder SN current month average to date.
2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap
indices. Values in red
are based on the definitive international
GFZ Potsdam WDC ap
indices.
4) Source: WDC-SILSO, Royal Observatory
Of Belgium, Brussels
Sunspot counts in August 2024 were much higher than during any previous solar cycle 25 month. In comparison only 3 months during solar cycle 23 had higher SSN. Sunspot counts in early September are still high, although lower than in the beginning of August. With at least 5 consecutive months of high sunspot counts the projected peak for the smoothed ISN (365 days smoothing) has increased significantly to above 160 and could easily surpass 170 if the current activity lasts through October. The month of the peak is likely to occur sometime between July and November 2024.
--------------------------------------------------------------------------------------
This report has been prepared by Jan Alvestad. It is based on the analysis of data from whatever sources are available at the time the report is prepared. All time references are to Universal Time. Comments and suggestions are always welcome.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.