The geomagnetic field was at quiet to unsettled levels on October 17 due to effects from CH1247. Solar wind speed at SOHO ranged between 383 and 464 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. The above 10 MeV proton flux was at background levels.
Solar flux density measured at 20h UT on 2.8 GHz was 173.5 - increasing 19.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 180.01. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 180.01 on April 18, 2024). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.5). Three hour interval K indices: 33210122 (planetary), 33311322 (Boulder), 44201154 (Andenes).
The background x-ray flux is at the class C1 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 17 active regions using 2K resolution (SN: 359) and in 16 active regions using 1K resolution (SN: 249) SDO/HMI images.
AR 13852 [S12W65] decayed slowly and was mostly
quiet.
AR 13854 [S06W58] still has a magnetic delta configuration in a small
leading penumbra. The delta was the origin of the largest flare of the day,
an M2.4 event peaking at 05:05 UT. C1 flares: C1.8 @ 13:45, C1.8 @ 13:53 UT
AR 13856 [N10W21] has two magnetic delta configurations, one in an
intermediate section penumbra, another in the largest trailing penumbra. C1
flares: C1.8 @ 01:11 UT
AR 13857 [S07E27] developed slowly and was polarity intermixing.
AR 13858 [S15E22] decayed slowly and quietly.
AR 13859 [S12W00] developed gaining area and spots. An M flare is possible.
C1 flares: C1.7 @ 18:36, C1.9 @ 23:17 UT
New AR 13860 [S07E15] emerged on October 16 and developed further the
next day when the spot group was numbered by SWPC. A small magnetic delta
configuration formed. C1 flares: C1.9 @ 17:13 UT
Spotted regions not observed (or interpreted
differently) by SWPC/USAF:
S10213 [S11W43] was quiet and stable.
S10231 [N15W19] was mostly quiet and stable. C1 flares: C1.8 @ 04:42
UT
S10234 [S06W12] reemerged with tiny spots.
S10240 [N27E09] reemerged with tiny spots.
S10241 [N07E22] reemerged with tiny spots.
S10242 [S31E20] reemerged with tiny spots.
S10243 [S02W61] decayed slowly and quietly.
S10247 [S24W26] was quiet and stable.
New region S10248 [N22W12] emerged with tiny spots.
New region S10249 [S08E82] rotated into view with a mature spot.
C2+ flares
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.0 | 00:12 | 13856 | GOES16 | ||
| C2.2 | 01:50 | 13854 | GOES16 | ||
| C2.1 | 02:02 | 13860 | GOES16 | simultaneous flare in AR 13855 | |
| M1.0 | 02:22 | 13856 | GOES16 | ||
| M2.4 | 05:05 | S04W54 (SDO/AIA) | 13854 | GOES16 | SWPC initially reports a very inaccurate location: S10W53 |
| C3.9 | 05:46 | 13855 | GOES16 | ||
| C2.6 | 07:10 | S10249 | GOES16 | ||
| C2.8 | 07:28 | 13860 | GOES16 | simultaneous flare in AR S10249 | |
| C2.7 | 07:42 | 13854 | GOES16 | ||
| C4.0 | 08:08 | 13856 | GOES16 | ||
| C2.7 | 08:49 | 13855 | GOES16 | ||
| C2.5 | 10:33 | 13852 | GOES16 | ||
| C2.0 | 13:17 | 13860 | GOES16 | ||
| C6.6 | 14:27 | 13860 | GOES16 | ||
| C2.6 | 15:48 | 13856 | GOES16 | ||
| C3.2 | 16:32 | 13860 | GOES16 | ||
| C2.0 | 16:48 | 13859 | GOES16 | ||
| C2.2 | 19:54 | 13860 | GOES16 | ||
| C5.4 | 21:12 | 13860 | GOES16 | ||
| C2.1 | 22:22 | 13855 | GOES16 | ||
| C2.1 | 00:01 | 13852 | GOES16 |
October 15-17: No obviously Earth directed CMEs were observed. Several halo CMEs were observed in LASCO imagery early on October 17, however, they probably have a backsided origin.
[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 large positive polarity northern hemisphere coronal hole (CH1247) rotated across the central meridian on October 14-16. Another positive polarity northern hemisphere coronal hole (CH1248) will probably become Earth facing on October 18-19.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be at quiet to active levels on October 18-20 while effects from CH1248 could extend that activity level until October 22.
| 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 | ||||||||||
| 13852 | 2024.10.06 | 9 | 9 | 4 | S13W65 | 0180 | CAO | CAO |
 |
 |
area: 0220 location: S12W65 |
| 13853 | 2024.10.08 2024.10.10 |
N22W61 |
location: N20W60 |
||||||||
| S10213 | 2024.10.08 | 3 | 1 | S11W43 | 0005 | AXX |
 |
 |
|||
| 13854 | 2024.10.08 2024.10.10 |
16 | 19 | 9 | S06W60 | 0300 | EHI | FSC |
 |
 |
beta-gamma-delta area: 0370 location: S06W58 |
| S10216 | 2024.10.09 | S15W33 | |||||||||
| 13856 | 2024.10.10 2024.10.13 |
12 | 26 | 16 | N10W19 | 0190 | DAI | DAC |
 |
 |
beta-gamma-delta location: N10W21 area: 0440 |
| 13855 | 2024.10.12 2024.10.13 |
3 | N15W90 | 0020 | CRO |
 |
rotated out of view | ||||
| S10230 | 2024.10.12 | N12W08 |
 |
||||||||
| S10231 | 2024.10.12 | 11 | 5 | N15W19 | 0025 | BXO |
 |
 |
|||
| S10232 | 2024.10.12 | N27W53 | |||||||||
| 13858 | 2024.10.13 2024.10.14 |
4 | 13 | 5 | S15E20 | 0010 | BXO | CRO |
 |
 |
area: 0020 location: S16E22 |
| S10234 | 2024.10.13 | 9 | 2 | S06W12 | 0020 | BXO |
 |
||||
| 13857 | 2024.10.13 2024.10.14 |
6 | 17 | 10 | S07E25 | 0130 | DAO | EAO |
 |
 |
location: S07E27 area: 0190 |
| S10236 | 2024.10.13 | N02W28 | |||||||||
| S10237 | 2024.10.13 | N32W14 | |||||||||
| S10238 | 2024.10.13 | S15W33 | |||||||||
| 13859 | 2024.10.15 2024.10.15 |
10 | 28 | 16 | S12W01 | 0110 | DAO | DRO |
 |
 |
beta-gamma location: S12W00 area: 0280 |
| S10240 | 2024.10.15 | 6 | 1 | N27E09 | 0012 | BXO |
 |
||||
| S10241 | 2024.10.15 | 4 | 2 | N07E22 | 0010 | AXX |
 |
||||
| S10242 | 2024.10.15 | 8 | 1 | S31E20 | 0015 | BXO |
 |
||||
| S10243 | 2024.10.16 | 4 | 2 | S02W61 | 0010 | BXO |
 |
 |
|||
| S10244 | 2024.10.16 | S03E07 |
 |
||||||||
| 13860 | 2024.10.16 2024.10.17 |
6 | 24 | 12 | S07E15 | 0070 | DAI | DRI |
 |
 |
beta-gamma-delta |
| S10246 | 2024.10.16 | S26W15 |
 |
||||||||
| S10247 | 2024.10.16 | 4 | S24W26 | 0008 | AXX |
 |
 |
||||
| S10248 | 2024.10.17 | 3 | 2 | N22W12 | 0013 | CRO |
 |
||||
| S10249 | 2024.10.17 | 1 | 1 | S08E82 | 0210 | HSX |
 |
||||
| Total spot count: | 66 | 189 | 89 | ||||||||
| Sunspot number: | 146 | 359 | 249 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 104 | 226 | 126 | (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): | 161 | 197 | 199 | ||||||||
| 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) | 15.36 |
| 2024.10 | 228.6 (1) | 84.7 (2A) / 154.5 (2B) / 201.5 (2C) | (165.4 projected, +2.3) | (26.5) | |
| 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
September 2024 saw a significant decrease in sunspot numbers compared to the previous month, however, activity was still fairly high. The average solar flux for the month ranks as number 3 of all months during SC25. Taking into account that we started seeing high sunspot numbers April 14, 2024, the most likely candidate for solar maximum would be at or just after October 14, 2024. Assuming that the average sunspot number from now until April 14, 2025 becomes 150, we would be looking at a 365 days smoothed sunspot maximum of 164.5 centered on October 14. Should the average sunspot number for that period become 160 we would get a peak near 169.7.
--------------------------------------------------------------------------------------
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.
