The geomagnetic field was quiet to active on May 9 under the influence of CME effects. A strong solar wind shock was recorded at SOHO at 22:16 UT as the May 7 CME arrived. Solar wind speed at SOHO ranged between 385 and 716 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels.
Solar flux density measured at 23h UT on 2.8 GHz was 173.4 - increasing 19.4 over the previous solar rotation. The measurement at 20h UT was discarded as it was flare enhanced. (Centered 1 year average SF at 1 AU - 183 days ago: 140.81. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 12.5). Three hour interval K indices: 43112224 (planetary), 34112314 (Boulder), 55233436(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 15 active regions using 2K resolution (SN: 370) and in 14 active regions using 1K resolution (SN: 249) SDO/HMI images.
Region 13293 [N12W43] decayed slowly and
produced a few flares. The trailing spot section is fairly close to the
leader spots of AR 13296.
Region 13294 [S07W22] was quiet and stable.
Region 13296 [N15W34] developed further and is a compact, very
complex region with multiple magnetic deltas. Major flares are likely.
Region 13297 [N09W18] lost a few spots and simplified magnetically.
There is still a chance of a major flare.
Region 13299 [S08W00] was mostly quiet and stable.
New region 13300 [N10E01] was first observed with spots on May 6,
then new flux emerged on May 8 and the region developed further on May 9
when it was numbered by SWPC. A small magnetic delta formed and a minor M
class flare is possible.
New region 13301 [ N12E69] rotated into view on May 8 and was
numbered by SWPC the following day.
New region 13302 [N19E74] rotated partly into view on May 8 with SWPC
numbering the region the next day.
New region 13303 [S10E58] rotated into view on May 7 and received its
NOAA number 2 days later as the region developed slowly.
Spotted regions not observed (or interpreted
differently) by SWPC:
S8528 [S05E03] was quiet and stable.
S8529 [S26E17] was quiet and stable.
S8541 [S22W00] was quiet and stable.
S8544 [N22E49] developed slowly and quietly.
New region S8549 [S18E52] emerged with tiny spots.
New region S8550 [S28W09] emerged with a tiny spot.
C2+ flares:
| Magnitude | Peak time (UT) | Location | Source | Recorded by | Comment |
| C2.7 | 00:33 | S8528 | GOES16 | ||
| C2.4 | 01:50 | 13296 | GOES16 | simultaneous flare in AR 13303 | |
| C3.5 | 02:18 | 13296 | GOES16 | ||
| C5.6 | 02:58 | 13296 | GOES16 | ||
| M6.5/1N | 03:54 | N12W13 | 13296 | GOES16 | moderate type II radio sweep |
| M1.2 | 06:13 | 13296 | GOES16 | ||
| M1.0 | 06:21 | 13296 | GOES16 | ||
| C5.2 | 08:14 | 13296 | GOES16 | incorrectly attributed to AR 13293 by SWPC | |
| C4.3 | 09:28 | 13296 | GOES16 | ||
| M1.3 | 10:20 | 13296 | GOES16 | ||
| C6.9 | 11:18 | 13296 | GOES16 | ||
| C4.0 | 12:10 | 13296 | GOES16 | ||
| C5.7 | 12:31 | 13299 | GOES16 | ||
| C3.0 | 13:30 | 13296 | GOES16 | ||
| C6.4/1B | 14:05 | 13296 | GOES16 | ||
| C7.3 | 14:42 | 13296 | GOES16 | incorrectly attributed to AR 13293 by SWPC | |
| C2.9 | 17:48 | 13296 | GOES16 | ||
| M4.2/1B | 18:58 | N13W31 | 13296 | GOES16 | full halo CME, proton event strong type IV radio sweep |
| M1.1 | 20:09 | 13296 | GOES16 | ||
| M5.0/1N | 20:52 | N14W35 | 13296 | GOES16 |
May 7: A halo CME was observed after the M1
long duration events in AR 13296 towards the end of the day. The CME
reached Earth late on May 9.
May 8: No obviously Earth directed CMEs were
observed.
May 9: A fast full halo CME was observed after the M4.2 flare in AR
13296 at 18:58 UT. The CME is expected to reach Earth on May 11.
[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]
An elongated northern hemisphere coronal hole (CH1146) will be Earth facing on May 8-11, but may be too far to the north to cause a geomagnetic disturbance.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is very poor. Propagation on long distance northeast-southwest paths is poor.
Unsettled to major storm conditions are likely on May 10 due to CME effects. The May 9 CME is expected to arrive on May 11 and increase the disturbance level to active to severe storm levels until at least May 12.
| Coronal holes (1) | Coronal mass ejection (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 | ||||||||||
| S8505 | 2023.04.29 | N19W55 | |||||||||
| 13293 | 2023.04.30 2023.04.30 |
8 | 27 | 12 | N09W48 | 0020 | CRO | DRO |
 |
 |
location: N12W43 area: 0050 |
| S8509 | 2023.04.30 | S25W39 | |||||||||
| 13294 | 2023.05.01 2023.05.02 |
1 | 12 | 4 | S08W21 | 0130 | HSX | CSO |
 |
 |
area: 0220 location: S07W22 |
| 13296 | 2023.05.02 2023.05.02 |
16 | 39 | 29 | N15W37 | 0280 | EKC | DKC |
 |
 |
beta-gamma-delta area: 0660 reversed polarities location: N15W34 |
| 13297 | 2023.05.02 2023.05.02 |
20 | 61 | 28 | N10W15 | 0510 | EKI | EKI |
 |
 |
beta-gamma area: 0470 location: N09W18 |
| 13298 | 2023.05.03 2023.05.04 |
S16W36 | location: S15W31 | ||||||||
| 13299 | 2023.05.03 2023.05.04 |
5 | 8 | 4 | S08E01 | 0010 | BXO | CRO |
 |
 |
location: S08W01 area: 0020 |
| S8528 | 2023.05.04 | 6 | 2 | S05E03 | 0010 | CRO |
 |
 |
|||
| S8529 | 2023.05.04 | 4 | 2 | S26E17 | 0008 | BXO |
 |
 |
|||
| S8530 | 2023.05.04 | S19W44 | |||||||||
| S8533 | 2023.05.06 | N17W23 | |||||||||
| 13300 | 2023.05.06 2023.05.09 |
5 | 24 | 13 | N10W01 | 0030 | CRO | DAI |
 |
 |
beta-delta area: 0110 location: N10E01 |
| S8537 | 2023.05.06 | N29W03 | |||||||||
| S8538 | 2023.05.06 | S30W57 | |||||||||
| 13303 | 2023.05.07 2023.05.09 |
3 | 10 | 5 | S10E54 | 0030 | CRO | DRO |
 |
 |
location: S10E58 |
| S8541 | 2023.05.07 | 10 | S22W00 | 0015 | BXO |
 |
 |
||||
| 13301 | 2023.05.08 2023.05.09 |
2 | 3 | 2 | N11E67 | 0120 | HSX | HSX |
 |
 |
area: 0200 location: N12E69 |
| S8543 | 2023.05.08 | N25E05 |
 |
||||||||
| S8544 | 2023.05.08 | 6 | 3 | N22E49 | 0020 | DRO |
 |
 |
|||
| 13302 | 2023.05.08 2023.05.09 |
1 | 7 | 3 | N18E72 | 0060 | HSX | CSO |
 |
 |
area: 0140 |
| S8546 | 2023.05.08 | S05W42 |
 |
||||||||
| S8549 | 2023.05.09 | 2 | 1 | S18E42 | 0004 | AXX |
 |
||||
| S8550 | 2023.05.09 | 1 | 1 | S28W09 | 0003 | AXX |
 |
||||
| Total spot count: | 61 | 220 | 109 | ||||||||
| Sunspot number: | 151 | 370 | 249 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 105 | 275 | 164 | (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): | 165 | 204 | 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 |
| 2021.09 | 87.0 | 88.2 | 51.3 | 40.2 (+4.8) | 6.33 |
| 2021.10 | 88.9 | 88.3 | 37.4 | 45.2 (+5.0) | 7.38 |
| 2021.11 | 86.2 | 84.4 | 34.8 | 50.8 (+5.6) | 9.83 |
| 2021.12 | 103.0 | 99.8 | 67.5 | 55.9 (+5.1) | 6.40 |
| 2022.01 | 103.8 | 100.5 | 55.3 | 60.1 (+4.2) | 8.92 |
| 2022.02 | 109.1 | 106.5 | 60.9 | 64.7 (+4.6) | 10.46 |
| 2022.03 | 117.0 | 115.8 | 78.6 | 68.7 (+4.0) | 10.20 |
| 2022.04 | 130.8 | 131.7 | 84.0 | 73.0 (+4.3) | 11.79 |
| 2022.05 | 133.8 | 136.8 | 96.5 | 77.4 (+4.4) | 7.48 |
| 2022.06 | 116.1 | 119.8 | 70.3 | 81.1 (+3.7) | 8.20 |
| 2022.07 | 125.4 | 129.5 | 91.4 | 86.7 (+5.6) | 9.51 |
| 2022.08 | 114.2 | 117.1 | 74.6 | 92.5 (+5.8) | 10.92 |
| 2022.09 | 135.1 | 136.5 | 96.0 | 96.4 (+3.9) | 12.18 |
| 2022.10 | 133.5 | 132.7 | 95.5 | 98.7 (+2.3) | 11.16 |
| 2022.11 | 123.4 | 120.7 | 80.5 | (100.4 projected, +1.7) | 9.33 |
| 2022.12 | 147.9 | 143.4 | 112.8 | (104.1 projected, +3.7) | 10.99 |
| 2023.01 | 182.4 | 176.6 | 143.6 | (110.1 projected, +6.0) | 8.73 |
| 2023.02 | 167.2 | 163.2 | 110.9 | (115.2 projected, +5.1) | 14.48 (current SC25 peak) |
| 2023.03 | 157.2 | 155.6 | 122.6 | (118.3 projected, +3.1) | 14.42 |
| 2023.04 | 145.4 | 146.4 | 96.4 | (123.7 projected, +5.4) | 13.3 |
| 2023.05 | 159.9 (1) | 33.6 (2A) / 115.9 (2B) / 157.1 (2C) | (129.3 projected, +5.6) | (10.8) | |
| 2023.06 | (132.5 projected, +3.2) | ||||
| 2023.07 | (132.0 projected, -0.5) | ||||
| 2023.08 | (133.0 projected, +1.0) | ||||
| 2023.09 | (136.4 projected, +3.4) | ||||
| 2023.10 | (138.3 projected, +1.9) | ||||
| 2023.11 | (141.4 projected, +3.1) | ||||
| 2023.12 | (142.5 projected max SC25) | ||||
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: SIDC-SILSO.
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.
