The next update is scheduled for the afternoon of December 28. The plan is to produce 2 updates a day (one update for each day after Dec.24 as there is a lot of data to process) and clear the back log by December 29.
The geomagnetic field was quiet on December 25. The high latitude magnetometer at Andenes recorded quiet to unsettled levels.
Solar flux density measured at 20h UT on 2.8 GHz was 130.7 - increasing 38.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 81.31). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.5). Three hour interval K indices: 21213220 (planetary), 11232321 (Boulder), 21113333 (Andenes).
The background x-ray flux was at the class C1 level (GOES 16).
At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 192) and in 8 active regions using 1K resolution (SN: 135) SDO/HMI images.
Region 12912 [S11W12] decayed slowly and
quietly.
Region 12914 [S18W28] reemerged with a tiny spot.
Region 12915 [N16W17] decayed slowly and quietly.
Region 12916 [S16E30] developed further and is a large, compact
region.
The region was mostly quiet, however, there is potential for a major flare.
C1 flares: C1.4 @ 01:34 UT.
Region 12917 [S27W05] decayed slowly producing several C flares. C1
flares: C1.8 @ 07:26 UT
Region 12918 [N20E15] developed further gaining spots and area. M class
flaring is possible. C1 flares: C1.1 @ 00:45, C1.3 @ 03:26 UT.
New region 12919 [S11E67] rotated into view on December 24 and was
numbered by SWPC the next day.
Spotted regions not observed (or interpreted
differently) by SWPC:
S7239 [S19W80] decayed slowly and quietly. SWPC
includes the spots in AR 12908.
S7256 [S16W18] developed slowly and quietly.
AR 12907 produced a C1.3 flare at 06:45 before rotating out of view while AR 12909 was the source of a C1.8 flare at 09:13 UT.
C2+ flares:
| Magnitude | Peak time (UT) | Location | AR | Recorded by | Comment |
| C2.2 | 09:51 | N23E21 | 12918 | GOES16 | |
| C3.0 | 12:24 | N22E20 | 12918 | GOES16 | |
| C3.3 | 13:30 | 12918 | GOES16 | ||
| C3.0 | 15:58 | 12917 | GOES16 | ||
| C3.1 | 16:19 | 12918 | GOES16 | ||
| C3.4 | 19:05 | 12918 | GOES16 |
December 23-25: No obviously Earth directed CMEs were observed in available LASCO imagery.
[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 extension (CH1050) of the northern polar coronal hole rotated across the central meridian on December 24. A recurrent trans equatorial coronal hole (CH1051) will likely become Earth facing on December 26. A recurrent northern hemisphere coronal hole (CH1052) could rotate into an Earth facing position on December 28.
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 quiet on December 26 becoming quiet to unsettled on December 27-28 due to effects from CH1050.
| 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 red colored.
| 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 | ||||||||||
| 12908 | 2021.12.14 2021.12.15 |
1 | S20W80 | 0050 | HAX |
SWPC data includes AR S7239 |
|||||
| 12909 | 2021.12.14 2021.12.15 |
S21W67 |
 |
location: S20W64 | |||||||
| S7239 | 2021.12.15 | 2 | 1 | S19W80 | 0008 | AXX |
 |
 |
|||
| 12911 | 2021.12.16 2021.12.16 |
N20W53 |
 |
location: N21W50 |
|||||||
| 12913 | 2021.12.17 2021.12.20 |
S25W37 | |||||||||
| 12914 | 2021.12.18 2021.12.21 |
1 | S17W33 | 0001 | AXX |
 |
location: S18W28 | ||||
| 12912 | 2021.12.18 2021.12.19 |
1 | 4 | 1 | S13W14 | 0020 | HRX | CRO |
 |
 |
|
| 12915 | 2021.12.18 2021.12.21 |
1 | 6 | 2 | N16W16 | 0010 | AXX | AXX |
 |
 |
|
| S7250 | 2021.12.20 | S21W48 | |||||||||
| 12916 | 2021.12.21 2021.12.21 |
21 | 22 | 16 | S18E28 | 0450 | EKC | EHC |
 |
 |
beta-gamma area: 0720 location: S16E42 |
| S7253 | 2021.12.21 | N24E12 | |||||||||
| 12918 | 2021.12.21 2021.12.22 |
17 | 38 | 23 | N19E11 | 0280 | DKI | DAI |
 |
 |
beta-gamma |
| 12917 | 2021.12.21 2021.12.22 |
5 | 11 | 3 | S28W06 | 0020 | CRO | BXO |
 |
 |
|
| S7256 | 2021.12.22 | 16 | 8 | S16W18 | 0040 | CRI |
 |
 |
|||
| S7257 | 2021.12.23 | S26W24 |
 |
||||||||
| S7258 | 2021.12.24 | N19W03 |
 |
||||||||
| 12919 | 2021.12.24 2021.12.25 |
1 | 2 | 1 | S11E59 | 0020 | HSX | HRX |
 |
 |
location: S11E67 |
| Total spot count: | 47 | 102 | 55 | ||||||||
| Sunspot number: | 117 | 192 | 135 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 83 | 126 | 79 | (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): | 129 | 106 | 108 | ||||||||
| 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 (solar max) | 7.88 |
| 2017.09 | 91.3 | 92.3 | 43.6 | 18.2 (-1.3) | 18.22 (cycle 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 |
| 2020.06 | 69.5 | 71.7 | 5.8 | 7.9 (+2.3) | 3.75 |
| 2020.07 | 69.5 | 71.8 | 6.3 | 9.0 (+1.1) | 4.28 |
| 2020.08 | 71.6 | 73.4 | 7.6 | 9.5 (+0.5) | 5.68 |
| 2020.09 | 70.7 | 71.4 | 0.7 | 10.5 (+1.0) | 8.59 |
| 2020.10 | 74.6 | 74.2 | 14.6 | 11.9 (+1.4) | 6.13 |
| 2020.11 | 89.9 | 88.0 | 34.5 | 13.6 (+1.7) | 4.77 |
| 2020.12 | 86.9 | 84.2 | 23.1 | 15.3 (+1.7) | 4.72 |
| 2021.01 | 76.0 | 73.6 | 10.4 | 17.3 (+2.0) | 4.39 |
| 2021.02 | 74.3 | 72.4 | 8.3 | 19.1 (+1.8) | 9.50 |
| 2021.03 | 76.0 | 75.2 | 17.3 | 21.8 (+2.7) | 10.17 |
| 2021.04 | 75.9 | 76.4 | 24.5 | 24.9 (+3.1) | 8.40 |
| 2021.05 | 75.3 | 77.1 | 21.2 | 25.9 (+1.0) | 6.50 |
| 2021.06 | 79.4 | 81.8 | 25.3 | (26.9 projected, +1.0) | 5.52 |
| 2021.07 | 81.0 | 83.6 | 34.4 | (29.9 projected, +3.0) | 5.51 |
| 2021.08 | 77.7 | 79.7 | 22.4 | (34.6 projected, +4.7) | 6.19 |
| 2021.09 | 87.0 | 88.2 | 51.5 | (40.3 projected, +5.7) | 6.33 |
| 2021.10 | 88.9 | 88.3 | 38.1 | (44.7 projected, +4.4) | 7.38 |
| 2021.11 | 86.2 | 84.4 | 35.1 | (49.3 projected, +4.6) | 9.83 |
| 2021.12 | 100.3 (1) | 53.4 (2A) / 66.2 (2B) / 70.6 (2C) | (55.1 projected, +5.8) | (6.7) | |
| 2022.01 | (58.7 projected, +3.6) | ||||
| 2022.02 | (63.5 projected, +4.8) | ||||
| 2022.03 | (68.9 projected, +5.4) | ||||
| 2022.04 | (74.0 projected, +5.1) | ||||
| 2022.05 | (80.4 projected, +6.4) | ||||
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.
