Solar Terrestrial Activity Report

Last major update issued on November 26, 2012 at 04:15 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update November 1, 2012)] [Cycle 24 progress (last update November 1, 2012) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update November 1, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update November 1, 2012)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update November 4, 2012)]

[POES auroral activity level since October 2009 - updated October 7, 2012]
[Solar polar fields vs solar cycles - updated June 27, 2011]

Recent activity

The geomagnetic field was quiet on November 25. Solar wind speed at SOHO ranged between 339 and 498 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 121.6 (increasing 13.2 over the last solar rotation). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.9). Three hour interval K indices: 12111211 (planetary), 01212211 (Boulder).

The background x-ray flux was at the class B6 level.

At midnight UTC the visible solar disk had 6 spotted active regions (in 2K resolution SDO images).

Region 11618 [N09W54] decayed slowly and quietly.
Region 11620 [S13W16] developed quickly as new flux emerged and became the largest region on the visible disk by the end of the day. The region has significant polarity intermixing and minor magnetic delta structures. An M class flare is possible.
Region 11621 [N15E65] was quiet and stable.

Spotted regions not numbered by NOAA/SWPC:
S2066 [S08W36] was quiet and stable.
S2070 [S23E31] developed slowly and quietly.
S2072 [S17E39] developed slowly and quietly.

Coronal mass ejections (CMEs)

November 23: A filament eruption in the southern hemisphere was observed starting at 11:42 and peaking just after 14h UTC. In LASCO imagery it is difficult to determine if this CME was geoeffective due to a CME with an origin in an active region behind the northeast limb occurring a little earlier. STEREO imagery indicate that a faint component of the CME could be Earth directed.
November 24-25: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.

Coronal holes

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 recurrent trans equatorial coronal hole (CH546) will likely rotate into an Earth facing position on November 27.

The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using this method, the extent and intensity of both CHs are consistent with other data sources.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to active on November 26-27 due to CME effects. Quiet conditions are likely on November 28-29. A high speed stream from CH546 could cause quiet to active conditions on November 30.

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: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.

Active solar regions

Click on image for higher resolution image) 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 (blue-green) is positive.

Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. 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.

Active region	Date numbered detected	Spot count			Location at midnight	Area	Classification		SDO / HMI 4K continuum image with magnetic polarity overlay		Comment
		SWPC	STAR SDO				SWPC	STAR	Current	Previous
			2K	1K
11616	2012.11.13 2012.11.14				N19W83						plage
11618	2012.11.15 2012.11.17	21	23	13	N08W55	0270	EKC	EAC			beta-gamma
S2059	2012.11.16				N08W48						merged with AR 11618 on Nov.25
S2060	2012.11.17				S13W55						plage
S2061	2012.11.18				S33W45						plage
11620	2012.11.18 2012.11.20	12	44	24	S13W14	0050	DAI	DAC			beta-gamma area: 0350
S2064	2012.11.19				S21W06						plage
S2066	2012.11.20		1		S08W36	0000					plage
S2067	2012.11.21				S17W26						plage
S2069	2012.11.22				N18W36						plage
S2070	2012.11.23		9	2	S23E31	0010		BXO
S2071	2012.11.23				S20W08						plage
11621	2012.11.24	1	2	2	N15E62	0100	HSX	HSX			area: 0190 location: N15E65
S2072	2012.11.24		2	2	S17E39	0010		BXO
S2073	2012.11.24				S11E10
S2074	2012.11.24				N15W04
S2075	2012.11.24				S05W18
Total spot count:		34	81	43
Sunspot number:		64	141	93	(total spot count + 10 * number of spotted regions)
Weighted SN:		54	96	58	(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):		38	49	51	k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official SIDC international sunspot number is typically 30-50% lower. 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 Potsdam WDC ap indices.

This report has been prepared by Jan Alvestad. It is based on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.