Solar Terrestrial Activity Report

Last major update issued on November 29, 2012 at 03:10 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 November 27, 2012]

Recent activity

The geomagnetic field was very quiet on November 28. Solar wind speed at SOHO ranged between 348 and 466 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 114.3 (increasing 15.9 over the last solar rotation). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.8). Three hour interval K indices: 11000011 (planetary), 01001111 (Boulder).

The background x-ray flux was at the class B3 level.

At midnight UTC the visible solar disk had 8 spotted active regions (in 2K resolution SDO images).

Region 11620 [S12W42] decayed in the trailing spot section while the leader spot took on a symmetrical shape. M class flares are possible as there is a magnetic delta structure in a a central penumbra. Flares >C5: M2.2/1F at 21:36 UTC.
Region 11621 [N15E38] decayed slightly and simplified magnetically near the large spot.
Region 11623 [N08E62] was mostly quiet and displayed little change.
New region 11624 [N19E08] emerged on November 27 and decayed slightly on Nov.28.

Spotted regions not numbered by NOAA/SWPC:
S2073 [S10W18] was quiet and stable.
New region S2082 [N14E64] emerged to the north of AR 11623.
New region S2083 [N04E08] emerged with a single spot.
New region S2084 [N10W09] emerged with tiny spots.

Coronal mass ejections (CMEs)

November 26, 28: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
November 27: Several interesting events were observed during the day. A filament eruption near AR 11621 began just after midnight and was later on associated with a partial halo CME in LASCO imagery. There's a chance this CME could reach Earth on November 30. A very slow filament eruption across the equator and mostly in the western hemisphere was observed during the morning. STEREO imagery indicate weak components of the associated CME could be Earth directed. Another filament eruption was observed beginning at 20:45 UTC between AR 11621 and AR S2080, however, the associated CME does not appear to have any Earth directed component.

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) was in 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 fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on November 29. A high speed stream from CH546 and several CMEs could cause quiet to active conditions on November 30 and December 1 with a chance of minor storm intervals.

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
11620	2012.11.18 2012.11.20	20	36	19	S12W57	0420	EKC	ESC			beta-gamma-delta area: 0650
S2064	2012.11.19				S21W45						plage
11622	2012.11.23 2012.11.26				S24W12						plage
S2071	2012.11.23				S20W47						plage
11621	2012.11.24	1	5	3	N15E25	0100	CSO	CSO			area: 0200
S2072	2012.11.24				S15W00						plage
S2073	2012.11.24		2		S10W18	0000		AXX
S2074	2012.11.24				N15W43						plage
S2075	2012.11.24				S05W57						plage
11623	2012.11.26 2012.11.27	3	7	4	N09E60	0360	EKO	DKO			location: N08E62 area: 0500
S2077	2012.11.26				S40W15						plage
S2078	2012.11.26				N11E07						plage
S2079	2012.11.27				S17E15						plage
11624	2012.11.27 2012.11.28	2	1	1	N20E08	0010	BXO	AXX
S2081	2012.11.27				N00W15						plage
S2082	2012.11.28		8	4	N14E64	0030		DRO
S2083	2012.11.28		1	1	N04E08	0000		AXX
S2084	2012.11.28		2	2	N10W09	0000		BXO
Total spot count:		26	62	34
Sunspot number:		66	142	104	(total spot count + 10 * number of spotted regions)
Weighted SN:		51	85	61	(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):		40	50	57	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.