Solar Terrestrial Activity Report

Last major update issued on November 21, 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 to active on November 20. Solar wind speed at SOHO ranged between 350 and 477 km/s increasingly under the influence of a high speed coronal hole stream.

Solar flux measured at 20h UTC on 2.8 GHz was 141.2 (increasing 5.6 over the last solar rotation). The Potsdam WDC planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 14.6). Three hour interval K indices: 33222343 (planetary), 23232333 (Boulder).

The background x-ray flux was at the class B5 level.

At midnight UTC the visible solar disk had 10 spotted active regions (in 2K resolution SDO images).

Region 11613 [S23W58] was quiet and stable.
Region 11614 [N14W47] decayed slowly and could soon become spotless.
Region 11616 [N20W16] decayed slowly and quietly.
Region 11617 [S17W71] reemerged with several spots.
Region 11618 [N08E13] developed in the central and trailing spot sections with significant polarity intermixing and a minor magnetic delta structure forming. Further M class flares are likely. Flares: long duration C3.0 peaking at 02:07, C3.9 at 06:33, C3.1 at 15:29 and M1.6 at 19:28 UTC.
Region 11619 [N10W12] decayed slowly and was mostly quiet.
New region 11620 [S12E57] rotated into view on November 18 and got its NOAA number on Nov.20.

Spotted regions not numbered by NOAA/SWPC:
S2059 [N08E19] was quiet and stable.
S2065 [N13E03] lost the spots observed the previous day and gained a trailing spot further north.
New region S2066 [S10E31] emerged with tiny spots.

The largest flare of the day, an impulsive M1.7 event at 12:41 UTC, occurred in a region at the northwest limb, probably AR 11611. A filament eruption near AR 11619 began at 11:12 UTC and was associated with an asymmetric full halo CME observed in LASCO imagery a few hours later. The CME was visible in STEREO imagery from 12:09 UTC

Coronal mass ejections (CMEs)

November 18-19: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
November 20: A full halo CME was observed after noon following a filament eruption near AR 11619. This CME could reach Earth on November 23.

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

No obvious coronal holes are currently in or near Earth facing positions.

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 fair to good.

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 21-22 due to CH effects and quiet to active on November 23-24 due to CME effects.

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
11611	2012.11.07 2012.11.08	1			N11W95	0030	HSX				rotated out of view
11612	2012.11.08	1			N06W85	0010	AXX				spotless
11613	2012.11.09 2012.11.11	1	1	1	S24W58	0050	HSX	HSX			area: 0140
11614	2012.11.10 2012.11.11		4		N14W48	0000		BXO
11615	2012.11.11				N07W62						plage
11617	2012.11.13 2012.11.16		4	2	S18W74	0010		BXO			location: S17W71
11616	2012.11.13 2012.11.14	3	8	2	N19W14	0010	BXO	BXO			area: 0010
S2051	2012.11.14				S12W41						plage
S2053	2012.11.14				S33W33						plage
S2055	2012.11.14				S27W26						plage
11618	2012.11.15 2012.11.17	29	31	22	N08E14	0270	EKC	EAC			beta-gamma-delta area: 0450
11619	2012.11.15 2012.11.17	13	19	9	N09W25	0150	DSO	DHO			area: 0320
S2059	2012.11.16		5	4	N08E19	0050		CRO
S2060	2012.11.17				S13E10						plage
S2061	2012.11.18				S33E20						plage
11620	2012.11.18 2012.11.20	1	5	2	S08E59	0040	CSO	HSX			area: 0090 location: S12E57
S2064	2012.11.19				S21E59						plage
S2065	2012.11.19		1		N13E03	0000		AXX
S2066	2012.11.20		2		S10E31	0000		AXX
Total spot count:		49	80	42
Sunspot number:		119	180	112	(total spot count + 10 * number of spotted regions)
Weighted SN:		79	108	70	(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):		71	63	62	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.