Solar Terrestrial Activity Report

Last major update issued on June 13, 2013 at 05:00 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update June 1, 2013)] [Cycle 24 progress (last update June 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update June 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update June 6, 2013)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated May 12, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was very quiet on June 12. Solar wind speed at SOHO ranged between 393 and 459 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 93.3 (decreasing 51.4 over the last solar rotation). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.8). Three hour interval K indices: 11111111 (planetary), 21212211 (Boulder).

The background x-ray flux was at the class B2 level.

At midnight UTC the visible solar disk had 7 spotted active regions (in 2K resolution SDO images).

Region 11765 [N08W79] decayed further and was quiet.
Region 11767 [S17E03] was quiet and stable.
New region 11768 [S11W19] emerged on June 11 and developed further on June 12 when it was numbered by SWPC.

Spotted regions not numbered by SWPC:
S2463 [N06W35] reemerged with penumbra spots.
S2469 [N13E03] gained some penumbra spots and was quiet.
New region S2474 [S13E83] rotated into view with one spot.
New region S2475 [S23E75] rotated into view with a few spots.

Coronal mass ejections (CMEs)

June 10-12: 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

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

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 on June 13-15.

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 2K 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 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
11765	2013.06.03 2013.06.05	1	2	1	N09W78	0030	HSX	AXX			area: 0010
S2463	2013.06.06		5		N06W35	0008		BXO
S2464	2013.06.07				N25W40						plage
11767	2013.06.07 2013.06.09		2		S17W00	0004		AXX			location: S17E03
S2467	2013.06.07				S12W32						plage
S2468	2013.06.08				S33E14						plage
S2469	2013.06.09		15	2	N13E03	0025		BXO	images/AR_S2469_20130612_2345.jpg	images/AR_S2469_20130611_2345.jpg
S2470	2013.06.09				S24W21						plage
S2471	2013.06.09				S13W57						plage
11768	2013.06.11 2013.06.12	6	20	13	S11W19	0050	DAO	DAI			area: 0130
S2473	2013.06.11				S13W15						plage
S2474	2013.06.12		1	1	S13E83	0090		HSX
S2475	2013.06.12		3		S23E75	0006		AXX
Total spot count:		7	48	17
Sunspot number:		27	118	57	(total spot count + 10 * number of spotted regions)
Weighted SN:		17	58	27	(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):		16	41	31	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.