Solar Terrestrial Activity Report

Last major update issued on July 9, 2013 at 06:20 UTC. Irregular updates are likely until July 12.

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

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated June 30, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet on July 8. Solar wind speed at SOHO ranged between 283 and 316 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 119.3 (increasing 29.8 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: 12211111 (planetary), 13322311 (Boulder).

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

At 15h UTC the visible solar disk had 6 spotted active regions (in 2K resolution SDO images).

Region 11784 [S15W63] decayed slowly and quietly.
Region 11785 [S11W17] decayed slowly with the leading penumbral structure splitting into several penumbrae. The region has a magnetic delta structure centrally. An M class event is still possible. C5+ event: C9.7 at 01:22 UTC.
Region 11787 [S15E06] lost the magnetic delta structure and appears to be decaying.
Region 11789 [S25E08] decayed slowly and quietly.

Spotted regions not numbered by SWPC:
S2523 [S23W15] was quiet and stable.
S2534 [N18E18] gained a few penumbra spots.

Coronal mass ejections (CMEs)

July 6-8: 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 mostly quiet on July 9-11.

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
11783	2013.06.29 2013.06.30				N07W57						plage
11784	2013.06.30 2013.07.01	7	7	3	S15W62	0010	BXO	CRO			area: 0025
11785	2013.07.01	59	93	34	S09W16	0570	EKC	EKC			beta-gamma-delta area: 0750 location: S11W17
11786	2013.07.01 2013.07.02				S31W67						plage
S2519	2013.07.01				S17W47						plage
11788	2013.07.01 2013.07.05				S15W24						merged with AR 11787
S2521	2013.07.01				N12W57						plage
S2523	2013.07.02		1		S23W15	0001		AXX
11787	2013.07.02 2013.07.03	34	64	22	S14E03	0200	EAC	EAC			beta-gamma area: 0280 location: S15E06
S2525	2013.07.02				N05W26						plage
S2526	2013.07.02				N05W17						plage
11789	2013.07.06 2013.07.07	3	3	1	S25E09	0010	BXO	BXO
11790	2013.07.06 2013.07.07				S15E30						plage
S2534	2013.07.06		7		N18E18			BXO
S2536	2013.07.07				S28E18						plage
S2537	2013.07.07				N22E35						plage
Total spot count:		103	175	60
Sunspot number:		143	235	100	(total spot count + 10 * number of spotted regions)
Weighted SN:		118	193	78	(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):		86	82	55	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 the 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.