Solar Terrestrial Activity Report

Last major update issued on June 4, 2014 at 02:55 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, 2014)] [Cycle 24 progress (last update June 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update June 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update May 1, 2014)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated June 4, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to unsettled on June 3. Solar wind speed at SOHO ranged between 280 and 380 km/s, increasing slowly after 11h and peaking near 17h UTC.

Solar flux at 20h UTC on 2.8 GHz was 107.0 (decreasing 38.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 140.1. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.9). Three hour interval K indices: 32111111 (planetary), 33121212 (Boulder).

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

At the time of counting spots (see image time), spots were observed in 8 active regions using 2K resolution (SN: 123) and 8 active regions using 1K resolution (SN: 103) SDO images on the visible solar disk.

Region 12075 [S08W68] decayed slowly and quietly.
Region 12077 [S04E17] lost umbrae on the trailing spots.
Region 12078 [S18W13] was quiet and stable.
Region 12079 [N12E40] gained a few spots and was quiet.
New region 12080 [S12E58] rotated into view on June 2 and was numbered the next day by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3492 [N12E14] reemerged with a penumbra spot.
S3494 [N04E41] was quiet and stable.
New region S3499 [S11E52] emerged ahead of AR 12080.

C2+ Flares (GOES):

Coronal mass ejections (CMEs)

June 1-3: 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 significant 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 upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be mostly quiet on June 4-6.

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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% 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	Magnetic (SDO)				SWPC	STAR	Current	Previous
			2K	1K
12075	2014.05.23	1	3	1	S09W69	0010	AXX	AXX			location: S08W68
S3477	2014.05.28				N16W57						plage
S3483	2014.05.29				S11W35						plage
S3484	2014.05.29				S13W23						plage
12077	2014.05.30	6	20	9	S08E17	0080	CSO	CAO			area: 0180 location: S04E17
12078	2014.05.30 2014.06.01	1	2	1	S19W13	0010	AXX	CRO			area: 0020
12079	2014.05.31 2014.06.01	1	7	4	N12E40	0090	HSX	HSX			area: 0210
S3492	2014.05.31		1	1	N12E14	0003		AXX
S3494	2014.06.01		1	1	N04E47	0011		HRX
S3495	2014.06.01				S10W01						plage
S3496	2014.06.02				N17E39						plage
12080	2014.06.02 2014.06.03	2	6	3	S13E57	0010	BXO	BXO			area: 0030
S3499	2014.06.03		3	3	S11E52	0012		BXO
Total spot count:		11	43	23
Sunspot number:		61	123	103	(total spot count + 10 * number of spotted regions)
Weighted SN:		21	59	39	(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):		37	43	57	k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

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 WDC-SILSO 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 GFZ 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.