Solar Terrestrial Activity Report

Last major update issued on May 12, 2014 at 04:50 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update May 1, 2014)] [Cycle 24 progress (last update May 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update May 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update May 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 April 17, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet to active on May 11. Solar wind speed at SOHO ranged between 334 and 452 km/s under the influence of a low to moderately high speed stream from CH616.

Solar flux at 20h UTC on 2.8 GHz was 164.4 (increasing 14.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.3. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.3). Three hour interval K indices: 43131122 (planetary), 34232312 (Boulder).

The background x-ray flux is at the class B8 level.

At the time of counting spots (see image time), spots were observed in 17 active regions in 2K resolution (SN: 387) and 15 active regions in 1K resolution (SN: 261) SDO images on the visible solar disk.

Region 12053 [N09W56] decayed slowly and quietly.
Region 12055 [N11W10] disecayed slowly and was mostly quiet.
Region 12056 [N05E05] had new flux emerging in the trailing spot section. A weak magnetic delta structure has formed and there is a fair chance for an M class flare.
Region 12057 [N15E14] was quiet and stable.
Region 12058 [S12E28] decayed significantly and was quiet.
Region 12059 [S01E07] developed slowly and has moved into the southern hemisphere.
New region 12060 [S16E37] was finally split off from AR 12058 by SWPC. The region is developing quickly and has lots of polarity intermixing and a magnetic delta. A major flare is possible.
New region 12061 [S24E69] rotated into view on May 10 and was numbered by SWPC the next day.
New region 12062 [S07W29] emerged on May 10 and developed significantly on May 11 when it was numbered by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3386 [S19W70] developed slowly and quietly.
S3394 [S18W38] was quiet and stable.
S3404 [N13W22] was quiet and stable.
S3405 [N09E08] decayed slowly and quietly.
S3411 [S13E04] was quiet and stable.
S3415 [N02E18] was quiet and stable.
New region S3417 [S23E45] emerged with penumbra spots.
New region S3418 [N22E74] rotated into view with a penumbra spot.

C2+ Flares (SDO/EVE):

Coronal mass ejections (CMEs)

May 9-11: 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

A southern hemisphere coronal hole (CH617) could rotate into an Earth facing position on May 12-13.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet on May 12-14 and quiet to active on May 15-16 due to effects from CH617.

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
12052	2014.05.01 2014.05.02	3			S12W74	0010	BXO				plage location: S12W68 strange observation from SWPC, data is a copy of the previous day, except the location. There are no spots in the area
S3380	2014.05.02				N10W57						plage
12053	2014.05.03	1	2	1	N09W57	0010	AXX	HRX
12054	2014.05.03 2014.05.04				S09W31						plage location: S13W24
S3385	2014.05.03				N10W33						plage
S3386	2014.05.03		8	2	S19W70	0020		BXO
12055	2014.05.04 2014.05.05	7	27	15	N12W09	0380	EKO	EKO			area: 0560
12056	2014.05.05 2014.05.06	14	37	25	N05E03	0310	EKI	EAC			beta-gamma-delta location: N05E05 area: 0500
S3394	2014.05.05		3		S18W38	0005		BXO
S3395	2014.05.05				S12W36						plage
12057	2014.05.06 2014.05.07	1	20	11	N15E12	0110	HSX	CSO			area: 0190
S3397	2014.05.06				S15E12						plage
S3398	2014.05.06				S26W49						plage
S3401	2014.05.07				N03E17						plage
12058	2014.05.07 2014.05.08	8	30	13	S11E30	0050	CAO	CRI
S3403	2014.05.07				N14W33						plage
S3404	2014.05.08		2	2	N13W22	0008		AXX
S3405	2014.05.08		1	1	N09E08	0003		AXX
12059	2014.05.08 2014.05.10	1	7	4	S00E08	0010	HSX	CRO			location: S01E07 area: 0030
12060	2014.05.08 2014.05.11	16	45	21	S16E37	0100	DAI	DAC			beta-gamma-delta area: 0220
S3408	2014.05.08				S33W32						plage
S3410	2014.05.09				S17W11						plage
S3411	2014.05.10		6	2	S13E04	0010		AXX
S3412	2014.05.10				N21W51						plage
12061	2014.05.10 2014.05.11	3	6	3	S24E67	0040	CAO	CAO			area: 0140
12062	2014.05.10 2014.05.11	7	15	7	S07W29	0030		CRO			area: 0180
S3415	2014.05.10		4	3	N02E18	0007		BXO
S3417	2014.05.11		3	1	S23E45	0010		AXX
S3418	2014.05.11		1		N22E74	0003		AXX
Total spot count:		61	217	111
Sunspot number:		161	387	261	(total spot count + 10 * number of spotted regions)
Weighted SN:		111	259	153	(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):		97	135	144	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.